HomeMy WebLinkAbout03-03-2026 Agenda Packet
Planning Commission
Regular Meeting
March 3, 2026 - 7:00 PM
City Hall Council Chambers
AGENDA
CALL TO ORDER
PUBLIC PARTICIPATION
A. The Planning Commission Meeting scheduled for Tuesday, March 3, 2026, at 7:00 p.m.
will be held in person and virtually.
Virtual Participation Link:
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PLEDGE OF ALLEGIANCE
ROLL CALL
AGENDA MODIFICATIONS
PUBLIC COMMENT
This is the place on the agenda where the public is invited to speak to the Board on any issue.
A. The public can participate in-person or submit written comments in advance.
Participants can submit written comments via mail or email. All written comments must be
received prior to 5:00 p.m. on the day before the scheduled meeting and must be 350
words or less.
Please mail written comments to:
City of Auburn
Attn: Tammy Gallier, Administrative Specialist
25 W Main St
Auburn, WA 98001
Page 1 of 758
Email written comments to: planning@auburnwa.gov
If an individual requires accommodation to allow for remote oral comment because of a
difficulty attending a meeting of the governing body, the City requests notice of the need for
accommodation by 5:00 p.m. on the day before the scheduled meeting. Participants can
request accommodation to be able to provide a remote oral comment by contacting the
Community Development Department in person, by phone (253) 931-3090 or by email
(planning@auburnwa.gov.)
APPROVAL OF MINUTES
A. February 3, 2026 Draft Minutes from the Regular Planning Commission Meeting
BUSINESS ITEM #1
A. Battery Energy Storage System (BESS) Code Update
Staff Introduction/Presentation (Clark)
Staff will present the proposed development standards and land use approval pathways for
BESS to Planning Commission for a recommendation to City Council.
B. Public Hearing
C. Deliberate and Vote
BUSINESS ITEM #2
A. Critical Areas Ordinance Update
Staff Introduction/Presentation (Tatro)
Staff will provide an update on the work being done to update the Critical Areas Ordinance,
Chapter 16.10 ACC, specifically regarding stream regulations.
BUSINESS ITEM #3
A. Downtown Design Standards and Code Update
Staff Introduction/Presentation (Tatro)
Staff will provide an update on the public outreach conducted for the draft Downtown
Design Standards and provide an overview of the changes made to Chapter 18.29 ACC.
BUSINESS ITEM #4
A. Citywide Design Standards and Code Update
Staff Introduction/Presentation (Reed)
Staff will provide an update on the public outreach conducted for the draft Citywide Design
Standards and provide an overview of the associated code updates.
COMMUNITY DEVELOPMENT REPORT
ADJOURNMENT
The City of Auburn Planning Commission is a seven member advisory body that provides
recommendations to the Auburn City Council on the preparation of and amendments to land use
plans and related codes such as zoning. Planning Commissioners are appointed by the Mayor and
Page 2 of 758
confirmed by the City Council.
Actions taken by the Planning Commission, other than approvals or amendments to the Planning
Commission Rules of Procedure, are not final decisions; they are in the form of recommendations to
the City Council which must ultimately make the final decision.
Page 3 of 758
AGENDA BILL APPROVAL FORM
Agenda Subject: Meeting Date:
February 3, 2026 Draft Minutes from the Regular Planning Commission
Meeting
March 3, 2026
Department: Attachments: Budget Impact:
Community Development 2-3-2026 Planning Commission
Meeting Minutes
Administrative Recommendation:
Background for Motion:
Background Summary:
See attached minutes.
Councilmember: Staff: Jason Krum
Page 4 of 758
Planning Commission
Regular Meeting
February 3, 2026 - 7:00 PM
City Hall Council Chambers
MINUTES
PUBLIC PARTICIPATION
The City of Auburn Planning Commission Meeting was held in person and virtually.
CALL TO ORDER
Chair Judi Roland called the meeting to order at 7:00 p.m. in the Council Chambers of
Auburn City Hall, 25 West Main Street.
ROLL CALL
Commissioners present: Chair Judi Roland, Julie Berry, Aaron Vanderpol, Lynn
Walters, and Kirk Hiller. Commissioner Ajay Ganesan arrived at 7:04 p.m.
Commissioner William Stewart was excused.
Staff members present: Planning Services Manager Alexandria Teague, Senior Planner
Alyssa Tatro, Senior Planner Dinah Reed, Planner II Gabriel Clark, Assistant City
Attorney Chandra Hein, and Deputy City Clerk Rebecca Wood-Pollock.
PLEDGE OF ALLEGIANCE
Chair Roland led those in attendance in the Pledge of Allegiance.
PUBLIC COMMENT
No one came forward to speak.
AGENDA MODIFICATIONS
There were no modifications to the agenda.
APPROVAL OF MINUTES
A. January 6, 2026 Draft Minutes from the Regular Planning Commission Meeting
Commissioner Walters moved and Commissioner Vanderpol seconded to
approve the January 6, 2026 Planning Commission Meeting minutes.
MOTION CARRIED UNANIMOUSLY. 5-0
Page 5 of 758
OTHER BUSINESS
A. Downtown Design Standards Update and associated Text Amendment
(Tatro)
Planning Commission to review the proposed updates to the Downtown Urban
Center Design Standards.
Planner Tatro provided the Commission with the Downtown Design Standards
Update and associated Text Amendment, including existing zoning districts, an
overview of the changes, applicability, a Block Frontage Standards overview,
transparency and visibility standards, usable residential recreation space,
public plazas, parking lots, garages, and drive access, building massing and
articulation, roofline design, building details, blank wall treatments, implications,
and the next steps in the process.
The Commission discussed accessibility, transparency standards and
advertising, public input, building costs, and existing standards.
B. Citywide Design Review Standards Update and associated Text
Amendments (Reed)
Planning Commission to review the proposed updates to the Citywide
(formerly Mixed-Use and Multifamily) Design Standards.
Planner Reed provided the Commission with the Citywide Design Review
Standards Update and associated Text Amendments, including the purpose for
the update, applicable locations, designated areas, Block Frontage Standards,
minimum setbacks, mixed block frontages, mixed-use street corner standards,
building massing and articulation, and parking.
The Commission discussed current construction, design standard purpose,
zoning development standards, public and private spaces, trees and
vegetation, transit lines, and affordable housing.
Chair Roland called for a recess at 8:16 p.m.
Chair Roland reconvened the meeting at 8:25 p.m.
C. BESS Code Update (Clark)
Planning Commission to review the proposed development standards for
Battery Energy Storage Systems.
Planner Clark provided the Commission with the BESS Code Update, including
objectives, the structure of the Supplemental Standards, General Standards,
zoning maps, Tier I, Tier II, and Tier III Standards, and the proposed timeline.
The Commission discussed prohibitions, flood plains, noise pollution, electric
vehicles, energy capacity, input from the Valley Regional Fire Authority, public
input, the timeline, environmental review requirements, the Tier Standards, and
necessity.
Page 6 of 758
D. Rules of Procedure (Hein)
Planning Commission to review and adopt the 2026 Rules and Procedures
and proposed amendments.
Attorney Hein presented the Commission with the final proposed version of the
updated Planning Commission Rules of Procedure, including the Commission's
approved changes and requested changes.
Commissioner Vanderpol moved and Commissioner Walters seconded to
adopt the Planning Commission Rules of Procedure as presented.
MOTION CARRIED UNANIMOUSLY. 6-0
COMMUNITY DEVELOPMENT REPORT
Manager Teague shared an update on the GSA site to be a Home Depot lumber sorting
site, and that the next meeting is scheduled for March 3, 2026.
The Commission discussed roundabout construction, road safety, and flood damage
restoration at the Auburn Golf Course.
ADJOURNMENT
There being no further business to come before the Planning Commission, the meeting
was adjourned at 9:21 p.m.
APPROVED this 3rd day of March, 2026.
_____________________________ _______________________________
JUDI ROLAND, CHAIR Rebecca Wood-Pollock, Deputy City Clerk
Page 7 of 758
AGENDA BILL APPROVAL FORM
Agenda Subject: Meeting Date:
Battery Energy Storage System (BESS) Code Update
Staff Introduction/Presentation (Clark)
Staff will present the proposed development standards and land use
approval pathways for BESS to Planning Commission for a
recommendation to City Council.
March 3, 2026
Department: Attachments: Budget Impact:
Community Development Planning Commission Staff
Report, Exhibit 1 - BESS
Presentation, Exhibit 2 - ACC
18.04.174 Text Amendment,
Exhibit 3 - ACC 18.07.020 Text
Amendment, Exhibit 4 - ACC
18.23.030 Text Amendment,
Exhibit 5 - Chapter 18.29 ACC
Text Amendment, Exhibit 6 -
ACC 18.31.240 Text
Amendment, Exhibit 7 - ACC
18.35.030 Text Amendment,
Exhibit 8 - 12/02/25 P.C. Memo,
Exhibit 9 - 12/02/25 P.C.
Presentation, Exhibit 10 -
01/06/26 P.C. Memo, Exhibit 11 -
01/06/26 P.C. Presentation,
Exhibit 12 - 02/03/26 P.C. Memo,
Exhibit 13 - 02/03/26 P.C.
Presentation, Exhibit 14 - Public
Comments
Administrative Recommendation:
Background for Motion:
Background Summary:
See attached Planning Commission Staff Report
Councilmember: Staff: Jason Krum
Page 8 of 758
Page 9 of 758
PLANNING COMMISSION STAFF REPORT
AGENDA SUBJECT/TITLE:
Battery Energy Storage System Code Update
CITY FILE NO(s).:
ZOA24-0004
APPLICANT/AGENT/OWNERS:
City of Auburn
REQUEST:
Planning Commission to hold a public hearing, deliberate, and take action on the revised proposed
regulations for Battery Energy Storage Systems.
LOCATION:
City-wide.
NOTIFICATION:
Hearing Notice was published in the Seattle Times and posted on the City’s Land Use Notice webpage and
physically at City Hall and City Hall Annex on February 20, 2026.
HEARING DATE:
March 3rd, 2026
SEPA STATUS:
A SEPA Environmental Checklist – Non-Project Action, was prepared by the City of Auburn as Lead
Agency. A Determination of Non-Significance (DNS) was issued on January 28, 2026, with the appeal
period expiring on February 25, 2026.
STAFF:
Gabriel Clark, Planner II, Dept. of Community Development
Planning@auburnwa.gov
253-470-2147
STAFF RECOMMENDATION:
Planning Commission to deliberate and take action to recommend to City Council approval of the Battery
Energy Storage System Code Update text amendments included in this staff report as Exhibits 2 through 7.
The proposed code updates modify Chapters 18.04 “Definitions,” Chapter 18.07 “Residential Zones,”
Chapter 18.23 “Commercial and Industrial Zones," Chapter 18.29 “Downtown Urban Center District,”
Chapter 18.31 “Supplemental Development Standards,” and Chapter 18.35 “Special Purpose Zones.”
Page 10 of 758
Staff Member: Clark Date: Feb. 17, 2026
Page 2 of 5
SUMMARY OF CODE CHANGES:
The proposal is a non-project action to amend portions of Title 18 “Zoning” Auburn City Code to regulate
the development of Battery Energy Storage Systems within City limits. The proposed code changes
include amendments to the following chapters.
- Chapter 18.04 ACC “Definitions”
- Chapter 18.07 ACC “Residential Zones”
- Chapter 18.23 ACC “Commercial and Industrial Zones”
- Chapter 18.29 ACC “Downtown Urban Center District”
- Chapter 18.31 ACC “Supplemental Development Standards”
- Chapter 18.35 ACC “Special Purpose Zones”
The proposed changes include defining BESS, designating proper land use approval pathways for each
zone and tier, and the establishment of development standards specific to each tier of BESS. These
amendments may permit Tier I (Accessory) in most zones with a capacity of up to 100 kWhs; may permit
Tier II (Commercial/Industrial) in high density commercial, industrial and residential zones with a capacity
of up to 4 MWhs through an administrative land use review process; and may pe rmit Tier III
(Regional/Utility) with capacities over 4 MW within the Heavy Commercial and Industrial zones through a
conditional use permit process.
Based on the concerns made to staff by the Planning Commission, staff is proposing to prohibit Tier II
systems in the Open Space Zone.
FINDINGS OF FACT:
Background Summary:
1. Battery Energy Storage Systems are systems which store and release electrical energy generated by
the grid. These systems have increased in popularity in our region due to changing legislation and
economic factors for end users. Enacted into law in 2019, Senate Bill (SB) 5116 defined specific
milestones which require the State’s electrical supply to be free of greenhouse gas emissions by 2045
(see Exhibit 8).
2. In 2021 Puget Sound Energy (PSE) published an Integrated Resource Plan which contains the Public
Utility District’s goals and policies over the next planning period for the agency. Of which Battery
Energy Storage Systems are identified as a central component to the Utility’s “Distributed Energy
Resource” goals of providing 3,222 MW of capacity by 2045 (see Exhibit 8).
3. In 2021 PSE consulted with Power Systems Consultants to perform a qualitative and quantitative
analysis for siting of possible energy storage systems within the PSE electrical system. This report
identified several sites suitable for BESS in and near the City of Auburn (see Exhibit 8).
4. Staff is proposing new development regulations to coordinate the siting, construction, and installation
of BESS within the City of Auburn.
Page 11 of 758
Staff Member: Clark Date: Feb. 17, 2026
Page 3 of 5
5. Due to a lack of regulations, the City instituted a six-month moratorium and extension on the siting,
construction, and operation of BESS within the City of Auburn. The moratorium and extension is set to
expire on May 5, 2026.
6. Staff held a roundtable discussion on October 2, 2025, with labor unions, the Valley Regional Fire
Authority, the Muckleshoot Indian Tribe, and Puget Sound Energy to gain a deeper understanding of
this technology and its associated impacts.
Procedural Steps:
7. By authorization of the Revised Code of Washington (RCW) 36.70A.390, the City Council of Auburn
established a six-month moratorium on the application, processing, or approval of Battery Energy
Storage Systems by passage of Ordinance No. 6978 on May 5, 2025.
8. By authorization of RCW 36.70A.390 the City Council of Auburn extended the moratorium six
additional months by passage of Ordinance No. 6995.
9. Staff discussed the proposed text amendments with the Planning Commission regular meetings on
December 2, 2025, January 6, 2026, and February 3, 2026, respectively. Staff memos provided
Planning Commission for the aforementioned meetings detail the purpose and scope of the
amendments to Title 18 “Zoning” ACC (see Exhibits 8, 10, and 12).
10. In accordance to RCW 36.70A.106(1) the Planning Staff provided the proposed development
regulations to the Department of Commerce for a 60-day comment review period on January 2, 2026,
with a comment period deadline of March 3, 2026. The Department of Commerce acknowledged the
request providing reference number 2026-S-11392. At the time this report was completed, the
Department of Commerce did not provide any comments on the proposed text amendments.
11. A SEPA Environmental Checklist – Non-Project Action, was prepared by the City of Auburn as Lead
Agency. A Determination of Non-Significance (DNS) was issued on January 28, 2026, with the appeal
period expiring on February 25, 2026. Comments received are provided in Exhibit 14.
12. ACC 18.68.025 outlines what text amendments may be initiated by the City or the Public.
A. City-Initiated Text Amendments
1. The director of community development may initiate an amendment to the text of this title
[Title 18] for the following purposes:
a. Change the text to increase the consistency with the comprehensive plan in
compliance with ACC 14.22.050, Conformance and consistency.
b. Change the text in response to changes in state and/or federal laws.
c. Change the text to correct errors, which are determined by the director of community
development to be substantive and beyond the scrivener’s error.
d. Change the text to increase internal consistency if this title (Zoning).
2. The mayor may request the director of community development to initiate an amendment to
the text of this title, or by the request of the mayor on behalf of the city council or the planning
commission.
Page 12 of 758
Staff Member: Clark Date: Feb. 17, 2026
Page 4 of 5
B. Public-Initiated Text Amendments.
Any member of the public may submit an application requesting to amend the text of this title
using the city’s established application process.
13. Staff will pursue option ACC 18.68.025(A)(1)(b) “change in text in response in state and/or federal
laws” as regulations pertaining to electrical storage systems (ESS) which include BESS have greatly
expanded (see Exhibit 12).
14. ACC 18.68.030 outlines the procedural requirements to complete a Substantive Zoning Text
Amendment.
B. A “Zoning Text Amendment” is an application to change the text of ACC Title 18. This type of
application or initiation shall be processed as a legislative nonproject decision, consistent with ACC
14.03.060. Public notice shall be provided consistent with ACC Title 14.
1. Substantive Zoning Text Amendments. For the purposes of this chapter, substantive zoning
text amendments shall be distinguished from procedural or administrative amendments in
accordance with the following: “Substantive” matters relate to regulations that define or limit
what can be done in terms of conduct, use or action (e.g., what land use may be made of property,
what requirements apply to development, and what public infrastructure may be required of
certain developments). “Procedural” or “administrative” matters are those that relate to the
process of how an application to take such action must be pursued (e.g., time limits for decisions
and appeals, what forms must be used, and where or how applications must be submitted.
Essentially, “procedural” or “administrative” matters are the mechanical rules by which
substantive issues may be pursued.) Substantive text amendments shall be reviewed by the
planning commission, and the planning commission shall conduct a public hearing and make a
recommendation before being presented to the city council for consideration and action.
15. A Notice of Public Hearing (NOH) will be issued on February 20, 2026. Pursuant to
ACC18.68.030(B)(1), the following methods of noticing for the Planning Commission public hearing
were conducted:
a. The NOH was published in the Seattle Times on February 20, 2026.
b. The NOH was posted in two general public locations (City Hall and City Annex).
c. The NOH was posted on City’s Public Land Use Notice webpage.
16. A public hearing is scheduled by the Planning Commission on March 3, 2026. The City has received
any comments pertaining to the NOH, however Staff will provide any comments received to Planning
commission at the time of the scheduled Public Hearing.
Page 13 of 758
Staff Member: Clark Date: Feb. 17, 2026
Page 5 of 5
EXHIBITS:
1. BESS Presentation
2. ACC 18.04.174 Text Amendment
3. ACC 18.07.020 Text Amendment
4. ACC 18.23.020 Text Amendment
5. Chapter 18.29 ACC Text Amendment
6. ACC 18.31.240 Text Amendment
7. ACC 18.35.030 Text Amendment
8. 12/2/2025 Planning Commission Memo
9. 12/2/2025 Planning Commission Presentation
10. 1/6/2026 Planning Commission Memo
11. 1/6/2026 Planning Commission Presentation
12. 2/3/2026 Planning Commission Memo
13. 2/3/2026 Planning Commission Presentation
14. Public Comments Received
Page 14 of 758
AUBURN
VALUES
S E R V I C E
ENVIRONMENT
E C O N O M Y
C H A R A C T E R
SUSTAINABILITY
W E L L N E S S
C E L E B R AT I O N
PLANNING COMMISSION
ENERGY STORAGE
SYSTEM CODE UPDATE
PRESENTED BY
GABRIEL CLARK, PLANNER II
MARCH 3, 2026
Department of Community Development
Planning Building Development Engineering Permit Center
Economic Development Code Enforcement
Page 15 of 758
Define tiers, separated by capacity
Determine appropriate zones
Determine appropriate land use approval pathways
Coordinate existing regulations with proposed
development standards
PURPOSE
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 16 of 758
Washington Administrative Code (WAC) 51-54A- 1207
International Fire Code (IFC) Chapter 12
National Fire Protection Association
City of Auburn Engineering Design Standards
APPLICABLE REGULATIONS
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 17 of 758
Allowed as a Type I
decision
Stored energy capacity
limited to 100 kWh
Accessory to primary use
TIER I
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 18 of 758
Allowed as a Type II
decision
Energy capacity up to 4
MWh
Restricted to higher
intensity land uses
TIER II
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 19 of 758
Allowed as a Type II or
Type III decision
Stored energy capacities in
excess of 4 MWh
Restricted to heavy
commercial and industrial
land uses
TIER III
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 20 of 758
R-FR-NMR-4 R-3R-2R-1RC
PPPPPPPTier I
XAAAXXXTier II
XXXXXXXTier III
ZONING CLASSIFICATION
RESIDENTIAL
Page 21 of 758
M-2M-1C-AGC-2C-1DUC
PPPPPPTier I
AAAAAATier II
AAXCXXTier III
ZONING CLASSIFICATION
COMMERCIAL & INDUSTRIAL
Page 22 of 758
ZONING CLASSIFICATION
SPECIAL PURPOSE
OSIP-1
PPPTier I
XAATier II
XXXTier III
Page 23 of 758
Concerns over fire safety
Concerns over environmental precautions
Concerns regarding the permitted thresholds
PUBLIC COMMENTS
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 24 of 758
Planning Commission to recommend to City Council
approval of the Battery Energy Storage System text
amendments included as Exhibits 2 through 7.
RECOMMENDATION
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
Page 25 of 758
AUBURN
VALUES
S E R V I C E
ENVIRONMENT
E C O N O M Y
C H A R A C T E R
SUSTAINABILITY
W E L L N E S S
C E L E B R AT I O N
Department of Community Development
Planning Building Development Engineering Permit Center
Economic Development Code Enforcement
QUESTIONS?
Page 26 of 758
Chapter 18.04 ACC, Definitions Page 1 of 1
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Chapter 18.04
DEFINITIONS
Sections:
18.04.174 Battery energy storage system (BESS)
18.04.174 Battery energy storage systems (BESS)
“Battery energy storage systems” means a rechargeable energy storage system consisting
of batteries, battery chargers, controls, and associated electrical equipment designed to
store and distribute electrical power. These systems are typically used to provide standby
or emergency power, an uninterruptable power supply, load shedding, load sharing, or
similar capabilities.
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 27 of 758
ACC 18.07.020, Uses Page 1 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.07.020 Uses.
Table 18.07.020. Permitted Use Table – Residential Zones
P = Permitted A = Administrative C = Conditional Use X = Not Permitted
Land Uses Zoning Designations
RC R-1 R-2 R-3 R-4 R-NM R-F
A. Residential Uses.
Accessory dwelling units subject to the provisions
contained in Chapter 18.32 ACC
P1 P1 P1 P1 P1 P1 P1
Accessory use, residential P P P P P P P
Adult family home P P P P P P1 P
Apartments (7 units or more) X X X P11 P P X
Bed and breakfast or short-term rentals P P P P P X P
Caretaker apartment X X X X X P X
Communal residence P P P P P X P
Foster care homes P P P P P X P
Group residence facilities (7 or more residents) X X X P P P P
Group residence facilities (6 or fewer residents) P P P P P P P
Keeping of animals4 P2 P2 P2 P2 P2 P2 P2
Middle housing subject to the provisions in Chapter
18.25 ACC (2 to 6 units)
P P P P P P P
Page 28 of 758
ACC 18.07.020, Uses Page 2 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
P = Permitted A = Administrative C = Conditional Use X = Not Permitted
Land Uses Zoning Designations
RC R-1 R-2 R-3 R-4 R-NM R-F
Neighborhood recreational buildings and facilities
owned and managed by the neighborhood
homeowners’ association
A6 A6 A6 A6 A6 P P
Use as dwelling units of (1) recreational vehicles
that are not part of an approved recreational
vehicle park, (2) boats, (3) automobiles, and (4)
other vehicles
X X X X X X X
Renting of rooms, for lodging purposes only, to
accommodate not more than two persons in
addition to the family or owner occupied unit8
P P P P P P P
Residential care facilities including but not limited
to assisted living facilities, convalescent homes,
continuing care retirement facilities
P P P P P P P
Single-unit detached dwellings, new P P P X X X P
Supportive housing (permanent), subject to the
provisions of ACC 18.31.160
P P P P P P P
Swimming pools, tennis courts and similar outdoor
recreation uses only accessory to residential or
park uses
P P P P P P P
Townhouses (attached) X X X X P P P
Transitional housing P P P P P P P
B. Commercial Uses.
Page 29 of 758
ACC 18.07.020, Uses Page 3 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
P = Permitted A = Administrative C = Conditional Use X = Not Permitted
Land Uses Zoning Designations
RC R-1 R-2 R-3 R-4 R-NM R-F
Commercial horse riding and bridle trails A X X X X X X
Commercial recreation facility, indoor X X X X P P X
Commercial retail establishment X X A A P P A
Convenience store X X X X P P X
Daycare, limited to a mini daycare center. Daycare
center, preschool or nursery school may also be
permitted but must be located on an arterial
X P P P P P P
Grocery or specialty food store X X X A P P A
Home-based (or family) daycare as regulated by
RCW 35.63.185 and through receipt of approved
city business license
P P P P P P P
Home occupations subject to compliance with
Chapter 18.60 ACC
P P P P P P P
Marijuana cooperative X X X X X X X
Marijuana processor X X X X X X X
Marijuana producer X X X X X X X
Marijuana-related business X X X X X X X
Marijuana researcher X X X X X X X
Marijuana retailer X X X X X X X
Page 30 of 758
ACC 18.07.020, Uses Page 4 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
P = Permitted A = Administrative C = Conditional Use X = Not Permitted
Land Uses Zoning Designations
RC R-1 R-2 R-3 R-4 R-NM R-F
Marijuana transporter business X X X X X X X
Mixed-use development310 X X X P P P P
Personal service shop X X A P P P P
Nursing homes X X X X C C C
Privately owned and operated parks and
playgrounds and not homeowners’ association-
owned recreational area
X A A A A P P
Professional offices X X A A P9 P P
Restaurant, café, or coffee shop X X A A P P A
Neighborhood retail establishment X X A A P P P
C. Resource Uses.
Agricultural enterprise:7
When 50 percent, or more, of the total site area is
dedicated to active agricultural production during
the growing season, and with 52 or less special
events per calendar year
A7 X X X X X X
When less than 50 percent of the total site area is
dedicated to active agricultural production during
the growing season, or with more than 52 special
events per calendar year
C7 X X X X X X
Page 31 of 758
ACC 18.07.020, Uses Page 5 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
P = Permitted A = Administrative C = Conditional Use X = Not Permitted
Land Uses Zoning Designations
RC R-1 R-2 R-3 R-4 R-NM R-F
Agricultural type uses are permitted provided they
are incidental and secondary to the single-family
use:
Agricultural crops and open fleld growing
(commercial)
P X X X X X X
Barns, silos and related structures P X X X X X X
Commercial greenhouses P X X X X X X
Pasturing and grazing4 P X X X X X X
Public and private stables4 P X X X X X X
Roadside stands, for the sale of agricultural
products raised on the premises. The stand cannot
exceed 300 square feet in area and must meet the
applicable setback requirements.
P X X X X X X
Fish hatcheries C X X X X X X
D. Government, Institutional, and Utility Uses.
Civic, social and fraternal clubs X X X X A A A
Government facilities A A A A A A A
Hospitals (except animal hospitals) X X X X X C C
Municipal parks and playgrounds A P P P P P P
Page 32 of 758
ACC 18.07.020, Uses Page 6 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
P = Permitted A = Administrative C = Conditional Use X = Not Permitted
Land Uses Zoning Designations
RC R-1 R-2 R-3 R-4 R-NM R-F
Museums X X X X A A A
Religious institutions, less than one acre lot size12 A A A A A A A
Religious institutions, one acre or larger lot size12 C C C C C C C
Transmitting towers C C C C C C C
Type 1-D wireless communications facility (see ACC
18.04.912(W) and 18.31.100)
P P P P P P P
Eligible facilities request (EFR) (wireless
communications facility – See ACC 18.04.912(H))
P P P P P P P
Utility facilities and substations C5 C5 C5 C5 C5 C5 C5
Battery Energy Storage Systems, Tier I P13 P13 P13 P13 P13 P13 P13
Battery Energy Storage Systems, Tier II X X X A13 A13 A13 x
Battery Energy Storage Systems, Tier III X X X X X X X
Small wireless facilities (ACC 18.04.912(Q)) P P P P P P P
1 An accessory dwelling unit may be permitted with an existing single-unit residence pursuant to Chapter
18.32 ACC.
2 Please see the supplemental development standards for animals in ACC 18.31.220.
3 Individual uses that make up a mixed-use development must be permitted within the zone. If a use making
up part of a mixed-use development requires an administrative or conditional use permit, the individual use
must apply for and receive the administrative or conditional use approval, as applicable.
Page 33 of 758
ACC 18.07.020, Uses Page 7 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
4 Proximity of pasture or livestock roaming area to wells, surface waters, and aquifer recharge zones is
regulated by the King or Pierce County board of health, and property owners shall comply with the provisions
of the board of health code.
5 Excludes all public and private utility facilities addressed under ACC 18.02.040(E).
6 Administrative use permit not required when approved as part of a subdivision or binding site plan.
7 Agricultural enterprise uses are subject to supplemental development standards under ACC 18.31.210,
Agricultural enterprises development standards.
8 An owner occupant that rents to more than two persons but no more than four persons is required to
obtain a city of Auburn rental housing business license and shall meet the standards of the International
Property Maintenance Code.
9 As component of mixed-use developments and/or office ground fioor uses permitted up to 5,000 square
feet.
10 Commercial uses permitted outright, or allowed administratively or conditionally in this table may be
allowed as part of mixed-use development.
11 Apartment buildings and mixed-use development consisting of no more than 20 units and three stories per
lot is permitted.
12 Reference ACC 18.31.165 for standards related to homeless encampments hosted by a religious
organization.
13 Reference ACC 18.31.240 for standards related to Battery Energy Storage Systems (BESS).
(Ord. 6977 § 1 (Exh. A), 2025; Ord. 6959 § 1 (Exh. A), 2024; Ord. 6799 § 5 (Exh. E), 2020; Ord. 6642 § 4, 2017; Ord.
6600 § 9, 2016; Ord. 6565 § 2, 2015; Ord. 6560 § 9, 2015; Ord. 6477 § 8, 2013; Ord. 6369 § 2, 2011; Ord. 6363 § 3,
2011; Ord. 6269 § 3, 2009; Ord. 6245 § 5, 2009.)
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 34 of 758
ACC 18.23.030, Uses Page 1 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.23.030 Uses.
A. General Permit Requirements. Table 18.23.030 identifles the uses of land allowed in each
commercial and industrial zone and the land use approval process required to establish each
use.
B. Requirements for Certain Specific Land Uses. Where the last column (Standards for Speciflc
Land Uses) in Table 18.23.030 includes a reference to a code section number, the referenced
section determines other requirements and standards applicable to the use regardless of
whether it is permitted outright or requires an administrative or conditional use permit.
C. Uses Affected by the Airport Overlay. Refer to Chapter 18.38 ACC to determine whether uses
are separately prohibited by that chapter or will be required to comply with additional
regulations that are associated with the airport overlay.
Table 18.23.030. Permitted, Administrative, Conditional and Prohibited Uses by Zone,
Commercial and Industrial Zones
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
INDUSTRIAL, MANUFACTURING AND PROCESSING, WHOLESALING
Building contractor, light X P X P P
Building contractor, heavy X X X A P
Manufacturing, assembling and packaging –
Light intensity
X P X P P ACC 18.31.180
Page 35 of 758
ACC 18.23.030, Uses Page 2 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Manufacturing, assembling and packaging –
Medium intensity
X A X P P ACC 18.31.180
Manufacturing, assembling and packaging –
Heavy intensity
X X X X A ACC 18.31.180
Marijuana processor X X X C C Chapter 18.59 ACC
Marijuana producer X X X C C Chapter 18.59 ACC
Marijuana researcher X X X C C Chapter 18.59 ACC
Marijuana retailer X C X C C Chapter 18.59 ACC
Marijuana transporter business X X X C C Chapter 18.59 ACC
Outdoor storage, incidental to principal
permitted use on property
X P X P P ACC 18.57.020(A)
Storage – Personal household storage facility
(mini-storage)
P P X P P ACC 18.57.020(B)
Warehousing and distribution X X X P C ACC 18.57.020(C)
Warehousing and distribution, bonded and
located within a designated foreign trade
zone
X P X P P
Page 36 of 758
ACC 18.23.030, Uses Page 3 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Wholesaling with on-site retail as an
incidental use (e.g., coffee, bakery)
X P X P P
RECREATION, EDUCATION AND PUBLIC ASSEMBLY USES
Commercial recreation facility, indoor P P P P A
Commercial recreation facility, outdoor X A A P A ACC 18.57.025(A)
Conference/convention facility X A X A X
Library, museum A A X A X
Meeting facility, public or private P P X A A
Movie theater, except drive-in P P P X X
Private school – Specialized
education/training (for proflt)
A P P P P
Religious institutions, lot size less than one
acre
P P A A A ACC 18.31.165
Religious institutions, lot size more than one
acre
P P A A A ACC 18.31.165
Sexually oriented businesses X P X P P Chapter 18.74 ACC
Page 37 of 758
ACC 18.23.030, Uses Page 4 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Sports and entertainment assembly facility X A X A A
Studio – Art, dance, martial arts, music, etc. P P P P A
RESIDENTIAL
Apartment units, as part of a mixed-use
development 2
X P P P X ACC 18.57.030
Apartments, standalone X X X X X
Caretaker apartment P P X P P
Indoor emergency housing or shelter P P P A A ACC 18.31.160
Live/work unit, as part of a mixed-use
development 2
X P P P X
Live/work unit, standalone 3 X X X X X
Work/live unit, as part of a mixed-use
development 2
X P P P X
Work/live unit, standalone 3 X X X X X
Marijuana cooperative X X X X X
Page 38 of 758
ACC 18.23.030, Uses Page 5 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Nursing home, assisted living facility P P C X X
Senior housing2 X A X X X
Supportive housing (permanent) P P P A A ACC 18.31.160
Transitional housing P P P A A ACC 18.31.160
RETAIL
Building and landscape materials sales X P X P P ACC 18.57.035(A)
Community retail establishment P P P P P
Construction and heavy equipment sales and
rental
X X X A P
Convenience store A P X P P
Drive-through espresso stands A P A P A
Drive-through facility, including banks and
restaurants
A P P P P ACC 18.52.040
Entertainment, commercial A P X A A
Groceries, specialty food stores P P P P X
Page 39 of 758
ACC 18.23.030, Uses Page 6 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Neighborhood retail establishment P P P P P
Nursery X P A P P ACC 18.57.035(C)
Outdoor displays and sales associated with a
permitted use (auto/vehicle sales not
included in this category)
P P P P P ACC 18.57.035(D)
Regional retail establishment X P P P A
Restaurant, cafe, coffee shop P P P P P
Tasting room P P P P P
Tavern P P P P A
Wine production facility, small craft distillery,
small craft brewery
P P P P P
SERVICES
Animal daycare (excluding kennels and
animal boarding)
A P A P P ACC 18.57.040(A)
Animal sales and services (excluding kennels
and veterinary clinics)
P P P P P ACC 18.57.040(B)
Page 40 of 758
ACC 18.23.030, Uses Page 7 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Banking and related flnancial institutions,
excluding drive-through facilities
P P P P P
Catering service P P A P P
Daycare, including mini daycare, daycare
center, preschools or nursery schools
P P P P X
Dry cleaning and laundry service (personal) P P P P P
Equipment rental and leasing X P X P P
Kennel, animal boarding X A X A A ACC 18.57.040(C)
Government facilities; this excludes offices
and related uses that are permitted outright
A A A A A
Hospital P P X P P
Lodging – Hotel or motel P P P A A
Medical – Dental clinic P P P P X
Mortuary, funeral home, crematorium P P X P X
Personal service shops P P P P X
Page 41 of 758
ACC 18.23.030, Uses Page 8 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Pharmacies P P P X X
Print and copy shop P P P P X
Printing and publishing (of books, newspaper
and other printed matter)
A P P P P
Professional offices P P P P P
Repair service – Equipment, appliances A P P P P ACC 18.57.040(D)
Veterinary clinic, animal hospital P P P P X
Youth community support facility P X X X X ACC 18.57.040(E)
TRANSPORTATION, COMMUNICATIONS AND INFRASTRUCTURE
Ambulance, taxi, and specialized
transportation facility
X A X P P
Broadcasting studio P P X P P
Heliport X C X C C
Motor freight terminal1 X X X X X See Footnote No. 1
Parking facility, public or commercial, surface P P P P X
Page 42 of 758
ACC 18.23.030, Uses Page 9 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Parking facility, public or commercial,
structured
P P P P X
Battery Energy Storage Systems, Tier I P P P P P ACC 18.31.240
Battery Energy Storage Systems, Tier II A A A A A ACC 18.31.240
Battery Energy Storage Systems, Tier III X C X A A ACC 18.31.240
Towing storage yard X X X A P ACC 18.57.045(A)
Utility transmission or distribution line or
substation
A A A A A
Wireless communications facility (WCF) (See
ACC 18.04.912(W))
* * * * * *See ACC 18.31.100 for
use regulations and zoning
development standards.
Eligible facilities request (EFR) (wireless
communications facility) (See ACC
18.04.912(H))
P P P P P
Small wireless facilities (ACC 18.04.912(Q)) P P P P P
VEHICLE SALES AND SERVICES
Page 43 of 758
ACC 18.23.030, Uses Page 10 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
PERMITTED, ADMINISTRATIVE, CONDITIONAL AND PROHIBITED USES BY
ZONE
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designation Standards for Specific
Land Uses C-1 C-2 C-AG M-1 M-2
Automobile washes (automatic, full or self-
service)
A P P P P ACC 18.57.050(A)
Auto parts sales with installation services A P P P P
Auto/vehicle sales and rental A P X P P ACC 18.57.050(B)
Fueling station A P P P P ACC 18.57.050(C)
Mobile home, boat, or RV sales X P X P P
Vehicle services – Repair/body work X P X P P ACC 18.57.050(D)
OTHER
Any commercial use abutting a residential
zone which has hours of operation outside of
the following: Sunday: 9:00 a.m. to 10:00 p.m.
or Monday – Saturday: 7:00 a.m. to 10:00 p.m.
A A A A A
Other uses may be permitted by the planning
director or designee if the use is determined
to be consistent with the intent of the zone
and is of the same general character of the
uses permitted. See ACC 18.02.120(C)(6),
Unclassifled Uses.
P P P P P
1 Any motor freight terminal, as deflned by ACC 18.04.635, in existence as of the effective date of the
ordinance codifled in this section, is an outright permitted use in the M-1 and M-2 zones. Any maintenance,
Page 44 of 758
ACC 18.23.030, Uses Page 11 of 11
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
alterations and additions to an existing motor freight terminal which are consistent with ACC 18.23.040,
Development standards, are allowed.
2 Any mixed-use development or senior housing project vested prior to Resolution No. 5187 (December 7,
2015) is an outright permitted use in the C-1 zone. Subsequently, if a nonresidential use within a vested
mixed-use development changes, then the nonresidential use shall maintain a minimum of 10 percent of the
cumulative building ground fioor square footage consisting of the uses permitted outright, administratively, or
conditionally, listed under “Recreation, Education, and Public Assembly,” “Retail,” or “Services” of the C-1 zone.
3 Any standalone live/work units or standalone work/live units vested prior to the effective date of the
ordinance codifled in this chapter are outright permitted uses.
(Ord. 6977 § 1 (Exh. A), 2025; Ord. 6959 § 1 (Exh. A), 2024; Ord. 6885 § 1 (Exh. A), 2022; Ord. 6838 § 1 (Exh. A),
2021; Ord. 6799 § 6 (Exh. F), 2020; Ord. 6728 § 3 (Exh. C), 2019; Ord. 6688 § 1 (Exh. 1), 2018; Ord. 6644 § 2, 2017;
Ord. 6642 § 9, 2017; Ord. 6508 § 1, 2014; Ord. 6433 § 26, 2012.)
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 45 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 1 of 3
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Chapter 18.29
DUC DOWNTOWN URBAN CENTER DISTRICT
Sections:
18.29.050 Use limitations.
18.29.053 Uses/activities requiring an administrative use permit.
18.29.050 Use limitations.
Hereafter, all buildings, structures or properties may be used for any use, unless speciflcally
prohibited herein. Ground fioor retail, restaurants and/or office use is required for all building
frontages facing Main Street. All uses shall be subject to review and approval by the director.
The following uses are prohibited:
A. Sexually oriented businesses as deflned in Chapter 18.74 ACC.
B. All industrial uses as deflned in the North American Industrial Classiflcation System (2022
Edition), categories 48 through 49 (transportation), 31 through 33 (manufacturing) and 42
(wholesale trade).
C. Outdoor storage of materials and equipment (except during active construction projects).
D. New automobile maintenance and repair businesses.
E. Work release facilities; secure community transition facilities.
F. Wrecking yards.
G. Solid waste transfer stations.
H. Car washes.
I. New gasoline stations.
J. Street-level ministorage.
K. Outdoor sales of vehicles, boats or equipment.
Page 46 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 2 of 3
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
L. Drive-in/drive-through facilities with direct vehicular driveway access onto Main Street.
M. All marijuana-related businesses and marijuana cooperatives.
N. New single-unit detached dwellings; except for DUC neighborhood residential district.
O. Battery Energy Storage Systems, Tier III.
PO. Other uses may be prohibited by the director if the use is determined to be inconsistent
with the intent of this zone or is of the same general character of the other prohibited uses
listed in this section. (Ord. 6959 § 1 (Exh. A), 2024; Ord. 6642 § 10, 2017; Ord. 6071 § 6 (Exh. A), 2007.)
18.29.053 Uses/activities requiring an administrative use permit.
The following uses/activities may be permitted when an administrative use permit has been
issued pursuant to the provisions of Chapter 18.64 ACC:
A. Expansions of existing automobile maintenance and repair businesses;
B. Expansions of existing gasoline stations;
C. Animal daycare businesses that feature outdoor exercise areas and/or kennels;
D. Wine production facility; small craft distillery; small craft brewery; and a tasting room is an
outright allowed use in the DUC zone;.
E. Battery Energy Storage Systems, Tier II2 (Ord. 6368 § 8, 2011; Ord. 6269 § 32, 2009.)
2 Battery Energy Storage Systems, Tier II shall comply with the supplemental standards contained in ACC
18.31.240.
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Page 47 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 3 of 3
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 48 of 758
Chapter 18.31 ACC, Supplemental Development Standards Page 1 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Chapter 18.31
SUPPLEMENTAL DEVELOPMENT STANDARDS
Sections:
18.31.240 Battery energy storage systems (BESS)
18.31.240 Battery energy storage systems (BESS)
A. Purpose. The requirements contained in this section are intended to capture the
minimum requirements set by International Code Councils, National Laboratories, and
State Law. This section contains general and speciflc standards applicable to all BESS, and
speciflc standards for each tier of BESS.
B. General Standards.
1. Adoption by reference. WAC 51-54A-1207 including any amendments thereto, are
adopted by reference as if fully set forth in addition to IBC, IFC, and NFPA.
2. Setbacks. BESS shall comply with the minimum setback requirements of the
underlying zoning district.
3. Noise. Average operational noises heard at the property line to adjacent land uses
shall subject to Chapter 8.28 ACC and be limited to;
a. Residential: 60 decibels.
b. Commercial: 65 decibels.
c. Industrial: 70 decibels.
4. Safety. BESS and equipment shall be UL 9540 certifled in accordance with IFC
1207.
5. Floodplain. BESS sited on properties which contain the 100-year fioodplain or
Special Flood Hazard Area (SFHA) shall be subject to the deflnitions and minimum
development standards contained in Chapter 15.68 ACC.
6. Critical Areas. In areas which contain regulated critical areas deflned in Chapter
16.10 ACC, BESS shall be subject to the standard buffer widths, applicable to each
critical area.
Page 49 of 758
Chapter 18.31 ACC, Supplemental Development Standards Page 2 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
7. Supplemental Information Required for Applications. For BESS installations that
surpass the energy storage capacities identifled in the Threshold Quantities table of
WAC 51-54A-1207 the permit application shall contain the following information:
a. Construction Documents. The applicant shall include all information
specifled in WAC 51-54A-1207.
b. Commissioning Plan. The applicant shall submit a commissioning plan
consistent with the requirements of WAC 51-54A-1207.
c. Decommissioning Plan. The applicant shall submit a decommissioning
plan consistent with the requirements of WAC 51-54A-1207.
d. Hazard Mitigation Analysis. The applicant shall submit a hazard mitigation
analysis consistent with the requirements of WAC 51-54A-1207.
C. BESS, Tier I.
1. Capacity Threshold. BESS, Tier I shall be limited to 100 kWh of total system
capacity.
2. Location. BESS, Tier I may be installed only in the following locations as specifled
in WAC 51-54A-1207:
a. Within utility closets, basements, and storage or utility spaces.
b. In attached or detached garages and detached accessory structures.
c. On exterior walls.
d. Outdoors on the ground.
3. Screening. If installed exterior to the structure, BESS, Tier I shall be screened from
the public right-of-way and located behind the extent of the front façade of the
primary structure on the property.
D. BESS, Tier II and BESS, Tier III
1. Capacity Threshold. BESS, Tier II shall not exceed a total energy capacity of 4
MWh. BESS Tier, III includes systems with a total energy capacity beyond 4 MWhs.
2. System Testing. Large-scale flre testing shall be conducted on a representative
BESS in accordance with UL 9540A by the methods contained in Chapter 12 IFC.
3. Location. If located within rooms, areas, or walk in structures shall not exceed the
maximum allowable quantities contained in WAC 51-54A-1207.
Page 50 of 758
Chapter 18.31 ACC, Supplemental Development Standards Page 3 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
4. Fencing. BESS that do not occur within an enclosed principle structure shall be
fenced with a self-locking gate in accordance to Chapter 12 IFC. Fencing shall
comply with ACC 18.31.020 applicable to the zone which the site is located.
5. Vegetation Control. Areas within 10 feet on each site of outdoor BESS shall be
cleared of combustible vegetation and other combustible growth per Chapter 12
IFC .
6. Secondary Containment and Spill Neutralization. Secondary containment
facilities shall meet the applicable standards contained in the current National
Pollutant Discharge Elimination System (NPDES) and the City of Auburn Engineering
Design Standards and as amended. Secondary spill containment and neutralization
shall comply with Chapter 12 IFC.
7. Access. Where access to a tier II Facility is provided from a street that would
otherwise function as a dead-end, a minimum of one secondary emergency vehicle
access EVA route shall be provided to allow alternate emergency repose access and
staging.
The secondary emergency vehicle access shall be designed and constructed in
accordance with the City of Auburn Engineering Design Standards and applicable
flre code requirements and shall provide a continuous, unobstructed route suitable
for emergency vehicle operations.
8. Hydrant Spacing. Hydrant spacing shall meet the minimum requirements for
commercial structures in the City of Auburn Engineering Design Standards and as
amended.
9. Insurance. The permit applications shall contain the information cited by ACC
18.31.240(B)(7) including:
a. Insurance. The owner and/or operator of the BESS facility shall maintain
insurance for the project with the City of Auburn named as co-insured. The
insurance shall cover the estimated costs associated to decommissioning
activities specifled by the decommissioning plan. The insurance policy shall
be active for life of the facility or until all requirements of the
decommissioning plan are satisfled. Proof of insurance shall be provided to
the City of Auburn.
i. Abandonment. BESS shall be considered abandoned when it ceases
to operate consistently or when permits issued for the facility have
been suspended or revoked. If the owner and/or operator fails to
Page 51 of 758
Chapter 18.31 ACC, Supplemental Development Standards Page 4 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
comply with decommissioning upon any abandonment, the City of
Auburn may, at its discretion, enter the property and utilize the
available insurance for the removal of the facility and restore the site
in accordance with the approved decommissioning plan.
10. Land Use Decision. In respect to the land use decision required by the
applicable zoning district, by authorization of an administrative use or conditional
use permit, the planning director or designee, or hearing examiner may attach
thereto conditions regarding the location, character, and other features of the
proposed structure or use as they may deem necessary to carry out the intent and
purpose of this title and in the public interest.
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 52 of 758
ACC 18.35.030, Uses Page 1 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.35.030 Uses.
A. General Permit Requirements. Table 18.35.030 identifies the uses of land allowed in each
special purpose zone and the planning permit required to establish each use.
B. Requirements for Certain Specific Land Uses. Where the last column (Standards for Specific
Land Uses) in Table 18.35.030 includes a section number, the referenced section determines
other requirements and standards applicable to the use regardless of whether it is permitted
outright or requires an administrative or conditional use permit.
Table 18.35.030. Permitted, Administrative, Conditional and Prohibited Uses by Zone
Permitted, Administrative, Conditional and Prohibited Uses by Zone
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designations Standards for
Specific Land Uses P-1 I OS
MARIJUANA-RELATED BUSINESSES
Marijuana processor X X X
Marijuana producer X X
18.
X
Marijuana researcher X X X
Marijuana retailer X X X
Marijuana transporter business X X X
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ACC 18.35.030, Uses Page 2 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Permitted, Administrative, Conditional and Prohibited Uses by Zone
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designations Standards for
Specific Land Uses P-1 I OS
PUBLIC
Animal shelter, public P X X
Government facilities; this excludes offices and
related uses that are permitted outright
P P C
Municipal parks and playgrounds P P P
RECREATION, EDUCATION AND PUBLIC ASSEMBLY
Campgrounds X P P
Recreational vehicle parks, private X P X
Cemetery, public P A X
Cemetery, private X A X
College, university, public A A X
Commercial recreation facility – Indoor X P X
Commercial recreation facility – Outdoor X A C ACC 18.57.025(A)
Conference/convention facility X A X
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ACC 18.35.030, Uses Page 3 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Permitted, Administrative, Conditional and Prohibited Uses by Zone
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designations Standards for
Specific Land Uses P-1 I OS
Library, museum P P A
Meeting facility, public or private P P A
Private school – specialized education/training (for
profit)
X P X
Public schools (K-12) and related facilities P X X
Religious institutions, lot size less than one acre X P X
Religious institutions, lot size more than one acre X P X
Studio – Art, dance, martial arts, music, etc. X X X
RESIDENTIAL
Middle housing subject to the provisions in
Chapter 18.25 ACC (2 to 6 units)
X A1 X
Home occupation X P P Chapter 18.60 ACC
Live/work, work/live unit X A X
Apartments (7 or more units) X A2 X
One single-unit detached dwelling X X P4
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ACC 18.35.030, Uses Page 4 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Permitted, Administrative, Conditional and Prohibited Uses by Zone
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designations Standards for
Specific Land Uses P-1 I OS
Nursing home, assisted living facility X P X
Senior housing X A X
RETAIL
Marijuana cooperative X X X
Restaurant, cafe, coffee shop, excluding drive-
through facilities
P A X
SERVICES
Banking and related financial institutions,
excluding drive-through facilities3
X X X
Daycare, including mini daycare, daycare center,
preschools or nursery schools
X P A
Home-based daycare X P P
Medical services – Clinic or urgent care3 X X X
Mortuary, funeral home, crematorium X X X
Professional offices X A A
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ACC 18.35.030, Uses Page 5 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Permitted, Administrative, Conditional and Prohibited Uses by Zone
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designations Standards for
Specific Land Uses P-1 I OS
Personal service shops X X X
Pharmacies X X X
TRANSPORTATION, COMMUNICATIONS AND INFRASTRUCTURE
Battery Energy Storage Systems, Tier I P P P See ACC 18.31.240
Battery Energy Storage Systems, Tier II A A X See ACC 18.31.240
Battery Energy Storage Systems, Tier III X X X See ACC 18.31.240
Utility facilities, substations, utility transmission or
distribution line
X X A See ACC
18.02.040(E)
Wireless communications facility (WCF) (See ACC
18.04.912(W))
* * * *See ACC 18.31.100
for use regulations
and zoning
development
standards.
Eligible facilities request (EFR) (Wireless
communications facility) (See ACC 18.04.912(H))
P P P
Small wireless facilities (ACC 18.04.912(Q)) P P P
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ACC 18.35.030, Uses Page 6 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Permitted, Administrative, Conditional and Prohibited Uses by Zone
P – Permitted
C – Conditional
A – Administrative
X – Prohibited
LAND USE
Zoning Designations Standards for
Specific Land Uses P-1 I OS
Emergency wireless communications facility
(EWCF)
X P X See ACC 18.04.912
and 18.31.100
OTHER USES THAT ARE NOT LISTED
Other uses may be permitted by the planning
director or designee if the use is determined to be
consistent with the intent of the zone and is of the
same general character of the uses permitted
P P P
Notes:
1 Minimum lot area not applicable; duplexes must meet other development standards of the I zone.
2 Minimum lot area not applicable; apartments must meet other development standards of the I zone,
dwellings; provided, that 2,400 square feet of lot area is provided for each dwelling unit.
3 Permitted within a public college or university as an amenity or service provided to students: A stand-alone
bank or medical services/clinic is not permitted.
4 One single-unit detached dwelling unit per existing legal lot. No residential subdivisions permitted in the
open space zone.
(Ord. 6959 § 1 (Exh. A), 2024; Ord. 6894 § 1 (Exh. B), 2022; Ord. 6799 § 9 (Exh. I), 2020; Ord. 6716 § 1 (Exh. A),
2019; Ord. 6677 § 3, 2018; Ord. 6642 § 11, 2017; Ord. 6434 § 1, 2012.)
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
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ACC 18.35.030, Uses Page 7 of 7
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 59 of 758
MEMORANDUM
TO: Judi Roland, Chair, Planning Commission
Bill Stewart, Vice-Chair, Planning Commission
Planning Commission Members
FROM: Gabriel Clark, Planner II
Department of Community Development
DATE: November 18th, 2025
RE: City File No. ZOA24-0004 – City of Auburn Battery Energy Storage Code
I. INTRODUCTION AND BACKGROUND
Battery Energy Storage Systems also known as BESS are systems of rechargeable batteries that
help to moderate the demand for electricity on our grid. During peak usage or extreme weather
events, BESS can react quickly, providing additional electricity. In extreme cases BESS protect
sensitive equipment such as transformers, transmission lines, switches and other infrastructure
from overload preventing blackouts or long-term service outages.
BESS are found in a variety of applications and are scalable based on the need. On the smaller
scale, they can be installed at a private residence, constructed at a wastewater treatment plant
or a hospital, to a stand-alone storage facility in a larger scale application.
In response to industry interest in developing these facilities within the City, staff proposes to
revise Title 18 “Zoning” to reflect the specific uses of these facilities. The revisions include
identifying which zones would be best suited for the size threshold and appliable land use
intensities. King County Ordinance (Attachment 2) for example, identifies 2 Megawatts (MW) as
the transition point between what is considered accessory use as seen in figure 1 to commercial
applications seen in figures 2 and 3.
Figure 1 Residential BESS Figure 2 Commercial BESS
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Figure 3 Commercial BESS
To fully understand how BESS interacts with the grid, the diagram on the following page depicts
an outline of the energy grid in a simplified manner. Within the grid are four elements (1)
generation, (2) transmission, (3) distribution, and (4) consumption that needs to be defined.
(1) Generation occurs at established power generation facilities such as wind and solar
stations located east of the Cascades and as far as Stillwater County, Montana.
(2) The electricity generated needs to travel from its source, to the location of demand. This
can be over many hundreds of miles and requires high voltage transmission lines.
(3) When the high voltage electricity enters the region of demand (Auburn) it needs to be
brought down to save levels for distribution.
(4) Consumers, both residential and commercial demand the electricity and demand can
shift rapidly given the environmental conditions.
Figure 4 Diagram of a Simplified Grid for full context
see attachment 14
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In 2019 and forward, the Washington State Legislature passed a series of laws affirming the
region’s commitment to climate resiliency and reduction in carbon emissions.
• The Clean Energy Transformation Act (SB 5116, 2019) - defines specific milestones
which require the State’s electricity supply to be free of greenhouse gas emissions by
2045. (Attachment 3)
• The Climate Commitment Act (SB 5126, 2021) - established the cap-and-invest
program, a market-based system that cost-effectively limits and lowers climate pollution
and generates revenue for climate and air quality projects. (Attachment 4)
As a result, enormous pressure is building for the region’s utility providers and local jurisdictions
to work together to become free of greenhouse gas emissions by the mid-century. Puget Sound
Energy (PSE) produced its first Integrated Resource plan (IRP) (Attachment 5) which identifies the
regional needs, its shortcomings, and sectors of energy production to reduce impacts on its
customers while reducing total carbon emissions.
The IRP identifies the trajectory of investments into cleaner natural gas, battery storage systems
and renewable energy sources.
Changes in the wholesale electricity market within the Western Interconnect (WI) means the
region is tightening supply as customers require power from clean energy sources. This includes
governments, industries, and customers. “Since 2016 nearly 15,000 MW of clean energy
resources, namely intermittent wind and solar, and 500 MW of batteries have been added to the
WI. At the same time, 12,000 MW of traditional dispatchable coal and natural gas resources have
been retired or mothballed.”
As a result of a tightening
supply, volatility has also
increased. On average,
wholesale energy prices
remain low in the Pacific
Northwest. However, spikes in
energy prices are becoming
more frequent. “Notable
events include the summer of
2018, when high regional
temperatures coincided with
forecasted outages at Figure 5 Transmission Interconnections in the United States
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Colstrip, and March 2019, when regional cold temperatures coincided with reduced Westcoast
Pipeline and Jackson Prairie storage availability. Most recently, in August 2020, a west-wide
heatwave cased many entities in the region to ta a range of actions from energy alerts to rolling
blackouts. To combat the future energy needs as the region transitions to clean energy sources,
PSE has identified six elements in the preferred energy portfolio. More information on these
elements can be found in the IRP.
(1) Accelerated Acquisition of Energy Conservation
(2) Increased Demand Response
(3) Integration of Distributed Energy Resources (BESS)
(4) Significant Investments in Renewable Resources
(5) Additional Need for Flexible Capacity
(6) Firm Resource Adequacy Qualifying Capacity Contracts.
The table on the following page shows a summary of the forecasted need for additional electrical
sources in the preferred portfolio. The capacity if resource additions is measured in terms of peak
hourly capacity over a planning horizon of 24 years. The preferred portfolio illustrates a diverse
mix of demand and supply side resources that meet the project capacity needs of the region.
Resource additions are added incrementally across three planning periods; 2022-2025, 2026-
2031, and 2032-2045.
Demand-side resources which includes a broad energy efficiency program and implementation
which may free 1,757 MW of energy that may have otherwise been wasted. This may include
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local and state policies on energy efficiency. Solar readiness and photovoltaic systems installed
on customer’s roofs or properties account for a planned 680 MW of total capacity resources.
BESS also makes 14% of the total capacity resource additions in the distributed resource
application and is significantly more responsive to changing demands than the development of a
large-scale generating station.
The Economic Development Element of the Comprehensive Plan (Attachment 6) describes
Auburn as a proud blue-collar community; leading in manufacturing employment since the
construction of the freight terminus for the Trans-Continental Railroad in the early 20th Century.
This momentum has not shifted as our community strength and core values continue to be
reflected in our land use practices, and economic development achievements. Our residents are
highly educated and experienced in manufacturing, construction, and wholesale trade and
deserve to continue to be supported by policies that promote the rapidly changing construction
and manufacturing industry. Figure 7 depicts the top industries by sector within the City.
As a result of regional manufacturing and other industries, Auburn’s median household income in
2021 was $79,415. The high concentration of the well-paying jobs in the City reflects a job to unit
of housing ratio at 1.48 which means the region benefits from the City’s continued evolution as a
manufacturing center for the Puget Sound. As this relates to affordability, the City recognizes the
need for attainable housing and has implemented land use and zoning changes to increase the
capacity of housing throughout the City (Attachment 7 – Housing Needs and Availability
Assessment).
In harmony with the existing conditions identified by the IRP, and market pressures for
development of Commercial BESS facilities (Attachment 15), the City does recognize the need to
update its Zoning Ordinance. Title 18 “Zoning” does not have a clear path forward for private
developers or utilities to develop these facilities within the City. The Department of Community
Figure 6 Electric Preferred Portfolio
Figure 7 Top Industry Sectors in Auburn (2002-2020)
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Development is working to develop additional land use policies to guide the siting, construction,
and operation of these facilities.
As a result, staff requested City Council of the City of Auburn to pass a 6-month development
moratorium on the acceptance, processing, and approval of BESS until proper development
standards are implemented. (See attachment 8)
As staff continued to research the development of the code, it became understood that
discussion with industry leaders was essential to understand the implications of developing or
prohibiting BESS.
In October of 2025, staff organized a roundtable meeting with industry leaders to discuss the
future of BESS in our community. A copy of the notes generated from the meeting has been
provided to you as Attachment 10. To summarize the discussion:
(1) Labor unions representing construction trades were supportive of the City to continue to
research these facilities as they provide expert technical training and experience.
(2) PSE provided information on the need for cities and counties to permit BESS near areas
near existing infrastructure and expressed the deep need for grid stabilization that BESS
can create.
(3) The Muckleshoot Tribe of Indians expressed their desire for microgrids and also shared
concerns of potential environmental impacts related to fires and construction.
(4) Valley Regional Fire Authority also expressed concerns with fire hazards and clarified of
new state requirements in the International Fire Codes (IFC) Chapter 1207 and National
Fire Protection Association (NFPA) Chapter 855.
Staff requested council to consider a six-month extension to the moratorium. Which is set to
expire at the beginning of May 2026. (See attachment 9)
Staff conducted a survey which included 101 community development offices throughout the
State. The survey resulted in 10 responses, and 13 separate conversations on how each of the
jurisdictions regulate BESS. The data collected shows BESS, when permitted are subject to a
variety of land use approvals. These approvals include Type II and Type III processes and are
typically applied to commercial and industrial land use designations, though there are several
exceptions. (Attachment 11)
The applicable zoning classification for BESS varied between Cities and Counties. Counties that
permitted BESS did so broadly and allowed BESS to be installed alongside solar generation
facilities in rural areas for example. In cities like Sumner, Puyallup, Mountlake Terrace additional
land use approvals are required and mainly concentrate in the commercial and industrial zones of
the City.
Another trend that was observed in the data was the definition of BESS. Some jurisdictions allow
BESS to be included within “Substation or other Public Utility”, and other jurisdictions define
BESS separately. While the code and its applications are unique to the jurisdiction that utilizes it,
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the City of Auburn intends to define BESS as a separate land use activity. The separate definition
would direct these infrastructure investments in areas of the City that have existing supportive
infrastructure and space where the potential visual, noise, and potential environmental impacts
are consistent with existing land use designations.
Title 18 “Zoning,” divides the City into zones where the location, height, and use of buildings, the
use of land, the size of setback areas, and other open space, and the provision of off-street
parking and loading are regulated and restricted in accordance with the Comprehensive Plan for
the City. These zones and regulations are deemed necessary and are made with reasonable
consideration, among other things, as to the character of each zone and its particular suitability
for specific uses (such as BESS), the need for such uses, the common rights and interests of all
within the zone as well as those of the general public, and with the view of conserving and
encouraging the most appropriate use of land throughout the City and to prevent and abate public
nuisances.
While staff recognizes the opportunities and investment BESS may bring, the City wants to
ensure development is orderly and reflects the intent of the Zoning Ordinance. The purpose of the
Zoning Ordinance is outlined in Section 18.02.030; BESS is described and how it meets or does
not meet the purpose of Title 18.
Purpose Statement Conformance with Title 18
Provide adequate public
facilities and services,
including utilities, roads,
schools, and parks in
conjunction with
development;
BESS provides emergency back-up generation during periods of
black-outs or power outages allowing public facilities and
services to continue to operate. This includes services such as
City administration, hospital operation, Fire Department
Administration, or regional load shedding.
In conjunction with residential development, BESS may pose
development challenges. Depending on the proposal, BESS
can occupy areas that would otherwise be used for residential
purposes.
To ensure BESS is able to meet the provisions of this title,
additional land use review is required for specific zones. A table
on page 8 of the report outlines the basic information pertaining
on project review types ensuring compatibility with the spirit
and intent of each zoning classification.
Provide housing with
essential light, air, privacy,
and open space;
The zones in which permitted BESS will have specific
regulations developed to ensure the provided housing
continues to support light, air, privacy and open space. The
measures include setbacks, screening, and additional
landscape requirement.
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Facilitate safe and efficient
movement of traffic on the
City’s streets
Throughout the City of Auburn, many of our traffic signals use
BESS as a way to continue normal operation even with energy
disruption.
Traffic impacts seen by commercial BESS would be negligible
after the site is in operation. Maintenance and inspection
teams would be the only of the few seen at the site during
normal operation. There may be temporary traffic impacts or
revisions during the construction periods.
Stabilize and enhance
property values
The argument that BESS decreases or improves property
values is multifaced and shall be reviewed on a project by
project basis. BESS that conforms to the screening and
landscaping requirements of the DUC zone may not have as
large of a potential negative impact to property values in the
surrounding vicinity. Compared to a Utility-scale facility that is
exposed and occupies a large portion of the area may have
some negative impacts and may not be considered under a
proposal. While impacts vary by context, it is important to
understand appropriate siting and design can mitigate potential
negative effects.
Facilitate adequate
provisions for doing public
and private business and
thereby safeguard the
community’s structure upon
which the prosperity and
welfare of all depends
BESS, when meeting the adequate provisions of the Title can
safeguard the community’s structure upon which the
prosperity and welfare depends. Allowance of BESS and
alternative energy systems can indeed capture development
and financial capital furthering Auburn’s manufacturing,
construction, and administrative industries. These industries
provide well-paying jobs and will help Auburn transition to
clean energy infrastructure.
Through such
achievements, help ensure
safety and security of home
life. Foster good citizenship,
and create and preserve a
more healthful, serviceable,
and attractive municipality
and environment in which to
live.
The response to ensure BESS aligns with the purpose of the
Zoning Ordinance in Title 18, includes a specific look into the
operations and available site conditions that are unique to each
site. Involving the community when input is needed fosters
good citizenry and active public discourse.
BESS also could allow the continuation of governmental
services in times of crises aiding to the safety and security of
the home life.
Figure 8 Alignment of BESS with Title 18
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As reviewed in the section above staff understands the need for the City’s Zoning Ordinance to be
updated to reflect the policies and goals of climate and energy resilience. Following, is a staff
analysis on how BESS integrates with the community for each zone. In most cases, BESS will be
applied as an accessory to a primary use such as a residence to emergency back-up for
commercial purposes and would be permitted in all zones.
As mentioned earlier, King County has adopted 2 MW (Attachment 1) as the threshold which
separates accessory use from commercial use. In the context of Auburn, staff proposes the
threshold to be delineated at 1 MW.
Commercial uses of BESS are the uses accessory or standalone which surpass the threshold
quantity of 1 Megawatt (MW). Commercial applications of BESS are substantially larger than
what is deemed as “accessory use” per ACC 18.04.020:
“Accessory use” means a use, a building or structure, or part of a building or other
structure which is subordinate to and the use of which is incidental to that of the main
building, structure or use on the same lot, including a residential garage. If an accessory
building is attached to the main building by a common wall or roof, such accessory
building shall be considered a part of the main building. Parking areas will not be
considered an accessory use under this definition. See related definitions for “Accessory
use, manufactured home community” and “Accessory use, residential.”
The following table presents a visual representation of the proposed zones and project review
requirements for Commercial applications of BESS within the City. The use is analyzed further
with the intent of each appliable zone. These determinations are not final and may be subject to
change.
As a reference, PSE provided staff with a model ordinance as a recommended guidance
document for amending City code to allow for BESS throughout the City. Seen in Attachment 12,
this ordinance is useful for understanding the legal requirements, but does not account for the
scope of BESS in the individual zones as analyzed below.
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Zoning Classification Type I Type II Type III Not
Permitted
Downtown Urban Center X
C-1, Light Commercial X
C-2, Heavy Commercial X
I, Institutional X
M-1, Light Industrial X
M-2, Heavy Industrial X
LF – Airport Lading Field X
OS – Open Space X
P-1, Public Use X
R-1, Residential 1 DU/Acre X
R-2, Residential Low X
R-3, Residential Moderate X
R-4, Residential High X
R-NM Neighborhood Mixed Use X
RC, Residential Conservancy X
RF, Residential Flex X
Planned Unit Development
District (PUD) X
R-MHC, Residential
Mobile Home Community X
Lakeland Hills PUD X
Figure 9 Land Use Activity and Applicability Table
Downtown Urban Center – Staff Analysis
The intent of the Downtown Urban Center (DUC) Zone is to create a distinct and strong identity
for downtown Auburn. The DUC Zone is intended to produce a concentration and mixture of
commercial, office, medical, retail, residential, and civic uses that attract shoppers, visitors, and
workers. Development that occurs within the downtown urban center zone often requires
architectural and site design review which can be either Type I or Type II decisions made by staff.
While the physical form of BESS may not always align with the intended character of a zone
particularly where space is typically reserved for shops, hotels, housing, or professional offices,
there is a strong case for allowing BESS through the Type III review process when serving
institutional needs.
BESS can provide critical emergency and backup power to essential facilities such as hospitals,
City Hall, and other public buildings that require uninterrupted power during outages. Without the
option to site BESS in this area, these institutions would remain reliant on diesel generators,
which are noisy, emit air pollutants, and require regular fuel replacement every 6–12 months
unless treated with stabilizers.
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There are specific sites, and applications of BESS that require additional review and public input
which supports the decision for a Type III Quasi-Judicial review and decision made by the hearing
examiner.
For these reasons, staff recommends Commercial BESS be conditionally permitted in the DUC.
C-1, Light Commercial – Staff Analysis
Support for siting BESS within the C-1 Zone is limited due to land use priorities and compatibility
concerns. Many C-1 parcels boarder low and moderate intensity residential zones and are
intended to serve as future local commercial destinations.
The purpose of the C-1 Zone is to promote a vibrant mix of small-scale, pedestrian oriented uses.
BESS facilities are typically enclosed and occupy the full extent of the parcel, which can diminish
the zone’s ability to meet its intended character and functions.
For these reasons, commercial scale BESS installations are recommended to be prohibited from
the C-1 Zone.
C-2, Heavy Commercial -Staff Analysis
The C-2 Zone supports a broad range of medium to high intensity land uses. While the zone is
primarily intended for retail, commercial, entertainment, and professional services, it also
accommodates high intensity uses such as low intensity industrial activities and utility
infrastructure through additional land use approvals.
A significant portion of the zone is located along the valley floor West of Auburn Way which
physically separates the C-2 Zoned parcels from a majority of the residentially zoned properties
and remains underutilized. This area is well-suited for the development of BESS, offering both
design flexibility and proximity to existing infrastructure.
For these reasons, staff recommends that commercial scale BESS be permitted through the Type
II administrative land use review process in the C-2 Zone.
I – Institutional Zone – Staff Analysis
The Institutional Zone (I) is designed to support public-serving uses such as educational, cultural,
and civic facilities. Distributed through the City, this zone meets both local and regional needs.
Historically, public and institutional facilities in this zone that require on-site power generation
have relied on diesel generators. This mirrors the patterns seen in the DUC zone. However, diesel
generators are noisy, polluting, and require frequent fuel replacement and maintenance.
For these reasons, staff recommends that commercial scale BESS be allowed in the I Zone
through the Type III conditional land use review process.
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M-1, Light Industrial and M-2, Heavy Industrial – Staff Analysis
The City’s industrial zones are designed to accommodate a broad spectrum of industrial,
manufacturing, and commercial activities. Residential uses are not permitted unless they are
already established, ensuring that these zones remain focused economic development and
operational flexibility as outlined in the Comprehensive Plan.
The M-1 Zone supports industrial and commercial uses based on the nature of operations rather
than the products produced such as warehousing and packaging. The M-2 Zone allows even
greater flexibility, including activities that process raw materials and may have more substantial
impacts on surrounding areas.
Given the purpose of these zones, the operational characteristics of BESS, and the presence of
high-capacity transmission infrastructure, industrial areas are well suited for BESS installations.
Impacts to nearby residents are minimal and unlikely to exceed those of existing permitted uses
in the M-1 and M-2 Zones.
For these reasons, staff recommends that commercial scale BESS be permitted outright in the
industrial zones.
LF – Airport Landing Field District – Staff Analysis
The Comprehensive Plan identifies airport hazards as threats to the safety of airport users and
nearby properties. Obstruction-type hazards, in particular, can reduce the available area for
aircraft to land, take off, and maneuver safely.
To protect public health, safety, and general welfare, it is essential to prevent the creation of such
hazards.
While BESS are not inherently dangerous, their presence within the LF District introduces
potential risks. In the event of an aircraft collision, BESS could trigger cascading impacts such as
fire, explosion, or widespread power outages. Additionally, the infrastructure required to support
BESS, particularly high-voltage transmission lines often exceeds 65 feet in height surpassing the
45-foot maximum height limit for the LF Zone.
For these reasons and regulatory constraints, staff recommends commercial scale BESS be
prohibited within the LF Zone.
OS – Open Space Zone – Staff Analysis
The OS zone is intended to permit land uses that tend to be managed in a largely undeveloped
character, including passive parks, watersheds, natural and urban conservancy shoreline
districts, significant wildlife habitats, and areas with significant development restrictions.
Permitting BESS in the OS Zone would require a demonstrated trend toward development, which
is inconsistent with the zone’s preservation-focused intent. While limited utility infrastructure,
such as substations, or transmission lines is allowed, these facilities are typically modest in
scale and impact compared to the potential footprint of a commercial scale BESS installation.
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Given the City’s commitment to preserving these areas to the fullest extent possible, staff
recommends commercial scale BESS be prohibited within the OS Zone.
P-1 Public Use Zone – Staff Analysis
The P-1 Zone, similar in purpose to the Institutional Zone, is intended to support public-services
at a community and regional scale. It provides space for cultural, educational, recreational, and
civic facilities such as schools parks, and government offices. The P-1 Zone is often located
within or near residential zones.
While BESS are generally developed in serve of the public good, their function does not
completely align with the core intent of the P-1 Zone, which emphasizes active, community
oriented uses. BESS would be best suited for facilities that rely on on-site power generation
mirroring the patterns in the Institutional and DUC zones. BESS could remove the reliance on
diesel generation and improve the overall reliability of the services provided.
For these reasons, staff proposes commercial BESS be allowed in the P-1 Zone through the Type
III conditional land use review process.
Residential Zones – Staff Analysis
Residential Zones are intended to support a range of housing types, from single family homes to
multistory apartment buildings while maintaining a focus on residential character and livability.
Commercial and industrial activities are either significantly restricted or outright prohibited in
these areas to preserve neighborhood integrity and minimize incompatible land uses.
Given these limitations, and the intent of residential zoning, staff recommends, that commercial
scale BESS be prohibited in all residential zones.
II. SUMMARY OF KEY CODE CHANGES
Staff is working to prepare revisions to Title 18 “Zoning,” and more specifically the following
Chapters:
• Chapter 18.04 ACC “Definitions”
• Chapter 18.07 ACC “Residential Zones”
• Chapter 18.23 ACC “Commercial and Industrial Zones”
• Chapter 18.29 ACC “DUC Downtown Urban Center District”
• Chapter 18.31 ACC “Supplemental Development Standards”
• Chapter 18.35 ACC “Special Purpose Zones”
The Washington State Amendments to the International Building Code IBC 2021 and the
International Fire Code, Washington Administrative Code (WAC) 51-54A-1207 (attachment 13)
contains development standards for stationary and mobile electrical energy storage systems
(BESS). Thus, reducing the burden of developing code that would eventually be in conflict with
the State’s trajectory of clean and resilient energy.
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Residential Zones
• Changes to this chapter include a revision to the use table ACC 18.07.020 to show
commercial applications of BESS as prohibited with “X.”
• There may be additional development standards for accessory uses referenced in the
supplemental development standards captured in Chapter 18.31 ACC.
Commercial and Industrial Zones
• Changes to this chapter include the use table ACC 18.23.030 to show “X” in the C-1
zone, “A” in the C-2 Zone, and “P” in both the M-1 and M-2 zones.
• There may be additional development standards referenced in the supplemental
development standards captured in Chapter 18.31 ACC.
DUC Downtown Urban Center District
• Changes to this chapter include the inclusion of BESS to the Uses/activities requiring an
administrative use permit.
• There may be additional development standards referenced in the supplemental
development standards captured in Chapter 18.31 ACC.
Special Purpose Zones
• Changes to this chapter include the use table ACC 18.35.030 to show “X” in the P-1 zone,
“X” in the I zone, and “X” in the OS zone.
• There may be additional development standards for accessory uses referenced in the
supplemental development standards contained in Chapter 18.31 ACC.
Supplemental Development Standards
• The inclusion of additional siting and screening requirements. Such as accessory uses of
BESS being required to be sited behind the front façade of the structure.
• Minor changes to required landscaping to prevent taller shrubbery from overtopping the
wall.
• Code will include references to code books such as the International Fire Codes 1207
and National Fire Protection Association 855 standards to reduce the administrative
burden on planning staff.
• Code will include specific standards for commissioning, decommissioning, and
operation. These standards will be referenced from IFC 1207 and other standards.
III. TEXT AMENDMENT
Draft text amendments have not been prepared for this meeting. Planning Services expects a
draft version of code to be presented to Planning Commission at the January 6th meeting.
IV. STAFF REQUEST
Staff requests Planning Commission to read through the items listed in the memo and
corresponding attachments.
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V. ATTACHMENTS
(1) Staff Presentation
(2) King County Ordinance No. 19824
(3) SB 5116 – Clean Energy Transformation Act
(4) SB 5126 – Climate Commitment Act
(5) 2021 PSE Integrated Resource Plan
(6) City of Auburn Economic Development Element
(7) Housing Needs and Characteristics Assessment Update
(8) City of Auburn Ordinance No. 6978 Establishment of 6-month Moratorium
(9) Round Table Meeting Notes
(10) City of Auburn Ordinance No. 6995 6-month Moratorium Extension
(11) Outreach and Survey Materials
(12) PSE Model Ordinance
(13) WAC 51-54A1207 Electrical Energy Storage Systems
(14) Outline and Functions of the US Energy Grid
(15) PSC Energy Storage System Location Study
VI. GLOSSARY OF KEY TERMS
(1) Accessory Energy Storage System (Accessory ESS / Accessory BESS)
A battery energy storage system with a capacity below the City’s proposed 1-
megawatt (MW) threshold. These systems are subordinate to a primary use—such as
a residence or small facility—and provide backup power or limited grid support.
(2) Administrative Use Permit (Type II Review)
An administrative land-use decision made by staff to determine whether a proposed
use—such as a Commercial BESS in the C-2 Zone—meets zoning and development
standards.
(3) Battery Energy Storage System (BESS)
A system of rechargeable batteries that stores electricity for later use. BESS improves
grid stability, captures excess renewable energy, and provides backup power for
homes, businesses, and essential facilities.
(4) Clean Energy Transformation Act (CETA)
Washington State legislation (SB 5116, 2019) that requires electric utilities to
transition to 100% clean electricity by 2045, increasing demand for renewable energy
and storage technologies.
(5) Climate Commitment Act (CCA)
Washington State legislation (SB 5126, 2021) establishing a cap-and-invest program
that limits carbon emissions and funds climate and air-quality initiatives.
(6) Commercial Energy Storage System (Commercial ESS / BESS)
A battery energy storage system that exceeds the City’s proposed 1-megawatt (MW)
threshold. These systems may serve utility-scale or standalone commercial functions
and require higher-level land-use review.
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(7) Conditional Use Permit (Type III Review)
A quasi-judicial land-use process requiring a public hearing and decision by the
Hearing Examiner. This review level is recommended for siting Commercial BESS in
zones where community input and compatibility review are necessary.
(8) Distributed Energy Resources (DERs)
Small-scale energy technologies located near where energy is consumed, such as
rooftop solar or BESS. DERs improve grid flexibility and local resilience.
(9) Downtown Urban Center (DUC)
A mixed-use zone intended for commercial, residential, civic, and medical uses.
Commercial BESS may be permitted through Type III review when serving institutional
or public-service needs.
(10) Energy Storage System (ESS)
A general term for installations that store energy for later use, including batteries,
control systems, and power-conversion equipment. ESS systems help balance supply
and demand on the electrical grid.
(11) Industrial Zones (M-1 Light Industrial and M-2 Heavy Industrial)
Zones intended for industrial, manufacturing, and commercial uses. These areas
contain compatible infrastructure and are proposed to allow Commercial BESS
outright.
(12) International Fire Code (IFC) Section 1207 / NFPA 855
State-adopted safety standards governing the design, installation, operation, and fire-
protection requirements for energy storage systems. These standards will be
referenced in Auburn’s zoning updates.
(13) Integrated Resource Plan (IRP)
Puget Sound Energy’s long-term energy planning document, identifying future energy
needs, renewable resource integration, and the role of BESS in meeting regional
capacity and reliability goals.
(14) Megawatt (MW)
A unit of electrical power equal to one million watts. Used to differentiate between
accessory-scale (<1 MW) and commercial-scale (>1 MW) battery storage facilities.
(15) Moratorium
A temporary halt on accepting or processing specific development applications.
Auburn established two consecutive six-month moratoriums on BESS projects to
allow time for research and zoning updates.
(16) Open Space (OS) Zone
A zone intended to preserve passive parks, watersheds, habitat areas, and
environmentally sensitive lands. Commercial BESS is proposed to be prohibited in
this zone.
(17) Public Use (P-1) Zone
A zone intended for civic, recreational, and community-serving public facilities.
Commercial BESS may be allowed through Type III review when supporting essential
public uses.
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(18) Quasi-Judicial Review
A formal land-use decision-making process involving public hearings and fact-finding,
typically associated with conditional use permitting for projects such as Commercial
BESS in sensitive zones.
(19) Residential Zones
Zones intended primarily for housing. Commercial BESS is proposed to be prohibited
in all residential zones, while accessory-scale BESS remains allowed.
(20) Supplemental Development Standards (ACC 18.31)
Citywide development requirements that apply across multiple zones, including
screening, siting, landscaping, and safety standards applicable to BESS installations.
(21) Transmission, Distribution, Generation, and Consumption
The four functional components of the electrical grid:
• Generation: where electricity is produced.
• Transmission: long-distance, high-voltage transport.
• Distribution: local delivery at safe voltages.
• Consumption: end-use by households, businesses, and institutions.
BESS supports all stages by storing and releasing energy as needed.
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C E L E B R AT I O NPLANNING COMMISSIONENERGY STORAGE SYSTEMCODE UPDATEPRESENTED BYGABRIEL CLARK, PLANNER IIDECEMBER 2, 2025Department of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementATTACHMENT 1
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ACCESSORY AND COMMERCIALSERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATIONAccessoryCommercialPage 80 of 758
COMMERCIAL BESSPage 81 of 758
CROSS SECTION OF A BESS CABINETPage 82 of 758
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATIONPRIMARY FUNCTIONS VISUALIZEDPage 84 of 758
WHAT IS THE DEMAND? SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATIONPage 85 of 758
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C E L E B R AT I O NDepartment of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementQUESTIONS? Page 88 of 758
MEMORANDUM
TO: Judi Roland, Chair, Planning Commission
Bill Stewart, Vice-Chair, Planning Commission
Planning Commission Members
FROM: Gabriel Clark, Planner II
Department of Community Development
DATE: December 26th, 2025
RE: City File No. ZOA24-0004 – City of Auburn Battery Energy Storage Code
I. INTRODUCTION AND BACKGROUND
Battery Energy Storage Systems (BESS) are systems of rechargeable batteries that balance the
demand for electricity on our grid. During peak usage or extreme weather events, BESS can react
quickly, providing electricity. In extreme cases BESS protects sensitive equipment such as
transformers, transmission lines, switches and other infrastructure from overloads, preventing
blackouts or long-term service outages.
At the December 2nd meeting, staff presented background information which described the
purpose of the code updates. At this meeting staff will introduce the land use tables of each zone
and the proposed “project permit decision” (Title 14 ACC) applicable to each tier of BESS.
Figure 1 BESS, Tier I [residential accessory BESS cabinet]
Figure 2 BESS, Tier II [commercial BESS cabinet]
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Figure 3 BESS, Tier III [utility BESS station, image includes BESS cabinets, accessory buildings, and substation connections]
How is the Capacity of BESS Measured?
The capacity of BESS is measured in two separate ways, one being a Watt-Hour (Wh) and the
second being a Watt (W).
A Watt-hour is the capacity of electrical energy in watts (W) BESS can store and discharge
over time (h). A typical BESS operates in capacities of kilowatt-hours (kWh) and a megawatt-
hours (MWh). Think of this portion of BESS as a reservoir to a dam, which can contain many
hundreds to millions of gallons of water to be sent over the spillway.
A Watt (W) is the maximum amount of energy that BESS can charge or discharge. A typical
BESS has charging and dishcarging capacities in kilowatts (kW) to megawatts (MW). Think of this
portion of BESS to the spillway of a dam, this portion of the dam controlls the amount of water
that can exit the system.
The appropriate capacity to regulate is the Wh component of BESS since it limits the amount of
stored energy at the site. This size limitation also restricts the number of BESS cabinets and the
scale of the facility which is more appropriate when considerting the siting within the City. WAC
51-54A-1207 has established precident to regulate this capacity as it targets the sizing of these
systems.
If the City were to regulate only the W component, then the threshold quantities would be a muut
point and BESS of larger scales could be installed in areas the City origionally saw as unfit for
operation leading to an inneffective code.
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Regulatory Breakdown
The regulations that determine the design, siting, construction, and operation are based on
several standards including Washington Administrative Code (WAC), the International Building
Code (IBC), International Fire Code (IFC), National Fire Protection Association (NFPA),
Underwriters Laboratories (UL), and Auburn City Code (ACC).
State Regulations
Chapter 51-54A WAC contains the State building code and its amendments and regulatory
information pertaining to electrical energy storage systems. These regulations are proposed do be
adiopted by reference to Auburn City Code.
As shown in Table 1207.1.1 (Figure 4), the State requires all electrical energy storage systems
exceeding the prescribed thresholds to comply with the minimum standards of the section.
These are dependant on the type of technology used. The minium standards of WAC 51-54A-
1207 include submitting 1) construction documents, 2) a hazard mitigation analysis, 3)
commissioning and decommissioning plans and 4) testing standards, size and separation
requirements, and explosion control documents to the permitting jurisdiction.
Spillway
(Watt)
Reservoir
(Watt-hour)
Figure 4 Grand Coulee Dam [comparing watt-hour to a reservoir and watt to the spillway]
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Figure 5 Threshold Quantities Table [a table depicting energy storage capacities in kilowatt hours which trigger state requirements]
II. SUMMARY OF KEY CODE CHANGES
Staff is preparing revisions to Title 18 “Zoning,” to incorporate these changes.
• Chapter 18.04 ACC “Definitions”
• Chapter 18.07 ACC “Residential Zones”
• Chapter 18.23 ACC “Commercial and Industrial Zones”
• Chapter 18.29 ACC “DUC Downtown Urban Center District”
• Chapter 18.31 ACC “Supplemental Development Standards”
• Chapter 18.35 ACC “Special Purpose Zones”
Given that the City is granted the authority to develop regulatory standards, the proposed code
will contain the following standards to supplement the regulatory minimums provided by statute.
Threshold Quantities
The capacity thresholds for each tier of BESS are dervied from the State’s standards for each type
of battery technology (per WAC 51-54A-1207). These are the most used and readily available to
the consumer. Table 1207.1.1 (Figure 4) includes specific thresholds to which these standards
apply. Additionally, the state has set the precident to measure the energy storage capacity by
watt-hour versus watt. As described in the introduction and background, codes regulating watt-
hour are critical to establishing boundaries for the size and scope of BESS.
BESS, Tier I operate in energy capacities of up to the threshold quantities identified in Table
1207.1.1. BESS that are below the threshold quantities for their specific battery chemistry do not
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require the applicant to submit additional application materials such as a hazard mitigation plan,
commissioning plans, decommissioning plans, and other materials.
This is generally considered sufficient for residential accessory use and is comperable home
back up generators. Compliance with the building, electrical, fire, and City codes and UL
certification is required.
BESS, Tiers II and III are larger in scale and surpass the threshold quantities listed in Table
1207.1.1. As a result State law requires the proponent of the project to meet the minimum
requirements of WAC 51-54A-1207. The proposed City Code intends to adopt by reference each
of these standards and as amended to ensure any development is regulated by the latest
available standards.
Permitted Zoning Districts
Figure 5 depicts the land use approval process for each Tier of BESS.
BESS, Tier I is permitted in most zoning districts.
BESS, Tier II is allowed in the high density residential and commercial zones with exception of the
R-F zone. This tier would be allowed through the administrative use permit process contained in
Chapter 18.64 ACC.
BESS, Tier III is limited to the City’s highest intensity zones. This tier would be allowed as an
administrative or conditional use process contained in Chapter 18.64 ACC.
Figure 6 Land Use Approval Process
Zoning District BESS, Tier I BESS, Tier II BESS, Tier III
RC P X X
R-1 P X X
R-2 P X X
R-3 P A X
R-4 P A X
R-NM P A X
R-F P X X
C-1 P A X
C-2 P A C
C-AG P A X
M-1 P A A
M-2 P A A
P-1 P A X
I P A X
OS P A X
DUC P A X
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*P = Permitted, A = Administrative Review, C = Conditional Review
III. TEXT AMENDMENT
Draft text amendments are shown by strikeout/underline and are attached to this memo as
Attachments 2 through 6.
IV. STAFF REQUEST
Staff requests Planning Commission to review the items listed in the memo and corresponding
attachments.
V. ATTACHMENTS
(1) Presentation
(2) ACC 18.04.174 Text Amendment
(3) ACC 18.07.020 Text Amendment
(4) ACC 18.23.030 Text Amendment
(5) Chapter 18.29 ACC Text Amendment
(6) ACC 18.35.030 Text Amendment
(7) PSE Response
VI. GLOSSARY OF KEY TERMS
(1) Battery Energy Storage System (BESS)
A system of rechargeable batteries that stores electricity for later use. BESS improves
grid stability, captures excess renewable energy, and provides backup power for
homes, businesses, and essential facilities.
(2) International Building Code (IBC)
Guidelines and requirements for the design, construction, and maintenance of
buildings. Aiming to protect the health, safety, and well-being of the occupants and
the surrounding community.
(3) International Fire Code (IFC)
A set of regulations designed to safeguard life and property from fire and explosion
hazards. It covers various topics including emergency planning, fire department
access, automatic sprinkler systems, fire alarm systems, and the storage and use of
hazardous materials.
(4) Kilowatt Hour (kWh)
A unit of energy that represents the amount of electricity generated or consumed over
a period of one hour. One kilowatt hour is the equivalent energy to using a 1,000 watt
microwave for 1 hour. This is a smaller unit of measurement and is most found on your
monthly electrical bill. The average household in the US consumes 30 kWh per day.
(5) National Fire Protection Association
A nonprofit organization dedicated to eliminating death, injury, property damage, and
economic loss due to fire, electrical, and related hazards.
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(6) Megawatt Hour (MWh)
A unit of energy that represents the amount of electricity generated or consumed over
a period of one hour. One Megawatt hour is equal to 1,000 kilowatt hours. The same
1,000-watt microwave could operate for 1 thousand hours or approximately 300 to
1,000 homes for one hour.
(7) Stored Energy Capacity
The total capacity of a BESS in either kilowatt hours or megawatt hours.
(8) Supplemental Development Standards (ACC 18.31)
Citywide development requirements that apply across multiple zones, including
screening, siting, landscaping, and safety standards applicable to BESS installations.
(9) WAC 51-54A-1207
Washington State’s adopted safety standards for electrical energy storage systems.
Including fire protection, hazard mitigation, separation distances, and commissioning
requirements.
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C E L E B R AT I O NPLANNING COMMISSIONENERGY STORAGE SYSTEM CODE UPDATEPRESENTED BYGABRIEL CLARK, PLANNER IIJANUARY 6, 2026Department of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementATTACHMENT 1
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WATT-HOUR VERSUS WATTReservoir(Watt-hour)Spillway(Watt)Page 100 of 758
THRESHOLD QUANTITIESWAC 51-54A-1207SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATIONPage 101 of 758
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R-FR-NMR-4 R-3R-2R-1RCPPPPPPPTier IXAAAXXXTier IIXXXXXXXTier IIIZONING CLASSIFICATION RESIDENTIALPage 109 of 758
M-2M-1C-AGC-2C-1DUCPPPPPPTier IAAAAAATier IIAAXCXXTier IIIZONING CLASSIFICATIONCOMMERCIAL & INDUSTRIALPage 110 of 758
ZONING CLASSIFICATION –SPECIAL PURPOSEOSIP-1PPPTier IAAATier IIXXXTier IIIPage 111 of 758
QUESTIONS FOR CONSIDERATION Reservoir(Watt-hour)Spillway(Watt)Page 115 of 758
JANPresent code to Planning CommissionFEBPlanned Planning Commission MeetingMARPlanned Public HearingAPRPlanned Council Study Session and ActionPROPOSED TIMELINEPage 118 of 758
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C E L E B R AT I O NDepartment of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementQUESTIONS?Page 119 of 758
MEMORANDUM
TO: Judi Roland, Chair, Planning Commission
Bill Stewart, Vice-Chair, Planning Commission
Planning Commission Members
FROM: Gabriel Clark, Planner II
Department of Community Development
DATE: January 14th, 2026
RE: City File No. ZOA24-0004 – City of Auburn Battery Energy Storage Code
I. INTRODUCTION AND BACKGROUND
Battery Energy Storage Systems, also known as BESS, are systems of rechargeable batteries that
moderate the demand for electricity on our grid. During peak usage or extreme weather events,
BESS can react quickly, providing electricity. In extreme cases BESS protect sensitive equipment
such as transformers, transmission lines, switches and other infrastructure from overload
preventing blackouts or long-term service outages.
Figure 1 BESS, Tier I
Figure 2 BESS, Tier II
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Figure 3 BESS, Tier III
At the December 2nd, 2025, meeting, staff presented background information which described
the purpose of the code updates. At this meeting staff will introduce the land use tables of each
zone and the proposed “project permit decision” (Title 14 ACC) applicable to each tier of BESS.
At the January 6th, 2026, meeting, staff presented contextual information to describe how BESS
are sized, what the intention of the regulations were, and formalized land use approval pathways
for each tier of BESS. Staff also briefed Planning Commission with a memo from Puget Sound
Energy advising staff to increase the threshold quantities of each tier to align with existing end-
user installations. A primary concern was limiting capacities with the Tier I systems which are
permitted in residential zones.
At the February 3rd, 2026, meeting, staff will present the proposed development standards, staff
comments received, and notification of any public comments received during the SEPA process.
II. SUMMARY OF KEY CODE CHANGES
Staff is preparing revisions to Title 18 “Zoning,” to incorporate these changes.
Given that the City is granted the authority to develop regulatory standards, the proposed code
will contain the following standards to supplement the regulatory minimums provided by statute.
Land Use Tables
Revisions to Chapters 18.04 “Deffinitions,” 18.07 “Residential Zones,” 18.23 “Commercial and
Industrial Zones,” 18.29 “DUC Downtown Urban Center District,” and 18.35 “Special Purpose
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Zones” do not change substationally. Changes are limited to expanding “BESS” to “Battery
Energy Storage System” in the land use tables where BESS has not been defined.
Supplemental Development Standards
In conjunction with Community Development, Public Works, Valley Regional Fire Authority, and
Legal staff members, a set of supplemental standards to regulate the development of BESS
throughout the City have been developed. These supplemental standards also include
regulations adopted by the State of Washington and the International Code Councils and their
amendments.
The structure of the code includes general standards which apply to each of the three Tiers,
followed by two sections which offer specific requirements for each tier.
General Standards
General standards include references to citations such as the Washington Administrative Code
(WAC) 51-54A-1207, International Building Code (IBC), and the International Fire Code (IFC)
1207 which provides supplemental standards for BESS facilities, fire suppression, secondary
containment, and spill neutralization. These three codebooks provide the foundation for the
City’s regulations, as such adopting the WAC, IBC, and IFC by reference allows the City to
incorporate standards of the best available science without needing to perform a code cycle
update.
This subsection also places general restrictions on BESS. These restrictions inclde prohibiting the
construction or siting of BESS within critical areas and the floodplain. According to the United
States Department of Transportation, lithium batteries have been classified as a hazardous
substance. Per our floodplain development code, Chapter 15.68 ACC, hazardous materials and
substances are prohibited from being located within the floodplain.
Additionally, Chapter 16.10 ACC prohibits development within the City’s regulated critical areas
and its buffers. As a result, BESS will be subject to the standard buffer widths aplicable to each
critical area.
BESS facilities that are below the threshold quantities table identified in WAC 51-54A-1207
would be exempt from portions of the chapter.
The next three sections will provide context for the three tiers of BESS; Tier I, Tier II, and Tier III.
BESS, Tier I
BESS, Tier I is intended to serve residential and small commercial customers due to the
restricted energy storage capacity of 100 kWh. These systems are required to be installed in one
of the four prescribed locations specified by WAC 51-54A-1207. If located on the exterior of a
structure, then some amount of screening would be required. This could include a fence or
located behind the front façade of the structure.
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It should be noted that when the energy storage capacity of BESS, Tier I surpasses the thresholds
set by the threshold quantity table of WAC 51-54A-1207, the applicant would be required to
submit commissioning plans, construction documents, hazard mitigation analyses, as well as
meet additional requirements of the WAC.
BESS, Tier II and Tier III
BESS, Tier II is intended to serve moderate intensity residential and commercial customers as the
threshold is designated at 4 MWh. The structure of this section incorporates language from Title
18 “Zoning” ACC, the model ordinance, and the WAC.
Similarly, BESS, Tier III systems are systems with energy storage capacities beyond 4 MWhs and
are intended to serve micro and regional grids. Tier III systems follow the same list of
requirements to Tier II systems.
At this capacity, large-scale fire testing, vegetation control, secondary containment, access,
hydrant spacing, and financial securities are required.
System testing, location, fencing, and vegetation controls are standards contained in the WAC,
IFC, or IBC standards.
Staff has worked with the Valley Regional Fire Authority to determine the minimum applicable
standards for emergency vehicle access and availability of hydrants. Included in the proposed
code are two standards (1) access and (2) hydrant spacing.
Valley Regional Fire Authority had significant concerns regarding access to the site, especially if
the site is served by a dead-end road. If a fire were to break out, a secondary access point would
provide a safe alternative to approach the site and avoid any additional exposure to the smoke.
If a BESS facility is proposed in an area where hydrants do not meet the minimum commercial
hydrant spacing requirements contained within the City of Auburn Engineering Design Standards,
the applicant is required to install hydrants to the minimum specification.
Since BESS, Tier II and Tier III are larger systems intended to support moderate to large
commercial/residential projects and the grids, staff determined the applicant of such system
shall provide a financial security or bond equal to 125% of the estimated costs associated to
decommissioning. The decommissioning security will aid to protect the interests of the City and
the applicant in the event of failure or abandonment.
The financial security will operate in a similar manner to a mitigation or landscape bond. When
the BESS facility is decommissioned in accordance with the approved decommissioning plan the
city may release the bond back to the owner of the facility. In the event the facility is abandoned
or ceases to operate consistenly, the City reserves the right enter the facility to decommission
the facility and utilize the available bond to cover the costs associated with the site.
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The site may be in operation for a number of decades resulting the need for language where the
financial security can be renewed on a regular basis to ensure the security maintains its position
with rising costs due to inflation. Staff are refining the language to ensure the requirement is clear.
III. STAFF COMMENTS
Staff has colleced the first round of comments from Public Works department, Valley Regional
Fire Authority, Legal Departlent, Building Division, and Development Engineering Divisions of the
City.
To summarize the comments:
1. Public Works has concerns over the existence of critical areas on sites where a BESS
facility may be sited and whether the City has the authority to have additional restrictions
for these sites.
a. Staff response: BESS and their impacts on critical areas are a concern of the City.
Development of a site which contains critical areas shall conform to the minimum
local, federal, and state requirements. Within the City of Auburn Title 16
“Environment” of the Auburn City Code provides explicit restrictions on the
development of critical areas. For projects that do have temporary or permanent
impacts, ACC 16.10.100 provides standards for alteration or development of
critical areas which requires mitigation strategies, monitoring, and implements
replacement/enhancement ratios. BESS shall meet the standard buffer width
required by the applicable critical area.
To reduce risk, the City proposes to incorporate a financial security component
which will provide the property owner or City with a direct source of funds to
decommission and restor the site to prior conditions when the BESS was planned.
This financial security will be a required component of the decommissioning plan.
2. Public Works had a concern with the language pertaining to noise. Public Works Staff
pointed to Chapter 8.28 ACC “Noise” which contains what are considered public
disturbances.
a. Staff response: Planning will incorporate by reference Chapter 8.28 ACC “Noise”
into the proposed code.
3. Public Works and Development Engineering provided recommendations for updated
language pertaining to secondary contaimment for Tier II and Tier III systems.
a. Staff response: Planning staff will update the language to include requirements for
BESS facilities to meet the minimum standards of City standards, International
Fire Code (IFC) and NPDES requirements.
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4. Public Works Staff provided comments for the required decommissioning bond.
a. Staff response: The applicant and/or owner of the BESS project will be required by
code to obtain a financial security and will not be released until the criteria of the
decommissioning bond have been satisfied. The exact bond and duration of the
bond is still under review. Staff is working with the City’s Legal department to
identify what type of security is the most risk adverse.
5. Valley Regional Fire Authority (VRFA) provided comments regarding secondary
emergency vehicle access (EVA) and hydrant spacing.
a. Staff response: staff has incorporated VRFAs comments to include a secondary
EVA route and compliance with the City of Auburn Engineering Design Standards
for commercial hydrant spacting for sites that do not meet these standards.
IV. SEPA
A DNS has been distributed to agencies and parties of record for comment. In accordance to
WAC 197-11-340 the City will not act on the proposal for a period of 14 days. The comment
period began on January 28th and is set to expire at 5:00 PM February 11th 2026.
Staff will provide comments received from agencies and the public at the February 3rd Meeting.
V. TEXT AMENDMENT
Draft text amendments are shown by strikeout/underline and are attached to this memo as
Attachment 2.
VI. STAFF REQUEST
Staff requests Planning Commission to review the items listed in the memo and corresponding
attachments.
VII. ATTACHMENTS
(1) Staff Presentation
(2) ACC 18.31.240 Text Amendment
(3) Model Ordinance (PSE)
(4) WAC 51-54A-1207
VIII. GLOSSARY OF KEY TERMS
(1) Battery Energy Storage System (BESS)
A system of rechargeable batteries that stores electricity for later use. BESS improves
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ZOA24-0004
Page 7 of 8
grid stability, captures excess renewable energy, and provides backup power for
homes, businesses, and essential facilities.
(2) Buffer or Buffer Area, Critical Area
Means a naturally vegetated, undisturbed, enhanced or revegetated zone surrounding
a critical area that protects the critical area from adverse impacts to its integrity and
value, and is an integral part of the resource’s ecosystem.
(3) Critical Areas or Environmentally Sensitive Areas
Means areas that possess important natural functions and embody a variety of
important natural and community values. Such areas include wetlands, streams, fish
and wildlife habitat, geologically hazardous areas, aquifer recharge areas, and flood
hazard areas. If not conducted properly, development or alteration of such areas may
cause significant impacts to the valuable functions and values of these areas and/or
may generate risks to the public health and general welfare, and/or to public and
private property.
(4) Floodplain or Flood Prone Area
Means any land area susceptible to being inundated by water from any source.
(5) International Building Code (IBC)
Guidelines and requirements for the design, construction, and maintenance of
buildings. Aiming to protect the health, safety, and well-being of the occupants and
the surrounding community.
(6) International Fire Code (IFC)
A set of regulations designed to safeguard life and property from fire and explosion
hazards. It covers various topics including emergency planning, fire department
access, automatic sprinkler systems, fire alarm systems, and the storage and use of
hazardous materials.
(7) Kilowatt Hour (kWh)
A unit of energy that represents the amount of electricity generated or consumed over
a period of one hour. One kilowatt hour is the energy equivalent to using a 1,000-watt
microwave for 1 hour. This is a smaller unit of measurement and is most found on your
monthly electrical bill. The average household in the US consumes 30 kWh per day.
(8) National Fire Protection Association
A nonprofit organization dedicated to eliminating death, injury, property damage, and
economic loss due to fire, electrical, and related hazards.
(9) Megawatt Hour (MWh)
A unit of energy that represents the amount of electricity generated or consumed over
a period of one hour. One Megawatt hour is equal to 1,000 kilowatt hours. The same
1,000-watt microwave could operate for 1 thousand hours or approximately 300 to
1,000 homes for one hour.
(10) Special Flood Hazard Area (SFHA)
Means the land subject to inundation by the base flood. Special flood hazard areas are
designated on Flood Insurance Rate Maps with the letters “A” or “V” including “AE
Page 126 of 758
ZOA24-0004
Page 8 of 8
(Floodway),” “AO,” “AH,” “A1-99”, and “VE.” The special flood hazard area is also
referred to as the area of special flood hazard or SFHA.
(11) Stored Energy Capacity
The total capacity of a BESS in either kilowatt hours or megawatt hours.
(12) Supplemental Development Standards (ACC 18.31)
Citywide development requirements that apply across multiple zones, including
screening, siting, landscaping, and safety standards applicable to BESS installations.
(13) WAC 51-54A-1207
Washington State’s adopted safety standards for electrical energy storage systems.
Including fire protection, hazard mitigation, separation distances, and commissioning
requirements.
Page 127 of 758
AUBURN
VALUES
S E R V I C E
ENVIRONMENT
E C O N O M Y
C H A R A C T E R
SUSTAINABILITY
W E L L N E S S
C E L E B R AT I O NPLANNING COMMISSIONENERGY STORAGE SYSTEM CODE UPDATEPRESENTED BYGABRIEL CLARK, PLANNER IIFEBRUARY 3RD, 2026Department of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementATTACHMENT 1
Page 128 of 758
REFERENCE BOOKS AND STANDARDS
FEBPlanning Commission MeetingMARPlanned Public HearingAPRPlanned Council Study Session and ActionPROPOSED TIMELINEPage 137 of 758
AUBURN
VALUES
S E R V I C E
ENVIRONMENT
E C O N O M Y
C H A R A C T E R
SUSTAINABILITY
W E L L N E S S
C E L E B R AT I O NDepartment of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementQUESTIONS?Page 138 of 758
Page 139 of 758
Page 140 of 758
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Valley Regional Fire Authority · Fire Marshal’s Office
Creating the safest community to live, work, and visit.
2905 C Street SW, Auburn, WA 98001 · (253) 288-5870 · Fax: (253) 288-5970
February 20, 2026
Subject: Response to Planning Commission Questions, Battery Energy Storage
Systems (BESS)
The increasing deployment of commercial-scale Battery Energy Storage Systems
(BESS) introduces operational and public safety considerations that differ significantly
from traditional commercial development. Tier II and Tier III BESS facilities represent
high-energy industrial installations with the potential for thermal runaway, toxic vapor
release, prolonged fire conditions, and re-ignition. The Valley Regional Fire Authority
(VRFA) provides the following responses to the Planning Commission’s questions
regarding these facilities and the proposed standards under ACC 18.31.240.
1. Equipment and training availability to combat an event at a BESS site.
VRFA is an all-hazards agency and will respond to any emergency incident involving a
BESS facility within our jurisdiction. All suppression personnel are trained to the
Hazardous Materials Operations Level in accordance with WAC 296-824-30005, Safety
Standards for Emergency Response, and three members are trained to the Technician
Level. An incident involving a Tier II or Tier III BESS would be managed as both a fire
and hazardous materials event and would likely require automatic and mutual aid from
regional partners. These responses may involve specialized air monitoring equipment,
extended use of self-contained breathing apparatus, and coordination among multiple
agencies. Due to the unique hazards of BESS incidents, response efforts focus on
scene safety, air monitoring, protecting nearby property, and mitigating the fire or
hazardous condition in coordination with facility experts.
2. The time needed to extinguish and monitor the event.
Lithium-ion battery fires are not typically extinguished in the conventional sense.
Industry best practices and national experience demonstrate that affected battery units
should be allowed to burn while protecting exposures and preventing fire spread.
Documented commercial BESS incidents have required operational commitments
exceeding 12 hours, with continued monitoring due to the risk of delayed reignition.
Such incidents may require extended road closures, evacuation considerations, and
regional resource commitments that span multiple operational periods. These realities
underscore the importance of site design features that support sustained and safe
emergency operations.
3. Any concerns/support VRFA has with the proposed code.
VRFA collaborated with the City of Auburn Development Office to address concerns
regarding BESS facilities. The proposed ACC Supplemental Standard 18.31.240
Page 143 of 758
Valley Regional Fire Authority
2
incorporates provisions specifically requested by VRFA for larger Tier II and Tier III
sites. These provisions are intended to enhance firefighter safety by requiring a
secondary emergency response access route and ensuring adequate on-site water
supply, as outlined in Section 18.31.240(D)(7) and (8). VRFA supports these
amendments and believes they appropriately address the public safety considerations
associated with commercial-scale energy storage facilities.
VRFA appreciates the opportunity to provide technical input and remains available to
assist the Planning Commission with any further clarification if requested.
Respectfully,
Andrew Bergford
Fire Marshal
Valley Regional Fire Authority
Page 144 of 758
February 11, 2026
City of Auburn
25 W Main Street
Auburn, WA 98001
RE: Comments on Proposed Battery Energy Storage System Code Updates - City File No. ZOA24-0004
Puget Sound Energy (PSE) appreciates the opportunity to provide input on the City of Auburn's proposed
Battery Energy Storage System (BESS) code updates following the development moratorium. As the
state's oldest and largest energy utility serving Auburn residents and businesses, PSE is committed to
delivering safe and reliable service while supporting the City's clean energy and resilience goals.
PSE staff reviewed the proposed language addressing BESS development in the Auburn City Code (ACC).
Please consider the enclosed information as the City contemplates updates to its municipal code to
address the development of BESS within City limits.
PSE’s regulatory obligations
PSE is a regulated utility with obligations under WAC 480-100 and WAC 480-90 to serve customers
reliably and cost-effectively. We are also subject to Washington state’s climate policies like the Clean
Energy Transformation Act (CETA) to supply 100% clean electricity by 2045. These obligations require us
to support distributed energy resources like BESS that enhance grid flexibility, defer costly infrastructure
upgrades, and support customer resilience.
BESS contributions to Auburn Comprehensive Plan goals and policies
Auburn's Comprehensive Plan establishes clear values and goals across multiple elements that directly
align with the benefits provided by appropriately regulated BESS installations. The City's stated values
emphasize infrastructure that supports economic resilience (Economy), environmental stewardship
(Environment), and sustainable growth (Sustainability).
• Climate Element Integration: Auburn's Climate Element Vision explicitly commits the City to
"taking action to mitigate the worst impacts of climate change" while "living out its commitment
to its core community values of sustainability, environmental stewardship, and economic
vibrancy." BESS installations directly support this vision by enabling clean energy integration and
enhancing grid resilience. Policy C-42 specifically calls for the City to "support local businesses'
efforts to generate and store renewable electricity on-site, which can provide back-up power
during emergencies and help ensure continuity of operations." Policy C-65 advocates for
"increased grid reliability through...environmentally responsible storage technologies that
reduce peak load and provide grid flexibility," explicitly recognizing BESS as beneficial
infrastructure.
• Renewable Energy and Resilience Goals: The Climate Element's Goal 17 aims to "reduce
greenhouse gas emissions by transitioning to renewable energy sources" and Policy C-57 calls to
Page 145 of 758
"expand local onsite renewable energy production." Policy C-50 promotes "improved energy
efficiency in existing commercial and residential buildings by offering expedited permitting
processes, limiting administrative barriers, and reducing costs for residential solar projects."
BESS systems are essential complements to solar installations, enabling customers to maximize
their renewable energy investments.
• Economic Development and Green Jobs: The Economic Development Element's Vision calls for
"economic growth carried out in a climate friendly manner" and Policy ED-7 emphasizes
attracting businesses "designing, creating, selling and distributing climate-friendly products." The
Climate Element's Policy C-40 supports developing "a green workforce" and Action 13.1
specifically supports "sustainable practices, green skills development, and the low carbon
transition."
• Utilities Element Integration: Policy U-2 requires that utility services be provided "in an
equitable manner that prioritizes easy access, and that offers pricing structures that strive to
reduce barriers." Policy U-1 calls for utility facilities to support coordinated infrastructure
expansion consistent with planned growth.
PSE Recommendations
1. Modify the definition of BESS provided in ACC 18.04.174
The proposed definition of BESS in ACC 18.04.174 is overly specific or prescriptive with regards to the
purpose of BESS. PSE advises that the following changes (additions in blue, deletions noted with a
strikethrough) be made to the definition in the draft code section:
“BESS means a facility designed and constructed for the purpose of storing and deploying
rechargeable energy storage system consisting of electrochemical storage batteries, battery
chargers, controls, and associated electrical equipment designed to provide electrical power to a
building or the grid. Battery energy storage system uses may include associated electrical
equipment including, but not limited to, generation interconnection lines, transformers, and
cooling equipment as facility components. The system is typically used to provide standby or
emergency power, an uninterruptable power supply, load shedding, load sharing, or similar
capabilities.”
2. Modify the upper capacity limits for BESS, Tiers I & II articulated in the draft section ACC 18.31.240.C &
D
PSE recommends that the City of Auburn modify the upper capacity limits for both Tiers I and II BESS in
ACC 18.31.240.D as outlined in the table below. These adjustments would better align Auburn's
regulatory framework with the size of distribution level behind-the-meter and front-of-the-meter BESS
installations, which are essential for achieving both local and state clean energy goals. Both types of BESS
are critical for the utility's clean energy transformation, with an estimated need for approximately 1,500
MW of storage by 2030 to support Washington's Clean Energy Transformation Act requirements.
Page 146 of 758
BESS Tier Tier maximum capacity proposed in
draft code section ACC 18.31.240
Tier maximum capacity range proposed
by PSE
Tier I 100 kWh 200-400 kWh
Tier II 4 MWh 12-20 MWh
Tier I: Behind-the-meter BESS installations
typically range from 5-100 kW with 4-hour
duration capabilities (20-400 kWh). However,
the current 100 kWh threshold constrains the
ability of Auburn residents and small
businesses to install appropriately sized
systems that can provide meaningful backup
power during extended outages or maximize
the value of paired solar installations.
Increasing the Tier I threshold to 200-400 kWh
would enable Auburn customers to install
systems capable of supporting critical loads for
12-24 hours during emergencies, rather than
the limited 2-4 hour backup capability
provided by systems under 100 kWh. This
modification would support Auburn's
Comprehensive Plan Climate Element goals,
particularly Policy C-42 which calls for the City
to "support local businesses' efforts to
generate and store renewable electricity on-
site, which can provide back-up power during
emergencies," and Policy C-65 which
advocates for "increased grid reliability
through...environmentally responsible storage
technologies." Additionally, this change would
maintain the streamlined permitting process
for residential-scale installations while
ensuring that larger utility-scale systems requiring more extensive review and safety measures remain
appropriately regulated under Tier II and III categories.
Tier II: Distribution-level, front-of-the-meter BESS resources typically range from 1-5 MW with 4-hour
duration, which translates to 4-20 MWh of energy capacity. Auburn's current 4 MWh threshold for Tier II
systems would effectively prohibit most utility-scale installations that could provide meaningful grid
benefits, forcing these beneficial projects into the more restrictive Tier III category or preventing them
entirely in many zones.
50 kW/332 kWh battery installed in 2023 at Samish
Island Fire Station to test new microgrid.
Behind-the-meter batteries (5-100 kW/20-400 kWh)
sized for the facility’s load with minimal footprint.
Page 147 of 758
Expanding Tier II to accommodate systems up to 12-20 MWh would enable Auburn to host appropriately
scaled utility infrastructure that can deliver community-wide grid resilience benefits, support renewable
energy integration, and help defer costly transmission upgrades. This modification would position
Auburn for more efficient deployment of clean energy infrastructure deployment rather than creating
barriers to said deployment, while still maintaining appropriate regulatory oversight through the existing
Tier II administrative permitting process.
The City of Auburn and PSE have shared goals to foster resilience, safety, and decarbonization of the grid
at a community level. The proposed code update draws from relevant state fire safety codes and from
other municipality precedents, and the draft code incorporates appropriate requirements for safety,
fencing, screening, lighting, and sound based on the scale, size, and location of the BESS installation. PSE
recommendation to increase maximum capacities of BESS Tier I and BESS Tier II not only aligns with the
proposed requirements, but also aligns the draft code with Auburn’s own comprehensive plan goals
referenced above.
Ongoing Collaboration
PSE requests that the City consider the unique benefits that appropriately regulated BESS can provide to
Auburn’s residents and businesses. We ask that the City engage with PSE technical staff to better
understand BESS operational characteristics and safety standards while drafting code updates, as well as
the ways in which BESS can contribute to Auburn’s stated Comprehensive Plan goals. We hope to help
the City foster the economic and resilience benefits that distributed energy resources can provide, and
to develop regulations that preserve community values while enabling beneficial technologies.
PSE looks forward to working collaboratively with the City to develop BESS regulations that protect
community interests while supporting energy resilience and clean energy goals. We welcome continued
engagement throughout this process and are available to provide technical expertise, operational data,
and policy guidance to support informed decision-making.
Front-of-the-meter BESS, roughly 1-5 MW with 4-hour
duration (4-20 MWh capacity), made up of a few
shipping containers (~700 sq ft/MWh).
2 MW/4.4 MWh lithium-ion BESS built in
2015 adjacent to existing Glacier
substation in Whatcom County.
Page 148 of 758
Please do not hesitate to contact me at (206) 716-2754 or at dylan.marcus@pse.com to discuss these
recommendations further.
Sincerely,
Dylan Marcus
Municipal Land Planner
Puget Sound Energy
Page 149 of 758
1
Gabriel Clark
From:Gabriel Clark
Sent:Friday, February 13, 2026 2:48 PM
To:'Zachary Pratt'
Subject:RE: Planning email regarding BESS code update and SEP24-0021
Good afternoon Zachary,
Thank you for providing your comments during the SEPA process. Your comment has been recorded and will be
transmitted to planning commission for consideration.
Please let me know if you have any further questions.
CODE QUESTIONS?
Book an online meeting: Virtual Permit Center - City of Auburn (auburnwa.gov)
Gabriel Clark, Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Office 253-470-2147| gclark@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map)
Customer Service Survey | Application Forms | Zoning Maps
From: Zachary Pratt <zachpratt25@gmail.com>
Sent: Wednesday, February 11, 2026 6:03 AM
To: Planning <planning@auburnwa.gov>
Subject: Planning email regarding BESS code update and SEP24-0021
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
As a long time resident of Auburn, I am deeply concerned that short term benefits were taking
precedence over permanent regional resource losses.
You are introducing a permanent hazardous material site capable of catching on fire at any time of day or
night that is inextinguishable, not containable and consequently exposing an entire region to forever
toxins that will affect every natural resource in King County and all neighboring counties.
BESS fires are a noticeable hazard in our community, as the resources used during a disaster are
complex, misunderstood and create a large culmative impact.
Page 150 of 758
2
Water doesn't put out the fire like a normal house fire, foam products for chemical fires don't work,
simply smothering them does effectively nothing. In many cases, the option is containment efforts and
let it burn.
The current guidelines for suppressing a Lithium Battery Storage Facility fire falsely use structure
firefighting standards, which do not work in this application.
A common structure fire such as a house or a commercial building advise fire department units to stage
100-300’ feet away from the burning structure to protect firefighters from heat and toxic smoke while the
engine pumps water to firefighters who wear protective gear and advance charged hose lines to the seat
of the fire.
But Battery Storage Facility fires create an excessive amount upwards and north of 2000 degrees. A fire
engine would melt and the personnel would burn to death if they tried to get within 100’-300’ of the
incident.
A safe distance would be 3,200’ - 5,000’ away which is not a plausible distance to spray water. Water
would just evaporate and turn into steam when in contact with such high heat.
Pictures of these facilities on Nextera’s website show them sitting on a slab of concrete out in the open
with rows of metal containers sitting feet away from each other.
There are no fire proof concrete walls to buffer them from sun, rain, snow and salty air.
There are no statistics about the long term integrity of the metal containers or how they are insulated or
treated to prevent corrosion.
Putting hundreds of units of temperature sensitive, flammable batteries in a metal box sitting outside
exposed to the variable temperatures we experience annually is a short sided idea. Especially given our
summers have gotten warmer over the years, management of these systems will be strained, opening up
to failure of these units.
They use water to cool them down. What happens to the water when it snows here? Can you imagine a
fire breaking out in freezing conditions?
Nextera, the company based in Juno Florida, has only just recently started building Litihum Ion Battery
Storage Facilities. They only have 50 across the United States. They are aggressively seeking property
across the nation to build as many as they possibly can. They made 7 Billion dollars last year.
Their builds show no infrastructure to contain the toxic water that is a bi product of trying to cool and
extinguish a fire. The toxic smoke would blow by prevailing winds hundreds of miles away while the site
would burn and hopefully not spread, but then how would you prevent spread to nearby target hazards
with heavy fuel loads such as the airport, or industrial areas these plants are supposed to be in.
By comparison, the oil refinery on March Point has large flammable liquid above ground storage tanks.
The grounds around them are designed to capture their contents should they fail. Fire suppression
systems are designed to pump water or extinguishing agents at pressure necessary to extinguish their
contents. Security and personnel are on duty 24 hours a day 7 days a week. The storage tanks are
Page 151 of 758
3
monitored physically and visibly. A responsible party is onsite at all times. All personnel are trained
annually to handle an emergency.
The type of energy storage you are creating has no redundancy to prevent catastrophic damage or
prevent spreading. These are major discrepancies left to emergency response agencies that are under
funded, under staffed, under trained and ill informed.
This is creating an unprecedented situation that has more potential to do irreversible harm than good.
I urge you to reconsider this decision and save this area from having to recover from a major disaster.
Please do not allow BESS sites in the city of Auburn and please advocate to not allow them in our area.
Zach Pratt
Page 152 of 758
1
Gabriel Clark
From:Gabriel Clark
Sent:Friday, February 13, 2026 8:55 AM
To:'bonnibusmaximus@aol.com'
Subject:RE: Battery Energy Storage Systems Code Update: SEPA
Good morning Bonnie,
Thank you for your thoughtful comments regarding the City’s proposed development regulations. Your comments
will be transmitted to the Planning Commission for consideration.
Regarding the adopted Building, Fire, and other national Codes, these standards are developed using the best
available science from industry experts. Because both the technology and the codes continue to evolve, it is
essential that the City reference the State-adopted Building and Fire Codes. This approach allows the City to
implement updated standards immediately as they are revised. Additional requirements are also incorporated
from Auburn City Code and the Engineering Design Standards.
International Fire Code (IFC) Chapter 1207 (2024) contains specific fire suppression and containment
requirements that the Valley Regional Fire Authority is aware of and will apply during project review. These
standards are referenced throughout the proposed supplemental development standards contained in Auburn
City Code.
For example:
- IFC 1207.1.7 requires large-scale fire testing in accordance with UL 9540A. This testing must demonstrate
that a fire involving one ESS will not propagate to adjacent units and, when located within a structure, will
remain contained for the duration of the test. The test must be conducted or witnessed by an approved
testing laboratory, and the report must be submitted to the fire code official for review and approval under
IFC 104.2.2.
- IFC 1207.5.5 requires that BESS facilities located within structures be equipped with an automatic fire
suppression system. Additional technology-specific requirements for ESS installations are outlined in IFC
1207.6.
There is a substantial amount of technical material involved, but I want to assure you that the City is applying the
most risk-averse standards available, grounded in established codes and the best available science. Where
existing codes do not fully address Auburn’s specific context, staff are proposing additional restrictions and
safeguards to protect critical areas and the locations where a BESS may be sited. Specifically, the proposed code
includes provisions to prevent the intrusion of pollutants into critical areas generated by a facility. Secondary
containment systems will be designed as independent structures, separate from any stormwater system and
increased buffer widths, to ensure that potential contaminants are fully isolated.
Please let me know if you have any additional comments or concerns,
CODE QUESTIONS?
Book an online meeƟng: Virtual Permit Center - City of Auburn (auburnwa.gov)
Gabriel Clark, Planner II
Department of Community Development
Page 153 of 758
2
City of Auburn | www.auburnwa.gov
Office 253-470-2147| gclark@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map)
Customer Service Survey | ApplicaƟon Forms | Zoning Maps
From: bonnibusmaximus@aol.com <bonnibusmaximus@aol.com>
Sent: Wednesday, February 11, 2026 1:14 AM
To: Planning <planning@auburnwa.gov>
Subject: Battery Energy Storage Systems Code Update: SEPA
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Hello,
I'd like to request that there be a hearing to discuss the details of the SEPA findings.
The WAC referenced that would be used as guidelines for siting is very generic and vague even in its
descriptions of fire suppression and monitoring systems. I'd also argue it is out of date as these
systems and chemistry have undergone several changes in code, yet continue to fail.¹
I'd also like to point out that there is new data regarding how hazardous materials are dispersed into
the environment as was discovered in new Moss Landing data collection.² They used different
methodology than the EPA did and learned about how the different metals and chemicals moved
through the environment. Given the recent flooding in the valley, I'd be very concerned how the
release of toxic and polluting battery components would affect our wetlands and move differently into
the environment. Since the ordinance is citywide, and the plume spread and dispersion of pollutants
can be miles long, I am worried a critical aquifer recharge area (CARA) would be negatively
impacted.
These are unlikely to serve as intended for emergency backup for the community.
"The SOC of a BESS affects the ability of the BESS to provide energy or other ERSs to the BPS at
any given time. In many cases, the BESS may have SOC limits that are tighter than 0–100% for
battery lifespan, and other equipment and performance considerations. SOC limits affect the ability of
the BESS to operate as expected, and any SOC limits will override any other ability of the BESS to
provide ERSs or energy to the BPS." "At this time, it is unlikely that most legacy BESS can support
system restoration activities as a stand-alone resource..." (see attached)
I also have concerns about placement of any tier 2 or 3 BESS in residential zones. The burden to
community services cannot be downplayed in the event of a failure as BESS continue to have no plan
to extinguish containers, and they are allowed to burn while being monitored.¹ These should be
placed only in heavy industrial zone and every project should be evaluated through the strictest
planning process, including public hearing/input whenever able.
Page 154 of 758
3
I appreciate the thoughtfulness of including financial responsibility requirements, but would these be
held by the land owner or BESS operator? Given how expensive response and clean up is, with some
BESS sites having now become superfund sites, what is a realistic number to put on the costs of
failure?³ These things and many more should be discussed at a hearing before any determination is
made.
Thank you,
Bonnie Helms
253-632-6085
¹ https://villageofwarwickny.gov/28-church-street-west-warwick-3-battery-energy-storage-site-fire-
information-updates/
² https://www.nature.com/articles/s41598-025-25972-8
³ https://americanbatterytechnology.com/epa-taps-abtc-for-large-scale-battery-recycling-project/
Page 155 of 758
1
Gabriel Clark
From:Gabriel Clark
Sent:Friday, February 13, 2026 2:40 PM
To:bonnibusmaximus@aol.com
Subject:RE: Battery Energy Storage Systems Code Update: SEPA
Good afternoon Bonnie,
Thank you for providing your comment regarding Battery Energy Storage System regulations in the City of Auburn.
Your comment has been attached with your second comment and will be provided to Planning Commission.
CODE QUESTIONS?
Book an online meeƟng: Virtual Permit Center - City of Auburn (auburnwa.gov)
Gabriel Clark, Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Office 253-470-2147| gclark@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for Map)
Customer Service Survey | ApplicaƟon Forms | Zoning Maps
From: bonnibusmaximus@aol.com <bonnibusmaximus@aol.com>
Sent: Wednesday, February 11, 2026 1:14 AM
To: Planning <planning@auburnwa.gov>
Subject: Battery Energy Storage Systems Code Update: SEPA
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Hello,
I'd like to request that there be a hearing to discuss the details of the SEPA findings.
The WAC referenced that would be used as guidelines for siting is very generic and vague even in its
descriptions of fire suppression and monitoring systems. I'd also argue it is out of date as these
systems and chemistry have undergone several changes in code, yet continue to fail.¹
I'd also like to point out that there is new data regarding how hazardous materials are dispersed into
the environment as was discovered in new Moss Landing data collection.² They used different
methodology than the EPA did and learned about how the different metals and chemicals moved
through the environment. Given the recent flooding in the valley, I'd be very concerned how the
release of toxic and polluting battery components would affect our wetlands and move differently into
the environment. Since the ordinance is citywide, and the plume spread and dispersion of pollutants
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2
can be miles long, I am worried a critical aquifer recharge area (CARA) would be negatively
impacted.
These are unlikely to serve as intended for emergency backup for the community.
"The SOC of a BESS affects the ability of the BESS to provide energy or other ERSs to the BPS at
any given time. In many cases, the BESS may have SOC limits that are tighter than 0–100% for
battery lifespan, and other equipment and performance considerations. SOC limits affect the ability of
the BESS to operate as expected, and any SOC limits will override any other ability of the BESS to
provide ERSs or energy to the BPS." "At this time, it is unlikely that most legacy BESS can support
system restoration activities as a stand-alone resource..." (see attached)
I also have concerns about placement of any tier 2 or 3 BESS in residential zones. The burden to
community services cannot be downplayed in the event of a failure as BESS continue to have no plan
to extinguish containers, and they are allowed to burn while being monitored.¹ These should be
placed only in heavy industrial zone and every project should be evaluated through the strictest
planning process, including public hearing/input whenever able.
I appreciate the thoughtfulness of including financial responsibility requirements, but would these be
held by the land owner or BESS operator? Given how expensive response and clean up is, with some
BESS sites having now become superfund sites, what is a realistic number to put on the costs of
failure?³ These things and many more should be discussed at a hearing before any determination is
made.
Thank you,
Bonnie Helms
253-632-6085
¹ https://villageofwarwickny.gov/28-church-street-west-warwick-3-battery-energy-storage-site-fire-
information-updates/
² https://www.nature.com/articles/s41598-025-25972-8
³ https://americanbatterytechnology.com/epa-taps-abtc-for-large-scale-battery-recycling-project/
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RELIABILITY | RESILIENCE | SECURITY
NERC | Report Title | Report Date
I
Reliability Guideline
Performance, Modeling, and Simulations of BPS-
Connected Battery Energy Storage Systems and
Hybrid Power Plants
June 2023
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Table of Contents
Preface ........................................................................................................................................................................... iv
Preamble ......................................................................................................................................................................... v
Executive Summary ........................................................................................................................................................ vi
High-Level Recommendations .................................................................................................................................... vi
Introduction ................................................................................................................................................................... ix
Fundamentals of Energy Storage Systems ................................................................................................................. ix
Fundamentals of Hybrid Plants with BESS .................................................................................................................. x
Co-Located Resources vs. Hybrid Resources ......................................................................................................... xii
Background ................................................................................................................................................................ xii
Chapter 1: BPS-Connected BESS and Hybrid Plant Performance.................................................................................... 1
Recommended Performance and Considerations for BESS Facilities ......................................................................... 1
Topics with Minimal Differences between BESS and Other Inverter-Based Resources .......................................... 4
Capability Curve ....................................................................................................................................................... 6
Active Power-Frequency Control ............................................................................................................................. 7
Fast Frequency Response ........................................................................................................................................ 7
Reactive Power-Voltage Control (Normal Conditions and Small Disturbances) ..................................................... 9
Inverter Current Injection during Fault Conditions ............................................................................................... 10
Grid Forming .......................................................................................................................................................... 10
Tesla’s Grid Forming + Grid Following Philosophy ................................................................................................ 11
System Restoration and Blackstart Capability ....................................................................................................... 11
State of Charge ...................................................................................................................................................... 12
Recommended Performance and Considerations for Hybrid Plants ........................................................................ 14
Topics with Minimal Differences between AC-Coupled Hybrids and Standalone BESS Resources ....................... 18
Capability Curve ..................................................................................................................................................... 19
Active Power-Frequency Control ........................................................................................................................... 20
Fast Frequency Response ...................................................................................................................................... 20
Reactive Power-Voltage Control (Normal Conditions and Small Disturbances) ................................................... 21
State of Charge ...................................................................................................................................................... 21
Operational Limits ................................................................................................................................................. 22
Chapter 2: BESS and Hybrid Plant Power Flow Modeling ............................................................................................. 23
BESS Power Flow Modeling ....................................................................................................................................... 23
Hybrid Power Flow Modeling .................................................................................................................................... 24
AC-Coupled Hybrid Plant Power Flow Modeling ................................................................................................... 24
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DC-Coupled Hybrid Plant Power Flow Modeling ................................................................................................... 26
Chapter 3: BESS and Hybrid Plant Dynamics Modeling ................................................................................................ 28
Use of Standardized, User-Defined, and EMT Models .............................................................................................. 28
Dynamic Model Quality Review Process ................................................................................................................... 29
BESS Dynamic Modeling ............................................................................................................................................ 29
Scaling for BESS Plant Size and Reactive Capability ............................................................................................... 31
Reactive Power/Voltage Controls Options ............................................................................................................ 31
Active Power Control Options ............................................................................................................................... 32
Current Limit Logic ................................................................................................................................................. 32
State of Charge ...................................................................................................................................................... 32
Representation of Voltage and Frequency Protection .......................................................................................... 33
Hybrid Plant Dynamics Modeling .............................................................................................................................. 33
AC-Coupled Hybrid Modeling ................................................................................................................................ 33
DC-Coupled Hybrid Modeling ................................................................................................................................ 35
Electromagnetic Transient Modeling for BESS and Hybrid Plants ............................................................................ 35
Chapter 4: BESS and Hybrid Plant Short Circuit Modeling ............................................................................................ 37
BESS Short Circuit Modeling ...................................................................................................................................... 37
Hybrid Plant Short Circuit Modeling .......................................................................................................................... 38
Chapter 5: Studies for BESS and Hybrid Plants ............................................................................................................. 39
Interconnection Studies ......................................................................................................................................... 39
Hybrid Additions: Needed Studies ............................................................................................................................ 41
Transmission Planning Assessment Studies .............................................................................................................. 42
Blackstart Study Considerations ................................................................................................................................ 43
CAISO BESS and Hybrid Study Approach Example .................................................................................................... 44
CAISO Generation Interconnection Study ............................................................................................................. 44
CAISO Transmission Planning Study ...................................................................................................................... 45
Appendix A: Relevant FERC Orders to BESS and Hybrids .............................................................................................. 46
Contributors .................................................................................................................................................................. 50
Guideline Information and Revision History ................................................................................................................. 52
Metrics .......................................................................................................................................................................... 53
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Preface
Electricity is a key component of the fabric of modern society and the Electric Reliability Organization (ERO) Enterprise
serves to strengthen that fabric. The vision for the ERO Enterprise, which is comprised of NERC and the six Regional
Entities, is a highly reliable, resilient, and secure North American bulk power system (BPS). Our mission is to assure
the effective and efficient reduction of risks to the reliability and security of the grid.
Reliability | Resilience | Security
Because nearly 400 million citizens in North America are counting on us
The North American BPS is made up of six Regional Entities as shown on the map and in the corresponding table
below. The multicolored area denotes overlap as some load-serving entities participate in one Regional Entity while
associated Transmission Owners/Operators participate in another.
MRO Midwest Reliability Organization
NPCC Northeast Power Coordinating Council
RF ReliabilityFirst
SERC SERC Reliability Corporation
Texas RE Texas Reliability Entity
WECC WECC
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Preamble
The NERC Reliability and Security Technical Committee (RSTC), through its subcommittees and working groups,
develops and triennially reviews reliability guidelines in accordance with the procedures set forth in the RSTC Charter.
Reliability guidelines include the collective experience, expertise, and judgment of the industry on matters that
impact BPS operations, planning, and security. Reliability guidelines provide key practices, guidance, and information
on specific issues critical to promote and maintain a highly reliable and secure BPS.
Each entity registered in the NERC compliance registry is responsible and accountable for maintaining reliability and
compliance with applicable mandatory Reliability Standards. Reliability guidelines are not binding norms or
parameters nor are they Reliability Standards; however, NERC encourages entities to review, validate, adjust, and/or
develop a program with the practices set forth in this guideline. Entities should review this guideline in detail and in
conjunction with evaluations of their internal processes and procedures; these reviews could highlight that
appropriate changes are needed, and these changes should be done with consideration of system design,
configuration, and business practices.
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Executive Summary
Interconnection queues across North America are seeing a rapid influx of requests for battery energy storage systems
(BESS) and hybrid power plants.1 While there are different types of energy storage technologies, BESS are
experiencing a rapid increase in penetration levels due to favorable economics, policies, and technology
advancements.2 Similarly, BESS are most commonly being coupled with inverter-based generating resources, such as
wind and solar photovoltaic (PV). Therefore, BESS and inverter-based hybrid power plants are the primary focus of
this reliability guideline.
NERC’s previously published reliability guidelines provided performance recommendations and suggested
improvements to interconnection requirements and planning processes for newly interconnecting inverter-based
resources. BESS and hybrid power plants were not specifically addressed in detail in these guidelines, and there are
certain considerations and nuances to the operation of this technology that warrant additional guidance. Hybrid
plants also provide new benefits to the BPS by combining operational capabilities across different technologies;
however, there are different types of hybrid configurations (ac-coupled versus dc-coupled), and complexities and
unique operational considerations of hybrid plants that need additional guidance as well. The reliability guideline
presented here provides guidance, clarifications, and considerations not covered in the other reliability guidelines,
focusing specifically on BESS and hybrid power plants. This document also contains guidance for Transmission
Operators (TO), Transmission Planners (TP), and Planning Coordinators (PC) to further enhance their interconnection
requirements and study processes for BESS and hybrid power plants.
The recommendations in this guideline should apply to all BPS-connected BESS and hybrid plants and should not be
limited only to Bulk Electric System (BES) facilities. Many newly interconnecting BESS projects and hybrid plants may
not meet the BES definition; however, having unified performance and behavior from all BPS-connected inverter-
based resources (including BESS and hybrid plants) is important for reliable operation of the North American BPS.
TOs are encouraged to incorporate the recommended performance characteristics into their interconnection
requirements per NERC FAC-001, and TPs and PCs are encouraged to incorporate the recommended modeling and
study approaches into their interconnection processes per NERC FAC-002.
This reliability guideline includes the recommended performance of BPS-connected BESS and hybrid power plants
that all Generator Owners (GOs) and developers seeking interconnection to the BPS should consider. TOs, TPs, and
PCs can also use these performance recommendations to improve their interconnection requirements and study
processes for these facilities. This guideline also covers recommended modeling and study practices that should be
considered by TPs and PCs as they perform planning assessments with increasing numbers of BESS and hybrid power
plants in the interconnection study process, annual planning process, and for any specialized studies needed to
ensure BPS reliability.
High-Level Recommendations
This reliability guideline contains detailed recommendations regarding BESS and hybrid power plant performance,
modeling, and studies. Industry is strongly encouraged to review the guidance, use the technical details, and
reference materials, and adapt the recommendations for their specific processes and practices. Table ES.1 provides
a set of high-level recommendations (categorized by performance, modeling, and studies) and their applicability 3 to
all aspects of the guidance contained throughout this reliability guideline.
1 A hybrid power plant is defined herein as “a generating resource that is comprised of multiple generation or energy storage technologies
controlled as a single entity and operated as a single resource behind a single POI.”
2 https://www.eia.gov/analysis/studies/electricity/batterystorage/
3 The applicability column for each of the recommendations made is solely intended to provide guidance for the entities that should consider
the recommendation for their business practices.
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Table ES. 1: High-Level Recommendations for BESS and Hybrid Plant Performance,
Modeling, and Studies
# Recommendation Applicable Entities
A1
Applicability: The recommendations in this guideline should be applied to all BPS-connected
BESS and hybrid plants and should not be limited to only BES facilities. Many newly
interconnecting BESS and hybrid power plants may not meet the BES definition; however,
having unified performance and behavior from all BPS-connected inverter-based resources is
important for reliable operation of the North American BPS.
TOs, TPs, PCs, BAs,
RCs, GOs, GOPs,
developers,
equipment
manufacturers
P1
BESS and Hybrid Plant Performance: Generation Owners (GO) of existing or newly
interconnecting BESS and hybrid power plants should closely review the recommended
performance characteristics outlined in this reliability guideline and adopt these
recommendations into existing and new facilities to the extent possible. Newly
interconnecting GOs of BESS and hybrid power plants should work closely with their
respective TOs, Balancing Authorities (BA), Reliability Coordinators (RC), TPs, and PCs to
ensure all entities have an understanding of the operational capabilities and limitations of the
facilities being interconnected. BESS and hybrid plant developers, in coordination with
equipment manufacturers, should also use the recommendation provided herein regarding
BESS/hybrid plant performance when designing new facilities.
GOs, GOPs,
developers,
equipment
manufacturers
P2
Interconnection Requirements and Processes: TOs should update or improve their
interconnection requirements to ensure they are clear and consistent for BESS and hybrid
power plants. TPs and PCs should ensure that their modeling requirements include clear
specifications for BESS and hybrid power plants. TPs and PCs should also ensure that their
study processes and practices are updated and improved to consider the unique operational
capabilities of those facilities.
TOs, TPs, PCs
P3
Unique Operational Capabilities of BESS and Hybrid Power Plants: All applicable entities
should consider the detailed guidance contained in this guideline and fully utilize the
operational capabilities of these new technologies to support reliable operation of the BPS.
Capabilities like grid forming technology, operation in low short-circuit networks, the ability
to provide primary and fast frequency response (FFR), and other functions more readily
available in these new technologies should be fully utilized (as needed) and are essential
reliability services (ERS) for the BPS.
TOs, TPs, PCs, BAs,
RCs, GOs, GOPs,
developers,
equipment
manufacturers
M1
Models Matching As-Built Controls, Settings, and Performance: All BESS and hybrid plant
GOs (in coordination with the developer and equipment manufacturers) should ensure that
the models used to represent BESS and hybrid power plants accurately represent the controls,
settings, and performance of the equipment installed in the field. This requires concerted
focus by the GO, developer, and equipment manufacturer during the study and
commissioning process as well as more rigorous verification and testing by the TP and PC
throughout. GOs should also provide updated models to the TP and PC that reflect as-built
settings and controls after plant commissioning. The TP and PC should study any
modifications to equipment settings that have an impact on the electrical performance of the
equipment prior to changes being made, per the latest effective version of NERC FAC-002.
TPs and PCs should ensure their modeling requirements and processes clearly define the
types of models that are acceptable, the level of detail expected for each model, and the
benchmarking between models required during the planning study process. GOs, Generation
Operators (GOP), and developers of each BESS and hybrid power plant (in coordination with
their TP, PC, and equipment manufacturer) should verify that the dynamic models fully
represent the expected behavior of the as-built facility.
TPs, PCs, GOs, GOPs,
developers,
equipment
manufacturers
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viii
Table ES. 1: High-Level Recommendations for BESS and Hybrid Plant Performance,
Modeling, and Studies
# Recommendation Applicable Entities
M2
Software Enhancements: The technological advancement of BESS and hybrid plant controls
is outpacing the capabilities available in the standardized library models. Simulation software
vendors should work with BESS and hybrid plant inverter and plant-level controller
manufacturers to develop more flexible dynamic models to represent these facilities.
Software developers should be proactive in addressing modeling challenges faced by TPs and
PCs in this area, particularly as the number of these types of resources rapidly increases in
Interconnection-wide base cases. Software vendors should support the advancement of using
“real-code”4 models or other user-defined models in a manner that does not degrade or limit
the quality and fidelity of the overall Interconnection-wide base case. Software vendors
should consider adding model validation, verification, quality review, and other screening
tools to their programs to support TP and PC review of model quality. Software vendors
should improve the steady-state model representation of hybrid plants such that engineers
are not required to use workarounds, such as modeling two separate units to represent a
single hybrid plant.
Simulation software
vendors, equipment
manufacturers
S1
Study Process Enhancements: TPs and PCs should improve their study methodologies for
both interconnection studies and annual planning studies to ensure they are appropriate for
a BPS with significantly more BESS and hybrid power plants. Determination of stressed
operating conditions, selection of study assumptions, inclusion of various modeling practices,
and determination of appropriate dispatch conditions are just a few areas where close
attention will be needed by TPs and PCs to ensure their study approaches align with the new
technologies.
TPs, PCs
S2
Expansion of Study Conditions: The variability and uncertainty of renewable energy
resources has led TPs and PCs to study different expected operating conditions than were
previously used for planning assessments. BESS and hybrid plants may help address some of
the operational variability; however, developing suitable and reasonable study assumptions
will become a significant challenge for future planning studies. TPs and PCs may need to
expand the set of study conditions used for future planning assessments as the most severe
operating conditions may change over time.
TPs, PCs
4 “Real code” models are a type of black box model that implement the actual control code from the equipment. The real-code aspects of the
model pertain mainly to the controller-related code in the turbine controls, inverter controls, protection and measurement algorithms, and
plant-level controller.
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Introduction
Fundamentals of Energy Storage Systems
Energy storage can take many different forms, and some are synchronously connected to the grid while others are
connected through a power electronics interface (i.e., inverter-based). Examples of different energy storage
technologies include, but are not limited to, the following:5
• Battery Energy Storage: There are many types of BESS, such as lithium-ion, nickel-cadmium, sodium sulfur,
redox flow, and others.6 Batteries convert stored chemical energy to direct current (dc) electrical energy, and
vice versa. Power electronic converters (i.e., inverters) are used to connect the battery to the alternating
current (ac) power grid.
• Pumped Hydroelectric Storage: Pumped hydroelectric power is one of the most mature and commonly used
large-scale electric storage technologies today. Water flowing through a hydroelectric turbine-generator
produces electric energy for the BPS. Energy is then stored by sending the water back to the upper reservoir
through a pump.
• Mechanical Energy Storage: Mechanical systems store kinetic or gravitational energy for later use as electric
energy. Flywheels are an example of mechanical energy storage; they work by accelerating a rotor to a very
high speed so that the inertia of the flywheel can then be delivered to the grid as energy when needed.
• Hydrogen Energy Storage: Hydrogen energy storage involves the separation of hydrogen from some
precursor material, such as water or natural gas, and storage of the hydrogen in vessels that range from
pressurized containers to underground salt caverns for later use. The hydrogen can later be used to produce
electricity with fuel cells or combined-cycle power plants.7
• Thermal Energy Storage: Thermal energy storage involves heating or cooling a material with a high heat
capacity and recovering the energy later by using the thermal gradient between the thermal storage medium
and the ambient conditions. For example, electric energy could be used to heat volcanic stones that can then
be converted back to electric energy by using a steam turbine.8 Concentrated solar plants use molten salt as
thermal storage medium and steam turbines to convert heat to electric energy.
• Compressed Air Energy Storage: Compressed air storage contains energy in the form of pressurized air in a
geological feature or other facility. Energy can be delivered back to the grid at a later time, usually by heating
the pressurized air and sending it through a turbine to generate power.
• Supercapacitors: Supercapacitors or ultracapacitors are high-power electrostatic devices with fast charging
and discharging capability (on the order of 1–10 seconds) and low energy density. No chemical reactions
occur during charging and discharging, so these units have low maintenance costs, long lifetimes, and high
efficiency. These devices are scalable, but their fast response can generally not be sustained due to the low
energy density.
There are multiple benefits of BPS-connected energy storage systems, including (but not limited to) the following:
• Providing balancing and fast-ramping services
• Mitigating transmission congestion
• Enabling energy arbitrage to charge during low price periods and discharge during high price periods
• Providing ERSs like frequency response and dynamic voltage support
5 https://www.nerc.com/pa/RAPA/ra/Reliability%20Assessments%20DL/Master_ESAT_Report.pdf
6 https://energystorage.org/why-energy-storage/technologies/solid-electrode-batteries/
7 https://energystorage.org/why-energy-storage/technologies/hydrogen-energy-storage/
8 https://www.siemensgamesa.com/products-and-services/hybrid-and-storage/thermal-energy-storage-with-etes
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Each of the energy storage technologies described can provide benefits to BPS reliability and resilience. The
interaction between battery energy storage devices and the electrical grid is dominated by the power electronics
interface at the inverter level and plant controller level, specifically on small time scales (from microseconds to tens
of seconds to minutes). The interactions that BESS and hybrid plants have with the BPS is the primary focus of this
guideline, and guidance provided also covers ways that industry can model and study these resources connecting to
the BPS.
Fundamentals of Hybrid Plants with BESS
Hybrid power plants are also becoming increasingly popular due to federal incentives, cost savings, flexibility, and
higher energy production by sharing land, infrastructure, and maintenance services. Hybrid power plants (“hybrid
resources”) are defined here as follows:
Hybrid Power Plant (Hybrid Resource): A generating resource that is comprised of multiple generation or energy
storage technologies controlled as a single entity and operated as a single resource behind a single point of
interconnection (POI).
There are many types of hybrid power plants that combine synchronous generation, inverter-based generation, and
energy storage systems;9 however, the most predominant type of hybrid power plant observed in interconnection
queues across North America is a combination of renewable energy (solar PV or wind) and battery energy storage
technologies.10 Due to this fact, this guideline concentrates primarily on hybrid plants that combine renewable
(specifically inverter-based) generation with BESS technology.
The conversion of dc to ac current occurs at the power electronics interface. However, the way this conversion occurs
within a hybrid plant affects how the resource interacts with the BPS, its ability to provide ERSs, how it is modeled,
and how it is studied. Hybrid plants can be classified as either of the following:
• AC-Coupled Hybrid Plants: An ac-coupled hybrid power plant couples each form of generation or storage at
a common collection bus after it has been converted from dc to ac at each individual inverter. Figure I.1
shows a simple illustration of one possible configuration of an ac-coupled hybrid power plant where a BESS
is coupled with a solar PV or wind power plant on the ac side. The BESS may be charged either from the
renewable generating component or from the BPS if appropriate contracts and rates are available.
• DC-Coupled Hybrid Plants: A dc-coupled hybrid power plant couples both sources at a dc bus tied to the grid
via a dc-ac inverter. There are often dc-dc converters between the individual units and the common dc
collection bus. Figure I.2 shows a simple illustration of another possible configuration of a dc-coupled hybrid
power plant where the energy storage component is coupled through a dc-dc converter on the dc side. The
dc–ac inverter can be unidirectional where the BESS can only be charged from the renewable resource or bi-
directional where the BESS can also be charged from the BPS (depending on interconnection requirements
and agreements).11 There are multiple possible configurations for dc-coupled facilities, particularly on the dc-
side between the generating resource, the BESS, and ways they connect through the ac–dc inverter.12
9 Such as natural gas and BESS hybrid plants, combined heat and power with BESS, or multiple types of inverter-based generation
technologies
10 Note that hybrid natural gas-BESS plants may be desirable in some areas where capacity shortages have been identified.
11 ERCOT has drafted a concept paper specifically on dc-coupled resources, which may be a useful reference:
http://www.ercot.com/content/wcm/key_documents_lists/191191/KTC_11_DC_Coupled_2-24-20.docx.
12 https://www.dynapower.com/products/energy-storage-solutions/dc-coupled-utility-scale-solar-plus-storage/
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Figure I.1: Illustration of AC-Coupled Hybrid Plant
Figure I.2: Illustration of DC-Coupled Hybrid Plant
Different technologies may deploy ac- and dc-coupled systems for different reasons. For example, it may be
economical for a solar PV and BESS system to be coupled on the dc-side whereas it may be more cost effective for
wind turbine generators to be coupled with a BESS on the ac-side. Each newly interconnecting hybrid will have its
reasons for using ac- or dc-coupled technology that ultimately comes down to which configuration provides the most
value for the given installation.
Hybrid plants combine many of the benefits of stand-alone BESS with renewable energy generating resources,
including (but not limited to) the following:13
• Cost Efficiencies: Integrating different technologies at the same location enables a developer to save on
shared electrical, controls, and communications equipment; simplifies siting; allows for shared personnel;
improves maintenance schedules; reduces electrical losses associated with ac/dc conversion efficiency (i.e.,
dc-coupled); and saves on other relevant operational costs.
• Reduced Interconnection Costs: In some cases, adding a battery that can charge and discharge on command
can reduce interconnection costs for a renewable generator by avoiding overloads on existing transmission
equipment or addressing reliability needs that may have required new transmission equipment.
13 The benefits noted are also generally applicable to stand-alone energy storage devices, such as BESS; the benefits noted here focus on how
addition of a BESS to a traditional renewable energy-generating project can improve the operational capabilities and flexibility of the resource.
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• Energy Arbitrage: The storage element in a hybrid plant can be used to charge during low-priced hours and
discharge during high-priced hours, therefore shifting energy production to those hours where energy is
needed. Current arbitrage for hybrids (and BESS) is on the order of hours and days; future technologies may
be able to further shift energy storage and production based on system needs.
• Excess Energy Harvesting: Hybrid plants have the added benefit of being able to capture any excess solar or
wind production that would otherwise be lost or “clipped” (e.g., due to curtailment or oversizing of PV panels
compared to inverter size). Capturing excess energy increases plant capacity factor and enables it to continue
operating when the generating resource output decreases.
• Frequency Response Capability: Adding energy storage to a renewable facility increases the ability of the
plant to respond to underfrequency events while still operating the renewable component at maximum
available power (given appropriate interconnection practices and agreements) as well as bringing some
certainty to providing this service. Addition of battery storage to a synchronous generator facility may also
allow the hybrid plant to provide FFR.14 The energy storage component can initially charge or discharge
rapidly, delivering initial performance of FFR, while the synchronous generator turbine-governor provides a
slower, longer-term sustained response.
• Reduce Generating Fleet Variability: As higher penetrations of renewable energy resources enter the BPS,
higher levels of uncertainty and variability are occurring. This requires additional flexibility in resources.
Hybrid plants with the BESS component can be a significant source of fast and flexible energy.
Co-Located Resources vs. Hybrid Resources
As described above, a hybrid power plant is “a single generating resource comprised of multiple generation or storage
technologies controlled as a single entity and operated as a single resource behind a single POI.” Similarly, some
transmission entities 15 are differentiating co-located power plants from hybrid plants due to their key differences.
Co-located power plants can be defined as follows:
• Co-Located Power Plants (Co-Located Resources): Two or more generation or storage resources that are
operated and controlled as separate entities yet are connected behind a single POI.
The key difference here is that the units are operated independently from one another even though they may be
electrically connected identically to a hybrid resource. This distinction is important when considering how and when
these resources will operate as well as how to model and study these resources in operations and planning
assessments.
Background
The North American generation mix, like many areas around the world, is trending toward increasing amounts of
inverter-based resources, most predominantly wind and solar PV resources. According to the U.S. Energy Information
Administration (EIA) Annual Energy Outlook 2020,16 wind power capacity in the United States more than doubled in
the past decade (39.6 GW in 2010 to 107.4 GW in 2019) and solar generation multiplied by 25x from 2.7 GW in 2010
to 67.7 GW in 2019. Wind and solar generation supplied nearly 7.2% and 2.7% of United States energy in 2019,
respectively. The EIA and many other organizations have projected continued rapid growth of both technologies over
the next several decades. This rapid evolution at both the BPS and distribution system challenges conventional
planning and operating practices yet poses benefits to BPS planning, operations, and design. One of the primary
14 For example, in ERCOT, a BESS was added to a quick-start combustion turbine for participation in ERCOT’s Responsive Reserve Service. The
combustion turbine is normally offline, and if frequency falls outside of a pre-defined deadband, the BESS will provide FFR until the combustion
turbine is turned on to sustain the provided response.
15 http://www.caiso.com/InitiativeDocuments/RevisedStrawProposal-HybridResources.pdf
http://www.caiso.com/Documents/IssuePaper-HybridResources.pdf
16 U.S. Energy Information Administration (EIA), “Annual Energy Outlook 2020 with projections to 2050,” Jan. 2020.
https://www.eia.gov/outlooks/aeo/pdf/aeo2020.pdf
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challenges is the variability and uncertainty of renewable energy resources, which leads to additional variability and
uncertainty in the planning and operations horizons. The need for flexibility, coupled with favorable economics, has
therefore led to an influx of BPS-connected energy storage projects and hybrid power plants that use energy
storage.17
Areas across North America are also seeking low-carbon power systems. For example, California requires 18 that
eligible renewable energy resources and zero-carbon resources supply 100% of retail sales of electric energy to
California end-use customers and 100% of electric energy procured to serve all state agencies by the end of 2045. As
such, the California Public Utilities Commission has seen a surge of new energy storage contracts, achieving its 2020
energy storage goal of 1,325 MW ahead of time,19 and is projected to have 55,000 MW of new storage by 2045.20 At
the same time, the risk and impact of wildfires in the area is leading California utilities, policymakers, and end-use
customers to more closely consider grid resilience and flexibility. Energy storage systems, particularly BESS and BESS
coupled with inverter-based resources to create hybrid power plants, are providing short-term energy and reliability
services, including ramping and variability control, voltage and frequency regulation, operation in low short-circuit
strength conditions, and other features.
Historically, BESS have not been a significant factor in planning and operating the BPS; however, interconnection
requests and projects being constructed today have scaled up to match the size of solar PV and wind plants. For
example, the Gateway Project in the San Diego Gas and Electric area consists of a 250 MW BESS providing energy and
ancillary services in the California Independent System Operator (CAISO) market.21 California recently approved a
proposed 1,500 MW battery at Moss Landing.22 Southern California Edison currently has several hundred megawatts
of BESS deployed in its footprint with much more in its interconnection queue.23 Figure I.3 shows a cursory review of
the CAISO interconnection queue (captured in early 2020) where most new interconnection requests are either
stand-alone BESS or hybrid plants that consist mainly of solar PV or wind combined with a BESS component.
Elsewhere, over 1,500 MW of BESS in ERCOT are under construction and 7,500 GW more are in advanced
development.24 These types of interconnection requests are observed across North America, and these newly
connecting resources will need to operate reliably to provide ERSs and be modeled appropriately. They will also need
to be studied as part of the interconnection process.
17 Hybrid plants combine multiple technologies of generation and energy storage at the same facility, enabling benefits to both the plant and
to the BPS. The majority of newly interconnecting hybrid resources are a combination of renewable energy and battery energy storage.
18 California Senate Bill No. 100: https://leginfo.legislature.ca.gov/faces/billNavClient.xhtml?bill_id=201720180SB100
19 https://www.cpuc.ca.gov/General.aspx?id=3462
20 Phil Pettingill, “Ensuring RA in Future High VG Scenarios – A View from CA”, ESIG Spring Workshop. April 10, 2020
21 https://www.lspower.com/ls-power-energizes-largest-battery-storage-project-in-the-world-the-250-mw-gateway-project-in-california-2/
22 https://pv-magazine-usa.com/2020/08/13/vistra-approved-to-build-a-grid-battery-bigger-than-all-utility-scale-storage-in-the-us-
combined/
23 https://www.edison.com/home/innovation/energy-storage.html
24 https://insight.factset.com/ercot-battery-dynamics-set-to-follow-caiso-trends
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Figure I.3: Review of CAISO Interconnection Queue for Hybrid Resources and BESS
Generation interconnection queues are currently inundated with requests for new interconnections of BESS and
hybrid power plants. TPs and PCs need the capabilities to accurately model and study these resources in
interconnection studies and annual planning processes. While early BESS were primarily proposed for energy
arbitrage and mitigating renewable resource variability, there has been more recent interest in installing BESS for
broader services as a generating resource or even as a source of transmission services, such as voltage support under
“storage as transmission facility”25 programs. Therefore, it is imperative to have clear guidance on how BESS and
hybrid power plants should perform when connected to the BPS and also to have recommended practices for
modeling and studying BESS and hybrid power plants for power flow, stability, short-circuit, and electromagnetic
transient (EMT) studies. These types of modeling practices and studies are the primary focus of this guideline.26
For the purposes of this guideline, the terms BESS and hybrid plant refer to the resource in its entirety up to the POI,
including the main power transformers; the terms do not refer only to the individual storage device or converters
themselves. As such, both BESS and hybrid plants are considered inverter-based resources.
25
https://cdn.misoenergy.org/20190109%20PAC%20Item%2003c%20Storage%20as%20a%20Transmission%20Asset%20Phase%20I%20Proposa
l%20(PAC%20004)307822.pdf
26 Other types of studies, such as harmonics and geomagnetic disturbance studies, are outside the scope of this guideline.
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Chapter 1: BPS-Connected BESS and Hybrid Plant Performance
BESS and hybrid plants have performance requirements similar to other BPS-connected inverter-based resources
(e.g., wind and solar PV plants). However, there are unique recommended operational and technological differences
to consider when describing the recommended performance for these facilities. This chapter describes the specific
technological considerations that should be made when describing the recommended performance for these
resources in more depth. The NERC Reliability Guideline: BPS-Connected Inverter-Based Resource Performance,27 as
a precursor to IEEE 2800-2022, provided a foundation of recommended performance for BPS-connected inverter-
based resources, including BESS and hybrid plants; however, the guideline is planned to be retired. For more
information regarding quantitative technical minimum performance requirements, consider relevant and specific
sections in IEEE 2800-2022.28
Recommended Performance and Considerations for BESS Facilities
Table 1.1 provides an overview of the considerations that should be addressed when describing the recommended
performance of BESS facilities compared with other BPS-connected inverter-based generating resources.
Table 1.1: High Level Considerations for BESS Performance
Category Specifications and Comparison with BPS-Connected Inverter-Based Generators
Momentary Cessation
There are no significant differences from other BPS-connected inverter-based generating
resources; momentary cessation should not be used to the greatest possible extent29
during charging and discharging operation.
Phase Jump Immunity This has no significant difference from other BPS-connected inverter-based generating
resources.
Capability Curve
The capability curve of a BESS extends into both the charging and discharging regions to
create a four-quadrant capability curve. The shape of many individual BESS inverter
capability curves is almost30 symmetrical for charging and discharging. From an overall
plant-level perspective, the capability curves may be asymmetrical. System-specific
requirements may not necessitate the use of the full equipment capability; however, the
resources should not be artificially limited from providing its full capability (particularly
reactive capability) to support reliable operation of the BPS. See Capability Curve section
for more information.
27https://www.nerc.com/comm/RSTC_Reliability_Guidelines/Inverter-Based_Resource_Performance_Guideline.pdf
28 https://standards.ieee.org/ieee/2800/10453/
29 This is true unless there is an equipment limitation or a need for momentary cessation to maintain system stability. The former has to be
communicated by the GO to the TP while the latter has to be validated by extensive studies.
30 The capability curve is almost symmetrical because when the BESS is operated in the second and third quadrant (consuming active power),
a rise in dc voltage could limit the amount of power absorption or consumption where reactive power also has to be consumed.
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Table 1.1: High Level Considerations for BESS Performance
Category Specifications and Comparison with BPS-Connected Inverter-Based Generators
Active Power-
Frequency Control
Active power-frequency controls can be extended to the charging area of operation for
BESS. The conventional droop characteristic can be used in both discharging and charging
modes. Furthermore, a droop gain 31 and deadband should be used in both operating
modes, and there should be a seamless transition between modes (i.e., there should not
be a deadband in the power control loop for this transition) unless interconnection
requirements or market rules preclude such operation. As with all resources, speed of
response 32 of active power-frequency control to support the BPS should be coordinated
with system needs. The fast response of BESS to frequency deviations can provide
reliability benefits. Consistent with FERC Order 842, there should be no requirement for
BESS resources to provide frequency response if the state of charge (SOC) is very low or
very high (which may be specified by the BA), though that service can be optionally
procured by the BA. See Active Power-Frequency Control section for more information.
Fast Frequency
Response
BESS are well-positioned to provide FFR to systems with a high rate-of-change-of-
frequency (ROCOF) due to not having any rotational components (similar to a solar PV
facility). The need for FFR is based on each specific Interconnection’s need.33 Sustained
forms of FFR help arrest fast frequency excursions and overall frequency control. BESS
are likely to be able to provide sustained FFR within their SOC constraints. With the ability
of BESS to rapidly change MW output across their full charge and discharge ranges (within
SOC limits), BPS voltage fluctuations should be closely monitored, especially on systems
of lower short-circuit strength. See Fast Frequency Response section for more
information.
Reactive Power-
Voltage Control
BESS should be configured to provide dynamic voltage control during both discharging
and charging operations to support BPS voltages during normal and abnormal conditions.
TOPs should provide a voltage schedule (i.e., a voltage set point and tolerance) to all
BESS, applicable to both operating modes.
Reactive Current-
Voltage Control
There is no significant difference from other BPS-connected inverter-based generating
resources. BESS should be configured to provide dynamic voltage support during large
disturbances both while charging and discharging.
Reactive Power at No
Active Power Output
There is no significant difference from other BPS-connected inverter-based generating
resources.
31 Droop should be set using the same base for both charging and discharging mode of operation (i.e., rated active power, Pmax), so that the
same rate of response is provided regardless of charging or discharging.
32 Speed of response is dictated by the controls programmed into the inverter-based resource (most commonly in the plant-level controller),
which is a function of the time constants and gains used in the proportional-integral controls as well as the droop characteristic.
33 NERC, “Fast Frequency Response Concepts and Bulk Power System Reliability Needs,” March 2020:
https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/Fast_Frequency_Response_Conce
pts_and_BPS_Reliability_Needs_White_Paper.pdf
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Table 1.1: High Level Considerations for BESS Performance
Category Specifications and Comparison with BPS-Connected Inverter-Based Generators
Inverter Current
Injection during Fault
Conditions
BESS should be configured to provide fault current contribution during large disturbance
events that can support legacy BPS protection and stability.34 Inverter limits will need to
be met, as with all inverter-based resources; however, SOC may not be an issue for
providing fault current for BESS since faults are typically cleared in fractions of a second.
Additionally, limits on dc voltage magnitude can apply. See Inverter Current Injection
during Fault Conditions section for more information.
Return to Service
Following Tripping
BESS should return to service following any tripping or other off-line operation by
operating at the origin (no significant exchange of active or reactive power with the BPS)
and then ramp back to the expected power output. This is a function of plant settings
and interconnection requirements set by the Balancing Authority (BA) or TO.
Balancing
There is no significant difference from other BPS-connected inverter-based generating
resources. The capability to provide balancing services for the BPS should be available
from all BESS. BAs, TPs, PCs, and RCs should ensure requirements are in place for
appropriate balancing of the BPS.
Monitoring There is no significant difference from other BPS-connected inverter-based generating
resources.
Operation in Low
Short-Circuit Strength
Systems
There is no significant difference from other BPS-connected inverter-based generating
resources. BESS should use grid forming control, as appropriate (see Grid Forming
category below), to support BPS stability and reliability in low short-circuit strength
operating conditions.
Grid Forming
BESS have the unique capabilities to effectively deploy grid forming technology to help
improve BPS reliability in the future of high penetration of inverter-based resources. Key
aspects that enable this functionality include availability of an energy buffer to be
deployed for imbalances in generation and load, low communication latency between
different layers of controllers, and robust dc voltage that enables synthesis of an ac
voltage for a wide variety of system conditions. In grids where system strength and other
stability issues are of concern, BESS may be required to have this capability to support
reliable operation of the BPS. TPs and PCs should develop interconnection requirements
and new practices, as needed, to integrate the concepts of grid forming technology into
the planning processes. See Grid Forming section for more information.
34 Large disturbance fault current contribution from inverter-based resources can help BPS protection schemes operate appropriately by
ensuring they have appropriate voltage-current relationships of magnitude and phase angles (i.e., appropriate positive and negative sequence
current injection).
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Table 1.1: High Level Considerations for BESS Performance
Category Specifications and Comparison with BPS-Connected Inverter-Based Generators
Fault Ride-Through
Capability
There is no significant difference from other BPS-connected inverter-based generating
resources. BESS should have the same capability to ride through fault events on the BPS
when point of measurement (POM) voltage and frequency is within the curves specified
in the latest effective version of PRC-024.35 This applies to both charging and discharging
modes; unexpected tripping of generation or load resources on the BPS will degrade
system stability and adversely impact BPS reliability. Ride-through capability is a
fundamental need for all BPS-connected resources such that planning studies can identify
any expected risks. However, the behavior during ride-through while discharging and
charging may be different.
System Restoration
and Blackstart
Capability
BESS may have the ability to form and sustain their own electrical island if they are to be
designated as part of a blackstart cranking path. This may require new control topologies
or modifications to settings that enable this functionality. Blackstart conditions may
cause large power and voltage swings that must be reliably controlled and withstood by
all blackstart resources (i.e., operation under low short-circuit grid conditions). For BESS
to operate as a blackstart resource, assurance of energy availability as well as designed
energy rating that ensures energy availability for the entire period of restoration
activities is required. At this time, it is unlikely that most legacy BESS can support system
restoration activities as a stand-alone resource; however, they may be used to enable
start-up of subsequent solar PV, wind, or synchronous machine plants. See System
Restoration and Blackstart Capability section for more information.
Protection Settings There is no significant difference from other BPS-connected inverter-based generating
resources.
State of Charge (new)
The SOC of a BESS affects the ability of the BESS to provide energy or other ERSs to the
BPS at any given time.36 In many cases, the BESS may have SOC limits that are tighter
than 0–100%37 for battery lifespan, and other equipment and performance
considerations. SOC limits affect the ability of the BESS to operate as expected, and any
SOC limits will override any other ability of the BESS to provide ERSs or energy to the BPS.
These limits and how they affect BESS operation should be defined by the equipment
manufacturers and plant developer, agreed upon by the GO, and provided to the BA,
TOP, RC, TP, and PC. See State of Charge section for more information.
Oscillation Damping
Support
BESS can have the capability to provide damping support similar to synchronous
generators and high-voltage direct current (HVDC)/flexible ac transmission systems
(FACTS) facilities. BPS-connected inverter-based resources could also provide damping
support. A major difference from other BPS-connected inverter-based resources is that
BESS can operate in the charging mode in addition to the discharging mode, which
provide greater capabilities of damping support.
Topics with Minimal Differences between BESS and Other Inverter-Based Resources
The following topics have minimal difference between the recommended performance of BESS and other BPS-
connected inverter-based resources:
35 Unless there is an equipment limitation, which must be communicated by the GO to the TP
36 https://www.nrel.gov/docs/fy19osti/74426.pdf
37 Or the values 0% and 100% can simply be defined as the normally allowable range of operation.
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• Momentary Cessation: To the greatest possible extent,38 BESS should not use momentary cessation as a form
of large disturbance behavior when connected to the BPS. Any existing BESS that use momentary cessation
should eliminate its use to the extent possible, and its use for newly interconnecting BESS should be
disallowed by TOs in their interconnection requirements. Sufficiently fast dynamic active and reactive current
controls are more suitable.39 If voltage at the POM is outside the curves specified in the latest effective
version of PRC-024, momentary cessation may be used to avoid the BESS tripping. However, momentary
cessation should not be used inside the curves, subject to limitations for legacy equipment. This
recommendation applies for both charging and discharging operation.
• Phase Jump Immunity: Similar to other inverter-based resources, BESS should be able to withstand all
expected phase jumps on the BPS; this applies during both charging and discharging operation. The TO (in
coordination with their TP and PC) should clearly specify worst-case expected phase jumps during grid events
so that newly interconnecting projects can test their performance against them.
• Reactive Current-Voltage Control (Large Disturbances): Fundamentally, there are no significant differences
between BESS and other BPS-connected inverter-based resources with respect to reactive current-voltage
control during large disturbances. BESS inverters should maintain stability, adhere to inverter current limits,
and provide fast dynamic response to BPS fault events in both charging and discharging modes. Transitions
from charging to discharging (e.g., caused by active power-frequency controls) during large disturbances
should not impede the BESS from dynamically supporting BPS voltage and reactive current injection. Studies
should ensure stable performance for charging and discharging.
• Reactive Power at No Active Power Output: BESS should have capability to provide dynamic reactive power
to support BPS voltage while not discharging or charging active power. This is one of the benefits of inverter-
based technology and it can be used by grid operators to help regulate BPS voltages. Every BESS should have
the capability to perform such operation, and the actual use of such capability should be coordinated with
the TOP and RC regarding any voltage regulation requirements and scheduled voltage ranges.
• Return to Service Following Tripping: BESS should adhere to any requirements set forth by its respective BA.
In general, following any tripping or other off-line operation, BESS should return to service starting at their
origin point on the capability curve (i.e., operation at no active or reactive power loading) and then ramp to
their expected operating point based on recommendations or requirements provided by the BA (or TO in
their interconnection requirements).
• Return to Normal Operation Following Large Disturbance: BESS output should return to pre-disturbance
active power levels as soon as possible without any artificial ramp rate limit or delay imposed by the power
plant controller. Plants connected to low short-circuit strength systems or under other special circumstances
may require a slower dynamic response to BPS faults and should be studied appropriately by the TP and PC
during interconnection studies. In these circumstances, the plant performance necessary for BPS reliability
takes precedence over these recommendations.
• Balancing: BAs, TPs, PCs, and other applicable entities should understand what services BESS provide;
however, all BESS should have the capability to provide the BA with balancing services to ensure BPS
reliability.
• Monitoring: BESS should have equipment that provides the functionality of a digital fault recorder (DFR),
dynamic disturbance recorder, sequence of events recorder, harmonics recorder, and battery management
38 Unless there is an equipment limitation or a need for momentary cessation to maintain system stability. The former has to be communicated
by the GO to the TP while the latter has to be validated by extensive studies.
39 In rare cases, momentary cessation may be admissible based on reliability studies performed by the TP and PC on a case-by-case basis.
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system (BMS)40 monitoring capability. TOs (in coordination with the TOP, TP, and PC) should include clear
requirements and specifications for the types of data needed for BESS facilities (and other inverter-based
resources).
• BESS Stability: Appropriate studies should be conducted to ensure that the BESS would operate stably in its
electrical environment and in any of its operating modes. For example, if the short-circuit strength is low, the
TP and PC should study the operation of the hybrid resource in detail with EMT simulations as appropriate.
Studies should also be conducted to ensure that no instability modes exist at higher frequencies. In addition,
the ability of newly interconnecting BESS to operate with grid forming technology 41 (described in section
below) enables BESS to operate in very low short-circuit strength networks and further provide BPS support
beyond other grid-following inverter-based resources. Refer to recommendations from NERC Reliability
Guideline: Integrating Inverter-Based Resources into Low Short Circuit Strength Systems.42
• Fault Ride-Through Capability: BESS, like other BPS-connected inverter-based resources, should have the
capability to ride through voltage and frequency disturbances when RMS voltage at the POM is within the
curves of the latest effective version of PRC-024, subject to limitations for legacy equipment. Ride-through
performance requirements should apply to both charging and discharging modes since unexpected tripping
of any generation or load resources on the BPS will degrade system stability and adversely impact BPS
reliability. Ride-through capability is a fundamental need for all BPS-connected resources so that planning
studies can identify any expected risks.
• Protection Settings: Appropriate protections should be in place to operate BESS facilities safely and reliably
when connected to the BPS. To ensure proper site coordination with the interconnecting TO, protection
settings and coordination should be clearly documented and provided to the TO for approval by the BESS
owner. Additionally, BESS owners should provide protection settings to their TP, PC, TOP, RC, and BA to
ensure all entities are aware of expected performance of the BESS during planning and operations horizons.43
The following sub-sections outline the additional topics from Table 1.1 that warrant additional details and where
BESS have specific considerations to be addressed.
Capability Curve
BESS are generally four-quadrant devices that extend into the charging region. BESS inverters may be nearly
symmetrical 44 (see Figure 1.1). From an overall plant-level perspective, the capability curves may be asymmetrical
and further impacted by collector system losses and any dependencies on external factors, such as ambient
temperature (if applicable). Capability curves should capture the gross and net ratings of the facility, accounting for
station service, losses, and other factors. Capability curves for the overall BESS should be provided by the GO to the
TO, TP, PC, TOP, and RC to ensure sufficient understanding of the capabilities of the BESS to provide reactive power
under varying active power outputs.
40 System-level BMS data related to SOC and state of health (SOH) should be accessible to the GOP, TOP, and RC (as deemed necessary) for
independent evaluation to verify accuracy of reported metrics, assess operational issues, and correct any apparent miscalculations. All critical
data and metrics (e.g., SOC and SOH) of the BMS should have accuracy requirements established by the GO, which could be based on equipment
standards (where applicable).
41 There are different types of control topologies or definitions that could be considered “grid forming.” Inverter manufacturers are beginning
to offer commercial products that can support the BPS more broadly using these capabilities.
42 https://www.nerc.com/comm/PC_Reliability_Guidelines_DL/Item_4a._Integrating%20_Inverter-
Based_Resources_into_Low_Short_Circuit_Strength_Systems_-_2017-11-08-FINAL.pdf
43 See NERC Reliability Standard PRC-027-1: https://www.nerc.com/_layouts/15/PrintStandard.aspx?standardnumber=PRC-027-
1&title=Coordination%20of%20Protection%20Systems%20for%20Performance%20During%20Faults&Jurisdiction=United%20States
See NERC System Protection and Control Working Group technical reference document, Power Plant and Transmission System Protection
Coordination:
https://www.nerc.com/comm/PC/System%20Protection%20and%20Control%20Subcommittee%20SPCS%2020/SPCS%20Gen%20Prot%20Co
ordination%20Technical%20Reference%20Document.pdf
44 This is due to effects of BESS dc voltage and inverter derating due to temperature and altitude impacting reactive and active power output.
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Figure 1.1: Example of 2.7 MVA BESS Capability Curve [Source: SMA America]
Active Power-Frequency Control
BESS should have the capability to provide active power-frequency control that extends to the charging region; the
conventional droop characteristic can be extended into this region, and operation along the droop characteristic can
occur naturally. Deadbands, droop settings, and other response characteristics should be specified by the BA based
on studies performed by TPs and PCs. The droop characteristic and deadbands should be symmetrical, meaning that
the mode of operation settings for charging is the same for discharging. Droop should be set using the same base for
both charging and discharging mode of operation (i.e., rated active power, Pmax) so that the same rate of response is
provided regardless of operation mode (charging/discharging). Any transition between charging and discharging
modes of operation should occur seamlessly (i.e., a continuous smooth transition between charging and discharging).
The speed of response should also be coordinated with the BA based on primary frequency response needs.
Consistent with FERC Order 842, there should be no requirement for BESS resources to maintain a specific SOC for
provision of frequency response. Any active power-frequency control should be sustained unless the BESS SOC limits
power consumption or injection from the resource. However, the capacity and energy needed to support
interconnection frequency control is relatively small and for a short period; the BA may specify sustaining times. The
number of times active power-frequency controls change power output outside of the defined deadbands will have
a small but finite impact on battery lifespan depending on the technology used.
Fast Frequency Response
As the instantaneous penetration of inverter-based resources continues to increase, on-line synchronous inertia may
decrease and rate-of-change of frequency (ROCOF) may continue to increase. High ROCOF systems may be faced with
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the need for faster-responding resources to ensure that unexpected underfrequency load shedding (UFLS) operations
do not occur.45
BESS have the capability to provide FFR to counter rapid changes in frequency due to disturbances on the BPS. Similar
to solar PV, there are no rotational elements and therefore the active power output is predominantly driven by the
controls that are programmed into the inverter. BESS should have at least the following functional capabilities that
may be used if the BESS is within SOC and set points limits consistent with FERC Order 842:
• Configurable and field-adjustable droop gains, time constants, and deadbands within equipment limitations;
tuned to the requirements or criteria specified by the BA
• Real-time monitoring of BESS SOC to monitor performance limitations imposed on FFR capabilities
• The ability to provide a specified power response for a predetermined time profile in coordination with
primary frequency response as defined by the BA
Many different simulations can be performed to show the benefits of utilizing BESS for improving frequency response,
particularly improving the nadir of system frequency following a large loss of generation. Figure 1.2 illustrates one
study demonstrating these effects. The blue trace shows the response following a large generation loss for a
synchronous generation-based system. The red plot shows the same system (with same amount of reserves) with
the synchronous generation replaced with BESS (with one option of frequency control enabled). The green plots show
the system with BESS with a different frequency control logic and tuned appropriately. The system dominated by
synchronous machines exhibits an initial inertial response followed by a slower turbine-governor response. On the
other hand, while the BESS system does not have physical inertia like a synchronous machine, its controls can be
tuned to provide a suitably fast injection of energy such that the initial ROCOF remains nearly the same (or even
improves) and the frequency nadir is significantly improved. Note that voltages should be monitored closely as high-
speed active power responses can cause high-speed voltage fluctuations, especially in low short-circuit-ratio
conditions.
45https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/Fast_Frequency_Response_Con
cepts_and_BPS_Reliability_Needs_White_Paper.pdf
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Figure 1.2: Demonstration of Impacts of a BESS on Frequency Response
[Source: EPRI]
Reactive Power-Voltage Control (Normal Conditions and Small Disturbances)
BESS should have the capability to provide reactive power-voltage control in both charging and discharging modes;
however, it is useful to separate out the recommendations into each mode of operation:
• Discharging Operation: There are no significant differences between BESS during discharge operation and
other BPS-connected inverter-based generators with respect to reactive power-voltage control. BESS should
have the ability to support BPS voltage control by controlling their POM voltage within a reasonable range
during normal and abnormal grid conditions.
• Charging Operation: BESS should have the capability to control POM voltage during normal operation and
abnormal small disturbances on the BPS while operating in charging mode. The ability for resources
consuming power to support BPS voltage control adds significant reliability benefits to the BPS and may be
required by TOs as part of their interconnection requirements or by BAs, TOPs, or RCs for BPS operations.
As the resource transitions from charging to discharging modes of operation (or vice versa) or operates at zero active
power output while connected to the BPS, the BESS should have the capability and operational functionality enabled
to continuously control BPS voltage. This should be coordinated with any requirements established by the TO or TOP.
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Inverter Current Injection during Fault Conditions
BESS should behave similar to other inverter-based resources during fault conditions in terms of active and reactive
current injection. Active and reactive current injection during severe fault events should be configured to support the
BPS during and immediately following the fault event. Inverter-based resources, including BESS, should ensure that
the appropriate voltage-current relationships of magnitude and phase angles (i.e., appropriate positive and negative
sequence current injection) are applied. Inverter current limits should be adhered to in order to avoid unnecessary
tripping of inverters during fault events. Injection of current during and immediately after faults should be configured
to enable the inverter-based resource to remain connected to the BPS and support BPS reliability.
BESS will need to ensure adherence to SOC limits. A BPS fault typically persists for fractions of a second, and thus,
SOC should typically not be a concern; however, the SOC limits are always in effect and closely monitored by BESS. If
necessary, it may be possible to reserve a minor amount of energy for transient response to fault conditions.
The reactive current injection during fault conditions while the BESS is charging or discharging will depend on the
specific inverter controls and settings as well as the BESS PQ curve and its symmetry; in either case, dynamic reactive
current injection should support BPS voltages in both operating states. Furthermore, controls should be configured
for each specific installation such that voltage support (i.e., reactive current injection) has priority and the BESS can
stably recover active current output very quickly. Typically, this should occur in less than one second; however, this
will need to be studied by the TP and PC and configured accordingly.
Grid Forming
Most commercially available inverters currently require an external source to provide a reference voltage to which
the inverter phase-locks. These inverters are termed “grid following.”46 An alternative option is to control the BESS
in a way that it does not rely on external system strength for stable operation (i.e., termed “grid forming”).47 While
there is currently no standard industry definition for grid forming technology, a broad definition can be as follows:
Grid Forming: An inverter operating mode that enables reliable, stable, and secure operation when the
inverter is operating on a part of the grid with few (or zero) synchronous machines along with the possibility
of weak or non-existent ties to the rest of the BPS.
Four key aspects that enable achieving this operation mode are the following:
• Availability of an “energy buffer” to be deployed for imbalances in generation and load
• Ability of the inverter to contribute toward regulation of voltage and frequency
• Minimal communication latency between different layers of controllers
• A robust dc voltage that enables synthesis of an ac voltage for a wide variety of system conditions
BESS have these attributes and can effectively employ grid forming technology to improve BPS performance in the
future as penetrations of inverter-based resources continue to grow. Operation in grid forming mode may help
support BPS reliability and inverter stability during low short-circuit strength conditions. The capability to enable this
feature should be provided by all future BESS and used by the TP and PC as a possible solution option if necessary to
mitigate reliability issues that would otherwise result in costly reinforcement projects. However, the application of
grid forming technology is unlikely to be the sole solution that addresses all issues and thus, it should be used in
coordination with other possible solutions.
46 If short-circuit strength falls too low (i.e., the apparent fundamental-frequency impedance of the grid source becomes too high due to high
impedance or lack of available fault current), the sensitivity of the POM voltage to the active and reactive current injection of the inverter-
based resource increases and grid-following inverters can be susceptible to instability or control malfunction. There are multiple mitigation
options for these low short-circuit strength issues to help stabilize the ac voltage.
47 https://www.epri.com/research/products/000000003002018676
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Tesla’s Grid Forming + Grid Following Philosophy
Tesla BESS currently use a concept of “grid forming + grid following” where the BESS can provide both functionalities
based on BPS reliability needs. When the BESS is operating in virtual machine mode, the dynamics of a virtual
synchronous condenser are added to the output of the current-source inverter (see Figure 1.3). In a high short-circuit
strength grid, the virtual machine remains naturally inert and preserves the rapid, precisely controllable behaviors of
traditional inverter controls. On a lower short-circuit strength grid, the machine model reinforces grid strength by
providing subcycle phase response, voltage stability, and fast fault current injection that helps in smooth transitions
between different operating states. With such a hybrid approach, the BESS remains responsive to active and reactive
power dispatch commands while providing ERSs to the BPS during dynamic grid events. While there are many possible
ways to accomplish grid forming capabilities, Tesla has implemented this feature into its products to support BPS
operation with decreased inertia and overall system strength.
Figure 1.3: Concept of Tesla “Grid Forming + Grid-Following” Mode
[Source: Tesla]
System Restoration and Blackstart Capability
In the event of a large-scale outage caused by system instability, uncontrolled separation, or cascading, system
operators are tasked with executing blackstart plans to re-energize the BPS and return electric service to all
customers. This process is relatively slow as the blackstart plan identifies the boundaries of outage conditions, system
elements, critical loads, etc.; reconnects pre-defined generators and load points to the overall BPS; and carefully
resynchronizes regions or portions of the BPS. Throughout this entire process, grid operators are closely balancing
generation and demand as well as managing BPS voltages within operating limits. In order to actively participate in
blackstart and system restoration, a BESS will need to perform the following:
• Generate its own voltage and seamlessly synchronize to other portions of the BPS
• Reliably operate during large frequency, voltage, and power swings, and in low short-circuit strength
networks (detailed EMT studies should be conducted to demonstrate the ability to operate under these
conditions)
• Provide sufficient inrush current to energize transformers and transmission lines and start electric motors,
coordinating with the blackstart load (note that BESS, like other inverter-based resources, have limited ability
to provide high levels of inrush current relative to their nominal current rating)
• Assure availability immediately after a large-scale outage requiring system restoration activities; BESS will
need to be available for their RC and TOP at any point in time to be considered as a blackstart resource
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• Have sufficient energy to remain on-line and operational for the time required to ensure blackstart plans can
be successfully executed.48 Therefore, BESS energy ratings should be designed to achieve the required
periods and their states of charge should be maintained above a limit to ensure enough energy is available
for blackstart purposes
• Be able to quickly respond to and control fluctuations in system voltage and frequency
• Be able to start rapidly to minimize system restoration times
• Have redundancy to self-start in the event of any failures within the facility
• Make all control design, settings, configurable parameters, and accurate models available to the BA, TP, PC,
TOP, and RC, in order to ensure proper integration into the overall system blackstart scheme and
coordination between resources via appropriate engineering studies
• Have remote startup and operational control capabilities to avoid requiring dispatch of personnel to the field
State of Charge
SOC represents the present level of charge of an electric battery relative to its capacity, within the range of fully
discharged (0%) to fully charged (100%). Refer to the description of FERC Order No. 841 in Appendix A. The SOC of a
BESS affects the ability of the BESS to provide energy or other ERSs to the BPS at any given time.49 In many cases, the
BESS may have SOC limits that are tighter than 0–100% for battery lifespan and other equipment and performance
considerations. Alternatively, 0% and 100% may be defined as the normal range of operation, ignoring the extreme-
but-not-recommended charge and discharge levels.
In terms of performance, the following should be considered for the capability and operation of a BESS:
• Provision of ERSs to the BPS: All BESS should have the capability to provide ERSs, such as voltage support,
frequency response, and ramping capabilities, to support BPS operation. However, each BESS will be
configured to provide any one or multiple ERSs during on-line operation, based on real-time dispatch, SOC,
and system needs.
• Nearing SOC limits: As a BESS approaches its SOC limits, the BESS may ramp down its charging or discharging.
This ramp should be clearly defined by the owner of the BESS and communicated to the BA, TOP, and RC.
• SOC Limits and Frequency Response: Consistent with FERC Order 842, there should be no requirement for
BESS resources to maintain a specific SOC for provision of frequency response.
• SOC Limits and Reactive Power Support: Through the full range of SOC limits (i.e., SOCmin to SOCmax), the BESS
should be designed to provide full reactive power capability as required by the interconnection agreement.
SOC limits should not impact reactive power capability.
• SOC Limits and Blackstart Capabilities: SOC should be maintained above a limit to ensure there is energy to
fully execute a blackstart process as designed.
SOC limits affect the ability of the BESS to operate as expected, and any SOC limits will override any other ability of
the BESS to operate. These limits and how they affect BESS operation should be defined by the equipment
manufacturer, agreed upon by the BESS owner, and provided to the BA, TOP, and RC. For planning assessments, this
information is also important to the TP and PC as they establish planning cases.
48 This is defined by the TOP and RC. For example, PJM has requirements for blackstart resources to be operational for 16 hours:
http://www.pjm.com/-/media/markets-ops/ancillary/black-start-service/pjm-2018-rto-wide-black-start-rfp.ashx?la=en
49 https://www.nrel.gov/docs/fy19osti/74426.pdf
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The SOC of any BESS depends on the past operating conditions of the BESS and the services it is providing to the BPS.
To study BESS SOC, a time series (or quasi-dynamic) study can be used. Figure 1.4 shows an example of a BESS that
provides two services: peak shaving (charging in morning and discharging at night) and transmission line congestion
management around a set of wind power plants. The magnitude and duration of any other service provided by the
BESS (such as voltage control or frequency support capability) revolves around the two primary services. Figure 1.4
shows the evolution of the BESS SOC over two days, evaluated at half-hour time steps but with tracking of the
dynamic evolution of the SOC.
Figure 1.4: Example Time Series of BESS State of Charge
[Source: EPRI]
The assumption used in dynamic stability simulations is that SOC will not affect or limit the response of the BESS for
short-duration events (i.e., faults or short-term frequency excursions). However, longer-term issues, such as thermal
overload mitigation, may require more extensive information regarding BESS SOC. BESS manufacturers establish a
full operating range of the batteries (i.e., 0–100% SOC); however, the equipment manufacturer may also establish a
tighter range (e.g., 5–95% SOC) as the full operating range and this information may be provided to the GO or
developer. The full operating range of the BESS should be provided to the RC, TOP, BA, TP, and PC for inclusion in
tools and studies. It is important that the SOC base value (i.e., what establishes the operational 0–100% SOC) be well-
defined by the appropriate entities.
Oscillation Damping Support
Many synchronous generators are equipped with power system stabilizers (PSS) that provide damping to system
oscillation typically in the range of 0.2 Hz to 2 Hz. As these resources become increasingly limited (either retire or are
off-line during certain hours of the day), there is a growing need for oscillation damping support in certain parts of
the BPS. For example, in the West Texas area of the ERCOT footprint where significant amounts of renewable
generation resources connect, synchronous generators in West Texas may be off-line under a high renewable output
condition and could lead to insufficient damping support required to maintain stability for high-power long distance
power transfer during and after large disturbances. Currently, renewable generation resources are not required to
provide damping support in ERCOT, and synchronous condensers typically are not equipped with PSS. A study
conducted by ERCOT in 2019 identified oscillatory responses around 1.8 Hz between synchronous condensers in the
Panhandle area and other synchronous generators far away from this area under a high renewable generation
penetration condition with large power transfers to electrically distant load centers.50
50 http://www.ercot.com/content/wcm/lists/197392/2019_PanhandleStudy_public_V1_final.pdf
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Newly interconnecting BPS-connected inverter-based resources (IBR) should have the capability to provide power
oscillation damping controls. A major difference from BPS-connnected inverter-based resources is that BESS can
operate in the charging mode in addition to the discharging mode, which provide greater capabilities of damping
support. TPs and PCs may identify a reliability need for this type of control as the penetration of inverter-based
resources continues to increase. At that time, TOs should develop requirements to ensure that the capability is
activated and that BESS properly damps power oscillations in the range of 0.2 Hz to 2 Hz (typically) when the resources
are on-line and operational. Newly interconnecting facilities require detailed studies that would ensure the controls
provide oscillation damping as intended. Controls may need to be tuned (and possibly retuned after interconnection)
for optimal performance as the grid evolves over time. These types of studies are critical to ensure reliable operation
of the BPS over time. TOs should ensure interconnection requirements suitably address this functionality so the
capabilities can be used when needed.
Recommended Performance and Considerations for Hybrid Plants
Hybrid power plants, as described in the Introduction, include both dc-coupled and ac-coupled facilities. In terms of
describing the nuances and differences across technologies and configurations, it is useful to differentiate between
ac- and dc-coupled plants. Therefore, the following sub-sections introduce dc-coupled plants first (since there are
minimal differences between these facilities and standalone BESS facilities) and then provide more details around
considerations for ac-coupled plants. As previously mentioned, the guideline focuses primarily on hybrid plants
combining inverter-based renewable generation with BESS technology. The recommended performance
characteristics for hybrid plants generally refer to the overall hybrid facility since they are coordinated at the plant-
level; however, this guideline may refer to individual BESS or generation components within the facility where
necessary.
DC-Coupled Hybrid Plants
There is no significant difference in recommended performance between dc-coupled hybrid plants and stand-alone
BESS. The following performance characteristics are practically the same and are covered in Table 1.1 and in the
previous section:
• Momentary cessation
• Phase jump immunity
• Reactive current-voltage control during large disturbances
• Reactive power at no active power output
• Return to service following tripping
• Inverter current injection during fault conditions
• Balancing
• Monitoring
• Operation in low short-circuit strength systems
• Fault ride-through capability
• System restoration and blackstart capability
• Grid forming51
• Protection settings
51 The entire plant can have the capability to be grid forming, the capabilities will be limited by the inverter current limits and size of the BESS
portion of the dc-hybrid.
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• State of charge
• Damping support
Additionally, the following topics from Table 1.1 warrant additional details where dc-coupled hybrids have specific
considerations that need to be taken into account:
• Reactive Capability Curve: It is likely that total installed capacity of BESS and of other generating resources
behind the common inverter will be higher than the common inverter rating. Therefore, reactive capability
of dc-coupled hybrid during both active power injection and withdrawal, as well as zero active power, will be
limited by the inverter rating.
• Active Power – Frequency Controls and FFR: For these two topics, dc-coupled performance considerations
will be similar to that of ac-coupled hybrid as discussed in the next section. Overall, a dc-coupled plant’s
capability to provide frequency control both for under- and over-frequency events will be further limited by
the common inverter rating.
• Monitoring: BAs, TPs, PCs, independent system operators/regional transmission organizations (ISO/RTOs)
may require telemetry from each individual component within the facility (e.g., separate metering points for
the BESS and the generating component) to support forecasting, situational awareness tools in the control
room, and operations and planning study dispatch assumptions.
• State of Charge: State of charge has performance considerations similar to ac-coupled hybrids; they are
discussed in the next section.
AC-Coupled Hybrid Plants
Table 1.2 provides an overview of the considerations that should be addressed when describing the recommended
performance of ac-coupled hybrid plants compared with other BPS-connected inverter-based generating resources.
Table 1.2: High Level Considerations for AC-Coupled Hybrid Plant Performance
Category Comparison with BPS-Connected Inverter-Based Generators
Momentary Cessation
There are no significant differences from other BPS-connected inverter-based generating
resources; for the BESS part of the hybrid, momentary cessation should not be used to the
greatest possible extent 52 during charging and discharging operation.
Phase Jump Immunity There is no significant difference from other BPS-connected inverter-based generating
resources.
Capability Curve
The overall composite capability curve of a hybrid plant is the aggregation of the individual
capability curves of the generating resources and BESS plus any other reactive devices and
less any losses within the facility as measured at the plant POI. The capability curve
extends into the BESS charging region to create a four-quadrant capability curve. The
curve is not symmetrical for injection and withdrawal. On the injection side, the capability
curve will be equal to the sum of capability curves of a generator and capability curve of
BESS during discharging. On the withdrawal side, capability will be equal to BESS capability
curve, when charging. Note that interconnection requirements may not allow the full use
of hybrid resource capability depending on how the BESS can charge and discharge with
the generating component and with the grid. See Capability Curve section for more
information.
52 Unless there is an equipment limitation or a need for momentary cessation to maintain BPS stability. The former has to be communicated
by the GO to the TP while the latter has to be validated by extensive studies.
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Table 1.2: High Level Considerations for AC-Coupled Hybrid Plant Performance
Category Comparison with BPS-Connected Inverter-Based Generators
Active Power-
Frequency Controls
There is no significant difference from other BPS-connected inverter-based generating
resources and BESS. The conventional droop characteristic can be used in both generating
and charging modes of the hybrid. Active power-frequency control capability may be
limited by total active power injection and/or the withdrawal limit of the hybrid plant at
the POI that may be set lower than the sum of active power ratings of the individual
resources within the hybrid plant. Due to the presence of the BESS, a hybrid plant can also
have the capability of providing frequency response for under frequency conditions,
subject to the SOC and set point limits outlined in FERC Order 842. See Active Power-
Frequency Controls section for more information.
Fast Frequency
Response
FFR capability will depend on the resources making up the hybrid plant. BESS are well-
positioned to provide FFR to systems with high ROCOF due to absence of any rotational
components (similar to a solar PV facility). However, if the BESS is combined with wind
generation facility, coordination between resources within the hybrid may be needed to
achieve sustained FFR. Additionally, hybrid plant FFR capability may be limited to total
active power injection and/or withdrawal limit of the hybrid plant. The need for FFR varies
with each Interconnection’s specific needs.53 Sustained forms of FFR help arrest fast
frequency excursions but also help overall frequency control. BESS are likely to be able to
provide sustained FFR within their SOC constraints. Consistent with FERC Order 842, there
should be no requirement for hybrid resources to reserve headroom or violate set point
or SOC limits to provide frequency response though the BA can procure that service. See
Fast Frequency Response section for more information.
Reactive Power-
Voltage Control (Small
Disturbances)
There is no significant difference from other BPS-connected inverter-based generating
resources. The dynamic voltage support capability of a hybrid is a combination of
capability of the generating resource(s) and BESS, which are part of the hybrid. The BESS
portion of the hybrid has the capability to provide dynamic voltage control during both
discharging and charging operations. Note that system specific requirements may not
necessitate use of the full equipment capability of the hybrid plant. TOPs should provide
a voltage schedule (i.e., a voltage set point and tolerance) to the hybrid that can apply to
both operating modes (injection and withdrawal). See Reactive Power-Voltage Control
(Small Disturbances) section for more information.
Reactive Current-
Voltage Control
(Large Disturbance)
There is no significant difference from other BPS-connected inverter-based generating
resources. The BESS portion of the hybrid can be configured to provide dynamic voltage
support during large disturbances both while charging and discharging.
Reactive Power at No
Active Power Output
There is no significant difference from other BPS-connected inverter-based generating
resources.54
Inverter Current
Injection during Fault
Conditions
There is no significant difference from stand-alone BPS-connected inverter-based
generating resources and BESS. See Inverter Current Injection during Fault Conditions
section for more information.
53 NERC, “Fast Frequency Response Concepts and Bulk Power System Reliability Needs,” March 2020:
https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/Fast_Frequency_Response_Conce
pts_and_BPS_Reliability_Needs_White_Paper.pdf
54 As the resource transitions from charging to discharging modes of operation (or vice versa) or operates at zero active power output while
connected to the BPS, the BESS should have the capability and operational functionality enabled to continuously control BPS voltage.
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Table 1.2: High Level Considerations for AC-Coupled Hybrid Plant Performance
Category Comparison with BPS-Connected Inverter-Based Generators
Return to Service
Following Tripping
There is no significant difference from other BPS-connected inverter-based generating
resources. A hybrid plant should return to service following any tripping or other off-line
operation by operating at the origin (no significant exchange of active or reactive power
with the BPS), and then ramp back to the expected set point values, as applicable. This is
a function of settings and any requirements set forth by the BA (or TO in their
interconnection requirements).
Balancing There is no significant difference from other BPS-connected inverter-based generating
resources.
Monitoring There is no significant difference from other BPS-connected inverter-based generating
resources.
Operation in Low
Short-Circuit Strength
Systems
There is no significant difference from other BPS-connected inverter-based generating
resources.
Grid Forming
The BESS portion of a hybrid plant has unique capabilities to effectively deploy grid
forming technology to help improve BPS reliability in the future of a high penetration of
inverter-based resources. Newly interconnecting hybrid plants should consider using grid
forming technology to support the BPS under these future conditions. See Grid Forming
section for more information.
Fault Ride-Through
Capability
There is no significant difference from other BPS-connected inverter-based generating
resources. A hybrid plant should have the same capability to ride through fault events on
the BPS, when point of measurement (POM) voltage is within the curves specified in the
latest effective version of PRC-024, subject to limitations of legacy equipment. For the
BESS part of the hybrid, this applies to both charging and discharging modes. Unexpected
tripping of generation or load resources on the BPS will degrade system stability and
adversely impact BPS reliability. Ride-through capability is a fundamental need for all BPS-
connected resources such that planning studies can identify any expected risks.
System Restoration
and Blackstart
Capability
Hybrid plants may have the ability to form and sustain their own electrical island if they
are a part of a blackstart cranking path. This may require new controls topologies or
modifications to settings that enable this functionality. Blackstart conditions may cause
large power and voltage swings that must be reliably controlled and withstood by all
blackstart resources (i.e., operation under low short-circuit grid conditions). For the hybrid
to operate as a blackstart resource, assurance of energy availability and a designed energy
rating that ensures energy availability for the entire period of restoration activities are
needed. At this time, it is unlikely that most legacy hybrid plants can support system
restoration activities as a stand-alone resource; however, they may be used to enable
start-up of subsequent solar PV, wind, or synchronous machine plants and accommodate
fluctuations in supply and demand. See System Restoration and Blackstart Capability
section for more information.
Protection Settings There is no significant difference from other BPS-connected inverter-based generating
resources.
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Table 1.2: High Level Considerations for AC-Coupled Hybrid Plant Performance
Category Comparison with BPS-Connected Inverter-Based Generators
Power Quality There is no significant difference from other BPS-connected inverter-based generating
resources.
State of Charge (new)
Similarly to the standalone BESS, the SOC of a BESS portion of the hybrid may affect the
ability of the hybrid to provide energy or other ERSs to the BPS at any given time.55 These
limits and how they affect BESS operation should be defined by the hybrid owner and
provided to the BA, TOP, RC, TP, and PC.
BESS SOC will be optimized by the hybrid plant controller in coordination with other parts
of the hybrid (wind or solar) based on irradiance and/or wind conditions, market prices,
energy, and ERS obligations of the hybrid plant. In addition, the manner in which the BESS
would charge is to be communicated by the GO. Here, system loading conditions and
generation from other parts of the hybrid plant will play a role. For example, in a wind-
BESS hybrid plant during low load high renewable scenarios, the BESS may be charged
directly from the wind output. In this scenario, the hybrid plant will not appear as a load
on the system. Alternatively, the plant may be directed to charge from the network in
order to increase the loading on the system to satisfy stability considerations. See State
of Charge section for more information.
Operational Limits
(new)
Based on economics or design considerations, the BESS portion of the hybrid may be
operated to only charge from the wind and/or solar part of the hybrid or to charge from
the grid as well. The hybrid owner should provide this information to the BA, TOP, RC, TP,
and PC. Hybrid plant owners may choose to limit injection/withdrawal at the POI to a level
that is lower than actual capability of the hybrid. The hybrid owner should also provide
this information to the BA, TOP, RC, TP, and PC. Where such limit exists, the studies as well
as voltage support and frequency support requirements may apply only up to the limit.
See Operational Limits section for more information.
Damping Support
BESS can have the capability of providing oscillation damping support, similar to
synchronous gnerators, HVDC/FACTS facilities, and other BPS-connected inverter-based
resources. BESS can operate in both charging and discharging modes, which provides
greater capabilities for damping support.
Topics with Minimal Differences between AC-Coupled Hybrids and Standalone BESS Resources
Ac-coupled hybrid plants and standalone BESS share the following performance characteristics:
• Momentary cessation
• Phase jump immunity
• Reactive current-voltage control during large disturbances
• Reactive power at no active power output
• Return to service following tripping
• Inverter current injection during fault conditions
• Balancing
55 https://www.nrel.gov/docs/fy19osti/74426.pdf
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• Monitoring
• Operation in low short-circuit strength systems
• Fault ride-through capability
• System restoration and blackstart capability
• Grid forming56
• Protection settings
• Damping support
The following sub-sections outline the additional topics from Table 1.2 that warrant additional details and where ac-
coupled hybrids have specific considerations that need to be addressed.
Capability Curve
The overall active and reactive power capability of an ac-coupled hybrid plant is the summation of the capabilities for
each of the BESS and generating components within the facility. In terms of establishing the capability curve for an
ac-coupled hybrid plant, both the BESS and generating component should have their own capability curve that
simulation models would represent separately. The capability curve the GO provides to the RC, TOP, BA, TP, and PC
for their tools and studies should explicitly document and provide for any contractual limits that may limit active
power to a pre-determined level. Furthermore, the facility should not be unnecessarily limited from providing its full
reactive power capability by any plant-level controls. In general, the overall plant-level capability of an ac-coupled
hybrid plant will be asymmetrical with more active and reactive power capability when both the generating
component and BESS are injecting active power to the BPS. Figure 1.5 illustrates an example of an ac-coupled hybrid
plant consisting of a solar PV generation component with a BESS component.
TOs should ensure their interconnection requirements are clear on how capability curves are provided for BESS and
hybrid power plants, and TPs and PCs should ensure that their modeling requirements are also clear on how to
represent steady-state capability curves in the simulation tools used to study these resources.
56 The BESS component of an ac-coupled hybrid can have the capability to provide grid forming capability; if the hybrid facility is dc-coupled,
the entire plant can have the capability to be grid forming.
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Figure 1.5: Example of AC-Coupled Solar PV + BESS Hybrid Plant Capability Curve
[Source: NREL]
Active Power-Frequency Control
Active power-frequency controls can be extended to the charging region of operation for the BESS part of the
hybrid as described in detail in standalone BESS section earlier. The overall active power-frequency control
capability of the hybrid is equal to combined capability of all resources that are part of the hybrid plant. The overall
capability may be limited by total active power injection and/or withdrawal limit of the hybrid plant that may be set
lower than the sum of active power ratings of the individual resources within the hybrid plant.
Fast Frequency Response
BESS and solar PV have the capability of providing FFR to rapid changes in frequency disturbances on the BPS. Since
there are no rotational elements, the controls that are programmed into the inverter drive the active power output
predominantly. Wind generating resources can provide FFR through tapping into kinetic energy of rotating mass of a
wind turbine.57 Such response, however, cannot be sustained. To obtain sustained FFR from hybrid plants containing
wind/solar PV generating resources along with the BESS, the FFR capability of the ac-coupled hybrid plant is equal to
combined capability of all resources that are part of the hybrid plant. The resources within the hybrid can be
coordinated to optimize total FFR and achieve required sustain time. The overall capability may be limited by total
active power injection and/or withdrawal limit of the hybrid plant that may be set lower than actual capability of the
plant.
57https://www.nerc.com/comm/PC/InverterBased%20Resource%20Performance%20Task%20Force%20IRPT/Fast_Frequency_Response_Con
cepts_and_BPS_Reliability_Needs_White_Paper.pdf
Combined P-Q characteristic
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An ac-coupled hybrid plant should have at least the following capabilities that may be used based on BA requirements
and BPS reliability needs:
• Configurable and field-adjustable droop gains, time constants, and deadbands tuned to the requirements or
criteria specified by the BA
• Real-time monitoring of BESS SOC to understand performance limitations that could impose on FFR
capabilities from the hybrid
• The ability to provide sustained response, coordinated with primary frequency response as defined by the
BA
• Consistent with FERC Order 842, there should be no requirement for hybrid plants to maintain a specific SOC
for provision of frequency response
Reactive Power-Voltage Control (Normal Conditions and Small Disturbances)
There are no significant differences between ac-coupled hybrids and BPS-connected inverter-based resources with
respect to reactive power-voltage control during normal grid conditions and small disturbances. In essence, the
hybrid plant should have the capability to provide reactive power-voltage control both during power injection at the
POM and power withdrawal (during BESS charging); however, it is useful to separate the recommendations for each
mode of operation:
• Power Injection: There are no significant differences between hybrid plants during power injection into the
grid and other BPS-connected inverter-based generators with respect to reactive power-voltage control. The
hybrid plant should have the ability to support BPS voltage. Voltage control needs to be coordinated between
all resources within the hybrid plant to control the hybrid plant’s POM voltage within a reasonable range
during normal and abnormal grid conditions.
• Power Withdrawal: Hybrid plants should have the capability to control POM voltage during normal operation
and abnormal small disturbances on the BPS while the BESS part of the hybrid is operating in charging mode.
The ability for resources consuming power to support BPS voltage control adds significant reliability benefits
to the BPS and may be required by TOs as part of their interconnection requirements or by BAs, TOPs, or RCs
for BPS operations.
As the resource transitions from charging to discharging modes of operation (or vice versa) or operates at zero active
power output while connected to the BPS, the BESS should have the capability and operational functionality enabled
to continuously control BPS voltage. This should be coordinated with any requirements established by the TO or TOP.
Generally, the output voltages of inverter-based renewable energy resources vary severely due to large fluctuations
and rapid changes in the availability of their energy resources. Therefore, if used individually, it is difficult to control
these resources’ voltage; however, this issue is resolved in a hybrid power plant. Since the output voltage variation
of the BESS from a fully charged to a discharged state is typically less, this variation can be easily controlled to
maintain a stable output voltage. In addition, the battery is capable of balancing the power fluctuations either by
absorbing the excess power from the renewable energy resources during charging or by supplying the power to
satisfy the load-demand changes during discharging. As the resource transitions from charging to discharging modes
of operation, or vice versa, a hybrid power plant should continuously have the ability to control BPS voltage
throughout the transition.
State of Charge
SOC considerations for the BESS portion of the ac-coupled hybrid plant are similar to those of a stand-alone BESS
discussed earlier. The SOC of a BESS portion of the hybrid may affect the ability of the BESS to provide energy or other
ERSs to the BPS at any given time.58 The hybrid owner should define these limits and how they affect BESS operation
58 https://www.nrel.gov/docs/fy19osti/74426.pdf
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and provide these definitions to the BA, TOP, RC, TP, and PC. A BESS SOC will be optimized by the hybrid plant
controller in coordination with other parts of the hybrid (wind or solar) based on irradiance and/or wind conditions,
market prices, energy, and ESR obligations of the hybrid.
Operational Limits
Based on economics or design considerations, the BESS portion of a hybrid plant may be operated to only charge
from the generating component or to charge from the grid as well. Technical, economic, and policy considerations
will dictate whether the hybrid plant charges from the grid or only from the generating component.59 TOs and BAs
should clearly define the acceptable charging behavior from the hybrid plant and ensure that sufficient monitoring
capability is available to verify this performance. The hybrid owner should provide the charging characteristics and
any operational limitations to the BA, TOP, RC, TP, and PC.
The hybrid plant owner for various economic consideration may choose to set the injection/withdrawal limits at the
POI lower than actual capability of the hybrid plant. The hybrid owner should provide this information to the BA, TOP,
RC, TP, and PC. Where such a limit exists, the studies as well as voltage support and frequency support requirements
may apply only up to the limit.
59 In addition to any requirements imposed by the TO or BA regarding acceptable charging behavior, the structure of investment tax credits
may also contribute to the charging characteristic. For example, currently a hybrid plant may need to charge the BESS by renewable energy for
more than 75% of the time for the first five years of commercial operation, and the tax credit value for the storage component is derated in
proportion to the amount of grid charging between 0% and 25%.
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Chapter 2: BESS and Hybrid Plant Power Flow Modeling
BPS-connected BESS and hybrid plants are modeled very similarly to other BPS-connected inverter-based resources,
such as solar PV and wind power plants. This chapter provides a brief overview of the presently recommended power
flow modeling practices.
BESS Power Flow Modeling
The power flow representation for a BPS-connected BESS is similar to other types of BPS-connected inverter-based
resources. Figure 2.1 shows a generic 60 power flow model for a BPS-connected BESS facility. The power flow
representation of a BPS-connected BESS facility includes the following components:
• Generator Tie Line: Where the BESS is connected to the BPS (to the POI) through a transmission circuit (i.e.,
the generator tie line), this element should be explicitly modeled in the power flow to properly represent
active and reactive power losses and voltage drops or rises.
• Substation Transformer: Any substation transformers 61 (also referred to as “main power transformers”)
should be explicitly modeled in the power flow base case. All relevant transformer data, such as tap ratios,
load tap changer controls, and impedance values, should be modeled appropriately.
• Collector System Equivalent: Based on the cabling and layout of the BESS facility, some GOs may choose to
model an equivalent collector system to capture any voltage drop across the collector system. However, BESS
facilities are not geographically and electrically dispersed like wind and solar PV facilities, so BESS collector
system equivalent impedances are likely much smaller. Therefore, this may or may not be included in the
BESS power flow model.
• Equivalent Pad-Mounted Transformer: Each of the inverters interfacing the battery systems with the ac
electrical network will include a pad-mounted transformer. An equivalent pad-mounted transformer is
typically modeled, scaled to an appropriate size to match the overall MVA rating of the aggregate inverters
at the BESS facility.
• Equivalent BESS: An equivalent BESS generating resource is modeled to represent the aggregate amount of
inverter-interfaced BESS installed at the facility. The capability is scaled to match the overall capability of
aggregate inverters. The equivalent BESS is modeled as a generator in the power flow, and appropriate
voltage control settings (and other applicable control settings) should be specified in the model. In situations
where different inverter types (i.e., make and model of inverter) are used62 within the BESS, each different
inverter type is typically separately aggregated. GOs should consult with their TP and PC for recommended
modeling practices.
• Shunt Compensation and Reactive Devices: The plant may include shunt reactive devices to meet the
reactive capability and voltage requirements defined by the TO and TOP. These may include shunt capacitors
and reactors, FACTS devices, or synchronous condensers as applicable. If these devices are installed, they
should be modeled appropriately. Figure 2.1 also denotes that these installations could even be located at
the POI within the boundary of the GO and GOP and should also be modeled appropriately.
• Plant Loads: The plant may include a small load to represent station service load as deemed necessary based
on the TP and PC modeling requirements. Auxiliary loads supplied by the dc bus are generally not modeled.
60 Different configurations may exist for BESS facilities based on considerations at each individual installation. The power flow model provided
by the GO to the TP and PC should be an accurate representation of the actual installed (or expected) facility and should not use any default or
generic parameters or configurations.
61 Some BESS may have more than one substation transformer, and each should be explicitly modeled.
62 This occurs more frequently in inverter-based generating resources, either installed in different phases or often in large facilities.
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Elements in Figure 2.1 shown in red are elements that may or may not be represented in BESS models based on each
specific installation’s modeling needs, with the goal of capturing all the needed electrical effects. The elements
described in black should be modeled in all BPS-connected BESS facilities. Common voltage levels are shown in Figure
2.1 for illustrative purposes.
Figure 2.1: Generic Power Flow Model Example for BESS
The GO, TP, and PC will need to consider the following aspects of steady-state power flow modeling for BESS:
• Charging Operation: Charging capability can be modeled by setting the equivalent BESS generator with an
appropriate negative value for the active power limit, Pmin. Note that the maximum charging limit (Pmin) may
be different from the maximum discharging limit (Pmax). These Pmin and Pmax limits in the equivalent BESS
generator record should be set to any limits imposed by the plant and inverter controllers in coordination
with the capability of the inverters. In addition, the BA, TOP, RC, TP, and PC should ensure they understand
how the other BESS facility components (e.g., shunt compensation) operate during charging operation such
that the overall BESS model can be set up correctly in both charging and discharging modes.
• Point of Voltage Control and Power Factor Mode: As with other generating resources, the generating
resource (i.e., the equivalent BESS) can be configured to operate in either a power factor control mode or a
voltage control mode with a specific control point in the grid (i.e., the POM or POI). This should be configured
appropriately in the generator record voltage controls. Newer models may have advanced controls such as
voltage droop characteristic. Generator voltage reference can be changed to meet the voltage schedule.
Hybrid Power Flow Modeling
The configuration of hybrid plants will likely vary more than BESS facilities, based on the size of the plant, the type of
technologies used, and the overall layout of the facility. Regardless, each hybrid plant should be modeled according
to the expected63 or actual facilities installed in the field. Furthermore, hybrid plants may be modeled differently
depending on whether they are ac-coupled or dc-coupled facilities. GOs should consult with their TP and PC to
determine the appropriate modeling approach based on whether the facility is ac-coupled or dc-coupled.
AC-Coupled Hybrid Plant Power Flow Modeling
Figure 2.2 illustrates a generic model representation for an ac-coupled hybrid plant.64 Since the BESS and the
generating resource are connected through the ac network, each component should be represented accordingly, as
shown in Figure 2.2. An equivalent BESS generation, an equivalent pad-mounted transformer and an equivalent
collector system (if needed to properly represent the electrical effects) should be represented. For the example
63 During the interconnection study process
64 There are many different ac-coupled hybrid plant configurations; this is used as an example only.
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shown in Figure 2.2, where the ac-coupling is at the low voltage side of the substation main power transformer, the
inverter-based generating resource is coupled to the BESS at this point. The inverter-based generating resource also
has its own equivalent generator model, equivalent pad-mounted transformer, and equivalent collector system
modeled appropriately. The substation main power transformers and generator tie line are also modeled explicitly.
Any shunt compensation, such as shunt reactors, capacitors, FACTS devices, or synchronous condensers, should be
modeled as well. Again, elements shown in red may or may not be represented in the model based on each specific
location, and elements shown in black should be modeled for all facilities. Common voltage levels are shown only for
illustrative purposes.
Figure 2.2: Generic Power Flow Model Example for AC-Coupled Hybrid Power Plants
The GO, TP, and PC will need to consider the following aspects of steady-state power flow modeling for ac-coupled
hybrid power plants:
• Plant Configuration: The ac-coupled hybrid plants can have significantly different configurations on the ac-
side of the inverter interface. Therefore, special attention should be given to ensuring that the power flow
model accurately represents the overall configuration of the plant (which may be different from Figure 2.2).
• Coordinated Operation of BESS and Generating Component: Since the BESS is explicitly modeled, charging
and discharging capability can be represented by setting the equivalent BESS generator Pmin and Pmax values
appropriately. The Pmin and Pmax limits in the equivalent BESS generator record should be set to any limits
imposed by the plant and inverter controllers in coordination with the capability of the inverters. BESS
operation should be modeled by setting active power output, Pgen, accordingly. The BA, TOP, RC, TP, and PC
should ensure they understand how the BESS is expected to operate in relation to the inverter-based
generating component within the plant, such that the output of both resources is coordinated. This includes
at least the following:
Maximum Overall Plant Power Output (Plant Pmax): The maximum power output of the overall hybrid
facility may be limited by interconnection agreement, plant controller, or other means. While the
nameplate rating of the individual BESS and generating resources may exceed the limit, the power output
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of the overall facility may not; therefore, it is important to understand what the maximum operational
output of the plant will be. Most power flow software today does not have a way to represent this limit,
but the software industry should pursue the ability to explicitly model both the BESS and the generator
within an overall plant model with its own limitations. In the meantime, BAs, TOPs, RCs, TPs, PCs, and
GOs should develop a standardized way of documenting and communicating such limits.
BESS Charging from BPS or from Generating Resource: Depending on the interconnection agreement,
the hybrid plant may or may not be able to charge from the BPS. If allowed, the BESS may be able to
charge power from the BPS with the generating unit dispatched off. If not allowed, the BESS will only
charge using energy produced by the generating component of the plant. Most power flow software
today does not have an automatic or effective way to represent this limit, but the software industry
should pursue this capability. In the meantime, BAs, TOPs, RCs, TPs, PCs, and GOs should develop a
standardized way of documenting and communicating such limits.
Coordinating Voltage Controls for BESS and Generating Component: The hybrid power plant will have
obligations per VAR-002-4.1 to control voltage at its POI or POM, and the power flow base case should
be configured to ensure similar voltage control strategies as used in the field. In an ac-coupled hybrid
plant with the BESS and generating component modeled explicitly, the voltage controls will need to be
coordinated among both devices. Both equivalent generator records for the BESS and generating
component can be coordinated using the reactive power sharing parameter in each unit.65
The WECC Renewable Energy Modeling Task Force (REMTF) has developed recommendations for software vendors
to improve the capability for modeling BESS and hybrid plants,66 particularly for representing overall plant-level active
power limitations as well as plant-level coordinated voltage controls in the power flow base case. This will enable
more effective modeling of hybrid plant dispatch scenarios as well as overall plant voltage control.
DC-Coupled Hybrid Plant Power Flow Modeling
Figure 2.3 illustrates a generic model representation for a dc-coupled hybrid plant. For dc-coupled plants, the BESS
and inverter-based generating resources are coupled on the dc-side of the inverter. Therefore, the coupling is not
necessarily modeled in power flow simulation tools, and the coupled BESS and inverter-based generating resources
are aggregated to a single aggregate generator model. Since the coupling occurs at each individual generating
resource, there is no BESS inverter, pad-mounted transformer, or equivalent collector system represented. Only the
equivalent inverter-based generating resource (including the battery), the ac-side equivalent pad-mounted
transformer, and the equivalent collector system are represented. Similar to ac-coupled hybrid plants and other BPS-
connected inverter-based resources, the substation main power transformer and generator tie line are modeled
explicitly. Any shunt compensation, such as shunt reactors, capacitors, FACTS devices, or synchronous condensers
should be modeled as well. Again, elements shown in red may or may not be represented in the model based on each
specific location, and elements shown in black should be modeled for all facilities. Common voltage levels are shown
only for illustrative purposes.
65 This is similar to configuring multiple synchronous generators to control the same bus voltage.
66 WECC White Paper on Modeling Hybrid Power Plant of Renewable Energy and Battery Energy Storage System:
https://www.wecc.org/_layouts/15/WopiFrame.aspx?sourcedoc=/Administrative/WECC%20White%20Paper%20on%20modeling%20hybrid
%20solar-battery.pdf
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Figure 2.3: Generic Power Flow Model for DC-Coupled Hybrid Power Plants
The GO, TP, and PC will need to consider the following aspects of steady-state power flow modeling for dc-coupled
hybrid power plants:
• Charging and Discharging Operation: If the BESS only charges from the generating component (due to
interconnection requirements or if the ac/dc inverter is not bidirectional), then Pmin will remain zero for the
facility. If the BESS can charge from the grid, then Pmin for the equivalent generator component can be set to
the corresponding aggregate negative active power limit. Similarly, the maximum equivalent generator
power output, Pmax, should also be set according to equipment capabilities and plant limitations. Note that
the maximum charging limit (Pmin) may be different than the maximum discharging limit (Pmax). The TP and PC
should ensure they understand how the BESS and generating components are expected or required to
operate during charging and discharging operation so that the overall model can be set up correctly.
• Voltage Control: The appropriate type of voltage control should be accurately modeled (as with other
inverter-based resources), and all plant voltage control settings should be coordinated in the models.
• Frequency Response: While frequency response is modeled in the dynamic models, active power limits for
the facility should be coordinated between models so the resource is configured appropriately in the steady-
state and dynamic simulations. Droop gain should be configured appropriately to be consistent with per unit
representation of the plant and the actual MW response from the BESS portion.
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Chapter 3: BESS and Hybrid Plant Dynamics Modeling
With an appropriate power flow representation for the BESS or hybrid plant, dynamic models can be used to
represent the behavior of these resources during BPS disturbances. Dynamic modeling practices for BESS and hybrid
plants are similar to those of other BPS-connected inverter-based resources; however, there are some unique
characteristics to capture regarding four-quadrant operation of energy storage and consideration of SOC. This
chapter describes recommended practices for modeling BESS and hybrid plants including use of appropriate models,
model quality considerations, and EMT models.
Use of Standardized, User-Defined, and EMT Models
As with other inverter-based resources, the dynamic models used to represent BESS and hybrid power plants will
depend on TP and PC modeling requirements as well as the types of studies being conducted. GOs should refer to
the specific modeling requirements for each TP and PC when providing models during the interconnection study
process and should ensure that the models reflect the expected behavior of the facility seeking interconnection (or
facility installed in the field). TPs and PCs should consider updating their modeling requirements to ensure clarity and
consistency for modeling BESS and hybrids during interconnection studies, during annual planning assessments, and
any other studies being conducted. Some considerations for different model types include the following:
• Standardized Library Models: These types of models may be appropriate (and required) for Interconnection-
wide base case development. Standardized models, however, may not fully capture all BESS and hybrid
behavior and response characteristics during large disturbances. Standardized library models may not be able
to represent fully nonlinearities in control, communications delays across technologies, dynamic rise times,
etc. GOs should coordinate with their equipment manufacturers and any consultants developing plant-level
models to ensure these models are appropriate and suitably parameterized. TPs and PCs should ensure that
sufficient documentation is provided by the GO to verify that the actual field performance will sufficiently
match the dynamic model provided.
• User-Defined Models: These types of models are more appropriate for interconnection studies that may be
testing or screening for various issues, such as ride-through performance, operation in low short-circuit
conditions, local stability analysis, and other localized reliability assessments. The user-defined models may
be required in conjunction with the standardized library models, and TPs and PCs may require the GO to
provide benchmarking reports between the two models. A user-written dynamic model can be used to tune
the response of a standardized library model to represent the actual response of the resource as closely as
possible. Any discrepancies should be documented and explained by the equipment manufacturers. User
defined models that capture the “real code” of the inverters and plant-level controller installed in the field
are preferred.
• EMT Models: EMT platform allows for the most accurate representation of the dynamic response of an
inverter-based resource (including BESS and hybrid plants). TPs and PCs are recommended to require EMT
models for newly interconnecting BESS and hybrid plants since these models are the most appropriate to test
and analyze for ride-through capability, controls instability, unbalanced fault analysis, operation in low short-
circuit strength conditions, and any anomalous controls or instability performance that may be identified
during screening with the aforementioned model types. EMT models that capture the “real code” of the
inverters and plant-level controller installed in the field are preferred. As the grid continues to evolve,
modeling practices improve, and inverter control schemes get more complex, it is likely that EMT models will
be used more extensively. Reliability Guideline on EMT modeling 67 provides recommendations for the
development of EMT model requirements, EMT model collection, and model quality verification practices
specifically for EMT models used to represent BPS-connected inverter-based resources in reliability studies
67 Reliability Guideline: Electromagnetic Transient Modeling for BPS-Connected Inverter-Based Resources—Recommended Model
Requirements and Verification Practices
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conducted by TPs and PCs. The recommendations are intended to help ensure that EMT models provided by
GOs are representative of the expected behavior of the actual or planned facility to the greatest extent
possible so that potential reliability risks are adequately captured in the modeling studies. TPs and PCs are
advised to establish EMT model requirements and model quality verification practices as per the guideline.
As more BESS and hybrid plants interconnect to the BPS, it imperative that these resources are studied appropriately
with accurate models. TPs and PCs will weigh these considerations against their modeling practices and capabilities
and determine appropriate modeling requirements for existing and newly interconnecting generating resources.
Generating resources should not be allowed to interconnect without first meeting all modeling requirements of the
TPs and PCs.
Dynamic Model Quality Review Process
All TPs and PCs should have modeling requirements that include quality testing to ensure that the dynamic model is
a reasonable representation of the equipment installed in the field, that the model meets certain specifications, and
that the model performs reasonably when subjected to a set of simulation tests. Many TPs and PCs currently have
these types of quality tests in place,68 and all TPs and PCs are encouraged to strengthen their requirements,
particularly in the area of BESS and hybrid plant modeling. These quality tests can be applied to standardized library
models, to user-defined models, as well as to EMT models. The goal of these tests is to give the TP and PC assurance
that the model being used reasonably represents the equipment in the field and meets the expected performance
specifications established by the TO in their interconnection requirements. Examples of model quality tests used for
inverter-based resources that should also be applied to BESS and hybrid plants include, but are not limited to, the
following:
• Low and High Voltage Ride-Through Analysis: under various charging and discharging conditions (including
at power output limits), SOC conditions, and both consuming and producing reactive power
• Small Voltage and Frequency Disturbances: under various charging and discharging conditions (including at
power output limits), SOC conditions, and both consuming and producing reactive power
• Short-Circuit Strength Analysis: under varying levels of short-circuit strength with different (or stressed) local
dispatch scenarios for different charging and discharging conditions (including at power output limits) and
SOC conditions
BESS Dynamic Modeling
Although the implementation may be different among equipment manufacturers, the modeling structure of BPS-
connected BESS is (in principle) the same as BPS-connected solar PV and Type 4 wind plants. The overall structure
consists of a converter control module, an electrical control module, and a plant control module. Frequency ride-
through and voltage ride-through settings are modeled with the generator protection modules. This section describes
the use of the latest standardized library models to represent BESS (see Figure 3.1). The standardized library models,
with variation for each module, provide flexibility to simulate the overall plant dynamic behavior. The modules may
not directly match control blocks in the field, but they can be set up to achieve the desired performance by selecting
proper modules and control flags. User-defined models may also be required as described in this chapter. If user-
defined models are required by the TP and PC, specific modeling requirements should be in place that describe the
level of detail, transparency, functionality, and documentation.
68 ERCOT Model Quality Guide: https://www.ercot.com/files/docs/2021/04/20/Model_Quality_Guide.zip
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Q Control
P Control
Current
Limit
Logic
IqcmdIqcmd’
IpcmdIpcmd’
Generator
Model
Network
Solution
Plant Level V/
Q Control
Plant Level
P Control
VrefVreg
QrefQbranch
Pref
PbranchFreq_ref
Freg
Qext
Pref
REPC
Pqflag
REEC REGCVtVt
Iq
Ip
Figure 3.1: Block Diagrams of Different Modules of the WECC Generic Models 69
The different modules used in representing the dynamic behavior of a BESS include:
1. REGC (REGC_*)70 Module: used to represent the converter (inverter) interface with the grid. It processes the
real and reactive current command and outputs of real and reactive current injection into the grid model.
2. REEC (REEC_C/REEC_D)71 Module: used to represent the electrical controls of the inverters. It acts on the
active and reactive power reference from the REPC module, with feedback of terminal voltage and generator
power output, and gives real and reactive current commands to the REGC module.
3. REPC (REPC_*) Module: used to represent the plant controller. It processes voltage and reactive power
output to emulate volt/var control at the plant level. It also processes frequency and active power output to
emulate active power control. This module gives active/reactive power commands to the REEC module.
Table 3.1 shows the list of BESS simulation modules used in two common simulation platforms. Although
implementation across simulation platforms may differ, the modules have the same functionality and parameter sets.
Table 3.1: Dynamic Models used to Represent BESS in PSLF and PSSE
Module GE PSLF Modules Siemens PTI Modules
Grid interface regc_* REGC*
Electrical controls reec_c or reec_d REECC1 or REECD1
Plant controller repc_* REPC*/PLNTBU1
Voltage/frequency protection lhvrt/lhfrt VRGTPA/FRQTPA
Model invocation varies across software platforms, and users should refer to the software manuals for software-
specific implementations. The regulated bus and monitored branch in the REPC invocation should match the control
modes used in the REPC model. For example, if voltage droop control is used (droop control gain kc), then the
monitored branch should be specified in the model invocation.
69 WECC Solar PV Plant Modeling and Validation Guideline:
https://www.wecc.org/Reliability/Solar%20PV%20Plant%20Modeling%20and%20Validation%20Guidline.pdf
70 The symbol * is used throughout this document to refer to all available variation of the module (e.g., REGC_A, REGC_B, and REGC_C).
71 REEC_D and REPC_B model descriptions: https://www.wecc.org/Administrative/Memo_RES_Modeling_Updates_083120_Rev17_Clean.pdf
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Scaling for BESS Plant Size and Reactive Capability
Model parameters are expressed in per unit of the generator MVA base except in REPC_B. The specification of MVA
base is implementation-dependent.72 To scale the dynamic model to the size of the plant, the generator MVA base
parameter must be adjusted. It should be set to the sum of the individual inverter MVA ratings. The active and
reactive range are expressed in per unit on the scaled MVA base. The MVA base for the REPC_B model is always the
system MVA base in GE PSLF; Siemens PTI PSS/e implementation allows a different MVA base to be specified. The
per unit parameters of the REPC_B model should be expressed based on the MVA base used.
Reactive Power/Voltage Controls Options
The plant-level control module allows for the following reactive power control modes:
• Closed loop voltage regulation (V control) at a user-designated bus with optional line drop compensation,
droop response and deadband
• Closed loop reactive power regulation (Q control) on a user-designated branch, with optional deadband
• Constant power factor (PF) control on a user-designated branch active power and power factor. This control
function is available in REPC_B, not in REPC_A
In the electrical control module, other reactive control options are available as follows:
• Constant PF control based on the generator PF in the solved power flow case
• Constant reactive power based on either the equivalent generator reactive power in the solved power flow
case or from the plant controller
• Closed loop voltage regulation at the generator terminal
• Proportional reactive current injection during a user-defined voltage-dip event
Various combinations of plant-level and inverter-level reactive control are possible by setting the appropriate
parameters and switches. Table 3.2 shows a list of control options and respective models and the switch that would
be involved. Additional variations 73 of flag settings are not shown in Table 3.2 since they are not likely to be used for
BESS operation.
Table 3.2: Reactive Power Control Options for BESS Generic Models
Functionality Required Models pfflag vflag qflag refflag
Plant-level V control REEC + REPC 0 N/A* 0 1
Plant-level Q control and local
coordinated Q/V control REEC + REPC 0 1 1 0
Plant-level V control and local
coordinated Q/V control REEC + REPC 0 1 1 1
Plant-level PF control and local
coordinated Q/V control
REEC + REPC
(repc_b and above) 0 1 1 2
* "N/A" indicates that the state of the switch does not affect the indicated control mode.
72 For example, if MVA base is zero in reec_* or repc_*, then the MVA base entered for the regc applies to those models as well in the PSLF
implementation. The user may specify a different MVA if desired. In the PSSE implementation, the MVA base is set in the power flow model.
73 These unlikely variations include no representation of the plant-level controller (which is not likely with new facilities) and voltage regulation
options that would not meet automatic voltage regulation requirements found in NERC VAR Standards and most interconnection requirements.
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Active Power Control Options
The plant controller models include settable flags for the user to specify active power control. Table 3.3 shows the
active power control modes, the models, and parameters involved, respectively. These types of controls include the
following:
• Constant active power output based on the generator output in the solved power flow case
• Active power-frequency control with a proportional droop of different gains for over- and under-frequency
conditions, based on frequency deviation at a user-designated bus
The BESS is expected to provide frequency response in both upward and downward directions. The no response and
down only options are greyed out in Table 3.3 because they are unlikely to be approved by the transmission planning
entity (assuming interconnection requirements are fully utilizing the bi-direction capabilities of BESS technology). In
the WECC-recommended modeling enhancement for hybrid power plants,74 BaseLoad flag in the power flow model
could override the frqflag setting in the dynamic model. The frqflag/ddn/dup are meant to reflect the inverter
capability while BaseLoad flag represents the availability of the operational headroom. It is important to set BaseLoad
flag to zero for BESS generators regulating frequency.
Table 3.3: Active Power Control Options
Functionality BaseLoad flag* frqflag ddn dup
No frequency response 2 0 0 0
Frequency response, down only regulation 1 1 > 0 > 0
Frequency response, up and down 0 1 > 0 > 0
*BaseLoad flag is set in the power flow model.
Current Limit Logic
The electrical control module first determines the active and reactive current commands independently according to
the active power control option and reactive power control option. Each command is subject to the respective current
limit, 0 to Ipmax for active current and Iqmin to Iqmax for reactive current; then the total current of �Ipcmd2 +Iqcmd2 is limited by Imax. In situations where the current limit (Imax) of the equivalent inverter is
reached, the user should specify whether active or reactive current takes precedence by setting the pqflag parameter
in the REEC module.
State of Charge
The REEC_C module includes simulation of BESS’s SOC (see Table 3.2). An initial condition SOCini is specified. Then
Pgen is integrated during the simulation and added to SOCini. When SOC reaches SOCmax (i.e., fully charged),
charging is disabled by adjusting ipmin from a negative value to zero. Similarly, when SOC reaches SOCmin (i.e.,
depleted of energy), discharging is disabled by adjusting ipmax from a positive value to zero. This requires the user
to set SOCini based on the dispatching condition being analyzed. A common source of error has been that the BESS
is in the charging mode with SOCini = 1 and the Pgen is forced to zero in the simulation. Given the timeframe of
transient stability simulation, change of SOC throughout the simulation is negligible. For this reason, the SOC is
removed from the REEC_D module.
74 WECC White Paper on Modeling Hybrid Power Plant of Renewable Energy and Battery Energy Storage System:
https://www.wecc.org/_layouts/15/WopiFrame.aspx?sourcedoc=/Administrative/WECC%20White%20Paper%20on%20modeling%20hybrid
%20solar-battery.pdf
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Figure 3.2: Block Diagram of the Charging/Discharging Mechanism of the BESS
Representation of Voltage and Frequency Protection
Frequency and voltage ride-through are needed for transmission-connected solar PV plants. Because they are
simplified, the generic models may not be suitable to fully assess compliance with the voltage and frequency ride-
through requirement. Voltage ride-through is engineered as part of the plant design and needs far more sophisticated
modeling detail than is possible to capture in a positive-sequence simulation environment. It is best to use a
standardized (existing) protection model with voltage and frequency thresholds and time delays to show the
minimum disturbance tolerance requirement that applies to the plant. In addition, the frequency calculations in a
positive-sequence simulation tool are not accurate during or immediately following a fault nearby. It is best to use
the frequency protection relay model in a monitor-only mode and always have some time delay (e.g., at least 50
milliseconds) associated with any under- and over-frequency trip settings.75
Hybrid Plant Dynamics Modeling
The dynamic modeling approach to hybrid power plants also depends on whether they are ac-coupled or dc-coupled.
The modeling practices for the BESS component for ac-coupled hybrid resources generally follow the same principles
discussed in the BESS Dynamic Modeling section. This section provides additional considerations unique to the hybrid
power plants, both ac-coupled and dc-coupled.
As with stand-alone BESS modeling, model invocation is based on the specific simulation tool being used. The plant-
level controller model for ac-coupled hybrid resources will require careful consideration. In general, this model needs
to be invoked from one of the on-line generators in the plant, and the regulated bus and monitored branch must be
specified for the REPC_* model.
AC-Coupled Hybrid Modeling
For an ac-coupled hybrid plant, each resource type is modeled explicitly by a set of equivalent generator(s), equivalent
pad-mounted transformer(s) and equivalent collector system(s) in the power flow. Each generator has its set of REGC
and REEC models. It is recommended that REPC_B be used as the master plant controller to coordinate electrical
controls among all generators and apply plant-level active and reactive power limits. It is also recommended that
REEC_D be used for the non-BESS inverter-based generators for the reason discussed later in active power control.
Refer to Table 3.4 for implementations in two different software platforms.
Table 3.4: Models for AC-Coupled Hybrid Plants (in PSLF and PSSE)
Functionality GE PSLF Module Siemens PTI Module
BESS Grid Interface regc_* REGC*
BESS Electrical Controller reec_c or reec_d REECC1 or REECD1
75 https://www.wecc.org/Reliability/WECC_White_Paper_Frequency_062618_Clean_Final.pdf
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Table 3.4: Models for AC-Coupled Hybrid Plants (in PSLF and PSSE)
Functionality GE PSLF Module Siemens PTI Module
Plant-Level Controller repc_b 76 PLNTBU1
Auxiliary Controller REAX4BU1 or REAX3BU1
Voltage/Frequency Protection lhvrt/lhfrt VRGTPA/FRQTPA
Non-BESS Generation
Component of Hybrid Facility
Use appropriate modules for the generation type (i.e., applicable
models for wind, solar, synchronous generation, etc.)
Reactive Power Control
Each individual generation type in the hybrid power plant has its qmax and qmin specified in the REEC module. The
qmax and qmin values in REPC_B represent the reactive capability limits at the plant level. Depending on specific
interconnection requirements, the plant level limit could be contractual instead of physical. The qmax and qmin
values should reflect how the plant operates. The qmax and qmin values in REPC_B are provided on the system MVA
base instead of the generator MVA base. Similar practices need to be carefully applied when using other software
platforms.
The reactive power capability requirement is generally specified at the high side of the substation transformer(s). For
a hybrid power plant, an individual generation type may not have the capability to meet the requirement. Instead,
different generation types supplement each other to provide required var capability. Depending on the dispatch
condition, one type may have little reactive capability available and the other has full capability. The weighting factors
of voltage/var control (parameter kwi) need to be tuned for different operating conditions.
Active Power Control
Hybrid power plants may have a contractual plant-level Pmax less than the sum of the individual generator Pmax.
Pmax and Pmin in the REPC_B module represent the contractual plant level active power limits. Pmax and Pmin in
REPC_B are provided on the system MVA base instead of the generator MVA base. This should be carefully considered
in all models.
The frequency response is only modeled in REPC_B for the entire plant and pref is distributed among generators by
the weighting factors kzi. Kzi may need to be tuned for different operation conditions. But more often, the hybrid
plant relies on BESS for upward frequency response. REEC_D module should be used in conjunction with REPC_B to
block or enable frequency response at the generator level. See an example in Table 3.5. The generator type that does
not have headroom for upward frequency response has its BaseLoad flag set to 1. REEC_D module will set Pmax to
initial Pgen during the initialization, thus, blocking the upward frequency response. The BESS has its BaseLoad flag
set to 0 and will respond to the active power command from REPC_B.
76 The repc_b module in PSLF is equivalent to the combined PLNTBU1 and REAX4BU1/REAX3BU1 in PSS®E.
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Table 3.5: Active Power-Frequency Control Settings for Hybrid Configurations
Component BaseLoad Flag Module
Solar PV - Frequency response, down only regulation 1 reec_d
BESS - Frequency response, up and down 0 reec_c or reec_d
Plant controller N/A* repc_b with
Frqflag=1, dup > 0, ddn > 0
* The BaseLoad flag in the power flow is associated with each individual component. There is no BaseLoad flag for the plant.
DC-Coupled Hybrid Modeling
For a dc-coupled hybrid plant, one equivalent generator represents the inverters for multiple dc-side sources,
typically solar PV and battery storage. One set of REGC, REEC, and REPC models is needed for the equivalent
generator. The electrical control module suitable for the battery storage (REEC_C or REEC_D) could always be used
for these types of inverters. In case the battery does not charge from the grid, the user may choose to use the
electrical control module suitable for the other dc-side energy source, e.g., the REEC_A module. Refer to Table 3.6
for implementations in two different software platforms.
Table 3.6: Models for DC-Coupled Hybrid in PSLF and PSS®E
Component PSLF Module PSS®E Modules
Grid Interface regc_* REGC*
Electrical
Controls
May Charge from Grid reec_c or reec_d REECC1 or REECD1
DC-Side Charging Only reec_a or reec_d REECA1 or REECD1
Plant Controller repc_* REPC*/PLNTBU1
Voltage/Frequency Protection lhvrt/lhfrt VRGTPA/FRQTPA
The modeling considerations for a dc-coupled hybrid plant are the same as those discussed in the BESS Dynamic
Modeling section above.
Electromagnetic Transient Modeling for BESS and Hybrid Plants
Recommendations pertaining to EMT modeling of BESS and hybrid power plants are very similar to those outlined in
other NERC reliability guidelines.77 All TPs and PCs should establish EMT modeling requirements for all newly
interconnecting BESS and hybrid plants. GOs should coordinate with equipment manufacturers and any other entities
(e.g., consultants developing the models) to ensure the model represents the expected topologies, controls, and
settings of the plant seeking interconnections and to ensure that the models are updated after commissioning to
represent the as-built settings of the facility. TPs and PCs should collect sufficient data and supplementary
information from the GO to ensure that the as-built settings match the model.
It is important that the fundamental-frequency, positive-sequence dynamic models are a reasonable representation
of the facility as well, and the EMT models can help serve as a useful verification of those models. Benchmarking
becomes increasingly important, as plant-level controls get more complex across multiple manufacturers and
77 https://www.nerc.com/comm/PC_Reliability_Guidelines_DL/Reliability_Guideline_IBR_Interconnection_Requirements_Improvements.pdf
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different technologies. TPs and PCs should ensure that equipment manufacturers and GOs provide documentation
to explain how the plant controller works and how the model(s) map to those controls.
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Chapter 4: BESS and Hybrid Plant Short Circuit Modeling
BESS and hybrid plants should be modeled in short-circuit programs during the interconnection process and during
ongoing planning, design, and protection setting activities. TPs, PCs, TOs, and other entities should develop or
enhance modeling practices for BESS and hybrid plants as new capabilities and features for existing tools become
available. At a high-level, the recommendations for modeling BESS and hybrid plants are nearly identical to other full-
converter, inverter-based generating resources (i.e., Type 4 wind, solar PV, voltage source converter HVDC, and other
FACTS devices).78 The modeling practices described in this chapter should help the industry develop standardized
approaches for modeling BESS and hybrid plants (similar to other inverter-based resources) that capture the key
performance characteristics and other nuances 79 involved with modeling each specific facility appropriately and
representing equipment ratings.
BESS Short Circuit Modeling
The IEEE Power System Relaying and Control Committee Working Group C24 led the development of state-of-the-art
inverter-based resource short-circuit modeling practices and recently published Technical Report #78: Modification
of Commercial Fault Calculation Programs for Wind Turbine Generators.80 This report advised industry on necessary
modifications to commercial short-circuit programs to allow accurate modeling of wind turbine generators and wind
power plants. While the report does not specifically discuss modeling solar PV, BESS, or other inverter-based
resources, the recommendations for modeling Type 4, full-converter wind resources also apply to solar PV and BESS
facilities. Presently, software vendors for commercial short-circuit programs have incorporated the new modeling
approach to represent voltage-dependent current sources in their respective programs.81 TOs, TPs, and PCs should
coordinate to ensure that modeling requirements are reflective of these new capabilities and that well-defined
specifications are in place to collect all necessary short-circuit modeling information from the GO. GOs can work with
their inverter manufacturer to gather the necessary information to meet the modeling requirements.
In general, inverters are voltage-dependent current sources, meaning the amount of active and reactive current
injected by the inverter during a fault is dependent on its terminal voltage. Inverter control logic dictates the voltage
dependency (i.e., K-factor or closed-loop response) and is typically non-linear. As with wind and solar PV resources,
the fault current from a BESS also depends on the pre-fault current. Particularly for BESS, it also depends on whether
the BESS is charging or discharging prior to the fault. BESS fault current is relatively independent of BESS SOC since
the SOC does not modify any control loops or affect inverter overload current capability.82
The IEEE Power System Relaying and Control Committee Working Group C24 report recommends that fault current
injection information be provided for inverter-based resources in a tabular form (see Table 4.1 as an example). These
tables should be provided for different fault types as specified by the TO, TP, and PC. Furthermore, inverter controls
may take time to reach a steady-state fault current level so the report recommends that fault current data is provided
for various time instants after fault initiation (e.g., 1, 3, and 5 cycles). If the resource provides unbalanced fault
currents for unbalanced faults, then additional tables will be needed for the negative sequence current contribution.
Particularly for BESS, a different set of tables should be provided for BESS in charging and discharging operation. Most
TPs and PCs prefer data provided in sequence domain (positive, negative, and zero) rather than in phase domain.
Again, TOs, TPs, and PCs should ensure their modeling requirements are clear regarding the type of information (and
78 See Chapter 3 of NERC Reliability Guideline: Improvements to Interconnection Requirements for BPS-Connected Inverter-Based Resources:
https://www.nerc.com/comm/PC_Reliability_Guidelines_DL/Reliability_Guideline_IBR_Interconnection_Requirements_Improvements.pdf.
79 Such as capturing different control algorithms and any additional short-circuit current from BESS due to additional energy on the dc bus
80 IEEE PES Technical Report TR78: Modification of Commercial Fault Calculation Programs for Wind Turbine Generators:
https://resourcecenter.ieee-pes.org/technical-publications/technical-reports/PES_TP_TR78_PSRC_FAULT_062320.html
81 See “Siemens Technical Bulletin - Inverter-Based Generator Models with Controlled Power and Current – 2019 PSS CAPE User Group Meeting”
and “ASPEN Technical Bulletin – Modeling Type-4 Wind Plants and Solar Plants” for more details.
82 BESS SOC is closely managed and not expected to be operated near the edge of its charge or discharge limit during normal operation.
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format) needed, and GOs should coordinate with their inverter manufacturer to provide the necessary modeling
information.
Table 4.1 shows an example (and should only be taken as an example) of the steady-state fault current contribution
of a BESS to a symmetrical three-phase fault and assumes that the BESS only provides positive sequence current. In
this example, if a three-phase fault were to cause the inverter terminal positive sequence voltage to drop to 50%, the
inverter will inject 120% of rated current at a power factor angle of -45 degrees. A negative power factor angle (i.e.,
current lags voltage) means that the reactive current is injected into the network. Assuming that the inverter is not
designed to inject unbalanced current during unbalanced faults, the inverter would inject the same current if a Line-
to -Line fault on the network results in an inverter terminal positive sequence voltage of 50%. However, if the inverter
can inject an unbalanced current, then a similar table representing negative sequence quantities should be provided
by the GO. TOs, TPs, and PCs should ensure that their interconnection requirements clearly state how this short-
circuit behavior (and short-circuit models) must be provided during the interconnection process.
Table 4.1: Example Positive Sequence Fault Current from BESS
V1* (pu) I1* (pu) Angle between
V1 and I1 (deg) Active Reactive Total
0.9 1.00 0.17 1.01 -9.7
0.8 1.00 0.34 1.06 -18.8
0.7 1.00 0.51 1.12 -27.0
0.6 0.80 0.68 1.20 -34.5
0.5 0.85 0.85 1.20 -45.0
0.4 0.63 1.02 1.20 -58.3
0.3 0.15 1.19 1.20 -82.9
0.2 0.0 1.20 1.20 -90.0
0.1 0.0 1.20 1.20 -90.0
* V1 = positive sequence voltage; I1 = positive sequence current
Hybrid Plant Short Circuit Modeling
As with the steady-state and dynamics modeling recommendations described in Chapter 2 and Chapter 3,
respectively, short-circuit modeling recommendations depend on whether the plant is ac-coupled or dc-coupled:
• DC-Coupled Hybrid Plant: As noted earlier, the fault current contribution is dictated by the inverter that
couples the ac side with multiple resources on the dc side. The fault behavior of an inverter does not change
if there are multiple energy sources behind it. For the purpose of short-circuit modeling, inverter modeling
practices are the same as noted above (i.e., dc-coupled plants are modeled like other inverter-based
resources).
• AC-Coupled Hybrid Plant: An ac-coupled hybrid power plant couples each form of generation or storage at a
common collection bus on the ac side. The ac-coupled plants should have the generating component and the
BESS component modeled separately. The inverters used may be from different manufacturers, from
different models, and have different control philosophies that need to each be represented appropriately.
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Chapter 5: Studies for BESS and Hybrid Plants
As BESS and hybrid plants become more prevalent, it will become increasingly important to accurately reflect these
resources in simulations of BPS reliability, including studies during the interconnection process as well as operational
planning and annual planning assessments. When considering study assumptions, the primary difference between
BESS (including hybrid plants with BESS) revolves around the assumptions regarding charging and discharging
operating points under various system conditions when compared to other resources. This chapter describes
considerations to be accounted for in these studies that model the various dispatches and study the reliability impacts
of these resources.
Interconnection Studies
Interconnection studies for new or modified BESS and hybrid plants include the same types of studies performed for
any other IBR, including steady-state, short circuit, and stability analyses. These studies should be designed to
consider all reasonable charging and discharging scenarios the plant may be expected to experience and that may be
expected to stress the system and the plant under study. Given that a BESS or the battery component of a hybrid
resource are controllable and generally responsive to system conditions, study assumptions should be appropriate
for all possible operating scenarios (e.g., when the BESS or battery component of a hybrid plant are charging and
discharging). In addition, the most-stressed assumptions should be modeled to assess reliability while keeping in
mind that there can be different most-stressed scenarios for different hours of a year and for different local networks.
Consideration should be given to the characteristics of the system where the plant is interconnecting, including other
resource types in the area.
Interconnection studies should incorporate appropriate steady-state and dynamic ratings of all equipment, any
qualified changes to battery management system (BMS) firmware or site controls, and identify the most-limiting
elements that establish any system operating limits. Interconnecting entities should apply dynamic limits of
equipment as appropriate to support all services available from the BESS or hybrid plant. No administrative limits
should be applied. Entities should avoid establishing static limits that will limit BESS and hybrid plants from providing
dynamic services for the BPS. Short-circuit studies will also be needed in order to ensure appropriate breaker duty
ratings, protective relay settings, and sufficient and appropriate fault currents. EMT studies may also be needed,
based on specific system conditions at the POI (e.g., control interactions or control instability in low short-circuit
strength areas). All reliability studies should use models that have been validated and rigorously verified by the TP
and PC to be appropriate for the type of study being conducted.
Table 5.1 provides a list of example scenarios possibly studied during the interconnection process and considerations
for each. This list is not exhaustive nor is it necessary for every interconnection study. TPs and PCs should consider
the full extent of possible BESS and hybrid plant modes of operation based on the local interconnection requirements
or market rules and perform reliability studies to ensure reliable operation of the BPS under all expected operating
conditions. For example, hybrid plants may or may not be allowed to charge from the BPS depending on local
requirements. TPs and PCs will need to make these considerations as they develop their study approaches. In general,
BESS and hybrid plants will follow directives from the BA and RC based on system reliability needs and market
incentives where applicable, and TPs and PCs can use this assumption when determining appropriate charge and
discharge assumptions. For example, in a market environment, the battery will typically discharge during periods of
high power prices and charge during times of low power prices. Generally, the price of power will be higher during
peak demand and lower during low demand or high renewable output conditions.83 Table 5.1 was constructed with
these assumptions in mind with exceptions noted.
83 However, these assumptions may change over time as more BESS and hybrid plants connect to the BPS, changing the overall system’s
operational characteristics.
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Table 5.1: Potential BESS and Hybrid Plant Study Dispatch Scenarios
System
Conditions
Plant
Type Plant Dispatch Considerations
Peak net
demand
BESS
Fully discharging This is a feasible scenario.
Fully charging
Depending on market mechanisms and system rules, this
scenario may not be feasible. However, there may be
situations where this is a feasible scenario. For example, in a
system that has a lot of wind generation, a BESS may be
charging to prepare for a time later in the day when the wind
is expected to die down if there is high wind output at peak
load. Another feasible scenario would be when a BESS is
charging right before peak load, when the system is “near”
peak.
Hybrid
Maximum plant output
This is a feasible scenario. This scenario could be achieved by a
combination of maximum renewable generation output
and/or maximum battery output to achieve the maximum
facility rating as limited by the power plant controller.
Maximum renewable
generation output with
battery fully charging
This may be a feasible scenario. Though it is unlikely to stress
the system, this scenario could stress the plant and may need
to be studied in transient simulations.
No or low renewable
generation output with
battery fully discharging
This is a feasible scenario. The BESS component injects power
at its maximum capability with some or no contributions from
the generating component.
No or low renewable
generation output with
battery fully charging
from the grid
This is similar to the BESS fully charging scenario as described
above. Depending on interconnection requirements and
market rules, this scenario may not be feasible. However,
there may be situations where this is a feasible scenario
depending on localized transmission constraints.
Off-peak
(low) net
demand
BESS Fully discharging This is an unlikely scenario, but it is possible an area could have
a high price due to nearby constraints so it needs to be studied.
Fully charging This is a feasible scenario.
Hybrid
Maximum plant output
This is a feasible scenario. This scenario could be achieved by
maximum renewable generation output that is sustained for a
period long enough that the battery is no longer able to
charge.
Maximum renewable
generation output with
maximum battery
charging
This may be a feasible scenario. Though it is unlikely to stress
the system, this scenario could stress the plant and may need
to be studied in transient simulations.
No or low renewable
generation output with
battery fully discharging
This is unlikely to be feasible, but it may be a feasible scenario
for ac-coupled hybrids in some situations depending on
localized transmission constraints.
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Table 5.1: Potential BESS and Hybrid Plant Study Dispatch Scenarios
System
Conditions
Plant
Type Plant Dispatch Considerations
No or low renewable
generation output with
battery fully charging
from the grid
This may be a feasible scenario depending on interconnection
requirements, market rules, and plant design. Solar
investment tax credit rules may incent hybrids to not charge
from the grid during the first five years of operation, but it may
be feasible starting in year six.
High
system-
wide
renewable
generation
output
BESS Fully discharging This is an unlikely yet possible scenario.
Fully charging This is a feasible scenario.
Hybrid
Maximum plant output This is a feasible scenario.
Maximum renewable
generation output with
maximum battery
charging
This may be a feasible scenario. Though it is unlikely to stress
the system, this scenario could stress the plant and may need
to be studied in transient simulations.
Changes in
dispatch BESS Variable
BESS transitions between charging and discharging should be
tested in both steady-state and dynamic simulations. TPs and
PCs should test that the model matches required ramping
requirements (as applicable) and ensure that changes in power
dispatch do not adversely affect BPS reliability (e.g., power
quality, flicker, voltage deviations, successive operation 84 of
voltage control devices).
BESS can operate in different operating modes that may change over time. Examples include active power-frequency
control, peak shaving, and energy arbitrage. TPs should consider the impact of each operating mode on BPS
performance.
Hybrid Additions: Needed Studies
When a BESS component is added to an existing generating facility or BMS firmware of an existing BESS is changed
or updated, additional interconnection studies may be required per the latest version of the NERC FAC-002 Reliability
Standard, as this would constitute a qualified change of the existing facility. Studies of qualified changes are crucial
for ensuring that changes to facility ratings, performance, or behavior do not adversely affect BPS reliability. The
types of studies and the level of detail of those studies should be determined by the TP and PC as part of the study
process. This is particularly dependent on how the addition of the BESS affects the existing facility; see example
scenarios as follows:
• If the BESS connects through the same existing ac/dc inverter as the generating component (i.e., dc-coupled),
and no modifications to the ac/dc inverter occur
• If the BESS connects through the same existing ac/dc inverter as the generating component (i.e., dc-coupled),
and modifications to the ac/dc inverter occur or a new ac/dc inverter is used
• If the BESS connects through its own ac/dc inverter (i.e., ac-coupled)
84 Some voltage control devices, such as transformer load tap changers or fixed capacitors, are limited in the number of operations that are
allowed in a given timeframe.
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A key aspect to consider, particularly with the second and third scenarios in this list, is whether the modifications to
the facility and its new operational characteristics allow the BESS to charge from the BPS or only from the generating
component (a key factor for existing unidirectional inverter technology). The operational capabilities and
requirements in place should drive the specific types of studies the TP and PC will perform. Again, any modifications
to the facility that result in changes to its electrical behavior, operational characteristics, or performance should be
studied through the qualified change process in the latest version of the FAC-002 standard. Table 5.2 provides some
guidance on the studies that should be performed for these situations.
Table 5.2: Interconnection Study Needs for Battery Storage Addition at Existing Plant
Process/ Study
AC-Coupled or DC-Coupled
with New/Modified
Inverter
DC-Coupled with Existing
Inverter and Grid Charging
DC-Coupled without Grid
Charging (no inverter
changes)
Registration with and
Notification to the
TP/PC
Needed Needed Needed
Steady-State Power
Flow Study
Needed if the maximum
plant active power
injection or withdrawal
capability changes or if the
operational characteristics
change; not needed
otherwise
Needed to study charging
mode
May be needed to study
different operating
conditions
Short-Circuit Study Needed Not needed Not needed
Stability Study 85 Needed Needed to study charging
mode
May be needed to study
different operating
conditions
In all cases in Table 5.2 regarding the modification of an existing facility to convert it to a hybrid facility, the GO should
coordinate with their TP and PC to ensure that any necessary modeling, study, and performance requirements are
met with the changes being made. TPs and PCs should ensure that their interconnection process and requirements
clearly describe how studies are performed using accurate models of the expected facility modifications.
Transmission Planning Assessment Studies
Traditionally, system-assessment steady-state and stability studies tend to focus on peak-load and off-peak study
conditions. However, with the growth of variable energy resources combined with an increase in BESS and hybrid
resources, operational planning and long-term planning studies need to evolve to analyze more scenarios as there
may be critical and stressed conditions outside of those traditionally studied. TPs and PCs should develop a set of
study conditions that reasonably stress the system for their region. TPs and PCs may begin relying on the operational
flexibilities of BESS and hybrid plants in the future and will need to consider the operational limitations and energy
ratings of the BESS and hybrid plants. Planners will need to consider the impact of BESS SOC and the duration of
charge available to ensure that the operational solution can remain in place until other automatic or operator actions
take place. This is particularly important when performing steady-state contingency analysis, where TPs and PCs will
85 This includes review of system and plant stability as well as other types of performance tests such as voltage, frequency, and phase jump
ride-through performance.
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need to closely consider the duration of the outage and the energy available from BESS and hybrid plants to support
the BPS post-contingency.86 Refer back to Table 5.1 as a reference for study scenarios to begin these conversations.
A good approach to determine when the BESS or hybrid plant is expected to charge versus discharge is to employ
production cost simulation techniques. The results from production cost simulations can provide useful information
regarding the operational characteristics of the BESS or hybrid plant. The most stressed system conditions can then
be determined by using engineering judgement for future-year cases. Similar tools could also be used for the power
flow and dynamics analyses to avoid guessing at the most stressed conditions. One challenge with using production
cost approaches is determining the exact location and operational characteristics of future BESS and hybrid plants in
future year cases where system operational characteristics may be different than past experience. This poses a
challenge for grid planners in developing corrective action plans and planning a future system that has sufficient
operational flexibility.
Even when charging from the grid, a BESS or a hybrid plant is not considered to be load. Curtailment of charging
should not be considered non-consequential load loss if such curtailment is needed to meet performance
requirements of Table 1 of TPL-001-4/TPL-001-5.
Blackstart Study Considerations
In the near-term, it is not likely that BESS will be sized with sufficient energy to meet blackstart requirements (in
terms of sustained power output); however, it is likely that BESS and hybrid plants may be able to help support system
restoration. This will require that the BESS or hybrid plant can operate in “island mode” or stand-alone operation and
be able to transition to BPS-connected automatically. It also requires that the resource operate in “grid forming”
mode where it can develop its own local voltage (without any or minimal support from synchronous machines),
energize BPS elements, and connect to other local loads and generators. TPs and PCs performing blackstart studies
should ensure proper transitions to and from operation in islanding mode. Considerations for these studies include
the following:
• Transitioning to and from Islanding Mode: The objective is to ensure stable transition of BESS operation
between grid-connected mode and islanding mode. An example of such a study is to consider the loss of the
last synchronous machine in the network that results in the BESS or hybrid plant (possibly along with other
IBRs) being the only sources of energy to serve load. Following the transition, and for any subsequent events
within the island (for example, a fault or load change), the BESS or hybrid plant (and other IBR) controls
should be able to bring voltage and frequency back close to their nominal values while meeting existing
reliability and system security metrics. The same stable transition should be delivered when returning to a
grid-connected mode.
• Operating in Islanding Mode: The objective is to ensure that the BESS or hybrid plant can properly control
local voltage and frequency when connected to local load with no, or minimal, other synchronous machines
or other generators. Simulation tests to be performed may include load step up/down, ringdown, voltage
ride-through, and frequency ride-through tests.
• Blackstart: If the BESS or hybrid plant meets the TO, TP, and PC requirements for blackstart, then the
objective is to ensure the blackstart capability can be met whether the BESS or hybrid plant is the sole
resource or is deployed as part of the blackstart cranking path. A typical example of a blackstart study can be
conducted as follows: energize main power transformer from project side, connect the project to the local
BPS network and serve localized load, and then apply a bus fault at the POI to demonstrate that the resource
can stably and reliably serve that local load during the system restoration process.
86 This may become more complex as increasing numbers of BESS and hybrid plants connect to the BPS and are modeled in power flow studies.
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CAISO BESS and Hybrid Study Approach Example
This section provides a brief description of the CAISO approach for studying BESS and hybrid plants.
CAISO Generation Interconnection Study
Most of the active CAISO interconnection requests are hybrid plants. All hybrid plant requests are studied at the
hybrid plant full output level with the BESS at discharging mode. If the interconnection customer elects to charge
from the grid, the hybrid request is studied in the charging assessment as well. The maximum charging power is
specified in the interconnection request. The two studies that are performed include the following:
• Discharging Assessment: This assessment includes gross peak and off-peak daytime scenarios with dispatch
shown in Table 5.3. For hybrid power plant requests, the total hybrid plant active power is enforced.
• Charging Assessment: This assessment includes gross peak or shoulder peak and off-peak nighttime
scenarios. In shoulder peak and off-peak nighttime scenarios, solar power output is zero. For most of the
hybrid requests, this means on-site generation is not available to charge the energy storage and create the
most stressed condition for the transmission grid.
Table 5.3 shows the different assumptions that are used for the studies conducted. The purpose of the reliability
assessment is to define the boundaries of operation. Mitigation of a potential problem is usually through generation
re-dispatch (congestion management) or RAS actions. Careful consideration should be made during the
interconnection process regarding facilities with planned RASs. As the number of RASs increase on the BPS, the need
for a comprehensive system review should be considered.
Table 5.3: CAISO Reliability Assessment Dispatch Assumptions
Condition Peak Peak Charging Shoulder
Peak
Charging Off-Peak Daytime Off-Peak
Nighttime
Charging
Load Level87 1-in-10 years 1-in-10 years 75% of peak 50% ~ 65% of peak 40% of peak
Solar Generation Pmax Pmax 0 85% of Pmax 0
Wind Generation Pmax 50–65% of Pmax 50% of Pmax Pmax Pmax
Energy Storage
Dispatch
Max
discharging 88 Max charging 89 Max charging Max discharging Max charging
Other Renewable Pmax Pmax Pmax Pmax Pmax
Thermal
Generation Pmax As needed to
balance load
As needed to
balance load
As needed to
balance load
As needed to
balance load
Hydro
Generation
Based on
historical
data
Based on
historical data
Based on
historical data
Based on historical
data
Based on
historical data
Import Levels Historical max flows adjusted to accommodate output from renewable generation as needed
87 Forecasted demand levels for peak conditions are in likelihoods (1-in-10 is a 1 in 10-year likelihood) and are based on historical data for off-
peak conditions that are then scaled to selected study years.
88 Maximum steady-state positive output associated with the maximum net output in the Interconnection Request
89 Maximum steady-state negative output for re-charging of the energy storage facility
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BESS follow market dispatch instructions and will be discharged or charged according to system needs. A possible
solution to mitigate reliability issues is to dispatch the BESS in a different mode (charging or discharging). However,
there are challenges associated with reliance on this capability without knowing detailed information about the SOC
of the BESS. Furthermore, experience has shown that the frequency of deep cycling the BESS shortens its lifetime, so
BESS should be sized based on expected frequency profile at the POI.
CAISO also performs deliverability assessments90 as part of the interconnection study process. This includes a
deliverability assessment at peak demand for resource adequacy purposes as well as a delivery assessment at off-
peak demand to evaluate potential curtailment of intermittent resources (i.e., wind and solar). Table 5.4 shows the
assumptions used in these deliverability assessments.
Table 5.4: Study Assumptions for BESS and Hybrid Resources in Deliverability Assessment
Delivery Assessment Standalone BESS AC-Coupled Hybrid DC-Coupled Hybrid
Peak 4-hr discharging capacity 4-hr discharging capacity with total plant output <= plant
pmax
Off-Peak Pgen=0 from BESS. Existing BESS or hybrid may be put into charging mode in order to
mitigate overload.
CAISO Transmission Planning Study
Many different power flow and stability studies are conducted when considering the overall annual transmission
planning study program. The dispatch of BESS and hybrid plants are set based on the time stamp and assumptions
used for each scenario being studied. Production cost simulations are used to determine the appropriate dispatch
scenarios for future year cases.
90 http://www.caiso.com/Documents/IssuePaper-GenerationDeliverabilityAssessment.pdf
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Appendix A: Relevant FERC Orders to BESS and Hybrids
The Federal Energy Regulatory Commission (FERC) recently issued orders pertaining to electric storage resources that
are relevant to the guidance contained in this reliability guideline. FERC defined an electric storage resource as
follows:
• Electric Storage Resource (FERC Definition):91 a resource capable of receiving electric energy from the grid
and storing it for later injection of electric energy back to the grid.”
FERC’s determinations in Order No. 841, Order No. 842, and Order No. 845 are leading to new wholesale market
participation models, updates to interconnection studies processes, and new operating practices.
FERC Order No. 841
In Order No. 84192 (February 15, 2018), FERC required RTOs and ISOs under its jurisdiction to establish participation
models that recognize the physical and operational characteristics of electric storage resources. Each participation
model, per the order, must “ensure that a resource using the participation model for electric storage resources is
eligible to provide all capacity, energy, and ancillary services that it is technically capable of providing in the RTO/ISO
markets” and “account for the physical and operational characteristics of electric storage resources through bidding
parameters or other means.” These ancillary services may include blackstart service, primary frequency response
service, reactive power service, frequency regulation, or any other services defined by the RTO/ISO.
The Commission gave flexibility to both transmission providers in determining telemetry requirements as well as to
electric storage resources in managing SOC. To the extent that electric storage resources are providing ancillary
services, such as frequency regulation, an electric storage resource managing its SOC is required to follow dispatch
signals. For ease of reference, the Commission provided a chart of “physical and operational characteristics of electric
storage resources for which each RTO’s and ISO’s participation model for electric storage resources must account,”
as shown in Table A.1. How these characteristics are accounted for in participation models may vary between RTOs
and ISOs. Note that these definitions are not endorsed by the NERC Inverter-Based Resource Performance
Subcommittee (IRPS); rather, they are provided here only as a reference.
Table A.1: FERC Participation Model Parameters
Physical or Operational
Characteristic Definition
State of Charge The amount of energy stored in proportion to the limit on the amount of energy that
can be stored, typically expressed as a percentage. It represents the forecasted starting
SOC for the market interval being offered into.
Maximum State of
Charge (SOCmax)
A SOC value that should not be exceeded (i.e., gone above) when a resource using the
participation model for electric storage resources is receiving electric energy from the
grid (e.g., 95% SOC).93
Minimum State of
Charge
A SOC value that should not be exceeded (i.e., gone below) when a resource using the
participation model for electric storage resources is injecting electric energy to the grid
(e.g., 5% SOC).
91 FERC Order No. 841, paragraph 29
92 https://ferc.gov/sites/default/files/2020-06/Order-841.pdf
93 The IRPS notes that the base for defining the percentage SOC is not defined and therefore up to interpretation by the ISO/RTO.
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Table A.1: FERC Participation Model Parameters
Physical or Operational
Characteristic Definition
Maximum Charge Limit The maximum MW quantity of electric energy [power]94 that a resource using the
participation model for electric storage resources can receive from the grid.
Maximum Discharge
Limit
The maximum MW quantity that a resource using the participation model for electric
storage resources can inject to the grid.
Minimum Charge Time The shortest duration that a resource using the participation model for electric storage
resources is able to be dispatched by the RTO/ISO to receive electric energy from the
grid (e.g., one hour).
Maximum Charge Time The maximum duration that a resource using the participation model for electric storage
resources is able to be dispatched by the RTO/ISO to receive electric energy from the
grid (e.g., four hours).
Minimum Run* Time The minimum amount of time that a resource using the participation model for electric
storage resources is able to inject electric energy to the grid (e.g., one hour).
Maximum Run Time The maximum amount of time that a resource using the participation model for electric
storage resources is able to inject electric energy to the grid (e.g., four hours).
Minimum Discharge
Limit
The minimum MW output level that a resource using the participation model for electric
storage resources can inject onto the grid.
Minimum Charge Limit The minimum MW level that a resource using the participation model for electric
storage resources can receive from the grid.
Discharge Ramp Rate The speed at which a resource using the participation model for electric storage
resources can move from zero output to its Maximum Discharge Limit.
Charge Ramp Rate The speed at which a resource using the participation model for electric storage
resources can move from zero output to its Maximum Charge Limit.
* Note that the definitions here interchange “run” and “discharge.” The preferred term is “discharge.”
FERC Order No. 842
In Order No. 842 95 (February 15, 2018), the Commission determined that electric storage resources under its
jurisdiction are only required to provide primary frequency response (PFR) when they are “online and are dispatched
to inject electricity to the grid and/or dispatched to receive electricity from the grid.” This excludes situations when
an electric storage resource is not dispatched to inject or receive electricity.96 The Commission required electric
storage resources and transmission providers to specify an “operating range for the basis of the provision of primary
frequency response.” The operating range, the Commission explained, represents the minimum and maximum states
of charge between which an electric storage resource must provide PFR. The operating range for each electric storage
resource must ensure the following:
94 There is a disagreement between units in the FERC definitions. The term “power” is added to note that IRPS believes this refers to a power
term (i.e, MW) and it not intended to be a rate (i.e., MW/sec).
95 https://cms.ferc.gov/sites/default/files/whats-new/comm-meet/2018/021518/E-2.pdf
96 As in, electric storage resources are not obligated to provide any frequency response to the BPS if dispatched at 0 MW output. However, the
requirements in Order No. 842 are minimum requirements and an electric storage resource may provide this service if the market rules or
interconnection requirements are set up to enable this capability. Providing primary frequency response when dispatched at 0 MW could help
BPS frequency stability moving forward.
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• Be agreed to by the interconnection customer and the transmission provider, in consultation with the
Balancing Authority
• Consider the system needs for primary frequency response
• Consider the physical limitations of the electric storage resource as identified by the developer and any
relevant manufacturer specifications
• Be established in Appendix C of the Large Generator Interconnection Agreement (LGIA) or Attachment 5 of
the Small Generator Interconnection Agreement (SGIA)
The Commission noted that this suite of requirements “effectively allows electric storage resources to identify a
minimum and maximum set point below and above which they will not be obligated to provide primary frequency
response comparable to synchronous generation.” In summary, the Commission provided electric storage resource
interconnection customers with the ability to propose an operating range and the transmission provider or BA the
ability to consider system needs for primary frequency response before determining final operating ranges.
Given that “system conditions and contingency planning can change” and that “capabilities of electric storage
resources to provide primary frequency response may change due to degradation, repowering, or changes in service
obligations,” the Commission determined that the ultimate operating ranges may be dynamic values. If a dynamic
range is implemented, then transmission providers must also determine how frequently the operating range will be
reevaluated and the factors that may be considered during its reevaluation. The Commission provided electric storage
resources specific exemptions from PFR provision for a “physical energy limitation”:
“the circumstance when a resource would not have the physical ability, due to insufficient remaining charge
for an electric storage resource or insufficient remaining fuel for a generating facility to satisfy its timely and
sustained primary frequency response service obligation, as dictated by the magnitude of the frequency
deviation and the droop parameter of the governor or equivalent controls.”
The Commission also clarified that MW droop response is derived from nameplate capacity. If dispatched to charge
during an abnormal frequency deviation, the Commission required electric storage resources to meet PFR
requirements by increasing (for overfrequency) or decreasing (for underfrequency) the “rate at which they are
charging according to the droop parameter.” To illustrate, the Commission gave an example of an electric storage
resource charging at two MW with a calculated response per the droop parameter to increase real-power output by
one MW. According to the Commission, during an underfrequency deviation the electric storage resource could
“satisfy its obligation by reducing its consumption by one MW (instead of completely reducing its consumption by
the full two MW and then discharging at one MW, which would result in a net of three MW provided as primary
frequency response).” Electric storage resources are not required to change from charging to discharging, or vice
versa, if technically incapable of doing so during the event when PFR is needed.
The Commission also noted that requirements adopted in Order No. 842 are minimum requirements. An electric
storage resource may elect, in coordination with its transmission provider and BA, “to operate in a more responsive
mode by using lower droop or tighter deadband settings.”
As with all frequency-responsive resources connected to the BPS, speed of response has a significant impact on
frequency performance during large disturbances, particularly in low inertia systems with high ROCOF. FERC Order
No. 842 does not prescribe any speed of response characteristics for electric storage resources. See Chapter 1 for
more details on how the performance of BESS and hybrid plants can be configured to support BPS frequency response
needs.
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FERC Order No. 845
In Order No. 845 97 (April 19, 2018), the Commission clarified that “in certain situations, electric storage resources can
function as a generating facility, a transmission asset, or both.” The Commission made clear that electric storage
resources under its jurisdiction that are greater than 20 MW had the option to interconnect pursuant to the Large
Generator Interconnection Procedures (LGIP) and LGIA “so long as they meet the threshold requirements as stated
in those documents.” In the event the LGIA does not accommodate for the load characteristics of electric storage
resources, transmission providers may enter into non-conforming LGIAs.
Furthermore, in Order No. 845, the Commission declined to move forward with “any requirements for modeling
electric storage resources”:
“…given the limited experience interconnecting electric storage resources and the abundant desire for
regional flexibility, we are not imposing any standard requirements at this time and instead continue to allow
transmission providers to model electric storage resources in ways that are most appropriate in their
respective regions.”
Instead, the Commission encouraged transmission providers to continue to consider modeling approaches that will
“save costs and improve the efficiency of the interconnection process.”
FERC Order No. 845-A
In Order No. 845-A98 (February 21, 2019), the Commission reiterated that Order No. 845 allows electric storage
resources to interconnect pursuant to the LGIP and LGIA but declined to impose requirements on how transmission
providers study the load characteristics of electric storage resources. Instead, the Commission clarified that
transmission providers “have the flexibility to address the load characteristics of electric storage resources” within
studies, including studies of electric storage resource load characteristics and studies of the upgrades required to
accommodate electric storage resource load characteristics. Furthermore, the Commission stated that transmission
providers may enter into non-conforming LGIAs “when necessary” in order to accommodate a particular electric
storage resource.
97 https://www.ferc.gov/sites/default/files/2020-04/E-2_47.pdf
98 https://ferc.gov/sites/default/files/2020-06/Order-845-A.pdf
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Contributors
NERC gratefully acknowledges the contributions and assistance of the following industry experts in the preparation
of this guideline.
Name Entity
Mark Ahlstrom NextEra Energy
Hassan Baklou San Diego Gas and Electric
Fernando Benavides Southern California Edison
Leo Bernier AES
Sudipto Bhowmik Burns & McDonnell
Jeff Billo Electric Reliability Council of Texas
Doug Bowman Southwest Power Pool
Rajni Burra REPlantSolutions
Hung-Ming Chou Dominion Energy
Kevin Collins First Solar
Nicolas Compas Hydro Quebec
Gary Custer SMA America
Cole Dietert Electric Power Engineers
Ransome Egunjobi Lower Colorado River Authority
Evangelos Farantatos Electric Power Research Institute
Roberto Favela El Paso Electric Company
Lou Fonte California ISO
Vahan Gevorgian National Renewable Energy Laboratory
Michael Goggin Grid Strategies
Irina Green California ISO
Andy Hoke National Renewable Energy Laboratory
Warren Hess Midcontinent ISO
Kaitlyn Howling Invenergy
Shun-Hsien (Fred) Huang Electric Reliability Council of Texas
Henry Huang Pacific Northwest National Laboratory
Andrew Isaacs Electranix
Himanshu Jain National Renewable Energy Laboratory
Prashant Kansal Tesla
Venkat Konala Urban Grid
Dan Kopin Utility Services
Timothy Kopp Electric Power Engineers
Sergey Kynev Siemens
Chester Li Hydro One
Andrew Lopez Southern California Edison
Sudip Manandhar Southern Company
Adam Manty American Transmission Company
Brad Marszalkowski ISO New England
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Contributors
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Name Entity
Julia Matevosyan Electric Reliability Council of Texas
Hugo Mena Electric Power Engineers
Nihal Mohan Midcontinent ISO
Danny Musher Key Capture Energy
David Narang National Renewable Energy Laboratory
Om Nayak NAYAK Corporation
Siddharth Pant General Electric
Manish Patel Southern Company
David Piper Southern California Edison
Bill Quaintance Duke Energy Progress
Deepak Ramasubramanian Electric Power Research Institute
Matthew Richwine Telos Energy
Mark Robinson AES
Fabio Rodriguez Duke Florida
Michael Ropp Sandia National Laboratory
Thomas Schmidt Grau Vestas
Al Schriver NextEra Energy
Jay Senthil Siemens PTI
Lakshmi Srinivasan Lockheed Martin
Khundmir Syed Burns & McDonnell
Sirisha Tanneeru Xcel Energy
Chue Thor Sacramento Municipal Utility District
Farhad Yahyaie Powertech Labs
Billy Yancey Electric Power Engineers
Songzhe Zhu California ISO
Rich Bauer North American Electric Reliability Corporation
Stephen Coterillo North American Electric Reliability Corporation
Hongtao Ma North American Electric Reliability Corporation
Ryan Quint North American Electric Reliability Corporation
Alexander Shattuck North American Electric Reliability Corporation
Aung Thant North American Electric Reliability Corporation
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Guideline Information and Revision History
Guideline Information
Category/Topic:
BESS Modeling
Reliability Guideline/Security Guideline/Hybrid:
Reliability Guideline
Identification Number:
RG – MOD- 0623
Subgroup:
Inverter-Based Resource Performance Subcommittee
Revision History
Version Comments Approval Date
2
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Metrics
Pursuant to the Commission’s Order on January 19, 2021, North American Electric Reliability Corporation, 174 FERC
¶ 61,030 (2021), reliability guidelines shall now include metrics to support evaluation during triennial review
consistent with the RSTC Charter.
Baseline Metrics
All NERC reliability guidelines include the following baseline metrics:
• BPS performance prior to and after a reliability guideline as reflected in NERC’s State of Reliability Report and
Long Term Reliability Assessments (e.g., Long Term Reliability Assessment and seasonal assessments)
• Use and effectiveness of a reliability guideline as reported by industry via survey
• Industry assessment of the extent to which a reliability guideline is addressing risk as reported via survey
Specific Metrics
The RSTC or any of its subcommittees can modify and propose metrics specific to the guideline in order to measure
and evaluate its effectiveness, listed as follows:
• Review of the number of category 1i events99 involving utility-scale battery energy storage systems and
hybrid inverter-based resources under the NERC Event Analysis program
Effectiveness Survey
On January 19, 2021, FERC accepted the NERC-proposed approach for evaluating Reliability Guidelines. This
evaluation process takes place under the leadership of the RSTC and includes:
• industry survey on effectiveness of Reliability Guidelines;
• triennial review with a recommendation to NERC on the effectiveness of a Reliability Guideline and/or
whether risks warrant additional measures; and
• NERC’s determination whether additional action might be appropriate to address potential risks to reliability
in light of the RSTC’s recommendation and all other data within NERC’s possession pertaining to the relevant
issue.
NERC is asking entities who are users of Reliability and Security Guidelines to respond to the short survey provided in
the link below.
Guideline Effectiveness Survey
99 https://www.nerc.com/pa/rrm/ea/ERO_EAP_Documents%20DL/ERO_EAP_v4.0_final.pdf#search=EAP
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1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:18 AM
To:Gabriel Clark
Subject:FW: Catastrophic BESS fire in Moss Landing with scientific proof of 100x to 1000x
increase of toxic fallout as far downwind as 27.2 miles downwind
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 12:12 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: Fw: Catastrophic BESS fire in Moss Landing with scientific proof of 100x to 1000x increase of toxic fallout as far
downwind as 27.2 miles downwind
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
From: James DeLay <jamesdelay@hotmail.com>
Sent: Thursday, May 1, 2025 2:37 PM
Page 255 of 758
2
To: crakes@auburnwa.gov <crakes@auburnwa.gov>; kbaldwin@auburnwa.gov <kbaldwin@auburnwa.gov>;
ttaylor@auburnwa.gov <ttaylor@auburnwa.gov>; ytrout@auburnwa.gov <ytrout@auburnwa.gov>;
ctaylor@auburnwa.gov <ctaylor@auburnwa.gov>; LStirgus@auburnwa.gov <LStirgus@auburnwa.gov>;
hamer@auburnwa.gov <hamer@auburnwa.gov>
Cc: planning@auburn <planning@auburn>; publiccomment@auburnwa.gov <publiccomment@auburnwa.gov>
Subject: Catastrophic BESS fire in Moss Landing with scientific proof of 100x to 1000x increase of toxic fallout as far
downwind as 27.2 miles downwind
Good afternoon Auburn Leaders,
I hope you are all having a good day!
It has been a while since I emailed you to give you data about Battery Energy Storage Systems (BESS).
I am very appreciative that you are taking comments on a potential BESS moratorium for many reasons- but
#1 is for everyone's safety...
You probably haven't heard how Monterey, Elkhorn Preserve, Moss Landing, and surrounding California
counties have suffered a catastrophic contamination event that we won't know the full extent of damages to
the environment and people exposed for decades.
Monterey County declared a State of Emergency due to the Jan 2025 Moss Landing BESS fire.
Every lithium BESS is at risk of causing catastrophic consequences like in Moss Landing, as there is no
technology that can prevent lithium batteries from entering thermal runaway, no technology that can stop
thermal runaway, and no technology that can extinguish a lithium BESS fire.
A couple points:
Lithium battery fires start with what is called "Thermal Runaway" which simply put, is a chain reaction of
chemical reactions in a lithium-ion battery that causes the battery to overheat uncontrollably. There is no
known preventative technology that can stop thermal runaway, as once it starts the chemical reactions and
heat cannot be stopped.
Additionally, lithium battery fires are 100% self-feeding, and there is no extinguishing technology that can
safely, quickly, and totally extinguish a lithium BESS fire- so the current standard operating procedure for all
lithium battery BESS is to let the battery fire burn itself out.
In short, nothing can prevent a lithium battery from entering thermal runaway and once it does, nothing can
stop it.
Until there is a 100% effective, safe, and fast thermal runaway prevention solution AND a 100% effective, safe,
and fast extinguishing solution (both of which are guaranteed)- lithium batteries should not be used in BESS
anywhere near sensitive environments like schools, hospitals, homes nor should they be allowed near
sensitive environments like wetlands, rivers, streams, farmland, and aquifers.
Even the University of Washington's Clean Energy Institute declared "safety make Li-ion batteries a poor fit for
grid-scale energy storage."
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Fortunately, there a many safe grid scale and long duration energy storage solutions that don't have any of the
consequences and risks of lithium BESS...
Speaking of risks and consequences, as I mentioned briefly above, terrifying consequences have been
confirmed through access to over 10 years of documented scientific data after the January 16th 2025 Moss
Landing BESS fire (the 4th fire at this BESS at the time- in late February it re-ignited causing Moss Landing to
have its 5th fire forcing evacuations for people within 2.5 miles, shelter-in place orders for people beyond
that, Highway and road closures) that should make us all re-think our grid energy storage focus on lithium
battery based storage to alternative long duration energy storage options....
In short, the fallout from the January 16th 2025 Moss Landing BESS fire has been thoroughly documented by
San Jose State University's Moss Landing/Monterey Bay/Elkhorn Slough Wildlife Preserve research laboratory-
here's their public notice they issued:
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Here's an article about the San Jose State University Lab's findings:
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A Battery Fire Deposits Heavy Metals into Elkhorn Slough
Lithium-ion battery components—nickel, manganese, and cobalt—were found at concentrations thousands
of times greater after the fire. The implications for wildlife hang in the balance.
by Jillian Magtoto
February 6, 2025
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Ivano Aiello trudged through marshy banks of Elkhorn Slough in Monterey on January 21st to collect samples
from the soil’s surface and subsurface, 3 to 5mm deep, as he’s done for over a decade. This time, charred
plastic debris littered the ground. Chunks of concrete lay scattered in pieces among mats of pickleweed. Five
days earlier, a fire broke out about a mile away at Vistra Moss Landing Power Plant, the world’s largest
lithium-ion battery storage facility, according to the company. The smell of fire was gone, but he wondered
what lingered in the soil.
Aiello took about thirty samples along the main channel of the marsh over the course of a few hours, and
returned to his microscope at San Jose State University’s Moss Landing Marine Lab (MLML), where he is
department chair and a professor of marine geology. Out of the nearly 40 elements he detected in this quick
sample, three elements—nickel, manganese, and cobalt—showed dramatic increases. When he typed the
elements into his search bar, an ad for 300-dollar lithium batteries popped up. “That’s what I’m l ooking at,” he
thought to himself.
The fire at Vistra Moss Landing Power Plant, owned by Texas-based Vistra Energy, started January 16th and
burned for three days, consuming 75 percent of the plant and its 100,000 lithium-ion cells. These rechargeable
batteries store excess solar energy during the day, and deliver it to the grid at night, or on less sunny days.
Heavy metals like the ones Aiello identified are often used in these batteries because of their ability to store
large amounts of energy.
But these heavy metals are quite lightweight and travel far. The fire released contaminants that ended up at
least two miles away, settling over the water and soil at Elkhorn Slough, the country’s first estuarine research
sanctuary and home to 700 species, several of which are threatened and endangered.
Aiello returned with his team, collecting 100 soil samples within a two-mile radius of the plant over the course
of nearly three days. Nickel, manganese, and cobalt were present at concentrations hundreds to thousands of
times greater than when he last measured them two years ago. Now, his laboratory, nonprofits, and public
agencies are rushing to figure out what this means for the rest of the slough.
The metals “might start interacting with the environment,” says Aiello. “What we need to study is whether
they will become bioavailable”—whether they will absorb into the plant and animal tissues of life at the
slough.
Land meets the sea at Elkhorn Slough, a seven-mile stretch of water and wetland from Moss Landing to
Watsonville, home to California’s largest population of southern sea otters—about 150—and the state’s
second largest estuary. The flows of water between Monterey Bay and estuary creates opportunities for a
diversity of salt and freshwater-loving species living among intertidal marshes, mudflats, oyster communities,
and eelgrass beds, protected from harsh ocean waves. A hundred species of fish including bat rays and
leopard sharks swim in its channel; 550 species of invertebrates like oysters and moon snails plant themselves
on rocks and mud; hundreds of harbor seals and sea lions flank its docks and shores. The slough inhabits
endangered species like the California brown pelican, California least tern, Santa Cruz long-toed salamander,
and American peregrine falcon. “It’s very essential habitat,” says Aiello. “It’s one of a few wetlands in
California.”
Before it was a preserve, Elkhorn Slough was a hub of fishing and farming. Farmers drained water from the
slough to grow crops in the 1900s; the U.S. Army Corp of Engineers began dredging the mouth of the estuary
every three years to make way for bigger ships in the 1940s. About half of the tidal marsh in the slough has
been lost since then. Conservation didn’t begin until 1971, when The Nature Conservancy began purchasing
wetlands to protect the slough from major development. In 1979, the National Oceanic Atmospheric
Association (NOAA) established it as an estuarine preserve owned and managed by the California Department
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of Fish and Wildlife (CDFW). Three years later, the Elkhorn Slough Foundation was established as a land trust
and partner with NOAA and the CDFW. Since then, it has acquired and protected more than 4,200 acres—
making it the largest landowner in the watershed.
As conservation accelerated, a PG&E power plant facility was also developing at the mouth of the slough.
Marked by two 500-foot steam towers visible from Highway 1 and nearby farms, the plant began commercial
operation in 1950—equipped with gas-powered turbine and steam generators cooled by ocean water. The
plant changed hands among power companies a few times before Vistra Energy merged with previous owner
Dynegy Moss Landing in 2018, becoming Moss Landing Power Company in 2020. While using much of the
same infrastructure, the plant presented a way to store renewable energy for future use.
“I think there was actually quite a bit of enthusiasm on the part of the community,” says Mark Silberstein, the
executive director of the Elkhorn Slough Foundation. The plant presented a “way to store wind and solar
power during peak production, when otherwise it would be wasted.”
Lithium-ion battery plants, however, also pose dangers: fire, explosions, and toxic plumes and runoff.
Overheating begins with thermal runaway, a phenomenon in which lithium-ion cells start uncontrollably
heating up. While the heat should be able to escape from the cell, with damage, improper design, or a short
circuit, the cell can generate heat faster than it can dissipate. Heat and pressure build in the battery, leading to
fire and explosion, releasing gases like carbon monoxide, carbon dioxide, methane, and ethane. Fire ensues.
The Moss Landing Power Plant was no exception to these risks. After a couple of incidents of battery
meltdowns and overheating, since the plant began operating in 2019, a fire erupted. Over 1,200 people were
temporarily evacuated; Highway 1 closed for three days.
Vistra’s overheating response system is designed to inject water directly onto the batteries to cool them off,
and was working when the fire department arrived, says North County Fire Protection Department fire chief
Joel Mendoza. But a few hours after the fire began, it escalated—quickly. “I think we made the right call by
backing [the firefighters] out,” says Mendoza. “It was just too much fire for anybody to handle at that point.”
Because the batteries were sealed, the fire department could not do much to suppress the fire, other than
wait. “Imagine batteries burning inside a refrigerator,” says Mendoza. “You’re spraying water on the outside…
but the battery is still burning inside.”
A blaze this big was unexpected for local officials. Vistra’s emergency response plans are “not designed for
entire facility to go up like that,” says Mendoza, and “did not account for a fire of this size,” wrote Monterey
County supervisor Glenn Church in an email.
“It is not hyperbole to call this worst-case or even beyond a worst-case scenario,” wrote Church. “The flames
went up to 250 feet, or about halfway up the stacks. There was smoke for about two days.” The cause of the
fire still remains unknown, according to the county. The evening of the fire, at the request of Monterey
County, the EPA installed nine monitoring stations within the area of evacuation to test for hydrogen fluoride,
a highly toxic gas produced by lithium-ion battery fires, and particulates from combustion. Neither
contaminant was detected at levels that cause concern for human health, according to the EPA’s statement in
a press conference two days after the fire, though Monterey County citizens were left with headaches,
nosebleeds, and metallic tastes in their mouths.
Whether contamination reached soils remained an open question. In the meantime, the CDFW began
preparing for the worst. “Out of an abundance of caution, CDFW is modifying activities that disturb soil and
vegetation,” says Krysten Kellum, a CDFW spokesperson. Kellum did not provide comment, however, on what
these activities entail.
Nonetheless, Aiello decided to conduct soil testing himself, as soon as the evacuation orders were lifted for his
laboratory.
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“I was curious, because we just had a giant fire next door,” he says, at a battery plant he did not realize could
emit toxic chemicals. “It was completely off my mind,” Aiello says. “My life was focused on completely
different things than heavy metals.”
For the past decade, Aiello has been studying soils at restoration sites in Elkhorn Slough, measuring grain size,
moisture content, and soil composition. When Aiello introduced elemental analysis into his studies in 2023, he
began building a baseline of data for future comparisons—handy for measuring the impacts of disaster. After
the fire, he went back to his survey sites: 100 locations in various upland, riparian, and marsh environments.
“What we’re finding is that there’s a variability within the area,” he says. “But it’s all high, maybe much higher,
in some cases.”
Though he has yet to complete his investigation, he has already noticed some patterns. “The highest
concentration seems to be occurring where the wetlands are,” says Aiello. And there’s a likely explanation.
Not only can the metals be deposited through airborne deposition, but also in runoff and tidal flows, according
to Wesley Heim, head of the MLML marine pollution studies lab. His lab began collecting samples on January
31st to track metals that might enter the slough through runoff. “Once in the slough, these metals can bind to
sediments in marshes and mudflats, where they can accumulate over time, or dissolve in the brackish water,
making them more mobile,” Heim wrote in an email. “Cleanup will be very difficult, if not impossible.”
Consequences for wildlife will be a painful waiting game, especially when the state’s largest density of
southern sea otters lies at risk. As of now, “we haven’t yet found any unusual wildlife mortality from this
event,” says Ross Robertson, communications director of the Elkhorn Slough Foundation. “But it’s too early to
say that that’s not going to happen.”
“Because otters are at the top of the estuarine food chain, they are exposed to higher levels of heavy metals
than the organisms they consume,” writes Heim. Heavy metals can be absorbed by aquatic plants and travel
up the food chain to marine invertebrates, including crabs, sea urchins, clams, mussels, and snails—which
otters eat in daily quantities weighing a quarter of their body weight. Impacts on the otters will take time to
see, Heim writes. “But I think it is possible given the amount of heavy metals being found.”
As Aiello and his colleagues measure heavy metals, the Elkhorn Slough Foundation is monitoring wildlife as an
indicator of the slough’s health, through one species in particular.
“We’ve done some collections of oysters,” says Silberstein. Native Olympia oysters have naturally grown in the
slough since they were reintroduced in 2012, pumping water through their gills and trapping particles in their
mucus. “Focusing on filter feeders is a good place to start…if you want to know how compounds are flowing
through these aquatic ecosystems.”
For now, Vistra has closed the doors to its battery facility, and will continue operating its natural gas energy
production right next-door, writes Church. Vistra’s third-party consultant company, CTEH, will “continue to
monitor air quality up to the site boundary indefinitely,” according to Vistra’s response website. “There is a
robust plan on removing the rest of the building” and disposing of the remaining batteries, says Mendoza.
While the recent days of rains may ring alarm bells for water pollution, the good news is that “the runoff will
remain on scene,” he says. “They have ways of shutting down their storm drains… so that none of it goes off
site and to any of the waterways, including the slough or the ocean.”
Aiello and his colleagues, meanwhile, are continuing to return to their survey sites every day to understand
where the particles are going. But heavy metal sampling isn’t cheap.
“We need to get some funding; some of what we’re doing is kind of pro-bono,” he says. “We’re doing what we
can.”
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About the Author
Jillian Magtoto
Jillian Magtoto is a 2024–2025 editorial fellow at Bay Nature and a recent graduate of the Columbia School of
Journalism. A UC Berkeley alumna, she is excited to be back in the Bay and write stories on how humans and
wildlife are learning to live with one another.
https://baynature.org/2025/02/06/battery-fire-at-elkhorn-slough/
----------------
And, another one:
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Moss Landing battery fire: Unusually high concentrations of toxic metals found in wetlands near plant
Nickel, cobalt and manganese, found in lithium-ion batteries, increased dramatically at Elkhorn Slough after
the fire
Less than two weeks after a huge fire in Moss Landing at one of the world’s largest battery storage plants,
scientists affiliated with San Jose State University have discovered unusually high levels of toxic metals in soils
at Elkhorn Slough, roughly a mile away.
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Researchers at Moss Landing Marine Laboratories have detected microscopic particles of nickel, cobalt and
manganese — which are found in the thousands of lithium-ion batteries that burned at the Vistra Energy
battery storage plant — in the mudflats and tidal marshes at Elkhorn Slough at levels roughly 100 to 1,000
times higher than normal.
“Those three metals are toxic,” said Ivano Aiello, a marine geology professor at Moss Landing Marine Labs,
who led the soils testing. “They are hazardous to aquatic life. We want to understand how they will move and
interact with the environment, whether they will make it through the food web and at what level — from
microbes to sea otters.”
The dramatic fire at the 750-megawatt battery plant began on Jan. 16 and burned for two days. It caused the
evacuation of 1,200 local residents and the closure of Highway 1 for three days. The flames quickly
overwhelmed the fire sprinkler system at the plant, which is run by Vistra Energy, a Dallas-based company,
and located on the former site of a PG&E power plant that was build in the 1950s.
Lithium battery fires burn at high temperatures and are difficult to put out. As a result, fire fighters did not
battle the blaze and allowed it to burn out. The fire spread a large cloud of toxic smoke across the area near
the border of Santa Cruz and Monterey counties, and has raised questions about safety in other communities
where battery storage plants are planned. The plants are key to storing electricity from solar and wind power
to use at night, allowing California to continue to move from fossil fuels to renewable energy.
The discovery of battery toxins in the soils at Elkhorn Slough, a protected network of wetlands, creeks, and
wildlife habitat popular with birders and kayakers, turned up attention on the impact on humans who live in
communities near the plant.
Monterey County officials said Monday that the Monterey County Environmental Health Department is
continuing to work with officials from the California EPA to test soils in properties along the path of the smoke
plume. They expect to release the first results by the end of this week, said Nick Pasculli, a Monterey County
spokesman.
“We are totally dedicated to people’s safety and their health,” Pasculli said. “That’s our number one priority,
and protecting our environment. We are very interested in getting the data from the Elkhorn Slough samples
so we can analyze the findings and consult with state and federal agencies that have oversight to determine
the best path forward.”
Aiello said he took samples from roughly 100 sites. He has studied the area for more than 10 years. Analyzing
the soils with an electron microscope at Moss Landing labs, he said the spiked levels of battery metals were
found in the top few millimeters of soil, not lower levels. He said he took measurements on Jan. 21, 23 and 24
and compared them to soil samples taken at the same locations before the battery plant fire.
“The concentrations went from tens of parts per million to thousands of parts per million — 2 to 3 orders of
magnitude,” he said. “It’s a lot.”
Aiello said it is important that testing continue for weeks, months and years on the site to track how the
metals change and move. It rained this past weekend, he noted, and he planned additional testing to see the
impacts.
Aiello is not a medical doctor, but said it is important that state and local officials test soils in communities
around the plant to see how they have changed, and how they compare to Elkhorn Slough.
High levels of heavy metals such as nickel, cobalt, and manganese “bioaccumulate,” or move up the food chain
from plants and microbes into fish, and larger animals that eat the fish. At high levels they can cause
neurological harm, reproductive damage and other problems. It isn’t clear yet, Aiello said, whether the levels
have impacted the health of any fish or wildlife.
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“We know these particles are toxic,” he said. “They are heavy metals. Whether they are posing a hazard right
now, we don’t know. But we need to know. I live here. I work here. Let’s figure it out.”
“The future is going to be more battery storage facilities all over the world,” Aiello added. “We are moving
away from fossil fuels. Is this the solution? Is this the right technology?”
Officials from the U.S. Environmental Protection Agency set up air monitors on the night of the fire. They and
officials from the Monterey Bay Air Resources District said in the days after the fire that their monitors did not
detect levels of soot or hydrogen fluoride, a toxic gas from burning batteries, in unhealthy levels.
But at several public meetings dozens of local residents raised concerns about the impact of the smoke plume
not only on air, but water and soils in the surrounding communities. Some people complained of a metallic
taste, impacts to their asthma, and other health changes.
Pasculli said Vistra officials placed straw rolls around the plant for erosion control. Vistra has been meeting
with state, local and federal officials to plan the cleanup of the plant, which remains offline, he added. Last
week, Gov. Gavin Newsom called for an independent investigation by the California Public Utilities
Commission.Crashes and Disasters
https://www.mercurynews.com/2025/01/27/moss-landing-battery-fire-unusually-high-concentrations-of-
toxic-metals-found-in-wetlands-near-plant/?fbclid=IwY2xjawIplKZleHRuA2FlbQIxMAABHYuKMD5-
MfZumqkTsf1ItVw1y2EqhCD_uIi8ZhALI7998Sm3jky2Cg2H8Q_aem_mkqstKDEBcWr_J1Bc9LWYA
------------------
Here's a good overview of the fire and response:
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Fire Destroys Moss Landing BESS Burning Up Support for Local Project
Written by Neil Farrell
January 31, 2025
Featured Stories
The calm waters of Moss Landing Harbor are lit up Jan. 16 by a massive fire that greatly destroyed a battery
energy storage plant owned by Vistra Energy.
As its Battery Energy Storage System facility in Moss Landing smoldered, support for Vistra Energy’s proposed
battery facility in Morro Bay also seems to be going up in flames.
On Thursday, Jan. 16 at about 3 p.m. Vistra’s 300-megawatt BESS facility in Moss Landing caught fire and
within a short time, was burning out of control. The fire was in an old power plant building and part of Vistra’s
larger 750 MW battery storage complex.
“The first indication the incident had occurred,” reads a news report from The Pajaronian newspaper in
Watsonville “was a loud alarm that boomed it’s warning over the Moss Landing Harbor. Shortly afterwards, a
column of black smoke wafted into the sky alongside the pair of 500-foot concrete towers that were built in
1950.”
Morro Bay Connection
That old Moss Landing plant with its twin smokestacks, is a sister plant to Morro Bay, which has three
smokestacks. Pacific Gas & Electric built both in the 1950s (Morro Bay Units 3 & 4 were completed in 1964).
Neither one still produces electricity, though there is a newer, 1200 MW combined-cycle, natural gas power
plant at Moss Landing that was built by Duke Energy in the early 2000s and is now owned by Vistra and still
produces electricity.
It’s the exact same power plant that Duke tried to build at Morro Bay but was denied by state agencies.
Vistra’s is one of two battery storage facilities at Moss Landing. PG&E built and operates a smaller BESS on the
property and together they can store over 900 MW of energy.
PG&E’s plant uses Tesla batteries, while Vistra uses LG Energy Solutions lithium-ion batteries. LGES is a
subsidiary of LG Chem, a South Korean chemical company that has been making big batteries since 1992
according to their website.
Both of these battery plants have also had fires in the past, with now three fires at Vistra, according to news
reports, and the LGES batteries are what Vistra has said it would use in Morro Bay.
Fire System Failure
The plant apparently had a robust fire suppression system, too.
According to a report from KSBW-TV in Salinas, “Vistra employees did say there was a built-in fire suppression
unit, but it failed and wasn’t able to suppress the fire that started in the battery storage unit.”
KSBW asked Vistra’s Senior Director of Community Affairs, Brad Watson, what the plan was for this “worst-
case scenario” fire?
“There was a mitigation system that was water-based,” Watson replied. “Part of what we will be doing is
studying and investigating why that didn’t work as designed. That will be one of the many questions we will be
going through what happened here. We will investigate it and will find out what the cause is.”
A Growing Blaze
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The fire continued to grow Thursday afternoon and by that night, the fire had broken through the roof and
flames were reaching 200-feet into the sky. A plume of ominous, thick, black smoke rose in a massive column
over 1,000 feet and the flames could be seen for miles in videos posted online.
Firefighters were focused on keeping the fire contained but were not trying to put the fire out, as protocol is
reportedly to let it burn itself out.
Monterey County spokeswoman Maia Carroll told The Pajaronian, “It is unknown how long this incident may
last. No active fire suppression is taking place; the batteries must burn themselves out. No water can be used.
This is standard action for battery fires.”
It should be noted that a Vistra official said all their people got out safely and no injuries have been reported.
Moss Was Evacuated
This most recent fire marks at least the fourth time Moss Landing has had an emergency evacuation due to
the battery plants.
Caltrans and the Highway Patrol closed Hwy 1 and several other rural roads and highways in and around Moss
Landing, Watsonville and Castroville.
Some 1,200 people were evacuated from around the plant, with an evacuation center set up in Castroville the
southeast of Moss Landing.
The Elkhorn Slough Natural Reserve next door to the power plant was closed indefinitely.
Schools in the area canceled classes that Friday, a day early for the Martin Luther King Day, 3-day holiday.
Students returned to class on the following Tuesday, according to KSBW.
Residents Warned
The Monterey County Office of Emergency Services issued a warning on Thursday to residents: “At this time,
no imminent significant threat exists. Sensitive groups including those with respiratory difficulties should
monitor local air conditions at: www.iqair.com/us and consider wearing a mask. As a precaution, keep children
and pets indoors and keep doors and windows closed.”
The County OES claimed the smoke plume, while toxic, had not tested at harmful levels. One report stated
that the plume of smoke rose so high in the air that it didn’t affect air quality at ground level.
Nevertheless, residents miles from the plant were advised to close doors and windows, stay indoors and to
turn off ventilation systems. That advisory was echoed by officials in adjacent San Benito and Santa Cruz
Counties.
EPA Does Tests
The EPA reportedly responded to the fire scene and has been conducting air, water and soil sampling, looking
for the typical toxins that come from large lithium-ion fires.
The main concerns are high levels of hot particulates in the smoke and hydrogen fluoride gas.
According to the Centers for Disease Control, “Breathing in hydrogen fluoride at high levels can cause death
from an irregular heartbeat or from fluid on the lungs.” Minor exposure may cause mouth, nose and throat
irritations.
Hot particulates burn the nasal passages and lungs, just like in a wildland fire.
The fire burned out of control all Thursday night but by Friday morning, it had died down enough for the
County to lift the evacuation orders at about noon.
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However, a little after 1 p.m. Friday, the fire flared up again.
By Saturday, the active fire was out but the facility continued to smolder for several days. A Monterey County
Fire Chief said 75% of the building had burned.
After the weekend ended, the complaints from Moss Landing residents started being reported.
KSBW reported, “Moss Landing residents report health issues after a battery plant fire, including headaches,
sore throats, and a metallic taste in their mouths.”
‘Our Three-Mile Island’
The fire has elicited strong comments from elected officials and at least one Monterey County Supervisor was
downright angry.
Dist. 2 Monterey County Supervisor, Glenn Church, called the fire “our Three-Mile Island.”
“This is really a lot more than just a fire. It’s really a wake-up call for this industry,” Church said. “And if we are
going to be moving ahead with sustainable energy, we need to have a safe battery system in place.”
Dist. 30 Assemblywoman, Dawn Addis, who represents San Luis Obispo, Monterey, and Santa Cruz Counties
(including Morro Bay), and is an advocate for addressing climate change, announced that she’s had a change
of heart.
“While we urgently need climate solutions, they must be safe for our communities and environment,” Addis
wrote in a Facebook post. “With that in mind, I am calling on Vistra to end its plans for a battery energy
storage facility in Morro Bay and urging the California Energy Commission and the California Coastal
Commission to reject their permitting application under AB 205.”
BESS Was Paused
Vistra, last October, notified the City of Morro Bay that it was “pausing” its project with the City and would be
making application to the Energy Commission, under provisions created in 2022 with passage of AB 205.
That law gave projects like the Morro Bay BESS an option to apply directly to the CEC for a permit, when faced
with local opposition. But the company, which originally said it would apply to the CEC in December, has yet to
act.
A City Official told Estero Bay News that Vistra hasn’t communicated with the City since October, and the city
council planned to discuss sending an ultimatum to the company — either resume the project with the City or
formally withdraw it.
EBN asked Vistra’s Meranda Cohn about this and she replied, “At our request, consideration of the
development application of the Morro Bay project is paused with the City, and we have not yet submitted our
application with the State via Assembly Bill 205. Our immediate focus is working with the first responders and
leaders of Moss Landing and Monterey County to provide essential information to the community. Our
company’s top priority is safety.
“A comprehensive investigation of this incident will be conducted following this event, which will inform our
current and future energy storage operations. We will provide more information once we know more.”
State Sen. John Laird of the 17th Senate District that includes Moss Landing (and Morro Bay as well), said the
Moss Landing fire was “deeply troubling.”
Sen. Laird said when the fire broke out, he and the Chairman of the CEC, David Hochschild met with other
elected officials at the incident command center, “to receive an initial briefing on the fire’s timeline, air quality
and environmental concerns and potential impact on local residents.”
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He explained that in 2023, he authored Senate Bill 38 “to require battery storage facilities to develop and
submit an emergency safety plan, recognizing the growing prevalence of these systems to meet our state’s
clean energy goals.”
He said that SB 38 requires each BESS to write an emergency response and emergency action plan and file it
with the county, which he said Vistra had done before the bill’s passage. However, the company never filed
anything after passage of SB 38, according to Sen. Laird.
“There are questions as to whether the report covered plans for an incident of this magnitude,” Sen. Laird
said. “Furthermore, it appears that PG&E has not filed an emergency safety plan for their adjacent battery
storage facility in compliance with the law.”
Still a Believer
Days after the fire, EBN sought comment from Sen. Laird to see if the Moss Landing fire had changed his mind
about battery facilities?
“The fire at the Moss Landing battery storage facility,” Laird said, “and subsequent evacuations and shelter-in-
place orders is a tragedy for the community. Federal, State, and Local officials are working together to
determine both the cause and the near- and long-term impacts of the fire.”
He explained that Vistra’s burning BESS used “old technology.”
“What we do know,” Sen. Laird said, “is the impacted area of the battery storage facility was based off of older
technology, with fewer safeguards in place.
“Newer battery storage facilities are built to contain to small areas any potential issue. There have been no
reports of significant fire in the 75% of California’s battery storage that employs this newer technology. What
is important is that we come to a very clear understanding how safe these newer facilities are, and is that
something the community would be interested in learning more about?”
The Senator, who has been a leading proponent of offshore wind energy and battery storage, appears
steadfast in the fight against climate change.
“California’s renewable energy goals face many challenges,” Sen. Laird said. “This is an opportunity not just for
us as policy makers, however, also for the public to learn more about what does and does not work, so we can
all make informed decisions about siting of these needed facilities.”
Local residents — no doubt as well the residents of Moss Landing and Castroville — appear unconvinced.
Losing Local Support
Locally, the project has lost most if not all support, with the social media site, Next Door, blowing up with the
news of the Moss Landing fire.
EBN asked all five City Council members if the Moss Landing fire had changed their perspectives?
Councilwoman Zara Landrum has never supported the BESS in Morro Bay. “I always had safety concerns about
the idea of a BESS in that location,” Landrum said. “With the recent fire at Moss Landing, there’s no question
that the Vistra site would not work for a BESS in Morro Bay. Now we have confirmation that it is absolutely not
appropriate for Morro Bay and in fact it makes one question whether Lithium-Ion batteries help improve the
environment or are making it much worse.”
She said she was proud that Morro Bay voters passed Measure A-24 in November, a measure that requires the
City Council to ask voters’ approval to change the zoning at the power plant from “commercial/visitor-serving”
to “industrial” to accommodate the Vistra project.
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“They knew not to trust a Fortune 500 Company from Texas,” Landrum continued, “who is also ranked as the
largest CO2 producer in the nation when they told them how safe their technology is.
“No matter the promised revenue, if an accident occurred, not only would people’s safety be at risk, but it
would also financially devastate the City as well as the entire County’s economy.”
Landrum said they’ve all gotten inundated with calls and emails from concerned constituents. “Considering
the shocking severity that we’ve all watched of the Moss Landing incident,” Landrum said, “I would think even
many of the opponents of A-24 may agree that Morro Bay is not a fit for a BESS.”
She’s had enough of the Texas energy giant. “Vistra has caused untold damage to the environment and to
people’s lives in Monterey County. Who knows the cost to mitigate all of this?”
Councilman Bill Luffee said Moss Landing has changed his mind on the BESS.
“I have been a supporter of the BESS facility from the beginning,” Luffee said, “but the Universe spoke last
Thursday, and I have done a 180-degree stance and can no longer consciously support a lithium battery facility
in Morro Bay.
“It is anyone’s guess what will happen and to have an answer to that would be premature. The emails to the
council have been fast and forthcoming of never having a BESS plant in Morro Bay.
“Technology is changing every day so where we go from here on these facilities is yet to be known.”
Councilwoman, Edwards, who has been on the East Coast attending a funeral, first said she was speaking “on
behalf of myself and not the current or a previous council, said, “My thoughts have not changed, rather they
are more resolved.
“Safety has been my number one priority all along. I was vocal about my initial concerns during campaigning
and continued to do so in the last 2 years serving this community.”
She’s watched battery technology change rapidly. “I’ve been very clear,” Edwards said, “that the technology is
changing at a rapid pace, and I’ve questioned the use of lithium-ion, in both its current chemical makeup, the
systems, and mitigations in place.”
She’s been steadfast in her positions. “For the last 2 years, I’ve questioned these specifics from the dais and
while serving on the subcommittee on our behalf, I’ve continued to stress to the applicant, Vistra, that we
were not going to be another college campus for them to test technology.”
Mayor Wixom and Councilman Eckles did not respond before deadline. However, for the majority of last week,
four of five Council Members (all but Edwards) have been attending meetings and a leadership academy in
Sacramento.
The Council met with Assemblywoman Addis and Sen. Laird in their Sacramento offices. They also met with a
team form the Energy and Coastal Commissions. The Moss Landing fire, and Vistra’s Morro Bay project and
the move to the CEC under AB 205, were definitely on their agenda.
https://esterobaynews.com/featured-stories/fire-destroys-moss-landing-bess-burning-up-support-for-local-
project/
I have to break this email into two emails- so I will send the rest about the toxic fall-out data and
consequences momentarily....
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1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:15 AM
To:Gabriel Clark
Subject:FW: 2nd half of email: Catastrophic BESS fire in Moss Landing with scientific proof of
100x to 1000x increase of toxic fallout as far downwind as 27.2 miles downwind
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 12:56 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: 2nd half of email: Catastrophic BESS fire in Moss Landing with scientific proof of 100x to 1000x increase of toxic
fallout as far downwind as 27.2 miles downwind
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn leaders,
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Here's the rest of the email:
-----------
And finally, the results from the grass-roots sampling and labs tests:
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BREAKING: New Data Indicates Elevated Heavy Metal After Vistra Fire
Feb 11, 20255:55 pmBy:Till Daldrup Ruth Dusseault Michelle Cera Bay City NewsEditor:Sam Koppelman
Surface sample testing conducted by a grassroots community response group shows elevated heavy
metal concentrations near Vistra Corp.’s (NYSE: $VST) battery storage facility in Moss Landing,
California, after a lithium-ion battery fire burned for several days.
A Hunterbrook analysis of the testing data shows that samples taken within 20 miles of Vistra’s Moss
Landing facility on average have nickel and cobalt concentrations that are about 34 times higher than
the levels found in samples collected further away from the plant.
Preliminary soil test results published by Monterey County also show cobalt concentrations above
screening levels for all selected testing sites. San José State University researchers had already found
“unusually high concentrations” of nickel, manganese, and cobalt in marsh soil at a nearby estuary.
Planning documents obtained by Hunterbrook via FOIA request show that the Monterey County
Planning Commission waived a more thorough environmental review when it considered Vistra’s
application to build the Moss Landing battery energy storage facility in 2019.
More than three weeks after the fire, residents are still reporting health issues, including headaches,
respiratory issues, and fatigue.
When asked about the community surface sample tests, Vistra did not respond. On its incident
response website, the company acknowledged the preliminary soil test results published by Monterey
County, stating: “More sampling is needed to understand how the results compare to relevant
screening levels.”
MOSS LANDING, Calif. — “I have lithium in my blood,” Heather Griffin’s voice quivered as she spoke to
supporters at a demonstration across from Vistra’s battery storage facility in Monterey County, California, just
weeks after a multiday fire at the plant. “I got tested because I had a metallic taste in my mouth and gums,
soreness, and my teeth were sore even a week after the fire was put out.”
Griffin is one of dozens of residents who have reported suffering from an illness following the flames, with
symptoms including trouble breathing, painful sores, bloody noses, extreme fatigue, and persistent
headaches.
For some residents with preexisting conditions, such as asthma or COPD, conditions have worsened.
On Saturday morning, members of the community organized a demonstration under the banner of a new
grassroots group: Never Again Moss Landing. The group formed days after the Moss Landing battery energy
storage facility fire, with the goal of advocating for community interests and organizing volunteer efforts to
collect facts so that the January 16 fire, the second in three years after a fire at PG&E’s battery facility in 2022,
is the last.
The group has also decided to supplement testing efforts by Montere y County and take matters into their own
hands: On the weekend after the fire had apparently burned itself out, volunteers collected 124 surface wipe
samples throughout the Monterey Bay area, swabbing everything from patio tables to solar panels to hot tub
covers.
Data analysis reveals elevated heavy metal concentrations following path of plume
The samples were shipped to an independent laboratory in Utah for analysis and the group shared the results
with Monterey County, the California EPA, and journalists. It also intends to publish the raw data on its
website.
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A Hunterbrook analysis of the testing data shows that samples taken within 20 miles of Vistra’s Moss Landing
facility on average have nickel and cobalt concentrations that are abo
Several samples close to the facility showed elevated nickel and cobalt concentrations more than 180 times
higher than the average levels more than 20 miles away.
Manganese concentrations within the 20-mile radius are more than 12 times higher than outside. Lithium
levels are three times higher.
Hunterbrook’s data visualizations show that nickel, cobalt, and manganese levels are mostly elevated east and
northeast of the Vistra facility, which matches plume models generated by Peter Weiss-Penzias, a researcher
at University of California, Santa Cruz, that indicate the smoke from the fire moved in that direction —
suggesting a connection between higher heavy metal concentrations and the fire.
All of the highest concentrations for nickel, cobalt, manganese, and lithium — with the exception of one
sample with elevated manganese levels in the Santa Cruz area — were located in or in the direct vicinity of the
model showing the smoke plume’s extent about 24 hours after the fire started.
Roughly 25,000 people live in the area covered by the smoke plume model.
Trace elements such as nickel and cobalt occur naturally. Their compounds can be found in soil, plants, and
animals. While small amounts of cobalt and certain other metals can be beneficial for humans and plants, high
concentrations can become toxic. Long-term exposure may cause health problems and adversely affect plant
growth.
The samples in this community-organized test were collected with wipe sampling kits. While this data shows
that surface levels of heavy metals are elevated closer to the Vistra facility, it is not easily comparable with
heavy metal baseline data or EPA screening levels, according to Michael Polkabla, the industrial hygienist who
conducted the surface sample tests for the Moss Landing community group.
“What we wanted to capture was what was the impact of the Vistra fire incident and what was coming out of
that smoke plume and soil on surfaces,” he said. “We're looking at an increase as we get closer to the site.”
Community testing results build on data from county, university
The County of Monterey conducted soil tests in collaboration with the California Department of Toxic
Substances Control. Preliminary results were published on January 31.
Cobalt exceeded screening levels at all testing sites. One of the eight chosen testing sites exceeded screening
levels for nickel, manganese, and copper, in addition to cobalt. It is located northeast of the Vistra facility,
where the smoke plume moved. The County emphasized that the data has not been fully analyzed or validated
and is not conclusive.
When asked about the community surface sample tests, Vistra did not respond.
On its incident response website, the company acknowledged the soil test results published by Monterey
County, stating: “These are preliminary test results that are designed to determine areas that may benefit
from additional study. More sampling is needed to understand how the results compare to relevant screening
levels.”
Vistra also said that it is conducting its own soil sample tests with a third-party contractor. So far, however,
Vistra does not appear to have published the results.
The community and county test results add to other scientific evidence suggesting that the fire at Vistra’s
facility may have caused elevated heavy metal concentrations in the surrounding areas. After the fire, San José
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State University researchers found unusually high concentrations of nickel, manganese, and cobalt in marsh
soil at a nearby estuary.
Documents reveal Vistra avoided environmental review
Planning documents obtained by Hunterbrook show that the Monterey County Planning Commission waived a
more thorough environmental review when it considered Vistra’s application to build the Moss Landing
battery storage facility in 2019, stating that there was “no substantial evidence that the proposed project as
designed, conditioned and mitigated will have a significant effect on the environment.”
In the May 2019 meeting commission meeting where it voted to waive the review, the commission did not
discuss a fire at the Vistra facility and its potential environmental impact. The application included a fire safety
plan, which the local North County Fire Protection District reviewed and deemed acceptable.
The plan at the time of the application did not account for a multiday fire at the facility. An emergency
response plan from 2023 that Vistra posted on its incident response site assumed the “worst case” scenario to
be a fire extinguished after 30 minutes.
Hunterbrook obtained a letter that the Monterey County Board of Supervisors sent to Vistra and PG&E, which
operates an adjacent battery storage facility, in the aftermath of the January 16 fire. In the letter, the board
requests that both companies develop emergency response plans that include a “catastrophic worst case
scenario” defined as a “full conflagration” of the facilities.
“The approval of both Vistra and PG&E’s battery facilities never received the fullest review and robust public
discussion that they deserved,” wrote Glenn Church, supervisor for Monterey County District 2, in a blog post
about the Moss Landing fire. “They were promoted as a great step forward for our energy future. The
downside was never properly vetted.”
The Vistra facility is based in the Salinas Valley, an area also known as “America’s Salad Bowl.” It produces 70%
of the lettuce grown in California, as well as other fruits and vegetables, including broccoli, cauliflower,
spinach, strawberries, tomatoes, grapes, and artichokes.
According to the Monterey County Farm Bureau’s 2023 crop report, the region produces vegetables and fruits
with a gross production value of about $4.3 billion. Produce sourced from Salinas Valley is sold in grocery
stores across the country.
Because it’s winter, there were few crops in fields at the time of the fire, according to the Farm Bureau.
“[Agricultural] Associations are working to assess any impacts and ensure that crops, farmworkers, and
consumers are safe,” Norm Groot, the Farm Bureau’s Executive Director, wrote in an email to Hunterbrook. “It
should be noted that ‘heavy metals’ such as those involved in the emissions from this fire are elements
commonly found as natural plant micronutrients. Experts do not anticipate significant plant uptake or toxicity
concerns based on current soil pH levels and organic matter composition.”
New regulations may follow the fire
Rules for approving battery storage facilities may become stricter in California in reaction to the fire.
California Assemblymember Dawn Addis introduced a bill that would return approval authority over battery
energy storage facilities back to local communities, closing an authorization bypass through California’s Energy
Commission. It would also require facilities to be built at least 3,200 feet away from homes, schools, and
hospitals.
The California Public Utilities Commission (CPUC) also proposed new safety standards for battery facilities that
would “increase oversight over emergency response action plans” and establish “technical logbook
standards.” The proposal will be voted on at a CPUC meeting on March 13. The CPUC’s Safety and
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Enforcement Division has started an investigation of Vistra’s facility, “requesting information and updates”
from the company.
Residents say they continue to suffer
More than three weeks after the fire, local residents told Hunterbrook they are still experiencing health issues.
And many of them are frustrated with Vistra’s and county officials' responses.
The Monterey County Department of Health said that as of January 31, it had received 27 reports from people
concerned about their health and the Vistra power storage facility fire. The most common symptoms reported
included “eye, nose, and throat irritation; metallic taste or smell; and exacerbation of chronic respiratory
problems like asthma.”
Marcy Castro had a bad feeling when her daughter returned to elementary school, three days after the fire
apparently had burned itself out.
They both had experienced intense headaches and fatigue during and after the fire, and the school is only five
miles from the facility. She asked the school’s office staff and the principal about possible health impacts from
the fire and protocols for cleaning the playground from debris that may have traveled from the burning
battery facility. “‘Clueless’ I guess is a good word,” she said. “They're all kind of clueless about what should be
done.”
When she picked her daughter up from school, she noticed a peculiar — but somewhat familiar — taste.
“I notice that for a few hours afterwards I'm having that weird taste on the tip of my tongue like I've been
testing batteries all day,” she says. “Like you know we were kids and you tested the square batteries and you'd
have that weird taste and feeling on the tip of your tongue. I get that when I go over there.”
After she heard that her daughter’s class was running laps outside in gym class, she decided to keep her home,
fearing exposure to the air near the facility could impact her health.
Like many of the residents Hunterbrook spoke with, Sherry Okamoto has been navigating persisting symptoms
in the aftermath of the fire. What began as headaches turned into a hard time breathing, nausea, wheezing,
and rashes. Okamoto, who said she struggles with autoimmune disorders, has relied on respiratory support
since the fire.
“When things hit me, it hits me hard,” she said, and added, ”I’m lucky I have my breathing machines.”
Her two-year-old granddaughter has also experienced respiratory issues since the fire. One of her chickens
died, her cats and dog have been wheezing, and her duck pool is covered in an oily film. She is concerned her
homegrown produce and eggs might be contaminated.
“I’m not going to give it to my kids,” she said. So she pulled up her whole garden.
Okamoto feels left behind. “Nobody will answer us,” she lamented after detailing a lack of support and
information from Vistra and the state government.
Stephanie, who is using a pseudonym because she doesn't want her name published, is in a similarly difficult
position. The sole caretaker for her 77-year-old husband, who has Parkinson’s, her past few weeks have been
marked by extreme anxiety and stress. “I’ve never been this scared in my life,” she said. “My husband doesn’t
breathe well. He has a compromised system … I worry about him.”
Stephanie told Hunterbrook she and her husband never got evacuation warnings or information about air
contamination. “No one was looking out for us,” she said. And when the EPA released a statement informing
residents that the air posed no risk to public health, Stephanie mentioned she did not believe it. “We feel that
we were ignored.”
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Shiree Ames Goins and her husband were living about seven miles from the Vistra plant at the time of the fire.
She described a series of cascading symptoms that first night — headaches, nausea, a chemical taste in her
mouth, and eventually, a heavy feeling in her chest and belabored breathing.
After speaking on the phone with her doctor, she and her husband knew they had to leave the area. She told
Hunterbrook they rented an Airbnb north of their home for about two weeks. While their symptoms persisted
because the plume from the fire had also traveled north, they found that their symptoms became less intense
the farther they got from home.
When they returned to their home, her symptoms came back. She now worries her home will not be livable,
and she will be unable to sell it to someone else in good conscience. “We could end up being homeless.”
“We’re going into the third week,” Goins said, “and everybody’s still living here amongst this toxic, invisible,
possibly carcinogenic material.”
And she said she has had very little guidance or support from elected officials or Vistra: “I would have never
dreamt in Monterey County that this would not only happen but have such an underwhelming response.”
“The doctors and the labs don't know what to do,” said Brian Roeder, a community facilitator for Never Again
Moss Landing. Roeder said he spent $2,700 of his own money to help pay for the volunteer’s test kits.
Jill Amos, whose work as a realtor requires her to be outside a lot, has struggled to get heavy metals blood
testing done with her doctor. “No one is prepared, not even our medical facilities,” she told Hunterbrook.
Goins also had difficulty getting heavy metals testing done, and she recalled her doctor telling her that her
symptoms might be from anxiety. “You have to prove to people that you’re sick. They think it’s in your head.”
“I think they're waiting for Sacramento,” Roeder told Hunterbrook, referring to the county’s hesitance to take
big action on public health. “The cavalry is not coming. Look, guys, you need to tell the labs and the doctors: A)
People are going to come in. B) Something did happen. This is a test they need. This is how they can get it,
right. And we'd like to know the results. And none of that's happened because I think they're expecting the
feds and the state to come in and do that. And they haven’t. The EPA left, and that was it. The fire is out.
We're gone. Nothing happened. Nothing to see.”
https://hntrbrk.com/vistra-data/?fbclid=IwY2xjawIpziRleHRuA2FlbQIxMAABHbZN-
Mpvgu7UG0mwEeLBJcT15oJUbA2ZJP7ToVUukZfgru85D-8cSTY4bA_aem_d2nLua8E6flctsz9KUeaRA
---------------
To give you a better understanding of what the data means, here are some charts showing the OSHA, NIOSH,
and EPA limits allowed compared to the lab test results:
COBALT:
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Manganese:
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Lithium:
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Nickel:
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Here's a chart showing the comparison of the Moss Landing BESS fire fallout lab results compared to typically
high exposure jobs and the levels those jobs expose employees to:
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No one knows how long the effects of the fallout from the BESS will harm the environment and everything
living in the fallout zone that has been scientifically proven to have fallen as far out as 27.2 miles away:
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And have 100s of documented exposure victims as far away as 30-40 miles downwind:
The linked image cannot be displayed. The file may have been mov ed, renamed, or deleted.
Verify that the link points to the correct file
and location.
If you don't want to risk contaminating all the surrounding areas around lithium BESS, and help prevent
contamination potentially as far away as 27.2 miles downwind from each lithium BESS from being impacted by
toxic fallout, please open a line of communication with the Governor, any and all Agencies, Indian Tribes, and
communicate the risks based on evidence from previous BESS fires (especially the new fallout data from the
Jan 16th 2025 Moss Landing BESS fire).
#2 Please require soil samples to be taken at every property for at least a 2-mile radius surrounding BESS so
we have historical records- so when there is a lithium BESS fire, there is no question about toxins pre-existing
as we will have the historic sampling documentation.
#3 Require catastrophic levels of insurance for every lithium BESS to cover full medical coverage for exposure
victims, 100% property de-contamination, and 100% environmental clean up for at least the surrounding 2
miles- if not 10 or 20 miles...
#4 Please create setback requirements for all lithium BESS- CA has a proposed law (AB-303 Battery energy
storage facilities) requiring a 3200ft setback from any sensitive locations (homes, schools, hospitals, care
facilities) and sensitive environments. Ideally, we could get 5 miles or more in light of the fallout evidence
showing wind can carry the fallout 27.2 miles away...
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This should be enough proof that BESS have the potential to have significant (if not catastrophic)
environmental impacts and should not be allowed any where near sensitive environments like homes, schools,
hospitals, nor near environmentally sensitive environments.
And, in case you are wondering about spraying defensive and containment water spray/mist to capture the
toxins before they can be blown around by the wind, please don't forget the 3-miles of total fishkill at another
lithium battery fire where the run-off from fire fighting killed everything instantly almost 3-miles down stream
from the lithium battery fire:
https://www.ksdk.com/article/news/local/fredericktown-mo-battery-plant-fire-dead-fish-kill-updates-
investigation-firefighting-foam-lithium-battery-fire/63-02253d7c-de87-450d-a324-
c78b5d404b88?fbclid=IwY2xjawIp7zpleHRuA2FlbQIxMQABHY11eVpfaOMhlKHDPG4ok6I6qVmBOcV-
x_ERFUkkYxtcUtXUpjBQNjEnkA_aem_NzcL2KS7HteeIQWamlQsqQ
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Missouri battery plant fire leaves miles-long trail
of dead fish | ksdk.com
That's the one thought Dave Knuth, a fisheries
biologist with the Missouri Department of
Conservation, said he had when approaching the
site of a 2 1/2-mile-long fish kill Friday near
Fredericktown.
www.ksdk.com
If you have made it this far- thank you!
I know this is a lot and I would be more than happy to meet with you virtually or in person to discuss further-
as I barely touched on the evacuation and shelter-in-place orders, road/Highway closures, and why those are
needed (in short, due to all the gases and toxins that are released from burning lithium batteries) and to
answer all you questions...
The scary thing is, is there are hundreds of people that have exposure symptoms (burning eyes, nose, throat,
lungs, difficulty breathing, skin rashes/burns, headaches, dizziness, open sores, exhaustion, constant metallic
taste in mouth, and many other symptoms across Monterey and downwind into other Counties and many
lawsuits have been filed with many more on the horizon... People who evacuated said symptoms started
whent hey came back- people with symptoms who leave start to feel better, but once they return home the
symptoms return... Knowing about the toxic levels of fallout that are all over explains this... Unfortunately,
the BESS owner has only offered a $750 gift card to the people who live the closest to help cover evacuation
costs, but hasn't done anything to help people with clean up. Hasn't said anything about cleaning up Elkhorn,
Monterey Bay- and say it may be years before the BESS fire site is cleaned up due to toxicity/contamination....
People are still experiencing exposure symptoms today- two months after the fire started and there is a FB
Group with almost 4k members where people are posting up pics, sharing documents, and info about their
symptoms.
Monterey County didn't issue Guidance for Medical Providers until almost a month after the fire:
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So, finally... We know we need massive amounts of grid scale storage- but lithium BESS are NOT the
answer... So what is the solution? Fortunately, there are many solutions that are totally safe and have none
of the risks, concerns, issues of lithium BESS. To name a few categories, there are many types and many
vendors of each of the following: gravity based storage, pumped hydro storage, compressed air energy
storage, liquid to air energy storage, thermal energy storage, hydrogen storage, and even other non-lithium
based battery energy storage options.
We need everyone to understand that lithium BESS brings potential for significant/catastrophic impacts on the
environment.
Again, please do not hesitate to reach out with any questions.
Thank you,
James
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Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:14 AM
To:Gabriel Clark
Subject:FW: New evidence proves Lithium BESS require significant setbacks from schools,
hospitals, and homes
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 12:59 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: New evidence proves Lithium BESS require significant setbacks from schools, hospitals, and homes
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn leaders,
All lithium BESS will cause significant environmental impacts when they have an unpreventable and
unextinguishable thermal runaway event and they should require massive setbacks.
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FYI, two Lithium BESS that had fires are now under the EPA's control/management for cleanup (Otay Mesa, CA
and Moss Landing, CA), which is expected to take years.
Simply put, there is no 100% effective fire/thermal runaway prevention technology nor is there an 100%
effective extinguishing technology to make lithium BESS "safe"- current Standard Operating Procedure (SOP)
for emergency response crews is to evacuate the area and let the BESS burn itself out- with an option to spray
misting water to cool down nearby containers and/or attempt to capture the toxins in the mist and reduce the
spread of those toxins.
Here's new evidence about why we need significant setbacks/evacuation distances:
Industry influenced code that was cowritten by BESS developers, NFPA-855, says only a 10ft setback is
required from schools and homes:
Contrasting that significantly, is the 1/3rd mile Evacuation in all directions for fires involving "Lithium Ion and
Sodium Ion Batteries" found in the latest (2024) Emergency Response Guide Section 147 - which is the
firemen's ultimate guide to emergency responses:
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4
https://www.phmsa.dot.gov/sites/phmsa.dot.gov/files/2024-04/ERG2024-Eng-Web-
a.pdf?fbclid=IwY2xjawPffZNleHRuA2FlbQIxMABicmlkETFTVVg4Y1UwWklBeUR0MWtHc3J0YwZhcHBfaWQQMjI
yMDM5MTc4ODIwMDg5MgABHj8lwDu30wMHnGeYL9VfP6IxDzOeWTAJKN6Cp9qpK4-
5GKHIk4qiWTao10zY_aem_eSxkgWRuCVeJcnBWiFWHtQ
They also suggest 800 meter or ½ mile evacuation for toxic and/or corrosives in a fire:
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The EPA suggests at least a 330ft evacuation:
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https://www.epa.gov/electronics-batteries-management/battery-energy-storage-systems-main-
considerations-
safe?fbclid=IwY2xjawPffehleHRuA2FlbQIxMABicmlkETFMTThlZldyb1NUelloT0Z0c3J0YwZhcHBfaWQQMjIyMD
M5MTc4ODIwMDg5MgABHgigOXGqsrebgi-lJaRxe3UhB_KJPBhaek9pI-
_W8bbWDaGPeyWeLmfwNsC5_aem_2EOwLRfv-poeW5AdgdsxiA
Which is wholly inadequate in light of the new evidence from the April 2025 Firefighter injury incident where 4
of the 5 Sacramento Firefighters exposed to lithium battery smoke/gasses have been disabled from a single EV
battery fire's toxic smoke, and invisible gasses during a POST-fire/POST-extinguished off-gassing event after
the EV fire had already been extinguished and the area/air deemed "safe".
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The firefighters were in "cleanup mode" because the EV had already burned itself out, cooled down, and the
incident was considered over/completed and the area was deemed "safe" and the burned carcass of the EV
was being loaded up on the tow truck to be removed and taken to a safe storage facility where it can be
stored 50ft away from anything combustible due to the possibility of it spontaneously re-igniting up to a
month later.
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Because the scene was deemed safe, the firefighters removed their HAZMAT gear- including their breathing
apparatus to do clean-up.
Three of the firefighters were about 300ft away from the EV when it started off-gassing invisible toxic gases
AND they were exposed to the toxins for less than 3-4 minutes, and one was exposed for less than 5 minutes
and were taken to the ER quickly as soon as they showed exposure symptoms. The closest firefighter was
about 100ft from the EV and was engulfed in both the invisible toxic gasses and visible toxic smoke- he
recognized what was happening as he was being enveloped in the smoke and only took one deep breath while
in the cloud of smoke and was exposed to the smoke/gasses for 3-4 minutes before being transported to the
ER.
The volume of toxins released from a 60KW-90KW Tesla EV that had already burned itself out and had been
labeled "extinguished" and the area declared "safe" before the off-gassing started is absolutely miniscule
compared to the volumes of toxins that will be released from a single average-sized 3MW-5MW BESS
container (please note, BESS facilities can have 100s of these individual BESS containers) that enters thermal
runaway (please also be aware that the density is increasing rapidly and 14.5MW BESS containers are now
available in a 20ft container size by some Chinese manufacturers and would release nearly 5x-3x the toxins of
an average-sized 3MW-5MW BESS container).
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Comparing the largest Tesla Model Y EV battery size of 90kw vs the smallest BESS container size of 3MW, it is
reasonable to determine the BESS contains 40x the size/volume of batteries and that it would release 33x the
toxins...
Here's more info about the Tesla EV incident- Please study the above graphic closely.
Please note the EV car crash occurred on April 11th and all 5 firefighters showed exposure symptoms and
were hospitalized within an hour of exposure:
The closest firefighter (#3- who is a 36yr old male) was 100ft away and inside the visible smoke cloud and was
exposed to the toxic smoke/gasses for 3-4 minutes before experiencing "immediate nausea and dizziness"
The next closest firefighter (#2- who is a 48yr old male) was 280ft away and outside of the visible smoke cloud,
but in the "invisible" gas cloud and was only exposed to the toxic and invisible gasses for 1-3 minutes and
experienced "Scratchy throat, bitter taste"
The next two firefighters (#4- who is a 52yr old male and #1- who is a 40yr old male) were both 300ft away
and outside of the visible smoke cloud, but in the "invisible" gas cloud and #4 was only exposed to the toxic
and invisible gasses for 3-4 minutes (he "could taste it" and experienced "immediate nausea and dizziness")
and #1 was only exposed to the toxic invisible gasses for 3-5 minutes ("felt burning in throat and metallic
taste")
This occurred on April 11th 2025 and five (5) firefighters exhibited exposure symptoms from the invisible gas
cloud and the four (4) "firefighters shown in the graphic above are still unable to return to work due to injuries
sustained which include:
- Reduced lung function (<82%) - Sinus infection - Elevated heart rate, blood pressure and tachycardia - Mouth
blisters turned into lesions - Renal problems - High concentrations of sulfur, phosphorus & lithium in blood
tests"
Here are more details about the fire fighters being exposed to toxic lithium battery fire gasses/smoke:
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Here's a news channel video from September (9/30/25) where they mention that the firefighters are still
undergoing "experimental" blood transfusions to try to reduce the levels of heavy metals in their blood- and
they have no idea if there will be permanent damage to their lungs and bodies...
https://www.kcra.com/article/sacramento-firefighters-injured-toxic-ev-battery-fire/68141225
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Please note:
The four of the five firefighters are still suffering from their brief exposure more than 9 months later (after
getting to a hospital within an hour of exposure).
Three of the firefighters were in the "invisible" gas for less than 5 minutes
One firefighter was in the cloud of smoke (visible smoke and within 100ft of the Tesla EV) for 3 to 4 minutes-
but only took one deep breath.
One of the firefighters started throwing up out the window of the Fire truck while the fire truck was escorting
the tow truck to the salvage yard- that fire fighter returned to work a week later.
Another had flu like symptoms that dragged on for weeks and tried to return to work after a couple months,
but after reduced performance/capabilities, he was pulled off duty and after further testing, they found that
firefighter's lung function had dropped 20% compared to his previous test results and he has not been able to
return to work since.
A third firefighter exposed is fighting respiratory and renal symptoms as well as a low exercise tolerance,
persistent hyper-tension, tachycardia, and fatigue.
The fourth firefighter has severe fatigue, low exercise tolerance, ongoing respiratory symptoms.
The fifth firefighter, severe respiratory damage (20% loss of lung function), fatigue, cardiac issues, and renal
issues symptoms.
Remember, this was an EV's small lithium battery pack- NOT a massive 20ft-40ft shipping container filled with
lithium batteries (in a BESS)....
Using this incident as a baseline, a grid-scale BESS container representing a 33x increase in battery capacity
(approx. 3 MWh) would result in a massive escalation of toxic gas volume and reach.
1. Calculated Increase in Toxin Volume
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For simplicity and because we don't know what volume of toxins remained in the burned Tesla EV's battery
after burning for several hours, we will ignore the diminished potential max volume and instead base our
calculations on a intact Tesla battery's baseline (avg. 75–82 kWh) and empirical gas release data (approx. 150–
250 Liters of gas per kWh), the volume increase scales linearly with the number of cells in thermal runaway.
2. Impact on Spread and Isolation Zones
While volume increases 33.33x, the physical spread (toxic footprint) does not scale linearly because it is
influenced by atmospheric dispersion and the "jetting" force of the failure. However, the lethal concentration
zone expands significantly:
The "300ft Zone": In the Tesla incident, 300 feet was the point of permanent disability for less than 5
minutes of exposure. For a BESS fire, the gas density at 300 feet would reach Immediately Dangerous
to Life or Health (IDLH) levels almost instantaneously, likely resulting in a fatality rather than disability
for unmasked individuals.
Calculated Reach: To maintain the same toxic gas concentration experienced by the Sacramento crew
(baseline safety), the exclusion zone would need to expand to approximately 1,700 – 2,200 feet
(roughly 0.3 to 0.4 miles) to account for the increased volume and plume buoyancy of a container-level
event.
3. Key Findings from the Sacramento Incident
The "White Cloud": The "low-lying white cloud" described by firefighters was likely a concentrated
aerosol of electrolyte solvent and toxic acid gas (HF/POF3).
Documented Pathologies: The Baseline Formula for injury includes renal failure, <82% lung function,
heart lesions, and high blood metal concentrations (Lithium, Phosphorus, Sulfur).
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BESS Multiplier: Because BESS containers often utilize LFP (Lithium Iron Phosphate) or NMC
chemistries in high-density racks, a single "venting" event in a BESS unit can release the equivalent
toxin volume of 33 cars simultaneously, creating a plume that can overwhelm standard fire
department decontamination protocols.
Projected HF Concentrations (2,500-foot Radius)
The following estimates use standard dispersion modeling for large-scale lithium battery venting in outdoor
environments.
Critical Scaling Factors
Toxin "Loading": A standard BESS container can release between 50 and 500 kg of HF during a thermal
runaway event. For comparison, a single EV typically releases only 1.5–15 kg.
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The 300-Foot Baseline: In the Sacramento case, the 300-foot distance was only "safe" relative to the
small volume of one car. For a BESS, 300 feet is considered the "Hot Zone" where even standard
turnout gear provides insufficient protection against HF vapor, which penetrates skin and leaches
calcium from bones.
Vulnerability of Schools: Children are more vulnerable to these concentrations because they have a
higher lung surface area-to-body weight ratio, meaning they absorb a higher toxic dose than adults at
the same 2,500-foot distance.
Hydrogen Cyanide (HCN) is a highly toxic byproduct frequently associated with the combustion and thermal
decomposition of Lithium Iron Phosphate (LFP) batteries. Using the April 2025 Sacramento Tesla incident as a
baseline for firefighter disability, we can project the impact of an industrial-scale BESS container.
1. Calculated Increase in HCN Volume
HCN is an asphyxiant that interferes with the body's ability to use oxygen. While a single EV (75–82 kWh)
releases significant toxins, a 2,500 kWh (2.5 MWh) BESS container represents a 33.33x increase in fuel mass.
2. Projected HCN Concentrations (2,500-foot Radius)
The Sacramento crew was permanently disabled at 300 feet by a "low-lying white cloud." For a BESS fire, that
same 300-foot zone becomes a lethal environment for unmasked individuals.
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3. Comparison with the Sacramento Baseline
The "Metallic Taste" Indicator: The Sacramento firefighters reported an immediate "metallic taste,"
which is a classic symptom of cyanide and heavy metal exposure.
The 33.33x Multiplier: In a BESS event, the plume is not just larger; it is more "buoyant" and can travel
further before dissipating. The 10-minute AEGL-3 (lethal threshold) for HCN is 27 ppm. At 1,700 feet
from a BESS container fire, a bystander would likely inhale a toxic dose sufficient to cause permanent
disability or death in under 10 minutes.
Systemic Effects: Unlike HF (which causes acid burns), HCN causes systemic cellular hypoxia. The long-
term injuries seen in the Sacramento crew—renal failure and heart lesions—are exacerbated when
HCN and HF are inhaled simultaneously.
Based on the medical documentation from the April 2025 Sacramento Incident, the "white cloud" aerosol
acted as a delivery vehicle for heavy metals, leading to systemic toxicity. When scaling this to a BESS container
(33.33x increase), the concentration of these metals in the blood of exposed individuals would likely reach
critical "toxic metal syndrome" levels almost immediately.
Documented Blood Metal Levels and Pathologies
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The Sacramento crew exhibited specific "biochemical markers" that provide a baseline for calculating the risk
to residents near a BESS facility.
The "Aerosol Delivery" Problem
The reason these levels were so high at 300 feet (and would be catastrophic at 2,500 feet for a BESS) is due to
vapor-phase transport:
1. Micro-Particles: In a thermal runaway, metals are not just "burned"; they are vaporized into particles
smaller than 2.5 microns (PM2.5).
1. Deep Lung Penetration: These particles bypass the body's natural filters and enter the bloodstream
directly through the alveoli.
1. The BESS Multiplier: A BESS container contains approximately 10,000 to 20,000 lbs of lithium-ion cells.
A 33x increase in fuel means the "metal rain" or aerosol density within a 1,000-foot radius would be
thick enough to cause acute metal poisoning in minutes.
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Calculation of Injury Baseline
If a 75kWh car produced permanent disability at 300 feet, a 3MWh BESS fire creates a "Toxic Footprint" where
the Heavy Metal Load remains above the Sacramento disability baseline for at least 1.2 miles (6,300 feet)
downwind, depending on wind speed.
As the size and density of BESS increases, there are 14.5MW BESS in 20ft containers available now- just
stepping up to an industry average size of a 5MW BESS container has the following risk/dangers:
It represents a massive escalation in risk compared to the Sacramento Tesla baseline. A single Tesla Model Y
(approx. 75–82 kWh) is over 250 times smaller than a standard 5MW utility-scale container.
In the April 2025 Sacramento incident, firefighters were permanently disabled by a less-than 5-minute
exposure to a toxic "white cloud" at 300 feet away. For a BESS container fire, the "disability zone" expands
significantly due to the sheer volume of toxic loading.
5 MW BESS Toxin Scaling (vs. Sacramento Baseline)
The following projections use the Sacramento firefighter injuries—including renal failure, heart lesions, and
<82% lung function—as the medical baseline for "Permanent Disability".
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Projected Safe Distances for 5 MW BESS
Using air dispersion modeling centered on the Sacramento medical data, the danger zones for a 5 MW BESS
container fire are as follows:
0 – 1,500 feet: Lethal Zone. Concentrations of HF and HCN would likely exceed AEGL-3 (Lethal
Threshold) within seconds. Survival probability for unprotected civilians is near zero.
1,500 – 5,000 feet: Sacramento Disability Zone. This is where the "white cloud" density matches the
levels that permanently disabled the Sacramento crew. Residents and students in this range face high
risk of permanent organ damage.
1 – 2 miles: Acute Irritation/Evacuation Zone. Toxic gases remain at levels that cause respiratory
distress and systemic metal loading.
Consequences of Locating BESS Near Sensitive Areas
Siting 3-5 MW BESS near schools, homes, or hospitals amplifies risks, using Sacramento as baseline:
Schools: Children have higher lung surface-to-body ratios, absorbing 2-3x more toxins per breath. A 3
MW plume could reach IDLH at 1,700 ft, disabling students in minutes; 5 MW extends to 2,500 ft.
Evacuation challenges: Chaos for 500+ kids, with long-term effects like reduced lung function impacting
development.
Homes: Residential areas face stealthy invisible plumes traveling 1-2 miles downwind. Brief exposures
(e.g., 5 min outdoors) could cause Sacramento-like disabilities, including renal/cardiac issues in elderly
or vulnerable. Bioaccumulation of metals (Li, Ni) raises cancer risks over time.
Hospitals: Proximity endangers patients with compromised immunity. A 5 MW event's lethal zone (0-
1,500 ft) could force shutdowns; warning zones (1-2 miles) cause respiratory distress, overwhelming
ERs. HCN/CO asphyxiation risks ventilators.
Additional info about the Sacramento firefighter injury incident:
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The crash involved a high-speed impact into a tree, which compromised the battery pack, scattering
~5% of the lithium-ion cells across the roadway. Some of these scattered cells ignited intermittently
during the initial response.
Firefighters extricated the driver (who was hospitalized) and handled the scene with appropriate PPE
and SCBA (self-contained breathing apparatus).
The main visible fire/flames from the compromised pack were suppressed and declared "extinguished"
before the vehicle was loaded onto a tow truck for removal to a salvage yard.
The off-gassing event (releasing the toxic white/invisible clouds) occurred during or right after the
vehicle was moved for towing—triggered by disturbance of the remaining pack/cells. This was post-
extinguishment cleanup mode, when responders had removed their HAZMAT/SCBA gear, assuming the
area was safe.
Update: Updated Sacramento Baseline and Scaling Factors
Tesla Model Y Baseline (75 kWh):
Full Runaway: Assumes intact pack; volumes based on per-kWh data.
Diminished (Sacramento Actual): ~5-10x reduced due to prior burn-out.
Scaling to BESS:
3 MWh: 3,000 kWh / 75 kWh = 40x full EV baseline.
5 MWh: 5,000 kWh / 75 kWh ≈ 66.67x full EV baseline.
14.5 MWh: 14,500 kWh / 75 kWh ≈ 193.33x full EV baseline.
Compounded by the full-fuel state (vs. Sacramento's diminished), total effective multipliers vs. the incident
could reach 200-1,933x for toxins in worst-case BESS events.
Chart 1: Toxin Volume Scaling (Table Representation of Bar Chart)
This table shows calculated toxin releases, with the estimated diminished capacity, 75 kWh baseline fixed for
MAX battery size of the Tesla Model Y involved in this incident. Values for Sacramento are the diminished
actual values; full EV and BESS assume intact packs. Imagine this as a bar chart with a logarithmic y-axis to
capture the exponential growth.
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Chart 2: Projected Danger Zones (Table Representation of Radial Chart)
Recalculated zones using the 75 kWh baseline, with dispersion scaled by sqrt(volume) for plume spread
(adjusted for higher BESS buoyancy). Baseline: 300 ft caused disability in 5 minutes. Envision as concentric
circles on a map, expanding dramatically with size.
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Chart 3: Health Impact Projections (Table Representation of Impact Matrix)
Updated pathologies, scaled by recalculated exposure intensities. Assumes equivalent brief exposure (5
minutes) at distances matching Sacramento's 300 ft disability threshold (e.g., ~1,700 ft for 3 MWh, farther for
larger).
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In short, the setbacks need to be adjusted based on the new documented evidence of the firefighter's
exposure and injuries from the smoke and gasses released from a small 75kw LFP battery EV and the disabling
impacts an already extinguished Tesla EV's reduced total-volume/capacity had on the 4 unprotected
firefighters. It is the only well documented evidence of exposure on unprotected victims- like school children
and families would be when forced to suffer the impacts of a lithium BESS fire next to their school or homes...
In addition, because of the irrefutable scientific evidence from San Jose State University's Marine Lab showing
ash/fallout is a major concern- add in the documented grassroots lab test results showing fallout travelling (in
toxic quantities) up to 42 miles down wind- setbacks should be measured in miles for lithium BESS...
Developers always say no toxins were found during BESS fires by the EPA, by the fire Department/HAZMAT,
MBARD, BESS owner's systems, or anyone else...
After 10 previous lithium BESS fires in California, CA's Air Resource Board (MBARD) admitted after the Jan
2025 Moss Landing BESS fire where they said no toxins were detected and the air was safe, that they didn't
have the capability to test for the #1 toxin released by burning lithium BESS (HF):
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The EPA also doesn't have a refence concentration or reference dose for HF:
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Yet, the handheld air meters used in 2019 Surprise AZ BESS fire found many other toxins- but their air quality
sensors didn't have HF detecting ability either- yet nothing was found in the air from the Jan 2025 tests:
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Their air monitoring gauges were maxed out:
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https://d1gi3fvbl0xj2a.cloudfront.net/public/2021-
07/Four_Firefighters_Injured_In_Lithium_Ion_Battery_ESS_Explosion_Arizona_0.pdf?fbclid=IwY2xjawPg9sZle
HRuA2FlbQIxMABicmlkETFIT2lCaE94U2doQUxOcEF0c3J0YwZhcHBfaWQQMjIyMDM5MTc4ODIwMDg5MgABH
nUveDmwl1hYfod_S8aF7b4BfgbwU4uvB6s7fXPlUxygKXLO89gcGOACbJE9_aem_IXUYQqdBac5qhBzX0Nxafg
Additionally, people from miles around went into the hospital and spoke with their doctor- and Monterey
County eventually issued a Health notice:
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After the 2nd LFP BESS fire at a BESS in Warwick NY in December of 2025, an investigator got testing data back
about what they tested for before telling everyone the air was safe- here's her report:
"꺐꺑꺒꺓꺖꺔꺗꺕 IMPORTANT: What Orange County HAZMAT Actually Measured After the BESS Fire (and what they did
NOT) 꺐꺑꺒꺓꺖꺔꺗꺕
After the 12/19 Battery Energy Storage System (BESS) fire, Orange County HAZMAT released an air-monitoring
data log. Many residents understandably assumed this meant “the air was safe.”
But after reviewing the actual data, here is what the instruments were really checking — and what they
completely missed.
꺐꺑꺒꺓꺖꺔꺗꺕 What WAS measured
The equipment used was a portable emergency responder gas meter, designed to keep firefighters from
collapsing on scene. It monitored:
꺐꺑꺒꺓꺖꺔꺗꺕 Carbon Monoxide (CO) 꺐꺑꺒꺓꺖꺔꺗꺕 Hydrogen Cyanide (HCN) 꺐꺑꺒꺓꺖꺔꺗꺕 Ammonia (NH₃) 꺐꺑꺒꺓꺖꺔꺗꺕 Flammable gases (LEL &
Methane) 꺐꺑꺒꺓꺖꺔꺗꺕 Oxygen levels 꺐꺑꺒꺓꺖꺔꺗꺕 General VOCs (very crude detection) 꺐꺑꺒꺓꺖꺔꺗꺕 Radiation 꺐꺑꺒꺓꺖꺔꺗꺕 Temperature,
humidity, wind speed & direction
This tells responders: 꺐꺑꺒꺓꺖꺔꺗꺕 Is the air explosive? 꺐꺑꺒꺓꺖꺔꺗꺕 Will it knock firefighters out right now? 꺐꺑꺒꺓꺖꺔꺗꺕 Is oxygen too
low to breathe?
That’s it.
꺐꺑꺒꺓꺖꺔꺗꺕 What was NOT measured (this is the critical part)
None of the primary toxins from lithium-ion battery fires were monitored:
꺐꺑꺒꺓꺖꺔꺗꺕 Hydrogen Fluoride (HF) – extremely corrosive, burns lungs & skin 꺐꺑꺒꺓꺖꺔꺗꺕 Phosphoryl fluoride (POF₃) 꺐꺑꺒꺓꺖꺔꺗꺕
Phosphorus pentafluoride (PF₅) 꺐꺑꺒꺓꺖꺔꺗꺕 Fluorinated acids 꺐꺑꺒꺓꺖꺔꺗꺕 Lithium compounds 꺐꺑꺒꺓꺖꺔꺗꺕 Nickel, cobalt &
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manganese metal dust 꺐꺑꺒꺓꺖꺔꺗꺕 PM2.5 and ultrafine particles (the particles that get deep into lungs) 꺐꺑꺒꺓꺖꺔꺗꺕 Soil and
surface contamination 꺐꺑꺒꺓꺖꺔꺗꺕 Rain-wash runoff into wetlands and creeks
These are the chemicals that: • Settle on homes, cars, yards & playgrounds • Get tracked into buildings • Stay
in soil • Harm firefighters’ gear • Can cause long-term cancer and lung disease
None of that was measured.
꺐꺑꺒꺓꺖꺔꺗꺕 What this monitoring actually means
This equipment answers only one question:
“Is it safe for firefighters to stand here without dropping dead right now?”
It does NOT answer:
꺐꺑꺒꺓꺖꺔꺗꺕 Are residents breathing toxic fluorinated chemicals? 꺐꺑꺒꺓꺖꺔꺗꺕 Did heavy metals fall on homes and soil? 꺐꺑꺒꺓꺖꺔꺗꺕 Did
toxic particles settle into nearby wetlands and waterways? 꺐꺑꺒꺓꺖꺔꺗꺕 Did rain wash contaminants into the
watershed? 꺐꺑꺒꺓꺖꺔꺗꺕 Are kids, pets, and firefighters being exposed long after the fire?
Those hazards require laboratory-grade testing, not handheld emergency meters.
꺐꺑꺒꺓꺖꺔꺗꺕 Why this matters
This is the same mistake made after 9/11 — when officials said the air was “safe” based on simple gas
monitors while toxic dust and heavy metals were everywhere.
BESS fires are chemical fires, not just smoke.
Without: • Fluoride testing • Particle monitoring • Soil & surface sampling
No one can honestly say the area was safe.
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꺐꺑꺒꺓꺖꺔꺗꺕 Bottom line
Orange County’s own data proves this:
They checked for immediate firefighter danger — not for long-term community and environmental
contamination.
That’s a huge difference.
Communities deserve real testing — not false reassurance."
Check out the holes in the EPA's testing in Fredrickson, MO BESS battery recycling plant fire:
https://response.epa.gov/site/doc_list.aspx?site_id=16725
All of this to say we need massive setbacks for lithium BESS. We need BESS developers to equip all first
responders with appropriate air testing/monitoring equipment that can test for all the known toxins- as well
as have monitoring stations located throughout the evacuation area (5-mile radius). We need all first
responders to have breathing apparatus- as well as all schools, hospitals, public gathering places, and homes
within the evacuation zones to be supplied with breathing apparatuses to allow them to evacuate safely.
We need environmental/property insurance to cover the clean-up of toxins and ash for all surfaces in the
evacuation zones. We need to have cash held in escrow to pay for evacuees, cleanup, diminished value of all
impacted properties, long term health insurance and disability coverage for those not evacuated before being
exposed to the toxic smoke, gasses, and ash.
There are so many consequences to a lithium BESS when there is a fire- evacuations for 5 days on average,
millions of gallons of water used and contaminated (nearly 20M gallons were used in the Otay Mesa BESS fire-
and the toxic runoff is what caused the EPA to take over clean up.
FYI, there are many alternative grid-scale energy storage options that don't use lithium batteries and don't
bring any of the issues nor risk...
Thank you,
James
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Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:14 AM
To:Gabriel Clark
Subject:FW: Firefighters officially oppose lithium BESS near schools, neighborhoods, fire
stations, and other hard to evacuate locations- so should you!
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 1:03 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: Firefighters officially oppose lithium BESS near schools, neighborhoods, fire stations, and other hard to
evacuate locations- so should you!
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn Leaders,
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Lithium BESS have significant impacts on people and the environment when they have an unpreventable and
unextinguishable thermal runaway fire.
Here's a few Firefighter, Unions, and others that have taken a stand to protect citizens, school children, and
other neighbors from the dangers of lithium Battery Energy Storage Systems:
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Firefighter concerns
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Here's a news story, dated Sept 30th 2025 discussing the firefighter's exposure back in April and still today are
suffering exposure symptoms and are undergoing experimental IV-infused therapy to attempt to remove
heavy metals from their bloodstream:
https://www.kcra.com/article/sacramento-firefighters-injured-toxic-ev-battery-
fire/68141225?fbclid=IwY2xjawPSXvJleHRuA2FlbQIxMABicmlkETE0OXNEN2VINE0wRlVBSGJac3J0YwZhcHBfaW
QQMjIyMDM5MTc4ODIwMDg5MgABHo0vh7Z8VsTNnmvSAKugQftL2WTGk8TN_AtG-
xL7j4fMgC1uSU0eOJH4MtMc_aem_x5AyVtC4XEid3rZfR7vpRg
Here's a presentation from one of the Surprise AZ firefighters who was severely injured in the lithium BESS
explosion:
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https://youtu.be/USnTf1JPgts?si=UtbOWe5fg81ItGk4
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https://teex.org/news/teex-initiates-tests-on-first-responder-ppe-exposed-to-lithium-ion-battery-fires/
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https://pmc.ncbi.nlm.nih.gov/articles/PMC9566750/
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https://www.fireengineering.com/firefighting/lithium-ion-influenced-fires-back-to-basics/
Lithium BESS fires are unpreventable and unextinguishable:
https://www.cbs8.com/article/news/local/fire-safety-concerns-san-diego-county-battery-energy-storage/509-
ab9b0716-7784-47a6-9394-efeebd875279
https://www.newsdata.com/california_energy_markets/regional_roundup/researchers-assess-metal-fallout-
from-moss-landing-battery-fire/article_7d68d110-977d-4123-be33-ec4f39fdf09f.html
Thank you for your attention to this matter, and please step up and officially oppose lithium BESS being sited
within 1 mile of schools, homes, and other hard to evacuate locations.
Thank you,
James
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Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:13 AM
To:Gabriel Clark
Subject:FW: MORE Firefighters officially oppose lithium BESS near schools, neighborhoods, fire
stations, and other hard to evacuate locations- so should you!
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 1:04 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: RE: MORE Firefighters officially oppose lithium BESS near schools, neighborhoods, fire stations, and other hard
to evacuate locations- so should you!
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Community leaders and EFSEC leaders,
Here's more official opposition to lithium BESS:
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Oct 02, 2024
Joint Statement of International Longshore and Warehouse Union and California Professional Firefighters
On September 26th, a big rig carrying lithium-ion batteries at the San Pedro Bay Port Complex overturned,
igniting an intense fire that disrupted port operations and caused the closure of a major freeway. The
batteries burned for more than 24 hours while firefighters took a defensive stance to protect the surrounding
area.
Incidents like this are happening more frequently. Firefighters risk great bodily harm, even death, when
responding to these emergencies. ILWU members, who ensure the Ports of Los Angeles and Long Beach move
goods efficiently and safely, are also put at risk during these incidents.
While we understand the importance of clean energy technologies and the efforts to ensure community
safety, it is our firefighters who are bearing the brunt of risks posed by this technology. Over the past few
years, we have witnessed a surge in lithium-ion battery fires in vehicles on our highways and battery storage
facilities.
When these fires occur, entire highways are shut down and all traffic ceases. This impacts commercial
transportation and the surrounding communities. A greater concern is the health impacts on those who
respond to these fires. Even when wearing the proper personal protective equipment and respirators,
firefighters face dangerous exposures. A single exposure can lead to a firefighter being forced to medically
retire after suffering from irreversible damage to their body.
There is a current void in preparedness to respond to lithium-ion battery emergencies. When ignited, these
batteries off-gas and can shoot flames up to 10 feet high. Firefighters have no choice but to let these fires burn
out because water does little to quell the flames and intense heat.
CPF and ILWU will continue to collaborate on solutions to improve safety and reduce risk in the San Pedro Bay
Port Complex and beyond, including through the convening of state agencies called by Governor Newsom on
Friday, September 27th on this topic.
The ILWU dispatches longshore, marine clerk, foreman and security guard labor at 14 California Ports,
including the Ports of Los Angeles and Long Beach, day and night, 365 days a year to move the nation’s cargo
and provide fluidity to the global supply chain.
CPF, state council of the International Association of Firefighters, represents 35,000 professional firefighters
and emergency medical services personnel across California, including the firefighters who responded to the
lithium battery fire at the San Pedro Bay Port Complex.
https://www.cpf.org/news/news-updates/joint-statement-of-international-longshore-and-warehouse-union-
and-california-professional-
firefighters?fbclid=IwY2xjawPTkYBleHRuA2FlbQIxMABicmlkETFWeXlwYmJkTUNqV1hOeFFSc3J0YwZhcHBfaWQ
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QMjIyMDM5MTc4ODIwMDg5MgABHmCr-Ba-RSLwLq_Rha_bFKNjhr6BavEaSD-
ai26uXa191KVi0zTp5Ui_6GIC_aem_iWnHcgvKkaZ_DRwpiYfHxA
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 1:02 PM
To: crakes@auburnwa.gov <crakes@auburnwa.gov>; ttaylor@auburnwa.gov <ttaylor@auburnwa.gov>;
blott@auburnwa.gov <blott@auburnwa.gov>; ctaylor@auburnwa.gov <ctaylor@auburnwa.gov>;
lstirgus@auburnwa.gov <lstirgus@auburnwa.gov>; hamer@auburnwa.gov <hamer@auburnwa.gov>; info@vrfa.org
<info@vrfa.org>; Planning <planning@auburnwa.gov>
Subject: Firefighters officially oppose lithium BESS near schools, neighborhoods, fire stations, and other hard to
evacuate locations- so should you!
Good afternoon Auburn Leaders,
Lithium BESS have significant impacts on people and the environment when they have an unpreventable and
unextinguishable thermal runaway fire.
Here's a few Firefighter, Unions, and others that have taken a stand to protect citizens, school children, and
other neighbors from the dangers of lithium Battery Energy Storage Systems:
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Firefighter concerns
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Here's a news story, dated Sept 30th 2025 discussing the firefighter's exposure back in April and still today are
suffering exposure symptoms and are undergoing experimental IV-infused therapy to attempt to remove
heavy metals from their bloodstream:
https://www.kcra.com/article/sacramento-firefighters-injured-toxic-ev-battery-
fire/68141225?fbclid=IwY2xjawPSXvJleHRuA2FlbQIxMABicmlkETE0OXNEN2VINE0wRlVBSGJac3J0YwZhcHBfaW
QQMjIyMDM5MTc4ODIwMDg5MgABHo0vh7Z8VsTNnmvSAKugQftL2WTGk8TN_AtG-
xL7j4fMgC1uSU0eOJH4MtMc_aem_x5AyVtC4XEid3rZfR7vpRg
Here's a presentation from one of the Surprise AZ firefighters who was severely injured in the lithium BESS
explosion:
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https://youtu.be/USnTf1JPgts?si=UtbOWe5fg81ItGk4
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https://teex.org/news/teex-initiates-tests-on-first-responder-ppe-exposed-to-lithium-ion-battery-fires/
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https://pmc.ncbi.nlm.nih.gov/articles/PMC9566750/
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https://www.fireengineering.com/firefighting/lithium-ion-influenced-fires-back-to-basics/
Lithium BESS fires are unpreventable and unextinguishable:
https://www.cbs8.com/article/news/local/fire-safety-concerns-san-diego-county-battery-energy-storage/509-
ab9b0716-7784-47a6-9394-efeebd875279
https://www.newsdata.com/california_energy_markets/regional_roundup/researchers-assess-metal-fallout-
from-moss-landing-battery-fire/article_7d68d110-977d-4123-be33-ec4f39fdf09f.html
Thank you for your attention to this matter, and please step up and officially oppose lithium BESS being sited
within 1 mile of schools, homes, and other hard to evacuate locations.
Thank you,
James
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1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:13 AM
To:Gabriel Clark
Subject:FW: When Mayors are warning neighboring town officials about dangers of lithium
BESS after his town experienced 3 LFP BESS fires since Warwick, NY got their first BESS-
changed are needed
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 1:12 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: When Mayors are warning neighboring town officials about dangers of lithium BESS after his town experienced
3 LFP BESS fires since Warwick, NY got their first BESS- changed are needed
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn leaders,
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There are significant impacts on people and the environment when there is an unpreventable and
unextinguishable thermal runaway BESS fire. ALL BESS should start with a determination of significance.
As the article says, after Warwick NY's 3rd LFP BESS fire, he's warning other town officials about the dangers
and lies...
Warwick mayor warns Ulster town officials of lithium-ion battery issues
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A sign opposing a proposed lithium-ion plant at the former John A. Coleman High School in the town of Ulster,
N.Y., is posted on Main Street in Hurley, N.Y., on Tuesday morning, Aug. 19, 2025. (Dwayne Kroohs/Daily
Freeman)
By William J. Kemble | news@freemanonline.com
PUBLISHED:
December 26, 2025 at 1:29 PM EST
| UPDATED:
December 26, 2025 at 2:34 PM EST
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TOWN OF ULSTER, N.Y. – Warwick village Mayor Michael Newhard has sent warnings to the Ulster Town
Board about the promises made and failure to keep them by battery storage developers after a second
lithium-ion fire at a relatively small battery energy storage system.
During a Wednesday, Dec. 24, interview, the caution was specific against believing developers’ talking about
plans “meeting industry best practices” or “exceeds stringent state standards.”
The question that Warwick officials are now asking about the combined 11.4-megawatt Convergent Energy
system is the same question that town of Ulster officials need to ask for a proposed 250-megawatt Terr-Gen
lithium-ion system on the former Coleman Catholic High School on Hurley Avenue, Newhard said.
Newhard said municipalities should stand firm against having facilities near residential areas and, by all means,
demand that all schematics are shown for fire suppression systems and have all test results readily available to
prove that the equipment works.
“After the first incident (in 2023), we were more than guarded; we really pushed (system owner) Convergent
to do safety measures,” Newhard said. “Some they complied with. But some they haven’t. And so we are still
in that space where we really have a lack of trust, and our greatest concern, which was not forthcoming, was
public safety.”
Warwick has two locations for the same Convergent Energy system, with a fire occurring at the 8-megawatt
installation on June 26, 2023, on the Warwick Valley School District campus, which has three schools and the
district’s transportation building. That incident, which is in the town of Warwick, shut down the school district
for seven days and, according to minutes of the district’s July 6, 2023, meeting, the same rainstorm also
“triggered alarms” at the connected 3.4-megawatt system on Church Street in the village of Warwick.
There are 10 containers that are about 40 feet long, 8 feet wide and 9.5 feet tall on the school property, while
the village site has four containers of about the same height and width but about half the length.
At the site of the former Coleman High School on Hurley Avenue in the town of Ulster, Terra-Gen has
proposed about 300 containers measuring about the same dimensions as the Warwick village site.
Newhard said the 2023 incident in the village was a “potential fire event” that did require the fire suppression
system to be used before it reached the significant blaze phase that occurred at the school property. He
considers it a cautionary moment that foretold the Dec. 19, 2025, fire, which has already led to the village
issuing a violation notice to Convergent Energy for failing to live up to critical requirements set down by
officials to avoid health and safety risks.
“It’s great to have this new technology, but if the new technology puts us in harm’s way, then is that valuable
or worth it, or should we wait until it becomes a safer infrastructure?” he said.
“We’re going to go through a lot now because this trust had eroded during the original (2023) event,”
Newhard said. “Now, trust is pretty much completely off the table. Evaporated would be a good way to put it.”
The school fire gave village officials deep concerns because “multiple cells caught on fire (and) lasted for many
days,” Newhard said.
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“The plume of smoke on the first time around out of the school (site) really had everyone with great concern,”
he said.
“The testing came in (reporting) that there was never a point where the levels reached a threshold of being
harmful,” Newhard said. “That’s great, but we still have questions as, what are those numbers? And, give us
more information. We’re at a point where we’re really pushing to get as much information as possible after
the fact so that we really have a clearer picture.”
Recommendations to the town of Ulster are being made after Warwick found that Convergent Energy led its
village Planning Board to believe that everything would be “peaches and cream” in terms of safety, Newhard
said.
“Tread carefully,” he said. “Demand a level of protection on an ongoing basis if they do install it. … These
companies, they create these things and they basically walk away, and then they leave it in the lap of the
community, which has been a level of frustration for us, clearly.”
Wawrick officials wasted no time in issuing a violation notice for the Dec. 19 event, with a letter sent on Dec.
23 from village attorney J. Benjamin Gailey saying Convergent Energy needs to essentially shut down its
system.
A battery
energy storage facility fire that began Friday evening, Dec. 19, 2025, at a site located within the village of
Warwick. (town of Warwick photo)
“Convergent is operating the BESS facility without the required certificate of compliance,” he wrote.
“The village Building Inspector is ordering Convergent to immediately reduce the stored energy in the battery
units to the maximum extent feasible, take all other technical measures to assure there is no re-ignition, and
disconnect the facility from the electric grid and all other connections,” Gailey wrote. “A certificate of
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compliance will not be issued until the Building inspector and the village’s engineering consultant are satisfied
that all necessary safety measures have been implemented at the facility.”
Fueling the concerns of Warwick village officials, who earlier this year warned about “hazardous moisture
potential,” was an August 21, 2025, email from Convergent, saying leak detection inspections were not
necessary.
“This is obviously not the case,” Gaily wrote. “Convergent’s disregard of the village engineer and Building
Inspector requests and disregard of the safety of surrounding persons and property is appalling.”
Ulster town Supervisor James Quigley responded openly to the offer of suggestions from Warwick, and before
the Dec. 19 incident had already instructed fire officials to “do a deep dive” review of the 2023 blaze to
determine what could happen with a system on Hurley Avenue that would be 74 times larger.
“I asked the Spring Lake Fire Company leadership to personally reach out to the leadership of the fire
companies in the locations of the 2023 fires to understand what happened in their communities, to
understand the level of responses that was required by those organizations, and the level of resource usage
that was required by those events,” he said.
“I am not averse to picking up the phone and talking to the elected leaders in those communities and
discussing their experiences,” Quigley said. “I think that’s an important part of fact finding.”
Terra-Gen Vice President Mark Turner said in an email on Friday that his company is “distinctive among
storage developers” because it operates the battery energy storage facilities it constructs.
“Once a project is online you’ll see our operations team regularly on site—the people in the white hard hats
and the white trucks—conducting inspections, monitoring performance, and ensuring the facility operates
safely and efficiently in accordance with applicable codes, permits, and our internal standards,” he wrote.
Terra-Gen was fined $628,193.42 by the Federal Energy Regulatory Commission for “submitting false or
misleading information” to the California Independent System Operator. The penalty was levied on Aug. 2,
2021, for incorrectly reporting the “physical capabilities of the wind-powered electric generation” of its
subsidiary Cameron Ridge LLC and violating the state tariff regulations by “deviating its wind farm’s output”
from state instructions.
https://www.dailyfreeman.com/2025/12/26/warwick-warns-ulster-town-officials-of-lithium-ion-battery-
issues/
Here's the letter the City's outsourced lawyers sent:
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I apologize for the formatting as the original/full letter has been deleted from the internet...
We need to learn from other's suffering to avoid putting us at the same risks...
There is no way to prevent lithium BESS fires nor is there any way to extinguish them once they have started-
meanwhile everyone nearby will be forced to evacuate for an average of 5 days/nights while the lithium BESS
burns itself out.
Please protect us by creating BESS siting rules that are safety first and have adequate setbacks from schools,
homes, hospitals, fire stations, and other hard to evacuate locations- I would say a 2-5 mile buffer would
generally be adequate.
Thank you,
James
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Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:13 AM
To:Gabriel Clark
Subject:FW: BESS Toxins released- significant impact on people and environment
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 2:25 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: BESS Toxins released- significant impact on people and environment
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn Leaders,
As you know lithium BESS pose a significant environment impact and a significant impact on anyone exposed
to the toxic smoke, gasses, and ash released from 100s of thousands (potentially millions) of lithium batteries
burning and due to the immediate threat to life, evacuations are forced and usually last for 5 days....
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Since you should now be familiar with the Moss Landing Bess's 4th fire in Jan 2025 (they had a re-ignition a
month later at the same BESS and clean-up of the site is still in the early stages and will take years) and you
know how it spewed toxic ash for miles around- initially reported by San Jose State Research's lab te sts to be a
100x - 1000x increase of lithium battery heavy metals across their 2-mile radius research area and then further
lab testing found toxic levels of ash traveled 27.2 miles down wind.
People are always talking about lithium battery fires and the dangerous smoke- whether it is a cell phone or a
e-mobility device spontaneously combusting- a BESS, may have 100,000s of lithium batteries in each individual
BESS container and the BESS facility may have 100s of BESS containers- here's a list of some of the toxins
released from a burning lithium battery that will hit Auburn within minutes of the smoke/off-gassing starting
(depending on the wind) and will have to be evacuated ASAP along with ever yone and everything else within 5
miles of the BESS and remain evacuated for an average of 5 days- Here's a pic of a 5-mile radius area (circling
the estimated location) that would either have to be evacuated or locked down under shelter-in-place orders
and all roads closed when there is a fire and could be contaminated with most dangerous levels of toxic ash:
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Here's a refresher on the contents of the toxic smoke, gasses, and ash released when a lithium BESS burns:
Hydrogen cyanide (HCN):
Fatal if swallowed, is fatal in contact with skin, is fatal if inhaled, causes damage to organs through prolonged
or repeated exposure, is very toxic to aquatic life (with long lasting effects) and is an extremely flammable
liquid and vapour. From nitrogen-containing polymers (e.g., separators)—ScienceDirect (2024) lists HCN as 10x
higher in LFP vs. NMC. Typically reads off-the-charts when tested at BESS fire, exceeding 50 ppm (NIOSH IDLH)
and Lethal at 270 ppm (CDC), dermally absorbed (UFUA, McConville)
Hydrogen chloride (HCl):
Severe skin burns and eye damage, is toxic if inhaled, may damage fertility or the unborn child, causes serious
eye damage, may cause damage to organs through prolonged or repeated exposure, may be corrosive to
metals, may cause respiratory irritation and contains gas under pressure and may explode if heated.
Chlorine (Cl2):
Is a very toxic chemical element that can cause eye irritation, coughing, vomiting and other symptoms. It is
easily distinguishable by its greenish-yellow color and a bleach-like odor. Chlorine was even weaponized
during World War I and is estimated to have caused at least 1100 deaths in its first usage due to reactions with
other organic chemicals in the atmosphere leading to dangerous reactions.
Hydrogen sulfide (H2S):
Is a flammable and highly toxic substance that can be dangerous in both acute and chronic forms. One
exposure to high levels of H2S can cause immediate death, while health problems might not show up until
three days after the exposure. It is a chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with
trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs
Nitrogen dioxide (NO2):
Breathing smoke containing high levels of nitrogen dioxide (NO2) can irritate airways, impair lung function,
and increase the risk of respiratory infections, especially in children and those with asthma or COPD. Long-
term exposure can also contribute to chronic bronchitis and potentially cause permanent lung damage. Fatal if
inhaledin high levels, causes severe skin burns and eye damage; and may cause or intensify fire
(oxidiser).0.961.91
Sulphur dioxide (SO2):
Poses significant health risks, primarily affecting the respiratory system, causing irritation, coughing, and
difficulty breathing, particularly for those with asthma or other lung conditions. Severe skin burns and eye
damage and is toxic if inhaled.
Phosphoryl fluoride (POF3):
POF3 is a CORROSIVE CHEMICAL and contact can severely irritate and burn the skin and eyes with possible eye
damage. Breathing Phosphorus Oxychloride can irritate the nose and throat. Breathing Phosphorus
Oxychloride can irritate the lungs causing coughing and/or shortness of breath.
Ammonia (NH3):
Is hydroscopic, or water-seeking. When combined with moisture it forms a corrosive substance. Ammonia gas
is very irritating to the eyes, nose and respiratory system, and in high concentrations is also corrosive to the
skin and eyes. Breathing ammonia gas can be fatal. The level of danger depends on the concentration of
ammonia and length of exposure
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Hydrogen fluoride (HF):
Fatal if swallowed, is fatal in contact with skin, is fatal if inhaled and causes severe skin burns and eye damage.
The immediate dangerous to life or health (IDLH) level for HF is 0.025 g/m3 (30 ppm) and the lethal 10
minutes HF toxicity value (AEGL-3) is 0.0139 g/m3 (170 ppm). 20–200 mg/Wh from LiPF6 electrolyte
(ScienceDirect, 2017) Impact: Corrosive, lethal at 30 ppm (OSHA), skin-penetrating (UFUA). The release of
hydrogen Fluoride from a Li-ion battery therefore can be a severe risk.
Fluorinated Compounds (e.g., PF5, CF4)
Health Impacts: Phosphorus pentafluoride (PF5) and tetrafluoromethane (CF4) are highly reactive, causing
severe respiratory irritation and potential lung damage. PF5 hydrolyzes into HF, amplifying toxicity. Exposure
Levels: Limited specific data, but HF-related thresholds (30 ppm IDLH) apply. commonly associated with
lithium BESS fires Source: Decomposition of LiPF6 or fluorinated polymers.
Dioxins/Furans
Highly toxic, persistent organic pollutants causing skin lesions (chloracne), immune suppression, and cancer
(IARC Group 1) with long-term exposure. Exposure Levels: No acute threshold; chronic exposure at ppt levels is
hazardous. Source: Combustion of chlorinated/fluorinated materials (e.g., PVDF binders).
Carbon Monoxide (CO):
Is an odorless, colorless and tasteless gas produced when fuels such as gasoline, natural gas, oil, kerosene,
wood or charcoal are burned. When inhaled it reduces the blood's ability to carry oxygen and can reach
dangerous levels indoors or outdoors. Common symptoms of CO poisoning include headache, dizziness,
weakness, upset stomach, vomiting, chest pain, and confusion. If you breathe in a lot of CO it can make you
pass out or kill you; people who are sleeping or drunk can die from CO poisoning before they have a chance to
wake up. Toxic if inhaled, may damage the unborn child, causes damage to organs through prolonged or
repeated exposure and is an extremely flammable gas, Common in all BESS fires—EPRI (2025) notes CO as an
asphyxiant in 90+ incidents. NIOSH IDLH (1200 ppm) but hazardous (FSRI, p. 17).
Carbon dioxide (CO2):
Can be extremely dangerous for humans and the environment. High levels of CO2 indoors can reduce
cognitive performance score by up to 20%. Above 5,000 parts per million (ppm), asphyxiation may take place
as CO2 replaces oxygen in the blood. Cause headaches, dizziness, confusion, loss of consciousness, and
asphyxiation at high concentrations
Hydrocarbons:
Flammable Hydrocarbons, such as CH4, are described as acting as simple asphyxiants without other significant
physiologic effects when they are present in high concentrations, hence are not given limit values as the
significant factor is the availability of oxygen. This is assumed for H2 as well.
Hydrogen (H2):
Extremely flammable Hydrogen is described as acting as simple asphyxiants without other significant
physiologic effects when they are present in high concentrations, hence are not given limit values as the
significant factor is the availability of oxygen.
Solvents:
Highly flammable liquid and vapour [53]. Very irritating to eyes, skin and airways [44].DEC 700, PC 8.5cDEC
1000, PC 8.5c
Formaldehyde:
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Poses serious health risks, including irritation of the eyes, nose, and throat, as well as potential for respiratory
problems and, in some cases, an increased risk of certain cancers Eye/throat irritation, coughing (0.75 ppm+).
IARC Group 1—nasopharyngeal cancer, leukemia (Web ID 0). 0.75 ppm (8-hour TWA), 2 ppm (15-min STEL, 29
CFR 1910.1048).
Benzene:
Poses serious health risks, including short-term effects like dizziness and headaches, and long-term risks like
leukemia and other blood disordersIARC Group 1—leukemia, bone marrow damage (OSHA). 1 ppm (8-hour
TWA), 5 ppm (15-min STEL, 29 CFR 1910.1028).
Acetylene:
Poses significant fire and explosion hazards, and can cause asphyxiation due to oxygen displacement. It is an
extremely flammable gas that forms explosive mixtures with air or oxygen, and its cylinders can rupture
violently if heated Explosion risk, asphyxiation (high %LEL).No chronic toxicity—acute fire/asphyxiation only.
None—flammable, not toxicologically limited (29 CFR 1910.1000).
Heavy metals released in smoke/ash/fallout:
Lithium (Li):
OSHA PEL: None established—lacks specific workplace limit (Web ID 19). Short-Term Exposure Health Impacts:
BESS Fires: Grassroots 10–50 ppm (Chaumont, NY precedent) in soil/smoke—inhalation may cause nausea,
dizziness (ResearchGate, 2021). Surprise’s cloud likely included Li salts. Acute Effects: Irritates eyes, skin
(NIOSH Pocket Guide). Long-Term Exposure Health Impacts: BESS Fallout: Chronic low-level exposure
(untested in Moss Landing) risks kidney dysfunction, thyroid suppression (StatPearls, 2023)—unquantified in
fires. Environmental: Bioaccumulation in water/food (Valley Center missed it, Escondido.gov). Prescribed Side
Effects (Lithium Carbonate, Bipolar Disorder): Common: Tremors, thirst, nausea, weight gain, fatigue (Mayo
Clinic, 2023) and permanent damage to kidneys and thyroid. Serious: Kidney damage (nephrogenic diabetes
insipidus), hypothyroidism, arrhythmia—dose-dependent (500–1200 mg/day, NIH). Toxicity: Confusion,
seizures, coma (>1.5 mEq/L serum, StatPearls). Other Known Side Effects: Neurological (memory loss),
gastrointestinal distress (Occup-Med, 2024).
Cobalt (Co):
OSHA PEL: 0.1 mg/m³ (8-hour TWA, 29 CFR 1910.1000, Table Z-1). Short-Term Exposure Health Impacts: BESS
Fires: Inhalation of Co in smoke (e.g., Surprise, AZ cloud; UFUA McConville) causes respiratory irritation,
coughing, and shortness of breath. SJSU’s 13,300 ppm soil finding (Moss Landing, 2025) suggests dust
inhalation risks near homes/farms. Acute Effects: Skin contact (dermal absorption, UFUA) leads to rashes; high
doses (>0.1 mg/m³) may cause nausea, dizziness (NIOSH). Long-Term Exposure Health Impacts: BESS Fallout:
Chronic inhalation (Hunterbrook’s 200 ppm avg, 20 miles) risks lung fibrosis, asthma (OSHA), and
cardiomyopathy (StatPearls, 2023). Bioaccumulation in fish/animals (Monterey Bay) may lead to dietary
exposure. Carcinogenicity: IARC Group 2B (possibly carcinogenic)—lung cancer linked to Co dust
(ScienceDirect, 2017). Prescribed Side Effects: Cobalt isn’t prescribed, but cobalt chloride (historical use)
caused thyroid enlargement, heart failure (StatPearls). Other Known Side Effects: Neurotoxicity (tremors),
reproductive issues in high occupational exposure (Occup-Med, 2024).
Nickel (Ni):
OSHA PEL: 1 mg/m³ (8-hour TWA, 29 CFR 1910.1000, Table Z-1). Short-Term Exposure Health Impacts: BESS
Fires: Ni in smoke (Moss Landing, SJSU 500–5000 ppm) irritates lungs, throat—nosebleeds reported
(Hunterbrook). Surprise’s “deadly cocktail” likely included Ni particulates. Acute Effects: Skin contact causes
dermatitis (OSHA OTM)—common in welders (Web ID 0). Long-Term Exposure Health Impacts: BESS Fallout:
Page 415 of 758
7
Grassroots 50–100 ppm (27 miles) and Hunterbrook 180 ppm suggest chronic lung damage, asthma (OSHA).
IARC Group 1—nasal/lung cancer from prolonged inhalation (ScienceDirect, 2017). Systemic: Kidney damage,
reduced fertility (StatPearls, 2023). Prescribed Side Effects: Nickel isn’t medicinal—only toxic via exposure.
Other Known Side Effects: Allergic sensitization (rashes), neurological decline (Occup-Med, 2024).
Manganese (Mn):
OSHA PEL: 5 mg/m³ (Ceiling limit, 29 CFR 1910.1000, Table Z-1)—not to be exceeded at any time. Short-Term
Exposure Health Impacts: BESS Fires: Mn in Moss Landing soil (SJSU 1000–10,000 ppm) risks dust inhalation—
coughing, bronchitis (NIOSH REL 1 mg/m³, Web ID 10). Acute Effects: High doses (>5 mg/m³) cause headaches,
fatigue (OSHA). Long-Term Exposure Health Impacts: BESS Fallout: Chronic exposure (grassroots 50–100 ppm)
leads to manganism—Parkinson-like tremors, speech issues (Web ID 10). Neurotoxic via mitochondrial
damage (StatPearls, 2023). Other: Lung inflammation, memory loss (Occup-Med, 2024). Prescribed Side
Effects: Not prescribed—essential trace mineral, but excess is toxic. Other Known Side Effects: Psychiatric
disturbances (“manganese madness”), infertility (NIOSH).
Particulate Matter (PM2.5/PM10)
Fine particles penetrate deep into lungs, causing inflammation, asthma exacerbation, and cardiovascular
strain. Heavy metals (Li, Co, Ni, Mn) in PM increase toxicity, with chronic exposure linked to cancer and organ
damage (EPA, 2023). Exposure Levels: OSHA PM10 limit is 5 mg/m³; BESS fires often exceed this in fallout
zones. Source: Smoke and ash from burning batteries. Source: Smoke and ash from burning batteries.
There are so many safe alternative energy storage solutions that Lithium BESS should only be used as a last
resort and only be allowed miles and miles away from any sensitive receptors, locations, or environments...
I sent you two very long emails called Part 1 and part 2: "Catastrophic BESS fire in Moss Landing with scientific
documentation/proof of 100x to 1000x increase of toxic fallout as far downwind as 27.2 miles downwind" to
give you info and irrefutable scientific evidence of the environmental impacts lithium BESS have on the
surrounding areas when they burn- going into detail about the consequences of the Jan 2025 Moss Landing
BESS fire.
Please help protect Auburn by giving BESS a determination of significance instead of the proposed
determination of non-significance!
My best,
James
Page 416 of 758
1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:12 AM
To:Gabriel Clark
Subject:FW: 4th fire since 2021 at the Moss Landing lithium Battery energy Storage System
(BESS)- these are dangerous and we must have laws to protect us!
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 3:04 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: 4th fire since 2021 at the Moss Landing lithium Battery energy Storage System (BESS)- these are dangerous and
we must have laws to protect us!
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn Leaders,
Page 417 of 758
2
It has been over a year since the Jan 2025 BESS fire provided the first scientific and irrefutable evidence that
lithium BESS release toxic smoke and fallout/ash...
Prior to the fire, there had never been any proof that we should even be concerned about the
ash/fallout... There are significant impacts from lithium BESS and Auburn should not give developers an inch
by providing them with a determination of insignificance as a starting point.
Now we know- the email below was sent back when the Moss Landing BESS fire was still burning in Jan 2025...
I'll let this interview with the Monterey County Supervisor Glenn Church do the talking as it takes place during
the initial phases of the BESS fire- please note the people hacking and coughing in the background and watch
the fire and explosions:
https://youtu.be/VRYdVejcUdw?si=Ow3yWvhw6IjLjhBA
YouTube
Share your videos with friends, family, and the world
youtu.be
And, this is proof that BESS with hundreds of 40ft shipping container-like containers filled with lithium
batteries can have multiple fires!
The fires are unpreventable and unstoppable. You need to wake up and see how dangerous these BESS
facilities are and protect our kids and community!
The MOSS Landing BESS has had 4 fires (Sept 2021, Feb 2022, Sept 2022, and yesterday's in Jan 2025 that
started at 330pm)- and after each fire, the BESS owners say no concerns, no toxicity, nothing to see here, and
the evacuations/shelter-in-place orders were just gov officials being overly cautious.... And they always added
that the last fire was a learning experience and they implemented all their learnings and made improvements
and now have the safest most robust and redundant battery management systems (BMS), safest lithium
batteries, the best warning and detection systems, and state of the art fire suppression systems with back-up
systems for redundancy so fires won't be an issue in the future....
FYI, at 6:30pm an evacuation order was given for everyone within a 3-mile zone and shelter-in-place orders
were issued for those further out...
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Just now, evacuation orders are still in effect and about 1,500 are evacuated.
Watsonville, a city 9 miles away and in a different county has issued a shelter-in-place order:
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As part of the shelter-in-place orders, Watsonville (9-miles away) also shut down roads due to the toxic
smoke:
https://montereyco.maps.arcgis.com/apps/webappviewer/index.html?id=905a9458324b4868804d96b5593e
b978&fbclid=IwY2xjawH3bUBleHRuA2FlbQIxMAABHXKlMWtTR6LBWSv21Gso5kBg3g23UU8vaY8xFDw_JQb52s
3CvNCyKE2B9Q_aem_KALhPwKjFPUyu5LOKpQdTQ
Schools and colleges are being forced to close
Page 424 of 758
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Nature reserves are being closed:
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Whole classrooms full of kids in nearby school districts are reportedly experiencing exposure symptoms like
headaches, burning lungs, throat, cough, swollen throats, burning eyes, and other symptoms of exposure 9
miles down wind...
And more:
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A new fire or re-flareup has flared up at MOSS landing Friday afternoon after they thought the lithium
batteries were close to extinguishing themselves becuase the burned so fast and hot... - and reporter is saying
is fiercer and bigger than last nights- he can't tell if it is a new section or the original fire re-igniting:
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This plume is way bigger than yesterdays and spreading WAY farther:
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Please don't force us to deal with this and make strong BESS laws that prevent BESS from being located
anywhere near schools, hospitals, and homes...
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I'll share more info as this continues- but, as I've said these are dangerous and shouldn't be located anywhere
near schools, hospitals nor homes- especially when there are totally safe long duration energy storage systems
available..
And, seriously watch the interview of the County Supervisor- he calls out the lies of the developers who
promised that fires wouldn't be an issue ever again because of everything they implemented after the last
fires...
Thank you,
James
Page 435 of 758
1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:12 AM
To:Gabriel Clark
Subject:FW: BESS fires' smoke, gasses, and ash's toxicity immeditate threats to life and force
emergency health notices and evacuations and shelter in place orders
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 3:13 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: BESS fires' smoke, gasses, and ash's toxicity immeditate threats to life and force emergency health notices and
evacuations and shelter in place orders
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn Leaders,
Page 436 of 758
2
If you don't give BESS a determination of significance instead of your proposed determination of non-
significance, and make it difficult for BESS developers to locate lithium BESS near schools, hospitals, and
people's homes, you will be responsible for our emergency messaging systems sending messages like these to
everyone within 5-9 miles of a burning BESS like Monterey County, CA did when the BESS fire started in Jan of
2025 because people are still suffering and showing exposure symptoms- over a year after the BESS fire
started:
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It is the transcript of a message from the County Of Monterey's Emergency messaging system...
Here's another one:
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These were both sent on Tuesday January 21st 2025 afternoon and the fire and evacuations started Thursday
January 16th 2025...
Now, over a year later people are still suffering from exposure from smoke, gasses, and fallout.
Please do more to protect us!
Please make all BESS start out with a determination of significant impact.
My best,
James
Page 441 of 758
1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:11 AM
To:Gabriel Clark
Subject:FW: Let's learn from CA's BESS siting mistakes- we need strong laws to protect us- like
the proposed 3200ft setback CA is now considering
Follow Up Flag:Follow up
Flag Status:Completed
fyi
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 3:25 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: Let's learn from CA's BESS siting mistakes- we need strong laws to protect us- like the proposed 3200ft setback
CA is now considering
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn leadership,
We need to have BESS developers start with a determination of significant impact...
Page 442 of 758
2
This is what caring leadership looks like after experiencing a catastrophic BESS fire! Let's learn from their
suffering and not duplicate the risks and face the same consequences...
https://www.youtube.com/live/D0ibZMSm9RY?si=AO8qVrXVXwqRul7k
Addis Presents Battery
Energy Safety &
Accountability Act,
Preventing Future Energy
Storage Fires - YouTube
Assemblymember Dawn Addis invites you to
join a live press conference on January 23 at
3 p.m., where she will introduce the Battery
Energy Safety & Accountab...
www.youtube.com
Assembly member Addis of CA has just introduced a law (AB303) that says BESS can not be located within
3200ft of sensitive areas like schools, people's homes, and healthcare facilities and takes the power away from
the State level approval process and returns it to the local level...
Also in this this video, County Supervisor Glenn also says that cleanup is going to take months... But, it is now
estimated to take years- as we just passed the 1 year mark and they haven't been able to remove all the
burned batteries due to the toxicity of the former BESS site.
He says CA EPA, Office of Environmental Hazard Assessment, Dept of toxic substance control are working with
Monterey County Environmental Health and will all be involved in testing water and soil in the surrounding
communities...
Monterey County has declared a state of emergency due to Moss Landing BESS fire:
https://www.usatoday.com/story/news/nation/2025/01/23/moss-landing-lithium-battery-plant-fire-
vistra/77912642007/
Please make a safety-first BESS ordinance to protect your citizens and your king county neighbors, and King
County's environment from the significant and catastrophic event that BESS can cause!
Thank you,
James
Page 443 of 758
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1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:11 AM
To:Gabriel Clark
Cc:Alexandria Teague
Subject:FW: Thorough and Complete decontamination process required for everyone leaving
contaminated BESS site during cleanup
Follow Up Flag:Follow up
Flag Status:Completed
BESS Comment
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 3:48 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: Thorough and Complete decontamination process required for everyone leaving contaminated BESS site during
cleanup
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn leaders,
Page 445 of 758
2
Please take a look at the requirements for cleanup personnel for the Moss Landing BESS site clean up below-
they are required to undergo complete and thorough decontamination prior to exiting the impacted area of
the site:
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The fire happened over a year ago and the site is still so contaminated that every individual leaving the site
has to go complete and thorough decontamination process before exiting the site.
Please give lithium BESS a determination of significant impact!
Thank you,
James
Page 448 of 758
1
Gabriel Clark
From:Planning
Sent:Thursday, February 12, 2026 8:07 AM
To:Gabriel Clark
Subject:FW: Lithium BESS - noise level studies
Follow Up Flag:Follow up
Flag Status:Completed
BESS Comment
Owen Goode
Planner II
Department of Community Development
City of Auburn | www.auburnwa.gov
Phone: (253) 470-2170 | ogoode@auburnwa.gov
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Map)
Customer Service Survey | Application Forms | Zoning Maps
From: James DeLay <jamesdelay@hotmail.com>
Sent: Wednesday, February 11, 2026 5:04 PM
To: Cheryl Rakes <CRakes@auburnwa.gov>; Tracy Taylor <ttaylor@auburnwa.gov>; Brian Lott <BLott@auburnwa.gov>;
Clinton Taylor <ctaylor@auburnwa.gov>; Lisa Stirgus <LStirgus@auburnwa.gov>; Hanan Amer <hamer@auburnwa.gov>;
info@vrfa.org; Planning <planning@auburnwa.gov>
Subject: Lithium BESS - noise level studies
CAUTION: The following message originated from outside the City of Auburn. Be careful opening links and attachments
Good afternoon Auburn leaders,
I can't remember if I sent this to you already...
Page 449 of 758
2
PSE and BESS developers will tell you BESS aren't loud and that they won't exceed the rural/city/county noise
limits, but that is simply not true- at least not without a lot of sound mitigation.
Lithium BESS have to remain at their ideal temperature (70 degrees) to avoid overheating and entering
thermal runaway- the process of charging and discharging lithium BESS generates significant levels of heat (up
to 130 degrees)- due to the heat generated by every single lithium battery cell in a shipping container-like
BESS container being charged and discharged. Because of this, BESS containers usually have up to 6 massive
HVAC units cooling each individual BESS container 24/7 on all but the coldest nighttime sub-freezing temps.
It is a constant battle to keep the lithium batteries in a lithium BESS cool enough to avoid overheating and
triggering thermal runaway- several BESS fires have been caused by failure of the cooling system to keep the
batteries cool enough due to cooling systems being inadequately sized and can't keep up on the hottest
Summer days (this cause has been mostly eliminated by engineered oversizing), cooling system failures, faulty
cooling system installation or parts, failed cooling system components (Tesla Megapack at Moss Landing had
bearings in a fan cause too much resistance and reduced the fan speed/cooling ability), and failed accessory
parts (coolant line leaked in Tesla Megapack in Victoria, AUS).
BESS developers try to trick permitting agencies and make it sound like BESS aren't loud by flat out lying and
then back up their lies by paying an engineering firm to create a sound level study for their BESS and ask them
to issue a report that results in sound levels that meet the legal noise levels for the area...
In many cases, BESS developers have found that if they have the Sound Engineering firm run the tests or
simulations showing the BESS cooling systems operating at 40% of capacity, they can meet those noise
thresholds as seen here:
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4
https://efsec.wa.gov/sites/default/files/2025-06/Goldeneye%20ASC_Attachment%20O_Noise%20Memo.pdf
Please note, that even when operating at 40%, the overall sound levels for the BESS are still 84.9DB- which
massively exceeds most area's noise levels- except heavy industrial zoned areas (which is where lithium BESS
should be exclusively sited). The HV transformer releases 88db at 125hz (constant hum) and 83.4DB overall.
The medium voltage transformer releases 69db at 500hz and 72.4db overall- exceeding most zone's max
sound level- and this will be 24/7...
Remember, that is running at 40%.... On a hot Summer day, they will be running at 100%...
So, BESS developers specifically ask the sound engineers to make the test sound levels at lower fan speeds
(like 40%) to provide the best test result possible to get their permit through permitting...
Easy peasy!
But, in reality, the cooling systems of the BESS are in a constant fight with the heat created by the
continuously charging and discharging the lithium batteries- and, once lithium batteries overheat they go into
thermal runaway and ignite and or explode...
So cooling is the primary defense against thermal runaway- you don't want to be running your systems at 40%
just to avoid noise violation fees...
And, if you remember the June 13th 2023 BESS Developer presentation to the Covington City Council, you
would know that their answer to what happens if the BESS is louder than they say and exceeds the noise
limits- the BESS developer's response was, "We'd pay noise violation fines- that is just the cost of doing
business"...
The Covington City Council was far more educated about BESS and associated issues than the developer
planned and the meeting is worth a watch: https://www.youtube.com/watch?v=kYZ8AKr-T4E&t=1s
Fortunately, another engineering firm did a BESS sound level study on Tesla Megapack 2 and included both the
sound levels at 40% and 100% operational capacity...
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The "Goldeneye" Sedro Woolley noise study shared above (with only 40% fan speed), specifies that the BESS
developer specifically requested the engineering firm to do the study at 40% to skew the results in their
favor...
Ideally, you would not allow simulations, but instead require BESS to submit a sound study with microphones
set up at all the "receptors" sites within line of site and within 1+ miles and sound travels easily...
NIOSH recommends less than 15 minutes of exposure per day of any noises above 100db- BESS operate 24/7
and they want to put BESS next to schools and people's homes.
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7
Here's a BESS study showing a lithium BESS releasing highly hazardous sound levels (120db at 31.5hz):
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https://www.grantcountywa.gov/DocumentCenter/View/12601/Acoustic-Assessment-Report
Here's a noise study showing BESS units individually are 94db but when all combined it shows a total sound
power level 118db of noise- it also shows the reduction in sound levels with decreased fan speeds (decreasing
from 100% down to 20% utilization):
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https://wellingtonbess.com/wp-content/uploads/2024/02/Appendix-K-NVIA.pdf
Here's a noise study for a BESS showing 109db at low/bass frequencies and the transformer making 110db:
https://efsec.wa.gov/sites/default/files/2025-06/HopHill_ASC_Attachment_Q_AcousticAssessment.pdf
Here's a study showing a 110db- but also shows that a BESS can be installed in 16-20 weeks:
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https://majorprojects.planningportal.nsw.gov.au/prweb/PRRestService/mp/01/getContent?AttachRef=SSD-
35160796!20220906T051215.997%20GMT&fbclid=IwZXh0bgNhZW0CMTAAAR2Z3U6Ur18m0cW3UGDXmUM
QyMTPcObGjWtPZS9Kehg4PrGB5izUxmAek6k_aem_Afl-F4G-
oCrT5FUsSxPeJmR7HkPXjSgFcIywVjjGuP2hM0LAl5gbZJSaGTsIy5jzLau6ZrU1SJwGpGBYIB3UhanS
Here's a noise study showing he BESS generating an overall sound level of 106db:
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15
https://efsec.wa.gov/sites/default/files/2025-
07/Attachment%201_Wautoma_Data%20Request_Response_Noise.pdf
They play around with the numbers as well so that when you compare noise levels across BESS and it's
components it doesn't always make sense:
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https://efsec.wa.gov/sites/default/files/2025-
06/11_Wallula%20Gap_ASC_Attachment%20J_Acoustic%20Assessment%20Report.pdf
Sometimes things match- like this Carriger Solar BESS sound levels match the Wautoma BESS sound levels, but
then other components are different:
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https://efsec.wa.gov/sites/default/files/2025-06/Attachment_H_Carriger_Acoustic_Assessment_Report.pdf
Here's one that was officially submitted showing the BESS will be silent at 31.5hz vs every other sound study
showing between 36db and 120db at that low frequency:
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https://efsec.wa.gov/sites/default/files/2025-
06/16_Badger%20Mtn_ASC_Attach%20O_AcousticAssessment.pdf
Here's another sound study showing no sound output by the BESS at 31.5hz
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https://salinetownship.org/uploads/notices/HEI%20-
%20Voyager%20BESS%20Noise%20Study%2020250131%20(1).pdf
This one has similar results as the 40% Sedro Woolley BESS that I first shared- but never mentions that this
BESS sound study was done at reduced fan/cooling system speed:
Page 471 of 758
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25
https://efsec.wa.gov/sites/default/files/2025-05/20210119_Attch_I_AcousticAssessmentReport.pdf
Here's another sound study- the broadband number is 66db???? They say there are 14,946 BESS units but
they only make 66db of noise overall- that doesn't make sense?!?!?
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Page 474 of 758
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https://www.oregon.gov/energy/facilities-safety/facilities/Facility%20Exhibits/SSP/2024-05-16-SSPAPPDoc25-
25-ASC-Exhibit-Y-Noise.pdf
Here's another sound study where they didn't include the broadband power nor the sound levels at each
frequency:
Page 475 of 758
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https://www.enelgreenpower.com/content/dam/enel-egp/immagini/plants-in-development/capricorn-bess-
project/Appendix%20E%20-%20Noise%20Impact%20Assessment.pdf
This sound study includes the sound reductions created by "low noise cooling systems" and a combination of
8ft tall x 180ft long sound barrier, 15ft tall x 570ft long sound barrier wall, 14ft tall x 730ft long sound barriers:
Page 476 of 758
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30
https://portal.ct.gov/-/media/csc/1_dockets-
medialibrary/1_media_do500_600/do527/applicantsubmissions/application/15---appendix-m_acoustic-
assessment.pdf?rev=8d742930a650432c8afe6e9ac7c158ed&hash=F32A9F8007CEB809581E8BA508196068
Here's another study that hides all the frequency based sound levels:
Page 478 of 758
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32
https://mullaghclogher-windfarm.co.uk/media/nankxbzi/ta111-assessment-of-battery-energy-storage-
facility.pdf
Here's another 40% sound study that includes the largest range of sound frequencies out of any test I have
seen, but is missing 20hz, 31.5hz, and 40hz:
https://sftpbspomppprod01.blob.core.windows.net/applicationfiles/45276d90-2c12-ed11-b83d-
00224891e4e7_PA2201752-06-Thomastown%20Battery%20Energy%20Storage%20System-
Noise%20Modelling-191022.pdf
Page 480 of 758
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This noise study is all estimated sound levels and omit frequences below 60hz:
Page 481 of 758
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Page 482 of 758
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https://sftpbspomppprod01.blob.core.windows.net/applicationfiles/8f45eb39-ec94-ef11-8a68-
002248938a9c_PA2403305%20-%20Tarrone%20BESS%20-%20Noise%20Assessment.pdf
This sound study is incorporating a 4.5 meter tall sound barrier- and omitting frequences below 63hz:
Page 483 of 758
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Page 484 of 758
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https://sftpbspomppprod01.blob.core.windows.net/applicationfiles/587693da-ac20-ec11-b6e6-
000d3ad1e7ec_PA2101362-Rangebank%20BESS-Acoustic%20Report-Stamped-290921.pdf
Here's one where the sound levels were provided by the BESS developer- omitting frequencies below 63hz:
Page 485 of 758
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39
https://cdc.govt.nz/wp-content/uploads/2024/07/Appendix-10-Acoustic-Assessment.pdf
This study shows the sound levels behind a 5 meter tall acoustic barrier on the E, W, and S sides- but omits
frequences below 125hz for the BESS fans:
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41
https://www.boom-power.co.uk/content/uploads/2025/08/Accu-Acoustics-00005-Carrog-BESS-Substation-
merged.pdf
Here's a sound study that incorporates a 5M tall sound barrier AND fans operating at 30% to hit the required
noise levels- omitting BESS container frequencies below 100hz:
Page 489 of 758
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Page 491 of 758
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https://www.fieldcorriemoillie.co.uk/wp-content/uploads/2024/12/Noise-Impact-Assessment-Report.pdf
Here is a sound study that has considered a 4.5 meter tall sound barrier in it's sound level calculations:
Page 492 of 758
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https://www.studocu.com/en-au/document/university-of-melbourne/project-finance/rangebank-bess-
environmental-noise-assessment-s7794c1-may-2023/136793704
Page 493 of 758
46
Here's another BESS sound study- omitting frequencies below 63hz:
Page 494 of 758
47
Page 495 of 758
48
https://portal.ct.gov/-/media/csc/3_petitions-medialibrary/petitions_medialibrary/mediapetitionnos1601-
1700/pe1607/petitionersubmissions/petition/exhibit-e-qcells-bess-facility---acoustical-analysis-
report.pdf?rev=159515a1b5b846c4a4861c50160ec4c4&hash=9B2B2C4AA18072900DF8D76BAA47FD20
Here's another BESS sound study omitting frequences below 63hz:
Page 496 of 758
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50
https://docs.planning.org.uk/20240322/230/S8E8BLNSIF600/qy6uzgwsia1j6ii0.pdf
Another strategy BESS developers will have their hired engineering firms provide results only showing one
piece of data- hiding all the rest of the sound data:
Here's a noise study showing only the sound level at fan speed at 50% and only providing the average noise
level- please note, this does note, that "Reasonable worst-case fan load is 99db" which makes zero no sense-
and maybe they meant max fan load is 99% and they say the difference between 50% fan speed and worst
case of 99% fan speed only has a MAXIMUM increase of 5db???? The average seems to be about 3db
increase/decrease for every 10% of fan speed difference:
Page 498 of 758
51
Page 499 of 758
52
https://www.chbdc.govt.nz/assets/Document-Library/Resource-Consents/RM-240016/Acoustic-
Assessment.pdf
Here's a Tesla Megapack 2XL where they hide the sound level details but provide sound levels at nightime
levels operating at 50% and daytime levels operating at 60% (and is still at 96db at night 50% and 99db at
daytime 60%:
Page 500 of 758
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Page 501 of 758
54
https://www.mississippimills.ca/media/3mlgsfpa/appendix-l-almonte-bess-2-acoustic-assessment.pdf
Here's a study showing only the broadband DB sound level (hiding the rest of the sound levels):
Page 502 of 758
55
Page 503 of 758
56
https://www.icpds.com/assets/planning/draft-environmental-impact-reports/supplemental-le-conte-battery-
energy-storage-system-deir/le-conte-battery-energy-storage-system-app-f.pdf
Here's another showing only the broadband DB sound level (hiding the rest of the sound levels):
Page 504 of 758
57
Page 505 of 758
58
https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/FallbrookBatteryEnergyStorage/Noise%20Asse
ssment.pdf
Here's another showing only the broadband DB sound level (hiding the rest of the sound levels):
Page 506 of 758
59
Page 507 of 758
60
https://www.knightdalenc.gov/sites/default/files/uploads/projects/documents/419596.41.0604-de-kdl-noise-
study-report-240927_signed.pdf
Here's another showing only the broadband DB sound level (hiding the rest of the sound levels at each
frequency):
Page 508 of 758
61
Page 509 of 758
62
file:///C:/Users/James/Downloads/Kiewa%20Valley%20BESS%20-%20Noise%20Impact%20Assessment.pdf
This sound study shows only the sound levels per unit (hiding the rest of the sound levels data):
Page 510 of 758
63
Page 511 of 758
64
https://assets.lightsourcebp.com/app/uploads/2024/05/01140125/Noise-Survey-and-Acoustic-Report.pdf
Here's another sound study by the same company- where they don't give any details, but for a smaller BESS
and they reduced the soud levels by theroetically adding noise reducing features like a 4 meter tall sound
barrier wall (and inverters noise reduction kit for the air inlets and outlets, and ow noise HVAC systems should
be used for the battery containers):
Page 512 of 758
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Page 513 of 758
66
https://docs.planning.org.uk/20230821/15/RZHNBROKHZQ00/tqlaisxsynrwah7j.pdf
Here's a Tesla Megapack sound study showing higher fan speed for the day and reduced fan speed at night-
dropping the sound level by 15db:
Page 514 of 758
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Page 515 of 758
68
https://planning.walsall.gov.uk/swift/MediaTemp/73797-324158.pdf
ANother sound study hiding the frequency data:
Page 516 of 758
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Page 517 of 758
70
https://www.clune-windfarm.co.uk/media/153cmhi1/technical-appendix-113-bess-acoustic-assessment.pdf
This Noise study isn't represented in a chart as they only gave the average sound levels:
Page 518 of 758
71
Page 519 of 758
72
https://webportal.ribblevalley.gov.uk/planx_downloads/24_0366_Statement_Appendix_E_Noise_Impact_Ass
essment_Redacted.pdf
This sound study only says 88db at 60% and 82db at 40% and withholds all frequency data:
Page 520 of 758
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74
https://planningexplorer.barnsley.gov.uk/Home/FileDownload/01GEE4NB2HQ66LTJMKTFBJPOF2GUCLW6D4?
ApplicationNumber=2023%2F0322
This sound level study only gives the average sound level of a single "battery unit" and there will be 525
battery units:
Page 522 of 758
75
https://potentiaenergy.com.au/wp-content/uploads/2025/03/Capricorn-BESS-Noise-Impact-
Assessment_Final.pdf
Another study hiding the noise levels at the specified frequencies and only provided the Sound level:
Page 523 of 758
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Page 524 of 758
77
https://www.edf-powersolutions.uk/wp-content/uploads/2025/05/Noise-Assessment-1.pdf
Here's another study showing only one data point from the manufacturer:
Page 525 of 758
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https://portal.ct.gov/-/media/csc/3_petitions-medialibrary/petitions_medialibrary/mediapetitionnos1601-
1700/pe1604/petitionersubmissions/appendix-g---sound-
assessment.pdf?rev=b64e84c1a723454980ce779a944e30b2&hash=CC05362D3CCCA1AF8C23D77F8CE46228
Here's a liquid cooled BESS with the cooling system operating at 40% and 30%:
Page 527 of 758
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81
https://docs.planning.org.uk/20241214/78/SOE1VMJIHNO00/asxqjjdjnzk54tyh.pdf
Here's a study hiding all the noise levels and getting sound level data from BESS developer, but showing a
liquid cooled BESS:
Page 529 of 758
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83
https://www.scribd.com/document/736589960/3b3c8082-87fb-ed11-8f6e-002248933fc5-PA2302257-
Glenbrae-BESS-Acoustic-Report-Copie-2
This noise study claims that the BESS will be quiter than normal sound levels at 2 residences and a beach
nearby (but doesn't provide any details beyond that):
Page 531 of 758
84
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85
https://www.psegliny.com/aboutpseglongisland/proposalsandbids/-
/media/894B1477D1CD436CBE2435B8AD87FC80.ashx
This noise study doesn't disclose at what fan speed the tests were done- and instead says it was done at
nominal fan speed (software limted to 80%):
Page 533 of 758
86
Page 534 of 758
87
https://newenergystoragesystem.com/wp-content/uploads/2024/09/Willingham-by-Stow-BESS-Noise-
Impact-Assessment.pdf
And, these are my favorite:
CATL's noise levels are covered by an NDA and not shared at all- but they give Broadband sound levels:
Page 535 of 758
88
Page 536 of 758
89
https://www.pleanala.ie/publicaccess/Case%20Documentation/323761/Applicant%20Documents/Application
%20Docs/Vol.%201%20and%20Vol.%203%20Environmental%20Impact%20Assessment%20Report/Appendix%
2012-3%20Battery%20Storage%20Noise%20Assessment%20F%20-%202025.09.26%20-%20190723.pdf
Totally redacted:
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91
https://www.fieldbeauly.co.uk/wp-content/uploads/2025/02/Noise-Assessment.pdf
So, when PSE or a BESS developer or lobbyist come to you and say a BESS is quiet- you now know that they are
not...
Ideallly, you would require BESS developers to give you sound studies that include all frequencies at all fan
speeds- and that the BESS has multiple Db meters installed around the fenceline and provides you with live
and historical records- and when sound levels exceed the max limites submitted in their Sound study and or
exceed allowed noise levels you are pinged and they are fined $10k. Additionally, if the BESS is located
anywhere near schools, homes, or other locations that would be easily disturbed the developer has to provide
each location with professional and calibrated sound meters so they can take sound measurements- and if
they record a higher sound level and send in a pic and report the excess sound levels, the developer gets fined
and the person who lost their ability to have peace and enjoyment of their property gets 50% of the $10k fine
for reporting it...
BESS developers and PSE lie about many things.. Sound levels is just another one of the lies...
BESS are loud during normal operation and have a significant impact on surrounding receptors- and should be
determnied to have a significant impact!
Thank you,
James
Page 539 of 758
1
Gabriel Clark
From:Alexandria Teague
Sent:Friday, February 13, 2026 1:06 PM
To:Gabriel Clark
Subject:Fwd: Lithium BESS - noise level studies
Sent from my iPhone
Begin forwarded message:
From: Alexandria Teague <ateague@auburnwa.gov>
Date: February 13, 2026 at 08:35:00 PST
To: jamesdelay@hotmail.com
Subject: RE: Lithium BESS - noise level studies
Good morning James,
Thank you for the information. We have received this all of the emails that were sent on
Feb. 11th. They will be included in the packet for Planning Commission.
Sincerely,
Alexandria
Planning or Land Use Questions?
Book an online meeting with
staff<https://www.auburnwa.gov/cms/one.aspx?portalId=11470638&pageId=18097838>.
Check out our
FAQ<https://www.auburnwa.gov/cms/one.aspx?portalId=11470638&pageId=18097838>!
If inquiring about a specific site, please include the parcel number or address, or if
inquiring about a specific project, please include the City project number in your email.
Alexandria D. Teague, AICP, Planning Services Manager
Department of Community Development
City of Auburn | www.auburnwa.gov<http://www.auburnwa.gov/>
253.931.3003 | ateague@auburnwa.gov<mailto:ateague@auburnwa.gov>
Mailing Address: 25 W Main Street, Auburn, WA 98001
Permit Center Address: 1 E Main Street, Auburn, WA 98002 (Click Here for
Map<https://www.google.com/maps/dir/1+E+Main+St,+Auburn,+WA+98002/@47.307658
8,-
122.2291546,19z/data=!4m13!1m4!3m3!1s0x5490586fdf805021:0xc1488b17b5a4b4c5!2s
1+E+Main+St,+Auburn,+WA+98002!3b1!4m7!1m0!1m5!1m1!1s0x5490586fdf805021:0xc1
488b17b5a4b4c5!2m2!1d-122.2291546!2d47.3076588?hl=en>)
Customer Service Survey | https://www.surveymonkey.com/r/XNSL95J
Page 540 of 758
2
Application Forms | http://www.auburnwa.gov/services/resource_library/forms.htm
Zoning Maps | http://www.auburnwa.gov/services/resource_library/maps.htm
This email and your response are considered a public record and can be subject to
disclosure under Washington’s Public Records Act.
From: James DeLay <jamesdelay@hotmail.com<mailto:jamesdelay@hotmail.com>>
Sent: Wednesday, February 11, 2026 5:04 PM
To: Cheryl Rakes <CRakes@auburnwa.gov<mailto:CRakes@auburnwa.gov>>; Tracy Taylor
<ttaylor@auburnwa.gov<mailto:ttaylor@auburnwa.gov>>; Brian Lott
<BLott@auburnwa.gov<mailto:BLott@auburnwa.gov>>; Clinton Taylor
<ctaylor@auburnwa.gov<mailto:ctaylor@auburnwa.gov>>; Lisa Stirgus
<LStirgus@auburnwa.gov<mailto:LStirgus@auburnwa.gov>>; Hanan Amer
<hamer@auburnwa.gov<mailto:hamer@auburnwa.gov>>;
info@vrfa.org<mailto:info@vrfa.org>; Planning
<planning@auburnwa.gov<mailto:planning@auburnwa.gov>>
Subject: Lithium BESS - noise level studies
CAUTION: The following message originated from outside the City of Auburn. Be careful
opening links and attachments
________________________________
Good afternoon Auburn leaders,
I can't remember if I sent this to you already...
PSE and BESS developers will tell you BESS aren't loud and that they won't exceed the
rural/city/county noise limits, but that is simply not true- at least not without a lot of sound
mitigation.
Lithium BESS have to remain at their ideal temperature (70 degrees) to avoid overheating
and entering thermal runaway- the process of charging and discharging lithium BESS
generates significant levels of heat (up to 130 degrees)- due to the heat generated by every
single lithium battery cell in a shipping container-like BESS container being charged and
discharged. Because of this, BESS containers usually have up to 6 massive HVAC units
cooling each individual BESS container 24/7 on all but the coldest nighttime sub-freezing
temps.
It is a constant battle to keep the lithium batteries in a lithium BESS cool enough to avoid
overheating and triggering thermal runaway- several BESS fires have been caused by
failure of the cooling system to keep the batteries cool enough due to cooling systems
being inadequately sized and can't keep up on the hottest Summer days (this cause has
been mostly eliminated by engineered oversizing), cooling system failures, faulty cooling
Page 541 of 758
3
system installation or parts, failed cooling system components (Tesla Megapack at Moss
Landing had bearings in a fan cause too much resistance and reduced the fan
speed/cooling ability), and failed accessory parts (coolant line leaked in Tesla Megapack in
Victoria, AUS).
BESS developers try to trick permitting agencies and make it sound like BESS aren't loud by
flat out lying and then back up their lies by paying an engineering firm to create a sound
level study for their BESS and ask them to issue a report that results in sound levels that
meet the legal noise levels for the area...
In many cases, BESS developers have found that if they have the Sound Engineering firm
run the tests or simulations showing the BESS cooling systems operating at 40% of
capacity, they can meet those noise thresholds as seen here:
[cid:image002.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
06/Goldeneye%20ASC_Attachment%20O_Noise%20Memo.pdf
Please note, that even when operating at 40%, the overall sound levels for the BESS are
still 84.9DB- which massively exceeds most area's noise levels- except heavy industrial
zoned areas (which is where lithium BESS should be exclusively sited). The HV transformer
releases 88db at 125hz (constant hum) and 83.4DB overall. The medium voltage
transformer releases 69db at 500hz and 72.4db overall- exceeding most zone's max sound
level- and this will be 24/7...
Remember, that is running at 40%.... On a hot Summer day, they will be running at 100%...
So, BESS developers specifically ask the sound engineers to make the test sound levels at
lower fan speeds (like 40%) to provide the best test result possible to get their permit
through permitting...
Easy peasy!
But, in reality, the cooling systems of the BESS are in a constant fight with the heat created
by the continuously charging and discharging the lithium batteries- and, once lithium
batteries overheat they go into thermal runaway and ignite and or explode...
So cooling is the primary defense against thermal runaway- you don't want to be running
your systems at 40% just to avoid noise violation fees...
And, if you remember the June 13th 2023 BESS Developer presentation to the Covington
City Council, you would know that their answer to what happens if the BESS is louder than
they say and exceeds the noise limits- the BESS developer's response was, "We'd pay
noise violation fines- that is just the cost of doing business"...
The Covington City Council was far more educated about BESS and associated issues than
the developer planned and the meeting is worth a
watch: https://www.youtube.com/watch?v=kYZ8AKr-
T4E&t=1s<https://url.us.m.mimecastprotect.com/s/vf4oCwpAgNsvy7OpFVfqIJB1gB?dom
Page 542 of 758
4
ain=youtube.com>
Fortunately, another engineering firm did a BESS sound level study on Tesla Megapack 2
and included both the sound levels at 40% and 100% operational capacity...
[cid:image003.png@01DC9CC3.5E2AEEE0]
The "Goldeneye" Sedro Woolley noise study shared above (with only 40% fan speed),
specifies that the BESS developer specifically requested the engineering firm to do the
study at 40% to skew the results in their favor...
Ideally, you would not allow simulations, but instead require BESS to submit a sound study
with microphones set up at all the "receptors" sites within line of site and within 1+ miles
and sound travels easily...
NIOSH recommends less than 15 minutes of exposure per day of any noises above 100db-
BESS operate 24/7 and they want to put BESS next to schools and people's homes.
[cid:image004.png@01DC9CC3.5E2AEEE0]
Here's a BESS study showing a lithium BESS releasing highly hazardous sound levels
(120db at 31.5hz):
[cid:image005.png@01DC9CC3.5E2AEEE0]
https://www.grantcountywa.gov/DocumentCenter/View/12601/Acoustic-Assessment-
Report<https://url.us.m.mimecastprotect.com/s/TyLbCxkBj0cLxyGOFvhmIyK4CJ?domain
=grantcountywa.gov>
Here's a noise study showing BESS units individually are 94db but when all combined it
shows a total sound power level 118db of noise- it also shows the reduction in sound
levels with decreased fan speeds (decreasing from 100% down to 20% utilization):
[cid:image006.png@01DC9CC3.5E2AEEE0]
https://wellingtonbess.com/wp-content/uploads/2024/02/Appendix-K-
NVIA.pdf<https://url.us.m.mimecastprotect.com/s/CaEfCyPDk4h7LgjnfQixIxrHnn?domai
n=wellingtonbess.com>
Here's a noise study for a BESS showing 109db at low/bass frequencies and the
transformer making 110db:
[cid:image007.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
06/HopHill_ASC_Attachment_Q_AcousticAssessment.pdf
Here's a study showing a 110db- but also shows that a BESS can be installed in 16-20
weeks:
[cid:image008.png@01DC9CC3.5E2AEEE0]
https://majorprojects.planningportal.nsw.gov.au/prweb/PRRestService/mp/01/getConten
Page 543 of 758
5
t?AttachRef=SSD-
35160796!20220906T051215.997%20GMT&fbclid=IwZXh0bgNhZW0CMTAAAR2Z3U6Ur18
m0cW3UGDXmUMQyMTPcObGjWtPZS9Kehg4PrGB5izUxmAek6k_aem_Afl-F4G-
oCrT5FUsSxPeJmR7HkPXjSgFcIywVjjGuP2hM0LAl5gbZJSaGTsIy5jzLau6ZrU1SJwGpGBYIB3
UhanS<https://url.us.m.mimecastprotect.com/s/A2whCzpEl8sG43PLSKsXI9GlBs?domain
=majorprojects.planningportal.nsw.gov.au>
Here's a noise study showing he BESS generating an overall sound level of 106db:
[cid:image009.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
07/Attachment%201_Wautoma_Data%20Request_Response_Noise.pdf
They play around with the numbers as well so that when you compare noise levels across
BESS and it's components it doesn't always make sense:
[cid:image010.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
06/11_Wallula%20Gap_ASC_Attachment%20J_Acoustic%20Assessment%20Report.pdf
Sometimes things match- like this Carriger Solar BESS sound levels match the Wautoma
BESS sound levels, but then other components are different:
[cid:image011.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
06/Attachment_H_Carriger_Acoustic_Assessment_Report.pdf
Here's one that was officially submitted showing the BESS will be silent at 31.5hz vs every
other sound study showing between 36db and 120db at that low frequency:
[cid:image012.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
06/16_Badger%20Mtn_ASC_Attach%20O_AcousticAssessment.pdf
Here's another sound study showing no sound output by the BESS at 31.5hz
[cid:image013.png@01DC9CC3.5E2AEEE0]
https://salinetownship.org/uploads/notices/HEI%20-
%20Voyager%20BESS%20Noise%20Study%2020250131%20(1).pdf<https://url.us.m.mim
ecastprotect.com/s/T9qmCAD2OLcZEgmYFQtRIGNjsw?domain=salinetownship.org>
This one has similar results as the 40% Sedro Woolley BESS that I first shared- but never
mentions that this BESS sound study was done at reduced fan/cooling system speed:
Page 544 of 758
6
[cid:image014.png@01DC9CC3.5E2AEEE0]
https://efsec.wa.gov/sites/default/files/2025-
05/20210119_Attch_I_AcousticAssessmentReport.pdf
Here's another sound study- the broadband number is 66db???? They say there are 14,946
BESS units but they only make 66db of noise overall- that doesn't make sense?!?!?
[cid:image015.png@01DC9CC3.5E2AEEE0]
https://www.oregon.gov/energy/facilities-safety/facilities/Facility%20Exhibits/SSP/2024-
05-16-SSPAPPDoc25-25-ASC-Exhibit-Y-
Noise.pdf<https://url.us.m.mimecastprotect.com/s/6WwFCBB2EMuD81Zoc1uKI2SyOb?d
omain=oregon.gov>
Here's another sound study where they didn't include the broadband power nor the sound
levels at each frequency:
[cid:image016.png@01DC9CC3.5E2AEEE0]
https://www.enelgreenpower.com/content/dam/enel-egp/immagini/plants-in-
development/capricorn-bess-project/Appendix%20E%20-
%20Noise%20Impact%20Assessment.pdf<https://url.us.m.mimecastprotect.com/s/WW
a6CDk2EOco316PfRC8IjRHs9?domain=enelgreenpower.com>
This sound study includes the sound reductions created by "low noise cooling systems"
and a combination of 8ft tall x 180ft long sound barrier, 15ft tall x 570ft long sound barrier
wall, 14ft tall x 730ft long sound barriers:
[cid:image017.png@01DC9CC3.5E2AEEE0]
https://portal.ct.gov/-/media/csc/1_dockets-
medialibrary/1_media_do500_600/do527/applicantsubmissions/application/15---
appendix-m_acoustic-
assessment.pdf?rev=8d742930a650432c8afe6e9ac7c158ed&hash=F32A9F8007CEB8095
81E8BA508196068<https://url.us.m.mimecastprotect.com/s/hUkrCER2QgslpmAPIxFQI7u
EhE?domain=portal.ct.gov>
Here's another study that hides all the frequency based sound levels:
[cid:image018.png@01DC9CC3.5E2AEEE0]
https://mullaghclogher-windfarm.co.uk/media/nankxbzi/ta111-assessment-of-battery-
energy-storage-
facility.pdf<https://url.us.m.mimecastprotect.com/s/pvFKCG62KkTBAmyghrHJIBlWXi?do
main=mullaghclogher-windfarm.co.uk>
Here's another 40% sound study that includes the largest range of sound frequencies out
of any test I have seen, but is missing 20hz, 31.5hz, and 40hz:
[cid:image019.png@01DC9CC3.5E2AEEE0]
https://sftpbspomppprod01.blob.core.windows.net/applicationfiles/45276d90-2c12-
ed11-b83d-00224891e4e7_PA2201752-06-
Page 545 of 758
7
Thomastown%20Battery%20Energy%20Storage%20System-Noise%20Modelling-
191022.pdf<https://url.us.m.mimecastprotect.com/s/afzZCJ62XnTBKR4XhKIvIyCZVc?do
main=sftpbspomppprod01.blob.core.windows.net>
This noise study is all estimated sound levels and omit frequences below 60hz:
[cid:image020.png@01DC9CC3.5E2AEEE0]
https://sftpbspomppprod01.blob.core.windows.net/applicationfiles/8f45eb39-ec94-ef11-
8a68-002248938a9c_PA2403305%20-%20Tarrone%20BESS%20-
%20Noise%20Assessment.pdf<https://url.us.m.mimecastprotect.com/s/h1PPCKr2EosD
4lAJckSRI5HvOA?domain=sftpbspomppprod01.blob.core.windows.net>
This sound study is incorporating a 4.5 meter tall sound barrier- and omitting frequences
below 63hz:
[cid:image021.png@01DC9CC3.5E2AEEE0]
https://sftpbspomppprod01.blob.core.windows.net/applicationfiles/587693da-ac20-
ec11-b6e6-000d3ad1e7ec_PA2101362-Rangebank%20BESS-Acoustic%20Report-
Stamped-
290921.pdf<https://url.us.m.mimecastprotect.com/s/R3uhCL92BpikQAoviYT7Iy_FUx?do
main=sftpbspomppprod01.blob.core.windows.net>
Here's one where the sound levels were provided by the BESS developer- omitting
frequencies below 63hz:
[cid:image022.png@01DC9CC3.5E2AEEE0]
https://cdc.govt.nz/wp-content/uploads/2024/07/Appendix-10-Acoustic-
Assessment.pdf<https://url.us.m.mimecastprotect.com/s/4SSzCM82Bqs2zgolCqU6I8F2
MF?domain=cdc.govt.nz>
This study shows the sound levels behind a 5 meter tall acoustic barrier on the E, W, and S
sides- but omits frequences below 125hz for the BESS fans:
[cid:image023.png@01DC9CC3.5E2AEEE0]
https://www.boom-power.co.uk/content/uploads/2025/08/Accu-Acoustics-00005-
Carrog-BESS-Substation-
merged.pdf<https://url.us.m.mimecastprotect.com/s/lT4pCNk21rcZjAnRF3cwIyxNyY?do
main=boom-power.co.uk>
Here's a sound study that incorporates a 5M tall sound barrier AND fans operating at 30%
to hit the required noise levels- omitting BESS container frequencies below 100hz:
[cid:image024.png@01DC9CC3.5E2AEEE0]
[cid:image025.png@01DC9CC3.5E2AEEE0]
https://www.fieldcorriemoillie.co.uk/wp-content/uploads/2024/12/Noise-Impact-
Assessment-
Report.pdf<https://url.us.m.mimecastprotect.com/s/w5h5COY29vHNvJPGT9fQIGoOwF?
Page 546 of 758
8
domain=fieldcorriemoillie.co.uk>
Here is a sound study that has considered a 4.5 meter tall sound barrier in it's sound level
calculations:
[cid:image026.png@01DC9CC3.5E2AEEE0]
https://www.studocu.com/en-au/document/university-of-melbourne/project-
finance/rangebank-bess-environmental-noise-assessment-s7794c1-may-
2023/136793704<https://url.us.m.mimecastprotect.com/s/WjGsCPN9JwI03ODlfJhJIxQpvJ
?domain=studocu.com>
Here's another BESS sound study- omitting frequencies below 63hz:
[cid:image027.png@01DC9CC3.5E2AEEE0]
https://portal.ct.gov/-/media/csc/3_petitions-
medialibrary/petitions_medialibrary/mediapetitionnos1601-
1700/pe1607/petitionersubmissions/petition/exhibit-e-qcells-bess-facility---acoustical-
analysis-
report.pdf?rev=159515a1b5b846c4a4861c50160ec4c4&hash=9B2B2C4AA18072900DF8
D76BAA47FD20<https://url.us.m.mimecastprotect.com/s/beNOCQW2LxuXo8DxIliLIGW-
bZ?domain=portal.ct.gov>
Here's another BESS sound study omitting frequences below 63hz:
[cid:image028.png@01DC9CC3.5E2AEEE0]
https://docs.planning.org.uk/20240322/230/S8E8BLNSIF600/qy6uzgwsia1j6ii0.pdf<https:/
/url.us.m.mimecastprotect.com/s/AU2nCR60ByTG5JKVSVsvI1d8RV?domain=docs.planni
ng.org.uk>
Another strategy BESS developers will have their hired engineering firms provide results
only showing one piece of data- hiding all the rest of the sound data:
Here's a noise study showing only the sound level at fan speed at 50% and only providing
the average noise level- please note, this does note, that "Reasonable worst-case fan load
is 99db" which makes zero no sense- and maybe they meant max fan load is 99% and they
say the difference between 50% fan speed and worst case of 99% fan speed only has a
MAXIMUM increase of 5db???? The average seems to be about 3db increase/decrease for
every 10% of fan speed difference:
[cid:image029.png@01DC9CC3.5E2AEEE0]
https://www.chbdc.govt.nz/assets/Document-Library/Resource-Consents/RM-
240016/Acoustic-
Assessment.pdf<https://url.us.m.mimecastprotect.com/s/jTFDCVOkZDC2g74vCotwIEwP
v4?domain=chbdc.govt.nz>
Page 547 of 758
9
Here's a Tesla Megapack 2XL where they hide the sound level details but provide sound
levels at nightime levels operating at 50% and daytime levels operating at 60% (and is still
at 96db at night 50% and 99db at daytime 60%:
[cid:image030.png@01DC9CC3.5E2AEEE0]
https://www.mississippimills.ca/media/3mlgsfpa/appendix-l-almonte-bess-2-acoustic-
assessment.pdf<https://url.us.m.mimecastprotect.com/s/pilnCW6lBET6D2pkUMu6IokKB
j?domain=mississippimills.ca>
Here's a study showing only the broadband DB sound level (hiding the rest of the sound
levels):
[cid:image031.png@01DC9CC3.5E2AEEE0]
https://www.icpds.com/assets/planning/draft-environmental-impact-
reports/supplemental-le-conte-battery-energy-storage-system-deir/le-conte-battery-
energy-storage-system-app-f.pdf<https://url.us.m.mimecastprotect.com/s/5-
SuCXD0VGc4O16JTzCKIWcvYc?domain=icpds.com>
Here's another showing only the broadband DB sound level (hiding the rest of the sound
levels):
[cid:image032.png@01DC9CC3.5E2AEEE0]
https://www.sandiegocounty.gov/content/dam/sdc/pds/ceqa/FallbrookBatteryEnergyStor
age/Noise%20Assessment.pdf<https://url.us.m.mimecastprotect.com/s/RHq6CYEnXJiDA
Q08c1F9IxnrSl?domain=sandiegocounty.gov>
Here's another showing only the broadband DB sound level (hiding the rest of the sound
levels):
[cid:image033.png@01DC9CC3.5E2AEEE0]
https://www.knightdalenc.gov/sites/default/files/uploads/projects/documents/419596.41
.0604-de-kdl-noise-study-report-
240927_signed.pdf<https://url.us.m.mimecastprotect.com/s/gGoGCZ6oXKT7QEmGfwHrI
B6yze?domain=knightdalenc.gov>
Here's another showing only the broadband DB sound level (hiding the rest of the sound
levels at each frequency):
[cid:image034.png@01DC9CC3.5E2AEEE0]
file:///C:/Users/James/Downloads/Kiewa%20Valley%20BESS%20-
Page 548 of 758
10
%20Noise%20Impact%20Assessment.pdf<https://url.us.m.mimecastprotect.com/s/Ass
HCn5oJATXmzy5IkSLIJrHZL?domain=c>
This sound study shows only the sound levels per unit (hiding the rest of the sound levels
data):
[cid:image035.png@01DC9CC3.5E2AEEE0]
https://assets.lightsourcebp.com/app/uploads/2024/05/01140125/Noise-Survey-and-
Acoustic-
Report.pdf<https://url.us.m.mimecastprotect.com/s/4GkoC1wn7os6q1jRUPIrIV9S5c?do
main=assets.lightsourcebp.com>
Here's another sound study by the same company- where they don't give any details, but
for a smaller BESS and they reduced the soud levels by theroetically adding noise reducing
features like a 4 meter tall sound barrier wall (and inverters noise reduction kit for the air
inlets and outlets, and ow noise HVAC systems should be used for the battery containers):
[cid:image036.png@01DC9CC3.5E2AEEE0]
https://docs.planning.org.uk/20230821/15/RZHNBROKHZQ00/tqlaisxsynrwah7j.pdf<https
://url.us.m.mimecastprotect.com/s/-
bbYC2koJpcV8vxjU3SoI5qb9U?domain=docs.planning.org.uk>
Here's a Tesla Megapack sound study showing higher fan speed for the day and reduced
fan speed at night- dropping the sound level by 15db:
[cid:image037.png@01DC9CC3.5E2AEEE0]
https://planning.walsall.gov.uk/swift/MediaTemp/73797-
324158.pdf<https://url.us.m.mimecastprotect.com/s/DsC-
C31pJqsX2w8BInTzIQo8rY?domain=planning.walsall.gov.uk>
ANother sound study hiding the frequency data:
[cid:image038.png@01DC9CC3.5E2AEEE0]
https://www.clune-windfarm.co.uk/media/153cmhi1/technical-appendix-113-bess-
acoustic-
assessment.pdf<https://url.us.m.mimecastprotect.com/s/3qz5C4xqKrhzlyjotEUNI4cwve?
domain=clune-windfarm.co.uk>
This Noise study isn't represented in a chart as they only gave the average sound levels:
[cid:image039.png@01DC9CC3.5E2AEEE0]
https://webportal.ribblevalley.gov.uk/planx_downloads/24_0366_Statement_Appendix_E_
Noise_Impact_Assessment_Redacted.pdf<https://url.us.m.mimecastprotect.com/s/Qyyo
C5yr0vSM6onvCYcYIk0z8d?domain=webportal.ribblevalley.gov.uk>
This sound study only says 88db at 60% and 82db at 40% and withholds all frequency data:
[cid:image040.png@01DC9CC3.5E2AEEE0]
https://planningexplorer.barnsley.gov.uk/Home/FileDownload/01GEE4NB2HQ66LTJMKTF
Page 549 of 758
11
BJPOF2GUCLW6D4?ApplicationNumber=2023%2F0322<https://url.us.m.mimecastprote
ct.com/s/FGhoC68vVwsPyE3DfAfyI5F_nM?domain=planningexplorer.barnsley.gov.uk>
This sound level study only gives the average sound level of a single "battery unit" and there
will be 525 battery units:
[cid:image041.png@01DC9CC3.5E2AEEE0]
https://potentiaenergy.com.au/wp-content/uploads/2025/03/Capricorn-BESS-Noise-
Impact-
Assessment_Final.pdf<https://url.us.m.mimecastprotect.com/s/wGHEC73wJxuzZvPqtnh
7Io_8T7?domain=potentiaenergy.com.au>
Another study hiding the noise levels at the specified frequencies and only provided the
Sound level:
[cid:image042.png@01DC9CC3.5E2AEEE0]
https://www.edf-powersolutions.uk/wp-content/uploads/2025/05/Noise-Assessment-
1.pdf<https://url.us.m.mimecastprotect.com/s/ONa_C82xYyTXYlJrIPiBIyd_uG?domain=ed
f-powersolutions.uk>
Here's another study showing only one data point from the manufacturer:
[cid:image043.png@01DC9CC3.5E2AEEE0]
https://portal.ct.gov/-/media/csc/3_petitions-
medialibrary/petitions_medialibrary/mediapetitionnos1601-
1700/pe1604/petitionersubmissions/appendix-g---sound-
assessment.pdf?rev=b64e84c1a723454980ce779a944e30b2&hash=CC05362D3CCCA1A
F8C23D77F8CE46228<https://url.us.m.mimecastprotect.com/s/xBy3C9ryXzsz2vZ1t9s7Iq
AcbZ?domain=portal.ct.gov>
Here's a liquid cooled BESS with the cooling system operating at 40% and 30%:
[cid:image044.png@01DC9CC3.5E2AEEE0]
https://docs.planning.org.uk/20241214/78/SOE1VMJIHNO00/asxqjjdjnzk54tyh.pdf<https:/
/url.us.m.mimecastprotect.com/s/yF8YC0Rm3nskmKE8iQtlI99f4z?domain=docs.plannin
g.org.uk>
Here's a study hiding all the noise levels and getting sound level data from BESS developer,
but showing a liquid cooled BESS:
[cid:image045.png@01DC9CC3.5E2AEEE0]
https://www.scribd.com/document/736589960/3b3c8082-87fb-ed11-8f6e-002248933fc5-
PA2302257-Glenbrae-BESS-Acoustic-Report-Copie-
2<https://url.us.m.mimecastprotect.com/s/h3TYCgJGXquqGrgkHwu9I4iawS?domain=scri
bd.com>
This noise study claims that the BESS will be quiter than normal sound levels at 2
Page 550 of 758
12
residences and a beach nearby (but doesn't provide any details beyond that):
[cid:image046.png@01DC9CC3.5E2AEEE0]
https://www.psegliny.com/aboutpseglongisland/proposalsandbids/-
/media/894B1477D1CD436CBE2435B8AD87FC80.ashx<https://url.us.m.mimecastprotec
t.com/s/6HkvCjRkJwsYR269ClCmIm9t5V?domain=psegliny.com>
This noise study doesn't disclose at what fan speed the tests were done- and instead says
it was done at nominal fan speed (software limted to 80%):
[cid:image047.png@01DC9CC3.5E2AEEE0]
https://newenergystoragesystem.com/wp-content/uploads/2024/09/Willingham-by-Stow-
BESS-Noise-Impact-
Assessment.pdf<https://url.us.m.mimecastprotect.com/s/syp6CkRlMxsk57LNimFlIGhhn
K?domain=newenergystoragesystem.com>
And, these are my favorite:
CATL's noise levels are covered by an NDA and not shared at all- but they give Broadband
sound levels:
[cid:image048.png@01DC9CC3.5E2AEEE0]
https://www.pleanala.ie/publicaccess/Case%20Documentation/323761/Applicant%20Do
cuments/Application%20Docs/Vol.%201%20and%20Vol.%203%20Environmental%20Imp
act%20Assessment%20Report/Appendix%2012-
3%20Battery%20Storage%20Noise%20Assessment%20F%20-%202025.09.26%20-
%20190723.pdf<https://url.us.m.mimecastprotect.com/s/jGKXClYm6yH1Xy97UZHgIzfZiT
?domain=pleanala.ie>
Totally redacted:
[cid:image049.png@01DC9CC3.5E2AEEE0]
https://www.fieldbeauly.co.uk/wp-content/uploads/2025/02/Noise-
Assessment.pdf<https://url.us.m.mimecastprotect.com/s/wPTGCmZnXzhpWZ02CoIpIRH
zTT?domain=fieldbeauly.co.uk>
So, when PSE or a BESS developer or lobbyist come to you and say a BESS is quiet- you
now know that they are not...
Ideallly, you would require BESS developers to give you sound studies that include all
frequencies at all fan speeds- and that the BESS has multiple Db meters installed around
the fenceline and provides you with live and historical records- and when sound levels
exceed the max limites submitted in their Sound study and or exceed allowed noise levels
you are pinged and they are fined $10k. Additionally, if the BESS is located anywhere near
Page 551 of 758
13
schools, homes, or other locations that would be easily disturbed the developer has to
provide each location with professional and calibrated sound meters so they can take
sound measurements- and if they record a higher sound level and send in a pic and report
the excess sound levels, the developer gets fined and the person who lost their ability to
have peace and enjoyment of their property gets 50% of the $10k fine for reporting it...
BESS developers and PSE lie about many things.. Sound levels is just another one of the
lies...
BESS are loud during normal operation and have a significant impact on surrounding
receptors- and should be determnied to have a significant impact!
Thank you,
James
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Page 552 of 758
AGENDA BILL APPROVAL FORM
Agenda Subject: Meeting Date:
Critical Areas Ordinance Update
Staff Introduction/Presentation (Tatro)
Staff will provide an update on the work being done to update the Critical
Areas Ordinance, Chapter 16.10 ACC, specifically regarding stream
regulations.
March 3, 2026
Department: Attachments: Budget Impact:
Community Development Planning Commission
Memorandum, Attachment 1 -
PowerPoint Presentation,
Attachment 2 - Chapter 16.10
ACC Text Amendment,
Attachment 3 - Technical Memo
Prepared by Facet NW,
Attachment 4 - WDFW
Comments, Attachment 5 -
Existing Stream Buffers Map,
Attachment 6 - SPTH Buffers
Map, Attachment 7 - Proposed
Stream Buffers Map, Attachment
8 - Proposed Increased Stream
Buffers Map
Administrative Recommendation:
Background for Motion:
Background Summary:
See attached Planning Commission Memorandum
Councilmember: Staff: Jason Krum
Page 553 of 758
PLANNING COMMISSION MEMORANDUM
TO: Judi Roland, Chair, Planning Commission
Bill Stewart, Vice Chair Planning Commission
Planning Commission Members
FROM: Alyssa Tatro, Senior Planner
Dept. of Community Development
DATE: February 17, 2026
RE: Critical Areas Ordinance Code Update
I. BACKGROUND & PURPOSE
The City of Auburn is currently completing updates to Chapter 16.10 ACC, Critical Areas, as a follow-on
action to the 2024 Periodic Comprehensive Plan update required under the Growth Management Act
(GMA). The GMA requires local jurisdictions to designate and protect critical areas using best available
science (BAS) when developing policies and development regulations.
Planning Commission previously reviewed the proposed Critical Areas Ordinance updates on September
16, 2025. At that meeting, staff discussed the comments received from Washington Department of Fish
and Wildlife (WDFW) regarding stream regulations. WDFW recommended that Auburn consider the Site
Potential Tree Height (SPTH) method for stream buffer widths, consistent with current BAS for
stream/riparian protection.
Based on this feedback, the Planning Commission and city staff agreed that additional analysis was
needed to understand how the SPTH approach would apply within Auburn’s urban context. Following the
meeting, staff have been working with Facet Northwest, an environmental and engineering consulting
firm, to conduct a city-specific analysis of stream conditions and potential buffer changes. Since
September 2025, City staff and Facet have completed a technical review of stream and riparian science,
analyzed local stream conditions using GIS data, and evaluated how updated buffer approaches could
impact Auburn.
II. SUMMARY OF PROPOSED CODE CHANGES
Based on the technical analysis and BAS review, the City is proposing updates to stream regulations that
include:
• Increasing stream buffer widths to better align with best available science;
• Adding stream vegetated buffer standards; and
• Provision for buffer increases where vegetation standards are not met or minimization measures
are not implemented.
The proposed changes are intended to improve protection of stream and riparian functions while
maintaining flexibility for development through existing buffer averaging and enhancement provisions.
Page 554 of 758
Staff Member: Tatro Date: Feb. 17, 2026
2
III. ATTACHMENTS
1) PowerPoint Presentation
2) Chapter 16.10 ACC Text Amendment
3) Technical Memo prepared by Facet NW
4) WDFW Comments
5) Existing Stream Buffers Map
6) SPTH Buffers Map
7) Proposed Stream Buffers Map
8) Proposed Increased Stream Buffers Map
Page 555 of 758
AUBURN
VALUES
S E R V I C E
ENVIRONMENT
E C O N O M Y
C H A R A C T E R
SUSTAINABILITY
W E L L N E S S
C E L E B R AT I O NPLANNING COMMISSIONCRITICAL AREA ORDINANCE UPDATE –TEXT AMENDMENTPRESENTED BYALYSSA TATRO, SENIOR PLANNER MARCH 3, 2026Department of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementPage 556 of 758
BACKGROUND AND PURPOSE SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATIONPage 557 of 758
SERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATIONADDRESSING COMMENTSWDFW’S SPTHMAPPING TOOL:Page 558 of 758
TECHNICAL ANALYSIS FINDINGSSERVICE ENVIRONMENT ECONOMY CHARACTER SUSTAINABILITY WELLNESS CELEBRATION
STREAM TYPOLOGYSPage 560 of 758
SITE POTENTIAL TREE HEIGHT (SPTH)Page 561 of 758
SITE POTENTIAL TREE HEIGHT (SPTH)Page 562 of 758
SITE POTENTIAL TREE HEIGHT (SPTH)Page 563 of 758
Minimum Buffer Width (in feet)Stream TypeEXISTING BUFFERSPer SMPType S100
Type F50
Type Np50
Type NsStream buffers shall be established as follows: Page 565 of 758
EXISTING STREAM BUFFERS MAPPage 566 of 758
AUBURN GIS ANALYSISPage 567 of 758
Page 568 of 758
Page 569 of 758
PROPOSED STREAM (RIPARIAN) BUFFERSProposed Stream(riparian) BuffersStream TypeIncreased Buffer2Standard Buffer1Per SMPPer SMPType S200 ft150 ftType F133 ft100 ftType Np133 ft100 ftType Ns*1 Director decision based on site-specific conditions, such as presence of critical habitat for ESA species.*2 In addition to ESA review, an increase applies if the applicant does not implement applicable minimization measures and does not meet vegetated buffer standards. Page 570 of 758
PROPOSED STREAM BUFFERS MAPPage 571 of 758
To be considered fully functioning, a stream buffer (riparian management zone) must contain: i. An average of eighty percent (80%) native vegetation cover, with no more than ten percent (10%) noxious weed cover; and ii. A native plant community that includes tree, shrub, and groundcover proportions that mimic native forest for the region. VEGETATIVE STANDARDPage 572 of 758
PROPOSED STREAM (RIPARIAN) BUFFERSProposed Stream(riparian) BuffersStream TypeIncreased Buffer2Standard Buffer1Per SMPPer SMPType S200 ft150 ftType F133 ft100 ftType Np133 ft100 ftType Ns*1 Director decision based on site-specific conditions, such as presence of critical habitat for ESA species.*2 In addition to ESA review, an increase applies if the applicant does not implement applicable minimization measures and does not meet vegetated buffer standards. Page 573 of 758
PROPOSED INCREASED STREAM BUFFERS MAPPage 574 of 758
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AUBURN GIS ANALYSISPage 585 of 758
AUBURN GIS ANALYSIS Page 586 of 758
AUBURN GIS ANALYSIS Page 587 of 758
COMPARISON TO OTHER JURISDICTIONSMaple Valley (adopted)Covington (adopted)Burien (adopted)Kent (DRAFT; proposed to be adopted)Type F: 100’Type NP: 100’Type NS: 100’Type F: 125’ – 166’ Type NP: 100’ – 133’Type NS: 100’ – 133’Type F: 150’ - 199’ (was 100’) Type Np: 100’ – 133’ (was 50’) Type Ns: 100’ – 133’ (was 50’)Type F: 112-150’ (was 100’)Type NP: 100’ (was 40’)Type NS: 100’ (was 40’)SeaTac (adopted)Renton (adopted)Auburn (DRAFT; will be updated)Type F: 200’ (was 100’)Type NP: 100’ (was 50’)Type NS: 100’ (was 25’)Type F: 115’ – 200’Type NP: 75’ – 100’Type NS: 50’ – 67’Type F: 100’Type NP: 50’Type NS: 50’Page 588 of 758
SUMMARY OF CHANGESProposed CodeExisting CodeStream TypeIncreased Buffer2Standard Buffer1Maximum buffer1Minimum bufferPer SMPPer SMPPer SMPPer SMPType S200 ft150 ft150 ft100 ftType F133 ft100 ft100 ft50 ftType Np133 ft100 ft75 ft50 ftType NsPage 589 of 758
SUMMARY OF CHANGES CONT.
AUBURN
VALUES
S E R V I C E
ENVIRONMENT
E C O N O M Y
C H A R A C T E R
SUSTAINABILITY
W E L L N E S S
C E L E B R AT I O NDepartment of Community DevelopmentPlanning Building Development Engineering Permit CenterEconomic Development Code EnforcementThank you for your time.Questions?Page 592 of 758
Chapter 16.10 ACC, Critical Areas Page 1 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
Chapter 16.10
CRITICAL AREAS
Sections:
16.10.010 Purpose and intent.
16.10.020 Definitions.
16.10.030 Applicability – Regulated activities.
16.10.040 Exemptions and nonconforming uses.
16.10.050 Critical areas maps.
16.10.060 Relationship to other regulations.
16.10.070 Critical area review process and application requirements.
16.10.080 Classification and rating of critical areas.
16.10.090 Buffer areas and setbacks.
16.10.100 Alteration or development of critical areas – Standards and criteria –
Prohibited uses.
16.10.110 Mitigation standards, location, and timing, wetland replacement
ratios, and long-term protection requirements.
16.10.120 Performance standards for mitigation planning.
16.10.130 Monitoring program and contingency plan.
16.10.140 Procedural provisions.
16.10.150 Reasonable use provision.
16.10.160 Variances.
16.10.170 Special exception for public agencies and utilities.
16.10.180 Severability.
16.10.010 Purpose and intent.
A. The city of Auburn contains numerous areas that can be identifled and characterized as
critical or environmentally sensitive. Such areas within the city include wetlands, streams, flsh
and wildlife habitat conservation areas, geologic hazard areass, aquifer recharge areas, and
fiood hazards areas.
Page 593 of 758
Chapter 16.10 ACC, Critical Areas Page 2 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
B. The city flnds that these critical areas perform a variety of valuable and beneflcial biological
and physical functions that beneflt the city and its residents. Alteration of certain critical areas
may also pose a threat to public safety or to public and private property or the environment.
The city therefore flnds that identiflcation, regulation and protection of critical areas are
necessary to protect the public health, safety and general welfare. The city further flnds that the
functions of critical areas and the purpose of these regulations include the following:
1. Wetlands. Wetlands perform a variety of functions that include maintaining water
quality; storing and conveying storm water and fiood water; recharging groundwater;
providing important flsh and wildlife habitat; and serve as areas for recreation, education
and scientiflc study, and aesthetic appreciation.
Wetland buffers serve to moderate runoff volume and fiow rates; reduce sediment,
chemical nutrient and toxic pollutants; provide shading to maintain desirable water
temperatures; provide habitat for wildlife; and protect wetland resources from harmful
intrusion.
The primary goals of wetland regulation are to avoid adverse effects to wetlands; to
achieve no net loss of wetland function and value – acreage may also be considered in
achieving the overall goal; to provide levels of protection that refiect the sensitivity of
individual wetlands and the intensity of proposed land uses; and to restore and/or enhance
existing wetlands, where possible.
2. Streams and stream buffers (riparian management zone). Streams and their associated
riparian corridors provide important flsh and wildlife habitat; help to maintain water
quality; store and convey storm water and fiood water; recharge groundwater; recruit large
woody debris to create habitat structure; provide shade to maintain water temperatures
and dissolved oxygen levels; support bank integrity and root reinforcement to reduce
erosion; and serve as areas for recreation, education and scientiflc study and aesthetic
appreciation. Stream buffers serve to moderate runoff volume and fiow rates; reduce
sediment, chemical nutrient and toxic pollutants; provide shading to maintain desirable
water temperatures; provide habitat for wildlife; and protect stream resources from
harmful intrusion.
The primary goals of stream regulation are to avoid adverse effects to streams and
associated riparian corridors; to achieve no net loss of functions and values of the larger
ecosystem in which the stream is located; to protect flsh and wildlife resources; to protect
Page 594 of 758
Chapter 16.10 ACC, Critical Areas Page 3 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
water quality through appropriate management techniques; and, where possible, to
provide for stream enhancement and rehabilitation.
3. Fish and Wildlife Habitat Conservation Areas and Wildlife Habitat Corridors. Wildlife habitat
provides opportunities for food, cover, nesting, breeding and movement for flsh and
wildlife; maintains and promotes diversity of species and habitat; coordinates habitat
protection with elements of the open space system; helps to maintain air and water quality;
helps control erosion; serves as areas for recreation, education, scientiflc study, and
aesthetic appreciation; and provides neighborhood separation and visual diversity within
urban areas.
The primary goals of wildlife habitat regulation are to avoid adverse effects to critical
habitats for flsh and wildlife; to achieve no net loss of functions and values of the larger
ecosystem in which the wildlife habitat is located; to implement the goals of the
Endangered Species Act (ESA); to promote connectivity between habitat areas to allow for
wildlife movement; to provide multi-purpose open space corridors; and where possible to
provide for flsh and wildlife habitat enhancement and rehabilitation that refiect the
sensitivity of the species.
4. Aquifer Recharge Areas. Aquifer recharge areas provide a source of potable water and
contribute to stream discharge/fiow. Such areas contribute to the replenishingcharge of
aquifers, and springs and/or wells and are susceptible to contamination of water supplies
through inflltration of pollutants through the soil.
The primary goals of aquifer recharge protection regulations are to protect groundwater
resources and water quality by maintaining the quantity of recharge; avoiding or limiting
land use activities that pose potential risk of aquifer contamination; to minimizinge or
avoiding adverse effects to groundwater through the application of performance
standards, ; and to complying with the requirements of the Federal Safe Drinking Water Act
and Washington Administrative Code that require Group A public water systems to develop
and implement a wellhead protection program.
5. Geologically Hazardous Areas. Geologically hazardous areas means areas that, because
of their susceptibility to erosion, sliding, earthquake, volcanic activity, or other geological
events, are not suited to the siting of commercial, residential, or industrial development
consistent with public health or safety concerns.
Page 595 of 758
Chapter 16.10 ACC, Critical Areas Page 4 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
The primary goals of regulating geologic hazards areas are to avoid and minimize potential
impacts to life and property by regulating and/or limiting land uses where necessary, and
to conduct appropriate levels of analysis and ensure sound engineering and construction
practices to address identifled hazards.
6. Flood Hazard Areas. Refer to Chapter 15.68 ACC Floodplain Development Management.
Floodplains help to store and convey storm water and fiood water; recharge groundwater;
provide important areas for riparian habitat; and serve as areas for recreation, education,
and scientiflc study. Development within fioodplain areas can be hazardous to those
inhabiting such development, and to those living upstream and downstream. Floods also
cause substantial damage to public and private property that results in signiflcant costs to
the public and individuals.
The primary goals of fiood hazard regulations are to limit or condition development within
the regulatory fioodplain to avoid substantial risk of damage to public and private property
and that results in signiflcant costs to the public and individuals; to avoid signiflcant
increases in peak storm water fiows or loss of fiood storage capacity; to protect critical
habitat for flsh and wildlife, and to meet the purposes set forth in Chapter 15.68 ACC.
Requirements for the identiflcation, assessment, alteration, and mitigation of fiood hazard
areas are contained in Chapter 15.68 ACC.
C. This chapter and other sections as incorporated by reference contain standards,
procedures, criteria and requirements intended to identify, analyze, and mitigate potential
impacts to the city’s critical areas, and to enhance and restore degraded resources where
possible. The general intent of these regulations is to avoid impacts to critical areas. In
appropriate circumstances, impacts to specifled critical areas resulting from regulated activities
may be minimized, rectifled, reduced and/or compensated for, consistent with the
requirements of this chapter.
D. It is the further intent of this chapter to:
1. Comply with the requirements of the Growth Management Act (Chapter 36.70A RCW)
and implement rules to identify and protect critical areas and to perform the review of
development regulations required by RCW 36.70A.215;
2. Develop and implement a comprehensive, balanced and fair regulatory program that
avoids impacts to critical resources where possible, that requires that mitigation be
Page 596 of 758
Chapter 16.10 ACC, Critical Areas Page 5 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
performed by those affecting critical areas, and that thereby protects the public from
injury, loss of life, property or flnancial losses due to fiooding, erosion, landslide, seismic
events, soil subsidence, or steep slope failure;
3. Implement the goals and policies of the Auburn comprehensive plan, including those
pertaining to natural features and environmental protection, as well as goals relating to
land use, housing, economic development, transportation, and adequate public facilities;
4. Serve as a basis for exercise of the city’s substantive authority under the State
Environmental Policy Act (SEPA) and the city’s environmental review procedures, where
necessary to supplement these regulations, while also reducing the city’s reliance on
project-level SEPA review;
5. Provide consistent standards, criteria and procedures that will enable the city to
effectively manage and protect critical areas while accommodating the rights of property
owners to use their property in a reasonable manner;
6. Provide greater certainty to property owners regarding uses and activities that are
permitted, prohibited, and/or regulated due to the presence of critical areas;
7. Coordinate environmental review and permitting of proposals involving critical areas
with existing development review and approval processes to avoid duplication and delay
pursuant to the Regulatory Reform Act, Chapter 36.70B RCW;
8. Establish conservation and protection measures for threatened and endangered flsh
species in compliance with the requirements of the Endangered Species Act and the
Growth Management Act requirements to preserve or enhance anadromous flsheries, WAC
365-195-925;
9. Alert members of the public, including appraisers, assessors, owners, potential buyers
or lessees, to the development limitations of critical areas and their required buffers.
E. Best Available Science. The city has considered and included the best available science in
developing these regulations, consistent with RCW 36.70A.172 and WAC 365-195-900, et seq.
This has been achieved through research and identiflcation of relevant technical sources of
information, consultation with experts in the disciplines covered by this chapter, and
consultation and requests for technical information regarding best available science from state
and federal resource agencies.
Page 597 of 758
Chapter 16.10 ACC, Critical Areas Page 6 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
Preparation of this chapter has included the use of relevant nonscientiflc information, including
consideration of legal, social, policy, economic, and land use issues. This refiects the city’s
responsibilities under numerous laws and programs, including other provisions of the Growth
Management Act, and the need to weigh and balance various factors as part of decision making
to accomplish municipal objectives. This may result in some risk to the functions and values of
some critical areas; however, it is recognized that the Growth Management Act requires the city
to designate and protect critical areas. The city will also use its authority under the State
Environmental Policy Act (SEPA) to identify, consider and mitigate, where appropriate,
signiflcant adverse effects on critical resources not otherwise addressed by the regulations of
this chapter.
The city intends to review and monitor implementation of its critical areas regulations and to
use an adaptive management approach. It will make adjustments to the regulations, as
appropriate, in response to changing conditions, new information about best available science,
or empirical data indicating the effectiveness of its regulatory program. This will occur in the
context of the city’s ongoing review and revision of its comprehensive plan and development
regulations pursuant to the Growth Management Act.
Additional information, both scientiflc and nonscientiflc, regarding compliance with WAC 365-
195-915(c), including identiflcation of risks to resources and Washington State Department of
Ecology guidance, is contained in the flndings and conclusions and the overall record
supporting adoption of Auburn’s critical areas regulations. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6295 § 3,
2010; Ord. 5894 § 1, 2005.)
16.10.020 Definitions.
For purposes of this chapter, the following deflnitions shall apply:
“Anadromous flsh” means flsh that spawn and rear in freshwater and mature in the marine
environment, such as salmon, steelhead, sea-run cutthroat, and bull trout.
“Applicant” means the person, party, flrm, corporation, or other entity that proposes or has
performed any activity that affects a critical area.
“Aquifer” means , generally, anyunderground layer of water bearing soil or rock unit formation.
Speciflcally, an underground body of soil or rock formation that contains sufficient saturated
Page 598 of 758
Chapter 16.10 ACC, Critical Areas Page 7 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
permeable material to conduct groundwater and capable of and yielding economically
signiflcant quantities of groundwater to wells or springs.
“Aquifer recharge area” means areas with a critical recharging effect on aquifers used for
potable water, including areas where an aquifer that is a source of drinking water is vulnerable
to contamination that would affect the potability of the water, or is susceptible to reduced
recharge. are land areas that have a critical recharging effect on aquifers used for potable
water, including designated areas, such as wellhead protection zones, where an aquifer that is a
source of drinking water is vulnerable to contamination that would affect the potability of the
water, or is susceptible to reduced recharge.
“Artiflcially created wetlands” means wetlands created from nonwetland sites through
purposeful, legally authorized human action, such as irrigation and drainage ditches, grass-
lined swales, canals, retention or detention facilities, wastewater treatment facilities, farm
ponds, and landscape amenities.
Best Available Science. As deflned in the Procedural Criteria for Adopting Comprehensive Plans
and Development Regulations for Best Available Science at WAC 365-195-900, et seq.
“Buffer or buffer area, critical area” means a naturally vegetated, undisturbed, enhanced or
revegetated zone surrounding a critical area that protects the critical area from adverse
impacts to its integrity and value, and is an integral part of the resource’s ecosystem.
"Characterized by urban growth" refers to land having urban growth located on it, or to land
located in relationship to an area with urban growth on it as to be appropriate for urban
growth.
“City” means the city of Auburn.
“Clearing” means the removal of timber, brush, grass, ground cover or other vegetative matter
from a site, which exposes the earth’s surface of the site, or any actions which disturb the
existing ground surface. Means the destruction and removal of vegetation by manual,
mechanical, or chemical methods.
“Climate resilience” means the capacity of ecosystems and infrastructure to recover and adapt
to climate-related stressors including extreme weather, fiooding, drought, and wildflre.
Page 599 of 758
Chapter 16.10 ACC, Critical Areas Page 8 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Comprehensive plan” means the city of Auburn comprehensive plan as now adopted or
hereafter amended.
“Critical area report” means a report prepared by a qualifled professionalconsultant to
determine the presence, type, class, size, function and/or value of an area subject to these
regulations. Also see “Stream or wetland reconnaissance report,” “Wetland impact assessment
report” and “Wildlife report.”
“Critical areas” or “environmentally sensitive areas” means areas that possess important natural
functions and embody a variety of important natural and community values. Such areas include
wetlands, streams, flsh and wildlife habitat, geologically hazardous areas, aquifer recharge
areas, and fiood hazard areas, and any other areas designated as critical under state law,
including but not limited to those deflned in RCW 36.70A.030. If not conducted properly,
development or alteration of such areas may cause signiflcant impacts to the valuable functions
and values of these areas and/or may generate risks to the public health and general welfare,
and/or to public and private property.
“Critical erosion hazard areas” means lands or areas underlain by soils identifled by the U.S.
Department of Agriculture Soil Conservation Service (SCS) (now known as the Natural
Resources Conservation Service) as having “severe” or “very severe” erosion hazards. This
includes, but is not limited to, the following group of soils when they occur on slopes of 15
percent or greater: Alderwood-Kitsap (AkF), Alderwood gravelly sandy loam (AgD), Kitsap silt
loam (KpD), Everett (EvD), and Indianola (InD). Additional soil groups may be identifled through
site-speciflc analysis.
“Critical geologic hazard areas” means lands or areas subject to high or severe risks of geologic
hazard, including critical erosion hazard areas, critical landslide hazard areas, critical volcanic
hazard areas, and critical seismic hazard areas.
“Critical habitat” or “critical wildlife habitat” means habitat areas associated with threatened,
endangered, or sensitive species of plants or wildlife (pursuant to WAC 232-12-297(2.4), (2.5)
and (2.6)) and which, if altered, could reduce the likelihood that the species will maintain and
reproduce over the long term.
“Critical landslide hazard areas” means lands or areas where there is a high (Class III) or very
high (Class IV) risk of landslide due to a combination of slope, soil permeability, and water.
Page 600 of 758
Chapter 16.10 ACC, Critical Areas Page 9 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Critical seismic hazard areas” means lands or areas where there is a high risk of seismic events
and damage.
“Delineation manual,” “wetland delineation manual,” or “wetland delineation methodology”
means the methodology used for identiflcation of wetlands and delineation of their boundaries
and shall be done in accordance with the approved federal wetland delineation manual and the
Western Mountains, Valleys, and Coast Regional supplement, as required by WAC 173-22-035.
“Department” means the city of Auburn department of community development or successor
agency, unless the context indicates a different city department.
“Director” means the director of the city of Auburn department of community development or
successor agency.
“Earth/earth material” means naturally occurring rock, soil, stone, sediment, or combination
thereof.
“Ecosystem functions” means the products, physical and biological conditions, and
environmental qualities of an ecosystem that result from interactions among ecosystem
processes and ecosystem structures. Ecosystem functions include, but are not limited to,
sequestered carbon, attenuated peak streamfiow, aquifer water level, reduced pollutant
concentrations in surface and ground waters, cool summer in-stream water temperatures, and
flsh and wildlife habitat functions.
“Ecosystems values” are the cultural, social, economic, and ecological beneflts attributed to
ecosystem functions.
“Engineered slope” means a made slope that is speciflcally designed and constructed with the
intention of maintaining stability and preventing failure.
“Enhancement” means the improvement of an existing viable wetland, stream or habitat area
or the buffers established for such areas, through such measures as increasing plant diversity,
increasing wildlife habitat, installing environmentally compatible erosion controls, increasing
structural diversity or removing plant or animal species that are not indigenous to the area.
Enhancement also includes actions performed to improve the quality of an existing degraded
wetland, stream, or habitat area. See also “Restoration.”
Page 601 of 758
Chapter 16.10 ACC, Critical Areas Page 10 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Erosion” means a process whereby wind, rain, water, and other natural agents mobilize and
transport soil particles.
“Erosion hazard areas” means lands or areas that, based on a combination of slope inclination
and the characteristics of the underlying soils, are susceptible to varying degrees of risk of
erosion. Erosion hazard areas are classifled as “low” (areas sloping less than 15 percent) or
“high” (areas sloping 15 percent or more) on the following Soil Conservation Service (SCS), now
known as the Natural Resources Conservation Service (NRCS), soil types: Alderwood-Kitsap
(AkF), Alderwood gravelly sandy loam (AgD), Kitsap silt loam (KpD), Everett (EvD) and Indianola
(InD). Additional soil groups may be identifled through site-speciflc analysis.
“Excavation” means the removal or displacement of earth material by human or mechanical
means.
“Existing and ongoing agricultural activities” means those activities conducted on lands deflned
in RCW 84.34.020(2), and those activities involved in the production of crops and livestock. Such
activity must have been in existence as of July 1, 1990 (the effective date of the Growth
Management Act). The deflnition includes, but is not limited to, operation and maintenance of
farm and stock ponds or drainage ditches, irrigation systems, changes between agricultural
activities or crops, and normal operation, maintenance or repair of existing serviceable
structures, facilities, or improved areas. Activities, which bring an area into agricultural use from
a previous nonagricultural use, are not considered part of an ongoing activity. An operation
ceases to be ongoing when the area on which it was conducted is proposed for conversion to a
nonagricultural use or has lain idle for a period of longer than flve years, unless the idle land is
registered in a federal or state soils conservation program. Forest practices are not included in
this deflnition.
“Exotic” means any species of plant or animal that is foreign and not indigenous to the lower
Puget Sound area.
“Fill/flll material” means a deposit of earth material placed by human or mechanical means.
“Filling” means the act of transporting and placing (by any manner or mechanism) flll material
from, to, or on any surface water body or wetland, soil surface, sediment surface, or other flll
material. means the act of transporting or placing (by any manner or mechanism) flll material
from, to, or on any soil surface, natural vegetative covering of soil surface, or flll material
(including temporary stockpiling of flll material).
Page 602 of 758
Chapter 16.10 ACC, Critical Areas Page 11 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Fish habitat” or habitat that supports flsh life means habitat that is used by flsh life at any life
stage and at any time of the year including potential habitat likely to be used by flsh life, which
could reasonably be recovered by restoration or management and includes off-channel habitat.
“Geologically hazardous areas” means areas characterized by geologic, hydrologic, and
topographic conditions that render them susceptible to erosion, sliding, earthquake, or other
geological events.
“Geotechnical report” means a report prepared in accordance with the city’s engineering design
standards for geotechnical engineering and evaluation of soils.
“Grading” means any excavating, fllling, clearing, leveling or contouring of the ground surface by
human or mechanical means. means any excavating, fllling, clearing, or re-contouring of the
ground surface or combination thereof.
“Groundwater protection areas” means land areas designated by the city beneath which
groundwater occurs that is a current or potential future source of drinking water for the city.
Please see the deflnition of “aquifer recharge areas” for additional regulated areas.
“Habitat management” means management of land and its associated resources/features to
maintain species in suitable habitats within their natural geographic distribution so that
isolated subpopulations are not created. This does not imply maintaining all habitat or
individuals of all species in all cases.
“Hazardous substances” means any liquid, solid, gas, or sludge, including any material,
substance, product, commodity, or waste, regardless of quantity, that exhibits any of the
physical, chemical, or biological properties described in Chapter 173-303 WAC or Chapter
70.105 RCW.
“Hazard tree” means a tree that is considered a threat to life, property, or public safety. Due to
their high habitat value, except when in the public right-of-way, hazard tree removal shall not
adversely affect ecosystem functions to the extent practicable, encourage the creation of snags
(Priority Habitat features) rather than complete tree removal, involve an avoidance and
minimization of damage to remaining trees and vegetation, and require a qualifled arborist to
evaluate requests for hazard tree removal. When a hazard tree is within the right-of-way the
City Engineer shall determine its removal.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“In-kind wetland mitigation” means replacement of wetlands with wetlands whose
characteristics closely approximate those destroyed or degraded by a regulated activity.
“Injection well” means a well that is used for the subsurface emplacement of fiuids. (From WAC
173-218-030.)
“Intentionally created streams” means streams created through purposeful human action, such
as irrigation and drainage ditches, grass-lined swales, and canals. This deflnition does not
include stream modiflcations performed pursuant to city authorization, such as changes or
redirection of stream channels.
“Lahar” means mudfiows or debris fiows associated with volcanic activity and which pose a
threat to life, property, and structures.
“Landslide” means episodic downslope movement of a mass of soil or rock.
“Landslide hazard areas” means areas that, due to a combination of slope inclination, relative
soil permeability, and hydrologic conditions are susceptible to varying degrees of risk of
landsliding. Landslide hazard areas are classifled as Classes I through IV based on the degree of
risk as follows:
1. Class I/Low Hazard. Areas with slopes of 15 percent or less.
2. Class II/Moderate Hazard. Areas with slopes of between 15 percent and 40 percent and
that are underlain by soils that consist largely of sand, gravel or glacial till.
3. Class III/High Hazard. Areas with slopes between 15 percent and 40 percent that are
underlain by soils consisting largely of silt and clay.
4. Class IV/Very High Hazard. Areas with slopes steeper than 15 percent with identiflable
zones of emergent water (e.g., springs or groundwater seepage), areas of identiflable
landslide deposits regardless of slope and all areas sloping more steeply than 40 percent.
The slopes referenced above include only those where the surface drops 10 feet or more
vertically within a horizontal distance of 25 feet and are not an engineered slope part of a
project or development permitted by the city.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Mature and old-growth forested wetlands” means wetlands containing mature or old-growth
forested areas, generally requiring a century or more to develop. These systems represent two
priority habitats, as deflned by the Washington State Department of Fish and Wildlife.
“Mitigation” means activities which include:
1. Avoiding the impact altogether by not taking a certain action or parts of actions;
2. Minimizing impacts by limiting the degree or magnitude of the action and its
implementation, by using appropriate technology, or by taking affirmative steps to avoid or
reduce impacts;
3. Rectifying the impact by repairing, rehabilitating, or restoring the affected environment;
4. Reducing or eliminating the impact over time by preservation and maintenance
operations during the life of the action;
5. Compensating for the impact by replacing, enhancing, or providing substitute resources
or environments; and/or
6. Monitoring the impact and taking appropriate corrective measures.
While monitoring without additional actions is not considered mitigation for the purposes of
these regulations, it shall be part of a comprehensive mitigation program.
“Mitigation sequencing” means considering or performing mitigation actions, as deflned in the
deflnition of “mitigation,” in a preferred sequence from (1) through (6). Avoidance is preferred
and must be considered prior to pursuing other forms of mitigation.
“Monitoring and Adaptive Management” means the process of monitoring and improving
permits, regulations, and programs to ensure the protection of critical areas.
“Native” means any species of plant or animals which are or were indigenous to the lower Puget
Sound area.
“Natural heritage wetlands” means wetlands that are identifled by scientists of the Washington
Natural Heritage Program/DNR as high quality, relatively undisturbed wetlands, or wetlands
that support state-listed threatened or endangered plants.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“No net loss” refers to the actions taken to achieve and ensure no overall reduction in existing
ecosystem functions and values or the natural systems constituting the protected critical areas.
This may involve fully offsetting any unavoidable impacts to critical area functions and values
pursuant to the Growth Management Act, WAC 365-196-830 ‘Protection of critical areas,’ or as
amended.
“Off-site mitigation” means performance of mitigation actions, pursuant to standards
established in this chapter, on a site or in an area other than that proposed for conduct of a
regulated activity.
“Out-of-kind mitigation” means replacement of wetlands or habitat with substitute wetlands or
habitat whose characteristics do not closely approximate those adversely affected, destroyed,
or degraded by a regulated activity.
“Permanent erosion control” means continuous on-site and off-site control measures that are
needed to control conveyance or deposition of earth, turbidity, or pollutants after development,
construction, or restoration.
“Plant association of infrequent occurrence” means one or more plant species which because of
the rarity of the habitat and/or the species involved, or for other botanical or environmental
reasons, do not often occur in the city of Auburn. Examples include but are not limited to:
1. Wetlands with a coniferous forested class or subclass consisting of trees such as
western red cedar, Sitka spruce, or lodgepole pine growing on organic soils;
2. Bogs with a predominance of sphagnum moss, or those containing sphagnum moss,
and typically including one or more species such as Labrador tea, sundew, bog laurel, or
cranberry.
“Priority habitat and species (PHS)” means a classiflcation by the Washington Department of
Fish and Wildlife of habitats and species that require protective measures due to their
sensitivity, rarity, or ecological importance.
“Qualifled professionalconsultant,” for purposes of these regulations, shall mean a person who
has attained a degree from an accredited college or university in the subject matter necessary
to evaluate the critical area in question (e.g., biology, ecology, or horticulture/arboriculture for
wetlands, streams, wildlife habitat, and geology and/or civil engineering for geologic hazards,
and hydrogeologist for aquifer recharge areas), and/or who is professionally trained and/or
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Chapter 16.10 ACC, Critical Areas Page 15 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
certifled or licensed by the state of Washington to practice in the scientiflc disciplines necessary
to identify, evaluate, manage, and mitigate impacts to the critical area in question. In addition, a
qualifled professionalconsultant for wetlands and streams must be a professional wetland
scientist with at least two years of full-time work experience as a wetlands professional,
including delineating wetlands using the federal manual and supplements, preparing wetland
reports, conducting function assessments, and development and implementing mitigation
plans. A qualifled professionalconsultant for aquifer recharge areas must be a currently
licensed Washington State geologist holding a current specialty license in hydrogeology.
“Reasonable use” means a legal concept articulated by federal and state courts in regulatory
taking cases.
“Regulated activities” means activities that have a potential to signiflcantly impact a critical area
that is subject to the provisions of this chapter. Regulated activities generally include, but are
not limited to, any fllling, dredging, dumping or stockpiling, release of contaminants to soil or
water, draining, excavation, fiooding, clearing or grading, construction or reconstruction, driving
pilings, obstructing, clearing, or harvesting.
“Restoration” means actions taken to re-establish wetland, stream or habitat functional values,
and the characteristics that have been destroyed or degraded by past alterations (e.g., fllling or
grading). See also “Enhancement.”
“Riparian management zone” (RMZ) means the area that has the potential to provide full
riparian functions. In many forested regions of the state, this area occurs within one 200-year
site-potential tree height measured from the edge of the stream channel. In situations where a
CMZ is present, this occurs within one site potential tree height measured from the edges of
the CMZ. In non-forest zones, the RMZ is deflned by the greater of the outermost point of the
riparian vegetative community or the pollution removal function, at 100 feet. For delineating
RMZs, see the qualifled professional resources in Appendix A of Washington Department of
Fish and Wildlife’s Guidelines for Determining Site Potential Tree Height from Field
Measurements.
“Salmonids” means the family of flsh which includes salmon, trout, and char.
“Secondary habitat” means areas that offer less diversity of animal and plant species than
critical habitat but are important for performing the essential functions of habitat.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Seismic hazard areas” means areas that, due to a combination of soil and groundwater
conditions, are subject to risk of ground shaking, subsidence, or liquefaction of soils during
earthquakes. These areas are typically underlain by soft or loose saturated soils (such as
alluvium), have a shallow groundwater table, and are typically located on the fioors of river
valleys.
“Site” means the location containing a regulated critical area and on which a regulated activity is
proposed. The location may be a parcel or portion thereof, or any combination of contiguous
parcels where a proposed activity may impact a critical area.
“Slope” means an inclined earth surface, the incline of which is expressed as the ratio of
horizontal distance to vertical distance. The slopes referenced above include only those where
the surface drops 10 feet or more vertically within a horizontal distance of 25 feet.
“Sole source aquifer” means an area formally designated as such by the U.S. Environmental
Protection Agency under the federal Safe Drinking Water Act.
“Spring” means a source of water where an aquifer comes in contact with the ground surface.
“Stream or wetland reconnaissance report” means a type of critical area report prepared by an
applicant’s qualifled professionalconsultant to describe a stream or wetland and to characterize
its conditions, source of hydrologic support, wildlife, habitat values and water quality. The
report may also include an analysis of impacts but generally does not include adequate impact
assessment and deflnition of a mitigation proposal sufficient to meet all the requirements of a
more comprehensive critical areas report.
“Streams” means those areas where surface waters produce a deflned channel or bed that
demonstrates clear evidence of the passage of water and includes, but is not limited to,
bedrock channels, gravel beds, sand and silt beds and deflned-channel swales. The channel or
bed need not contain water year-round. This deflnition is not intended to include artiflcially
created irrigation ditches, canals, stormwater or surface water devices, or other entirely
artiflcial watercourses unless they are used by salmonids or created for the purposes of stream
mitigation.
“Structural diversity, vegetative” means the relative degree of diversity or complexity of
vegetation in a wildlife habitat area as indicated by the stratiflcation or layering of different
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
plant communities (e.g., ground cover, shrub layer and tree canopy), the variety of plant species
and the spacing or pattern of vegetation.
“Substrate” means the soil, sediment, decomposing organic matter or combination of those
located on the bottom surface of the wetland, lake, stream, or river.
“Temporary erosion control” means on-site and off-site control measures that are needed to
control conveyance or deposition of earth, turbidity, or pollutants during development,
construction, or restoration.
“Tertiary habitat” means habitat that supports some wildlife but does not satisfy the deflnition
of secondary or critical habitat.
“Tree” means any self-supporting perennial woody plant characterized by natural growth of one
main stem or trunk with a deflnite crown, and maturing at a height of at least six feet above the
ground.
“Tree base fee” means the current cost of the tree based on species and minimum code
required installation size, installation (labor and equipment), maintenance for two years and
fund administration.
"Urban growth" refers to growth that makes intensive use of land for the location of buildings,
structures, and impermeable surfaces to such a degree as to be incompatible with the primary
use of such land for the production of food, other agricultural products, or flber, or the
extraction of mineral resources. Urban growth typically requires urban governmental services.
“Utility” includes natural gas, electric, telephone and telecommunications, cable
communications, water, sanitary sewer or storm drainage and their respective facilities, lines,
pipes, mains, equipment and appurtenances.
“Variance” means permission to depart from the requirements of the speciflc regulations of this
title for a particular piece of property.
“Volcanic hazard areas” means areas identifled by the U.S. Geological Survey (maps dated 1998
or as hereafter revised) as subject to a risk of large lahars with a recurrence interval of 500 to
1,000 years.
"Watercourse" as deflned in WAC 220-660-030(154).
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
“Water dependent use” means a principal use which can only exist when the land/water
interface provides biological or physical conditions necessary for the use.
“Wellhead Pprotection Aarea” means the portion of a well’s, wellfleld’s or spring’s zone of
contribution within the 6-month, 1-year, 5-year, and 10-year time of travel boundary, or
boundaries established using alternate criteria approved by the State Department of Health in
those settings where groundwater time of travel is not a reasonable delineation criterion.
“Wetland” or “wetlands” means areas that are inundated or saturated by surface water or
groundwater at a frequency and duration sufficient to support, and that under normal
circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil
conditions. Wetlands generally include swamps, marshes, bogs, and similar areas. Wetlands do
not include those artiflcial wetlands intentionally created from nonwetland sites, including but
not limited to irrigation and drainage ditches, grass-lined swales, canals, detention facilities,
wastewater treatment facilities, farm ponds, and landscape amenities, or those wetlands
created after July 1, 1990, that were unintentionally created as a result of the construction of a
road, street, or highway. Wetlands may include those artiflcial wetlands intentionally created
from nonwetland areas created to mitigate conversion of wetlands. (Deflnition taken from RCW
36.70A.030(23).) Wetlands shall be classifled and rated according to the Washington State
Wetland Rating System for Western Washington: 2014 Update, Version 2.0 or latest approved
by Ecology.
“Wetland impact assessment report” means a report prepared by a qualifled
professionalconsultant that identifles, characterizes and analyzes potential impacts to wetlands
consistent with applicable provisions of these regulations. A wetland impact assessment may
be combined with and include a formal wetland delineation.
“Wetland mosaic” means an area with a concentration of multiple small wetlands, in which each
patch of wetland is less than one acre; on average, patches are less than 100 feet from each
other; and areas delineated as vegetated wetland are more than 50 percent of the total area of
the entire mosaic, including uplands and open water.
“Wildlife report” means a report prepared by a qualifled professionalconsultant that evaluates
plant communities and wildlife functions and values on a site, consistent with the format and
requirements established by this chapter. The report also includes an analysis of impacts. (Ord.
6733 § 3 (Exh. B), 2019; Ord. 6287 § 2, 2010; Ord. 5894 § 1, 2005.)
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
16.10.030 Applicability – Regulated activities.
A. The provisions of this chapter shall apply to any activity that potentially affects a critical area
or its buffer unless otherwise exempt. Such regulated activities include but are not limited to:
1. Removing, excavating, disturbing or dredging soil, sand, gravel, minerals, organic
matter, or materials of any kind;
2. Dumping, discharging or fllling with any material;
3. Draining, fiooding or disturbing the water level or water table, or diverting or impeding
water fiow;
4. Driving pilings or placing obstructions;
5. Constructing, reconstructing, demolishing, or altering the size of any structure or
infrastructure;
6. Destroying or altering vegetation through clearing, grading, harvesting, shading, or
planting vegetation that would alter the character of or impact a critical area;
7. Release of contaminants to soil or water;
8. Activities that result in signiflcant changes in water temperature, physical or chemical
characteristics of water sources, including quantity and pollutants; and
89. Any other activity potentially affecting a critical area or buffer not otherwise exempt
from the provisions of this chapter as determined by the director.
9. Activities that result in:
a. A signiflcant change of water temperature,
b. A signiflcant change of the physical or chemical characteristics of the sources of water
to the wetland,
c. A signiflcant change in the timing, frequency, depth, or duration of water entering or
within the wetland,
d. Immediate and substantial erosion and/or sediment transport of surface soils,
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
e. Sloughing of exposed surface soils,
f. The emergence, or an increase in the fiow, of water seeps or springs,
B. To avoid duplication, the following permits and approvals shall be subject to and
coordinated with the requirements of this chapter: land clearing; grading; subdivision or short
subdivision; building permit; planned unit development (if permitted by the city code); shoreline
substantial development; variance; conditional use permit; and any other permits that may lead
to the development or alteration of land.
C. Administrative actions, such as rezones, annexations, and the adoption of plans and
programs, shall be subject to the requirements of this chapter. However, the director may,
using discretion, permit any studies or evaluations required by this chapter to use
methodologies and provide a level of detail appropriate to the administrative action proposed.
(Ord. 6733 § 3 (Exh. B), 2019; Ord. 6187 § 3, 2008; Ord. 5991 § 3, 2006; Ord. 5894 § 1, 2005.)
16.10.040 Exemptions and nonconforming uses.
A. The following activities performed on sites containing critical areas as deflned by this
chapter shall be exempt from the provisions of this chapter:
1. Existing and ongoing agricultural activities, as deflned in this chapter;
2. Activities involving artiflcially created wetlands or streams intentionally created from
nonwetland sites, including but not limited to grass-lined swales, irrigation and drainage
ditches, retention or detention facilities, and landscape features, except wetlands or
streams created as mitigation or that provide critical habitat for salmonids and except
when the site contains another critical area;
3. Normal and routine maintenance, operation, repair and reconstruction of existing
roads, streets, utilities and associated structures; provided, that reconstruction of any
structures may not increase the impervious area and may not cause further encroachment
on the critical area or its buffer, and may not result in adverse impacts to surface water and
groundwater quality. Operation and maintenance includes vegetation management
performed in accordance with best management practices that is part of ongoing
maintenance of structures, infrastructure, or utilities; provided, that such management
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Chapter 16.10 ACC, Critical Areas Page 21 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
actions are part of regular and ongoing maintenance, do not expand further into the critical
area, are not the result of an expansion of the structure or utility, and do not directly
impact an endangered or threatened species;
4. Minor Utility and Street Projects. Utility or street projects which have minor or short
duration impacts to critical areas, as determined by the director in accordance with the
criteria below, and which do not signiflcantly impact the functions or values of a critical
area(s); as determined through a critical areas report; provided, that such projects are
constructed with best management practices and additional restoration measures are
provided through a mitigation plan. Minor activities shall not result in the transport of
sediment or increased storm water. Such allowed minor utility projects shall meet the
following criteria:
a. There is no practical alternative to the proposed activity with less impact on critical
areas;
b. The activity involves the placement of underground piping, conduit, traffic signal
equipment, lighting equipment, utility pole(s), signs, anchor, or vault or other small
component of a utility or street facility;
5. Normal maintenance, repair and reconstruction of residential or commercial structures,
facilities and landscaping; provided, that reconstruction of any structures may not increase
the previous fioor area;
6. The addition of fioor area within an existing building which does not increase the
building footprint;
7. A one-time Aadditions to a legally established single-family residential structure in
existence before May 13, 2005, located within a wetland or stream buffer may be permitted
if all of the following criteria area met:
a. The addition is no greater than 500 square feet of building footprint over that in
existence as of May 13, 2005;
b. The addition is not located closer to the critical area than the existing structure;
c. The addition is consistent with other applicable development regulations;
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Chapter 16.10 ACC, Critical Areas Page 22 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
dc. Impacts on critical area functions are avoided consistent with the purpose and
intent of this title and as demonstrated in a critical areas report by a qualifled
professional and as applicable mitigated through an approved mitigation
planconsultant; and
ed. There are no changes in slope stability, fiood conditions or drainage; Demonstrate
through analysis by qualifled professionals that other existing property conditions
covered by this title (e.g. – slope stability, fiood conditions, drainage) have not changed
with the proposed addition;
8. Site investigative work and studies that are prerequisite to preparation of an application
for development authorization including soils tests, water quality studies, wildlife studies
and similar tests and investigations; provided, that any disturbance of the critical area shall
be the minimum necessary to carry out the work or studies;
9. Educational activities, scientiflc research, and outdoor passive recreational activities,
including but not limited to interpretive fleld trips, birdwatching and hiking, that will not
have a signiflcant effect on the critical area;
10. Emergency activities necessary to prevent an immediate threat to public health, safety,
property or the environment which requires immediate action within a time too short to
allow full compliance with this chapter as long as any alteration undertaken pursuant to
this subsection is reported to the city as soon as possible. Only the minimum intervention
necessary to reduce the risk to public health, safety or welfare and/or the imminent risk of
damage to private property shall be authorized by this exemption. The director shall
conflrm that an emergency exists or existed and determine what, if any, additional
applications and/or measures shall be required to protect the environment consistent with
the provision of this section and to repair any damage to a pre-existing resource; the
director shall determine a time limit between 1-2 years for restoration, rehabilitation, or
replacement to minimize temporal loss of critical area functions and values;
11. Activities affecting previously legally fllled wetlands;
12. Activities in storm and water quality basins and “wetlands” created by poorly
maintained or plugged culverts or pipeslines, and artiflcially created ditches that are not
used by flshsalmonids;
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Chapter 16.10 ACC, Critical Areas Page 23 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
13. Minor activities not mentioned above and determined by the director to have minimal
impacts to a critical area, will not result in no net loss of ecological values and functions,
and are constructed with best management practices and additional restoration measures
are provided through a mitigation plan.
B. Notwithstanding the exemptions provided by this subsection, any otherwise exempt
activities occurring in or near a critical area shall comply with the purpose and intent of these
standards and shall consider on-site alternatives that avoid or minimize signiflcant adverse
impacts.
C. Exempt activities occurring in fiood hazard areas shall not alter fiood storage capacity or
conveyance except in conformance with fioodplain requirements of Chapter 15.68 ACC.
D. No property owner or other entity shall undertake exempt activities in subsection (A)(2), (7)
or (13) of this section without flrst providing 14 calendar days’ notice to the city in writing and
receiving conflrmation in writing that the proposed activity is exempt. In case of any question as
to whether a particular activity is exempt from the provisions of this section, the director’s
determination shall govern and shall be conflrmed in writing.
E. An established use or existing structure that was lawfully permitted prior to May 13, 2005,
but which is not in compliance with this chapter, shall be deemed a nonconforming use as
deflned in ACC 18.04.650. Unless otherwise provided for, existing structures, which intrude into
critical areas buffers, shall not be reconstructed in such a manner that results in the further
intrusion into the buffer area. Structures or developments that are nonconforming solely due
to being contrary to the provisions of this chapter shall not be subject to the nonconforming
use provisions of Chapter 18.54 ACC. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 5894 § 1, 2005.)
16.10.050 Critical areas maps.
Maps have been developed by the city that show the general location of critical areas. These
maps are available for reference at the city department of community development. These
maps shall be used for informational purposes as a general guide only for the assistance of
property owners and other interested parties; the boundaries and locations shown are
generalized. The actual presence or absence, type, extent, boundaries and classiflcation of
critical areas on a speciflc site shall be identifled in the fleld by a qualifled
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Chapter 16.10 ACC, Critical Areas Page 24 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
professionalconsultant and determined by the city, according to the procedures, deflnitions
and criteria established by this chapter. In the event of any confiict between the critical area
location or designation shown on the city’s maps and the criteria or standards of this section,
the criteria, deflnition, and standards shall prevail. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6287 § 2, 2010;
Ord. 5894 § 1, 2005.)
16.10.060 Relationship to other regulations.
A. These critical area regulations shall apply as an overlay and in addition to zoning, land use
and other regulations established by the city of Auburn. In the event of any confiict between
these regulations and any other regulations of the city, the regulations which provide greater
protection to critical areas shall apply.
B. Areas characterized by particular critical areas may also be subject to other regulations
established by this chapter due to the overlap or multiple functions of some sensitive or critical
areas. Wetlands, for example, may be deflned and regulated according to the wetland, habitat
and stream management provisions of this chapter. In the event of any confiict between
overlapping regulations for multiple critical areas on the same site, the regulations which
provide greater protection to critical areas shall apply.
C. Compliance with the provisions of this chapter does not constitute compliance with other
federal, state, and local regulations and permit requirements that may be required (for
example, shoreline substantial development permits, hydraulic project approval (HPA) permits,
Army Corps of Engineers Section 404 permits, National Pollutant Discharge Elimination System
(NPDES) permits). The applicant is responsible for complying with these requirements, apart
from the process established in this chapter. Where applicable, the director will encourage use
of information such as permit applications to other agencies or special studies prepared in
response to other regulatory requirements to support required documentation submitted for
critical areas review. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 5894 § 1, 2005.)
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
16.10.070 Critical area review process and application requirements.
A. Pre-Application Conference. A pre-application conference meeting is available and
encouraged prior to submitting an application for a project permit.
B. Application Requirements.
1. Timing of Submittals. Concurrent with submittal of a State Environmental Policy Act
(SEPA) checklist, or concurrent with submittal of an application for projects exempt from
SEPA, a critical area report must be submitted to the city for review when the city believes
that a critical area may be present. The purpose of the report is to determine the extent,
characteristics and functions of any critical areas located on or potentially affected by
activities on a site where regulated activities are proposed. The report will also be used by
the city to determine the appropriate critical area classiflcation and, if applicable, to
establish appropriate buffer requirements.
2. Report Contents. Reports and studies required to be submitted by this chapter shall
contain, at a minimum, the information indicated in the provisions of this chapter
applicable to each critical area. The director may tailor the information required to refiect
the complexity of the proposal and the sensitivity of critical areas that may potentially be
present.
C. Consultant Qualiflcations and City Review. All reports and studies required of the applicant by
this section shall be prepared by a qualifled professionalconsultant as that term is deflned in
these regulations. The city may retain a qualifled professionalconsultant paid for by the
applicant to review and conflrm the applicant’s reports, studies and plans if the following
circumstances exist:
1. The city has technical information that is unavailable to the applicant; or
2. The applicant has provided inaccurate or incomplete information on previous proposals
or proposals currently under consideration.
D. Review Process. This section is not intended to create a separate critical area review permit
for development proposals. To the extent possible, the city shall consolidate and integrate the
review and processing of critical area-related aspects of proposals with other land use and
environmental considerations and approvals. Any permits required by separate codes or
regulations, such as fioodplain development permits or shoreline substantial development
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
permits, shall continue to be required. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6295 § 4, 2010; Ord. 5894 § 1,
2005.)
16.10.080 Classification and rating of critical areas.
A. To promote consistent application of the standards and requirements of this chapter,
critical areas within the city of Auburn shall be rated or classifled according to their
characteristics, function and value, and/or their sensitivity to disturbance.
B. Classiflcation of critical areas shall be determined by the director based on consideration of
the following factors and in the following order:
1. Consideration of the technical reports submitted by qualifled professionalsconsultants
in connection with applications subject to these regulations;
2. Application of the criteria contained in these regulations; and
3. Critical areas maps maintained by the department of community development.
C. Classiflcation shall incorporate Best Available Science as deflned under WAC 365‑195‑900.,
and utilize statewide classiflcation schemes, such as Ecology’s Wetland Rating System, WDFW
Priority Habitats and Species maps, and the Washington Geologic Information Portal.
DC. Wetland Classiflcation. Wetlands shall be rated according to the Washington Department of
Ecology wetland rating system, as set forth in the Washington State Wetland Rating System for
Western Washington: 2014 Update, Version 2.0,2014 Update (Ecology Publication No. 14-06-
029, or as revised and approved by Ecology). Wetland rating categories shall not change due to
illegal modiflcations.
1. “Category I wetlands” include wetlands which: represent unique or rare wetland types,
are more sensitive to disturbance than most wetlands, are relatively undisturbed and
contain ecological attributes that are impossible to replace within a human lifetime, or
provide a high level of functions, as indicated by a rating system score of 23 points or more
on the classiflcation system referenced above.
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2. “Category II wetlands” provide high levels of some functions, being difficult, though not
impossible to replace, and have a moderately high level of functions, scoring between 20
and 22 points.
3. “Category III wetlands” have a score between 16 and 19 points, generally have been
disturbed in some way and are often less diverse or more isolated from other natural
resources in the landscape than Category II wetlands.
4. “Category IV wetlands” have the lowest levels of functions, scoring fewer than 16 points
and are often heavily disturbed. These are wetlands that should be able to be replaced, or
in some cases be improved. However, experience has shown that replacement cannot be
guaranteed in any speciflc case. These wetlands may provide some important functions,
and should be protected to some degree.
5. “Artiflcially created wetlands” are purposefully created landscape features, ponds and
storm water detention or retention facilities. Artiflcially created wetlands do not include
wetlands created as mitigation, and wetlands modifled for approved land use activities.
Purposeful creation must be demonstrated to the director through documentation,
photographs, statements and/or other evidence. Artiflcial wetlands intentionally created
from nonwetland sites are excluded from regulation under this section.
ED. Stream Classiflcation. Streams shall be classifled according to the water typing system as
provided in WAC 222-16-030, as amended, and designated as Type S, Type F, Type Np, and Type
Ns.
1. “Type S streams” are those natural streams identifled as “shorelines of the state” under
Chapter 90.58 RCW and the city of Auburn shoreline master program.
2. “Type F streams” are those natural streams that are not Class I streams and are either
perennial or intermittent and have one of the following characteristics:
a. Contain flsh habitat; or
b. Has signiflcant recreational value, as determined by the director.
3. “Type Np streams” are those natural streams with perennial (year-round) or
intermittent fiow and do not contain flsh habitat.
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4. “Type Ns streams” are those natural streams and drainage swales with channel width
less than two feet taken at the ordinary high water mark, that do not contain flsh habitat.
5. “Intentionally created streams” are those manmade streams deflned as such in these
regulations, and do not include streams created as mitigation. Purposeful creation must be
demonstrated through documentation, photographs, statements and/or other evidence.
Intentionally created streams may include irrigation and drainage ditches, grass-lined
swales and canals. Intentionally created streams are excluded from regulation under this
section, except manmade streams that provide “critical habitat,” as designated by federal
or state agencies, for salmonids, or streams that contain flsh. Intentionally created streams
must install flsh exclusion devices when applicable.
FE. Fish and Wildlife Habitat Conservation Areas.Wildlife Habitat Classiflcation. Land managed to
maintain populations of species in suitable habitats within their natural geographic distribution
so that the habitat available is sufficient to support viable populations over the long term and
isolated subpopulations are not created. Fish and Wildlife habitat conservation areas are listed
in WAC 365-190-130 and the following list are those that are present in the City of Auburn: shall
be classifled as critical, secondary or tertiary according to the criteria in this section:
1. “Critical habitat” are those habitat areas which meet any of the following criteria:
a. Areas where endangered, threatened, and sensitive species have a primary
association;The documented presence of species or habitat listed by federal or state
agencies as “endangered,” “threatened,” or “sensitive”; or
b. The presence of unusual nesting or resting sites such as heron rookeries;
c. Category I wetlands, as deflned in these regulations; or
d. Waters of the State or Type S streams, as deflned in these regulations.
e. Streams and rivers planted with game flsh by a governmental or tribal entity; and
f. Habitats and species of local importance.
2. “Priority habitat” are those habitat areas that require protective measures due to their
sensitivity, rarity, or ecological importance, and “Secondary habitat” is habitat which is
valuable to flsh and wildlife and supports a wide variety of species due to its undisturbed
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nature, a diversity of plant species and structure, presence of water, or the area’s size,
location, or seasonal importance.
3. “Tertiary habitat” is habitat which is not classifled as critical or secondary. It is habitat
which, while supporting some wildlife and performing other valuable functions, does not
currently possess essential characteristics necessary to support diverse wildlife
communities. Tertiary habitat also includes habitat which has been created purposefully by
human actions to serve other or multiple purposes, such as open space areas, landscape
amenities, and detention facilities.
GF. Aquifer Recharge Areas. The following areas are hereby designated as aquifer recharge
areas subject to review under this chapter:
1. Type I.
a. Sole source aquifers and wellhead protection areas designated pursuant to the
Federal Safe Drinking Water Act and WAC 246-290-135.
b. Areas established for special protection pursuant to a groundwater management
program as described by Chapters 90.44, 90.48 and 90.54 RCW and Chapters 173-100
and 173-200 WAC.
c. Any other area meeting the deflnition of “areas with a critical recharging effect on
aquifers used for potable water” as described in Chapter 365-190 WAC and the Auburn
comprehensive plan, including groundwater protection areas Nos. 1 through 3 as
designated in the “Water Resource Protection Report” prepared for the city by the
Paciflc Groundwater Group, December 2000.
2. Type II.
a. Groundwater protection area No. 4 as designated in the “Water Resource
Protection Report” prepared for the city by the Paciflc Groundwater Group, December
2000.
b. Any other area within the city that is not otherwise designated or that is added to
the city via annexation shall be treated as a Type II aquifer recharge area.
G. Geologic ally Hazard Areaous Classiflcations. Geologically hazardous areas shall be classifled
according to the criteria in this section:
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1. Critical Erosion Hazard Areas. Critical erosion hazard areas are lands or areas underlain
by soils identifled by the U.S. Department of Agriculture Soil Conservation Service (SCS),
now known as the Natural Resources Conservation Service, as having “severe” or “very
severe” erosion hazards. This includes the following group of soils when they occur on
slopes of 15 percent or greater: Alderwood-Kitsap (AkF), Alderwood gravelly sandy loam
(AgD), Kitsap silt loam (KpD), Everett (EvD), and Indianola (InD).
2. Landslide Hazard Areas. Landslide hazard areas are classifled as Class I, Class II, Class III,
or Class IV as follows:
a. Class I/Low Hazard. Areas with slopes of 15 percent or less.
b. Class II/Moderate Hazard. Areas with slopes of between 15 percent and 40 percent
and that are underlain by soils that consist largely of sand, gravel, or glacial till.
c. Class III/High Hazard. Areas with slopes between 15 percent and 40 percent that are
underlain by soils consisting largely of silt and clay.
d. Class IV/Very High Hazard. Areas with slopes steeper than 15 percent with mappable
zones of emergent water (e.g., springs or groundwater seepage), areas of known
(mappable) landslide deposits regardless of slope, and all areas with slopes 40 percent
or greater.
3. Seismic Hazard Areas. Seismic hazard areas are lands that, due to a combination of soil
and groundwater conditions, are subject to severe risk of ground shaking, subsidence, or
liquefaction of soils during earthquakes. These areas are typically underlain by soft or loose
saturated soils (such as alluvium), have a shallow groundwater table and are typically
located on the fioor of river valleys. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6287 § 2, 2010; Ord. 5894 § 1,
2005.)
16.10.090 Buffer areas and setbacks.
A. General Provisions. The establishment of on-site buffers, buffer areas or setbacks shall be
required for all development proposals and activities in or adjacent to wetlands, streams, flsh
and wildlife habitat conservation areas, and geologically hazardous areas. The purpose of the
buffer shall be to protect the integrity, function, value, and resources of the subject critical area
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(in the case of wetlands, streams, and/or flsh and wildlife habitat conservation areas), and/or to
protect life, property and resources from risks associated with development on unstable or
critical lands (in the case of geologically hazardous areas). Buffers shall typically consist of an
undisturbed area of native vegetation retained or established to achieve the purpose of the
buffer. No buildings or structures shall be allowed within the buffer unless as otherwise
permitted by this section. If the site has previously been disturbed, the buffer area shall be
revegetated pursuant to an approved enhancement plan. Buffers shall be protected during
construction by placement of a temporary barricade, notice of the presence of the critical area
and implementation of appropriate erosion and sedimentation controls. Restrictive covenants
or conservation easements may be required to provide long-term preservation and protection
of buffer areas.
B. Required buffer widths shall refiect the sensitivity of the particular critical area and resource
or the risks associated with development and, in those circumstances permitted by these
regulations, the type and intensity of human activity proposed to be conducted on or near the
critical area.
C. Buffers shall be measured as follows:
1. Wetland buffers – the buffer shall be measured perpendicular from the wetland edge as
delineated and marked in the fleld using the approved federal wetland delineation manual
and the Western Mountains, Valleys, and Coast Regional supplement. Wetland delineations
are valid for flve years; after such date the city shall determine whether a revision or
additional assessment is necessary;
2. Stream buffers – the buffer shall be measured perpendicular from the ordinary high
water mark;
3. Geologically hazardous area buffers shall be required for critical landslide hazard areas
and shall be measured from the top and toe and along the sides of the slope.
D. Buffer Width Variances. A variance from buffer width requirements may be granted by the
city subject to the variance criteria set forth in ACC 16.10.160. Minor variances, deflned as up to
and including 10 percent of the requirement, shall be considered by the director. Variance
requests which exceed 10 percent shall be considered by the hearing examiner. Variances to
buffer widths can only be made to the standard buffer widths noted in ACC 16.10.090(E)(1)(a)(ii)
and cannot be combined with buffer averaging provisions of ACC 16.10.090(E)(1)(b).
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E. Buffer widths shall be established for speciflc critical areas according to the following
standards and criteria:
1. Wetland buffers shall be established per the following table. Different buffer width
requirements may apply to various portions of a site, without requiring averaging or
variances, based on the site plan, the intensity of land uses in various locations, and
differences in the category of wetland.
Wetland
Category
Minimum Buffer Width (in feet) with
Minimization Measures Listed in ACC
16.10.090(E)(1)(a)(iii)
Minimum Buffer Width (in feet) without
Minimization Measures Listed in ACC
16.10.090(E)(1)(a)(iii)
Habitat Score* Habitat Score*
Low (3-5) Medium (6-7) High (8-9) Low (3-5) Medium (6-7) High (8-9)
Category I 75 110 225 100 150 300
Category II 75 110 225 100 150 300
Category III 60 110 225 80 150 300
Category IV 40 40 40 50 50 50
* As determined per ACC 16.10.080(C).
a. Standard buffer widths as noted in subsection (E)(1) of this section in the table
heading “without Minimization Measures” may be reduced to the buffer width in the
table heading “with Minimization Measures,” if all of the following minimization
measures are implemented and as follows:
i. The reduced buffer widths from implementing the minimization measures in
table ACC 16.10.090E(1)(a)(ii) cannot be further reduced by critical areas variance
or buffer averaging.
ii.ForFor wetlands that score six points or more for habitat function, a relatively
undisturbed, vegetated riparian corridor at least 100 feet wide between the
wetland and any other priority habitat as deflned by the Washington Department
of Fish and Wildlife (WDFW). is protected between the wetland and any other
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Priority Habitats as deflned by the Washington State Department of Fish and
Wildlife. The corridor must be protected for the entire distance between the
wetland and the Priority Habitat consistent with ACC 16.10.110(ED). Presence or
absence of a nearby habitat must be conflrmed by a qualifled biologist.
iii. For wetlands that score three to flve habitat points, only the minimization
measures are required. The following minimization measures are applicable to
wetlands and streams and stream buffers (riparian management zones).
Disturbance Required Measures to Minimize Impacts
Lights – Direct lights away from wetland
Noise – Locate activity that generates noise away from wetland
– If warranted, enhance existing buffer with native vegetation plantings adjacent to noise
source
– For activities that generate relatively continuous, potentially disruptive noise, such as
certain heavy industry or mining, establish an additional 10-foot heavily vegetated buffer
strip immediately adjacent to the activity
Toxic runoff – Route all new, untreated runoff away from wetland while ensuring wetland is not
dewatered
– Establish covenants limiting use of pesticides within 150 feet of wetland
– Apply integrated pest management
Storm water
runoff
– Retroflt storm water detention and treatment for roads and existing adjacent
development
– Prevent channelized fiow from lawns that directly enters the buffer
– Use Low Intensity Development techniques
Change in water
regime
– Inflltrate or treat, detain, and disperse into buffer new runoff from impervious surfaces
and new lawns
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Disturbance Required Measures to Minimize Impacts
Pets and human
disturbance
– Use privacy fencing or plant dense vegetation to delineate buffer edge and to discourage
disturbance using vegetation appropriate for the ecoregion
– Place wetland and its buffer in a separate tract or protect with a long-term conservation
easement
Dust – Use best management practices to control dust
Examples of
disturbances
Activities and uses that cause
disturbances
Examples of measures to minimize impacts
Lights • Parking lots
• Commercial/Industrial
• Residential
• Recreation (e.g., athletic fields)
• Agricultural buildings
• Direct lights away from wetland/stream
• Only use lighting where necessary
for public safety and keep lights off when not
needed
• Use motion-activated lights
• Use full cut-off filters to cover light bulbs and
direct light only where needed
• Limit use of blue-white colored lights
in favor of red-amber hues
• Use lower-intensity LED lighting
• Dim light to the lowest acceptable
intensity
Noise • Commercial
• Industrial
• Recreation (e.g., athletic fields,
bleachers, etc.)
• Residential
• Agriculture
• Locate activity that generates noise
away from wetland/stream
• Construct a fence to reduce noise
impacts on adjacent wetland/stream and
buffer
• Plant a strip of dense shrub
vegetation adjacent to wetland/stream
buffer
Toxic runoff • Parking lots
• Roads
• Commercial/industrial
• Residential areas
• Application of pesticides
• Landscaping
• Agriculture
• Route all new, untreated runoff away
from wetland and/or stream and buffer while
ensuring wetland and/or stream is not dewatered
• Establish covenants limiting use of
pesticides within 150 ft. of wetland and/or stream
and buffer
• Apply integrated pest management
(Note: These examples are not
necessarily adequate for minimizing
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toxic runoff if threatened or endangered
species are present at the site.)
Stormwater
runoff
• Parking lots
• Roads
• Residential areas
• Commercial/industrial
• Recreation
• Landscaping/lawns
• Other impermeable surfaces,
compacted soil, etc.
Retrofit stormwater detention and
treatment for roads and existing adjacent
development
• Prevent channelized or sheet flow
from lawns that directly enter the
buffer
• Infiltrate or treat, detain, and disperse
new runoff from impervious surfaces
and lawns
Pets and human
disturbances
• Residential areas
• Recreation
• Use privacy fencing
• Plant dense native vegetation to
delineate buffer edge and to
discourage disturbance
• Place wetland/stream and its buffer in a
separate tract
• Place signs around the wetland and/or stream and
buffer every 50-200 ft., and for subdivisions place
signs at the back of each residential lot
• When platting new subdivisions,
locate greenbelts, stormwater
facilities, or other lower-intensity land
uses adjacent to wetland/stream and buffers
Dust • Tilled fields
• Roads
• Use best management practices to
control dust
b. Buffer averaging to improve wetland protection may be permitted when all of the
following conditions are met:
i. The wetland has signiflcant differences in characteristics that affect its habitat
functions, such as a wetland with a forested component adjacent to a degraded
emergent component or a “dual-rated” wetland with a Category I area adjacent to
a lower-rated area.
ii. The buffer is increased adjacent to the higher-functioning area of habitat or
more sensitive portion of the wetland and decreased adjacent to the lower-
functioning or less sensitive portion as demonstrated by a critical areas report
from a qualifled wetland professional.
iii. The total area of the buffer after averaging is equal to the area required
without averaging.
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iv. The buffer at its narrowest point is never less than either 75 percent of the
required width or 75 feet for Category I and II, 50 feet for Category III, and 25 feet
for Category IV, whichever buffer is greater.
v. Averaging applies only to standard buffer widths, not reduced widths.
c. Certain uses and activities which are consistent with the purpose and function of
the wetland buffer and do not detract from its integrity may be permitted by the
director within the buffer depending on the sensitivity of the wetland. Examples of
uses and activities with minimal impacts which may be permitted in appropriate cases
include permeable pedestrian trails, viewing platforms, and utility easements. Trails
and easements should be limited to minor crossings having no adverse impact on
water quality. They should be generally parallel to the perimeter of the wetland,
located only in the outer 25 percent of the wetland buffer area, and located to avoid
removal of signiflcant trees. Trails should be limited to pervious surfaces no more than
eight feet in width for pedestrian use only. Raised boardwalks utilizing nontreated
pilings may be acceptable.
d. Where existing buffers are degraded, the director may allow limited fllling within
the buffer when the applicant demonstrates that the buffer will be enhanced according
to standards of this chapter, including revegetation, appropriate soil preparation, will
not result in slopes exceeding 25 percent, and there will be no net loss of wetland or
buffer functions and values.
e. Functionally Disconnected Buffer Areas. Buffers may exclude areas that are
functionally and effectively disconnected from the wetland by an existing public or
private road or legally established development, as determined by the director.
Functionally and effectively disconnected means that the road or other signiflcant
development blocks the protective measures provided by a buffer.
Signiflcant developments shall include built public infrastructure such as roads and
railroads, and private developments such as homes or commercial structures. The
director shall evaluate whether the interruption will affect the entirety of the buffer.
Individual structures may not fully interrupt buffer function. In such cases, the
allowable buffer exclusion should be limited in scope to just the portion of the buffer
that is affected. Where questions exist regarding whether a development functionally
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disconnects the buffer, or the extent of that impact, the director may require a critical
area report to analyze and document the buffer functionality.
2. Stream buffers (riparian management zones) shall be established as follows:
Stream Type Minimum Buffer
Width (in feet)
Increased Buffer
Width (in feet) 1
(Applicable when the
buffer does not meet
vegetation standards
of ACC
16.10.090(E)(2)(a)
Type S Per SMP Per SMP
Type F 15000 200
Type Np 10050 133
Type Ns 10050 133
1 In addition to ESA review, an increase applies if the applicant does not implement applicable minimization
measures under ACC 16.10.090(E)(1)(a)(iii) and does not meet vegetated buffer standards.
a. The applicable minimum buffer for Type S streams is listed in the city’s shoreline
master program (SMP). Required buffer widths for all other types are established
based upon stream type. The minimum buffer widths in the table above assume the
buffer is vegetated with a native plant community appropriate for the ecoregion. To be
considered fully functioning, a stream buffer (riparian management zone) must
contain:
i. An average of eighty percent (80%) native vegetation cover, with no more than
ten percent (10%) noxious weed cover; and
ii. A native plant community that includes tree, shrub, and groundcover strata in
proportions that mimic native forest for the region.
b. If the existing buffer does not meet the vegetative buffer standards above, the
buffer must be:
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i. Densely planted to create the appropriate native plant community through the
implementation of a buffer enhancement plan per ACC 16.10.110;
ii. Include impact minimization measures described in ACC 16.10.090(E)(1)(a)(iii);
and
iii. If applicable, a habitat corridor is provided connecting the habitats described
in ACC 16.10.090(E)(a)(ii); or
iv. Be widened by thirty-three percent (33%) to ensure that the buffer provides
adequate functions to protect the stream.
cb. The minimum buffer widths required in this section may be increased by the
director up to a maximum of 3350 percent for Type F, and Ns, and Np streams and up
to 100 percent for Type Np streams in response to site-speciflc conditions and based
on the report information submitted to characterize the functions and values of the
stream. This includes, but is not limited to, situations where the critical area serves as
habitat for areas where endangered, threatened, and sensitive species have a primary
association threatened, endangered or sensitive species. The applicant may propose to
implement one or more enhancement measures, listed in order of preference below,
which will be considered in establishing buffer requirements:
i. Removal of flsh barriers to restore accessibility to anadromous flsh.
ii. Enhancement of flsh habitat using log structures incorporated as part of a flsh
habitat enhancement plan.
iii. Enhancement of wildlife habitat by adding structures that are likely to be used
by wildlife, including wood duck houses, bat boxes, nesting platforms, snags, root
wads/stumps, birdhouses, and heron nesting areas.
iv. Additional mitigating measures may include but are not limited to:
(A) Landscaping outside the buffer area with native vegetation or a reduction
in the amount of clearing outside the buffer area;
(B) Planting native vegetation within the buffer area, especially vegetation
that would increase value for flsh and wildlife, increase stream bank or slope
stability, improve water quality, or provide aesthetic/recreational value;
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(C) Creating a surface channel where a stream was previously culverted or
piped;
(D) Removing or modifying existing stream culverts (such as at road
crossings) to improve flsh passage and fiow capabilities which are not
detrimental to flsh;
(E) Upgrading retention/detention facilities or other drainage facilities beyond
required levels; or
(F) Similar measures determined applicable by the director.
c. No structures or improvements shall be permitted within the stream buffer area,
including buildings, decks, docks, except as otherwise permitted or required under the
city’s adopted shoreline master program, or under one of the following circumstances:
i. When the improvements are part of an approved enhancement, restoration or
mitigation plan; or
ii. For construction of new public roads and utilities, and accessory structures,
when no feasible alternative location exists; or
iii. Construction of foot trails, according to the following criteria:
(A) Designed to minimize impact of permeable materials;
(B) Designed to minimize impact on the stream system;
(C) Of a maximum width of 12 feet;
(D) Located within the outer half of the buffer, i.e., the portion of the buffer
that is farther away from the stream; or
iv. Construction of footbridges; or
v. Construction of educational facilities, such as viewing platforms and
informational signs.
d. Buffer width averaging may be allowed for Type F and Type Np streams only;
provided, that all of the following are demonstrated by the applicant:
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i. One or more of the enhancement measures identifled in subsections (E)(2)(b)(i)
through (E)(2)(b)(iv) of this section are implemented;
ii. The total area contained within the buffer after averaging is no less in area than
contained within the standard buffer prior to averaging;
iii. The buffer width averaging will result in stream functions and values equal or
greater than before averaging; and
iv. The buffer width is not reduced by more than 25 percent in any location than
the buffer widths established by this chapter.
e. Stream buffer widths may be reduced by the director on a case-by-case basis by up
to 25 percent if an applicant demonstrates that a reduction will not result in any
adverse impact to the stream. Further, if an existing buffer is vegetated, a buffer
enhancement plan may be required to demonstrate how the function and values of
the buffer and stream will be improved. If the existing buffer has been disturbed
and/or is not vegetated, an enhancement plan shall be required that identifles
measures to enhance the buffer functions and values and provide additional
protection for the stream function and values. Enhancement plans are subject to
approval by the director.
e. Functionally Disconnected Buffer Areas. If a portion of a stream buffer (riparian
management zone) is determined to be functionally disconnected or isolated and
physically separated from the watercourse due to existing, legally established public
roadways public roadways, railroads, or other legally established structures, the
director may exclude this area from a riparian management zone provided:
i. The area does not provide any of the primary riparian management zone
functions of bank stability, shade, pollution control, wildlife habitat corridor
connection, or recruitment of large woody debris;
ii. A critical areas report conflrms the area of the riparian management zone as
being functionally isolated and physically separated from the watercourse.
3. Fish and Wildlife Habitat Conservation Areas.
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a. Buffer widths for critical habitat areas shall be determined by the director based on
consideration of the following factors: species recommendations of the Department of
Fish and Wildlife; recommendations contained in the wildlife report and the nature and
intensity of land uses and activities occurring on the site and on adjacent sites. Buffers
shall not be required for secondary or tertiary habitat. When designated Priority
Habitat or Species are present, buffer widths shall conform to the best available
science guidance. The director may require a critical area report prepared by a
qualifled professional to document compliance.
b. Buffer widths for critical habitat areas may be modifled by averaging buffer widths
or by enhancing or restoring buffer quality.
bc. Certain uses and activities which are consistent with the purpose and function of
the buffer for critical habitat areas and do not detract from its integrity may be
permitted by the director within the buffer depending on the sensitivity of the habitat
area. Examples of uses and activities with minimal impact which may be permitted in
appropriate cases include permeable pedestrian trails and viewing platforms and
utility easements; provided, that any impacts to the buffer resulting from permitted
facilities shall be mitigated. When permitted, such facilities shall generally be located as
far from the critical habitat area as possible.
4. Geologically Critical Landslide Hazardous Areas.
a. Required buffer widths for critical landslidegeologically hazardous areas shall
refiect the sensitivity of the critical landslidegeologically hazardous area in question
and the types and the risks associated with development and, in those circumstances
permitted by these regulations, the type and intensity of human activity and site design
proposed to be conducted on or near the area.
b. Required buffers may vary in width. The widths of the buffer shall refiect the
sensitivity of the geologically hazardous area in question and the types and density of
uses proposed on or adjacent to the geologic hazard. In determining the appropriate
buffer width, the director shall consider the recommendations contained in any
geotechnical report required by these regulations and prepared by a qualifled
consultant. Minimum buffer width from critical landslide hazard areas shall be equal to
the vertical height of the landslide hazard or 50 feet, whichever is greater, for all critical
landslide hazard areas that measure 10 feet or more in vertical elevation change from
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top to toe of slope, as identifled in the geotechnical report, maps, and fleld-checking.
No disturbance may occur within the buffer except as provided within this chapter.
c. Buffers may be reduced to a minimum width of 15 feet when the applicant
demonstrates through the geotechnical report that the reduction will adequately
protect the critical landslidegeologic hazard area and the proposed development
through use of proposed engineering techniques. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 5894 § 1,
2005.)
d. To increase the functional attributes of the buffer, the department may require that
the buffer be enhanced through planting of indigenous species. (Ord. 6733 § 3 (Exh. B),
2019; Ord. 5894 § 1, 2005.)
16.10.100 Alteration or development of critical areas – Standards and
criteria – Prohibited uses.
Alteration of speciflc critical areas and/or their buffers may be allowed by the director subject to
the criteria of this section. Alteration shall implement the mitigation standards as identifled in
ACC 16.10.110, and the performance standards of ACC 16.10.120 and the monitoring
requirements of ACC 16.10.130.
A. Wetlands.
1. Category I Wetlands. Alterations of Category I wetlands shall be avoided subject to the
reasonable use provisions of this chapter.
2. Category II Wetlands.
a. Alteration and mitigation shall comply with the mitigation performance standards
and requirements of these regulations;
b. Where enhancement, restoration or creation is proposed, replacement ratios shall
comply with the requirements of these regulations; and
c. No net loss of wetland functions and values may occur.
3. Category III and IV Wetlands.
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a. Alteration and mitigation shall comply with the mitigation performance standards
and requirements of these regulations;
b. Where enhancement, restoration or creation is proposed, replacement ratios shall
comply with the requirements of these regulations; and
c. No net loss of wetland functions and values may occur.
d. The following wetlands may be exempt from the requirement to avoid impacts and
they may be fllled if the impacts are fully mitigated based on the remaining actions. If
available, impacts should be mitigated through the purchase of credits from an in-lieu
fee program or mitigation bank, consistent with the terms and conditions of the
program or bank. Mitigation requirements may be determined using the credit/debit
tool described in Calculating Credits and Debits for Compensatory Mitigation in
Wetlands of Western Washington: Final Report (Ecology Publication No. 10-06-011, or
as revised and approved by Ecology). In order to verify the following conditions, a
critical area report for wetlands meeting the requirements in ACC 16.10.060 must be
submitted.
i. All non-federally-regulated Category IV wetlands less than 4,000 square feet
that:
(A) Are not associated with riparian areas or their buffers.
(B) Are not associated with shorelines of the state or their associated buffers.
(C) Are not part of a wetland mosaic.
(D) Do not score six or more points for habitat function based on the 2014
update to the Washington State Wetland Rating System for Western
Washington: 2014 Update Version 2.0 (Ecology Publication No. 14-06-029, or
as revised and approved by Ecology).
(E) Do not contain a priority habitat or a priority area for a priority species
identifled by the Washington Department of Fish and Wildlife, do not contain
federally listed species or their critical habitat, or species of local importance
identifled in ACC 16.10.080(E).
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ii. Wetlands less than 1,000 square feet that meet the above criteria and do not
contain federally listed species or their critical habitat are exempt from the buffer
provisions contained in this chapter.
B. Streams.
1. Relocation of a Type F, Np and Ns stream exclusively to facilitate general site design
shall not be allowed. Relocation of a stream may take place only when it is part of an
approved mitigation or enhancement/restoration plan. Consultation with Washington
Department of Fish and Wildlife (WDFW) and a functional assessment demonstrating equal
or improved aquatic and riparian ecosystem function, and no net loss of stream functions,
is recommended. and will resultThe result shall be in equal or better habitat and water
quality, and will not diminish the fiow capacity of the stream.
2. Bridges shall be used to cross Type S streams; boring/micro-tunneling, or other forms
of trenchless technologies may be considered for utility crossings if it would result in the
same or lower impacts as bridging.
3. Culverts are allowable only under the following circumstances:
a. Only in Type F, Type Np, and Type Ns streams;
b. When flsh passage will not be impaired;
c. When the following design criteria are met:
i. All new culverts shall be designed following guidance provided in the
Washington Department of Fish and Wildlife’s document: Water Crossing Design
Guidelines, 2013 (or most recent version thereof). The applicant shall obtain a HPA
from the Department of Fish and Wildlife;
ii. Culverts will include gradient controls and creation of pools within the culvert
for Type F streams;
iii. Gravel substrate will be placed in the bottom of the culvert to a minimum
depth of one foot for Type F and Type Np streams;
d. The applicant or successors shall, at all times, keep any culvert free of debris and
sediment to allow free passage of water and, if applicable, flsh. This responsibility shall
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be part of the required long-term preservation measure and may be subject to
securing all the necessary approvals for any ongoing maintenance.
4. The city may require that an existing culvert be removed from a stream as a condition
of approval, unless the culvert is not detrimental to flsh habitat or water quality, or removal
would be a long-term detriment to flsh or wildlife habitat or water quality.
C. Fish and Wildlife Habitat Conservation Areas.
1. Critical Habitat. Alterations of critical habitat shall be avoided, subject to the reasonable
use provisions of this chapter.
2. Priority Secondary Habitat. Alterations of secondarypriority habitat may be permitted;
provided, that the applicant consults with Washington Department of Fish and Wildlife
(WDFW), demonstrates no net loss of habitat, mitigates adverse impacts consistent with the
performance standards of ACC 16.10.120, and other requirements of this chapter.
3. Tertiary Habitat. Alterations of tertiary habitat are permitted consistent with applicable
provisions of these regulations and provided that no other regulated critical area is
present.
D. Aquifer Recharge Areas. The following land uses and activities applied for on or after the
effective date of the ordinance codifled in this chapter, as amended, shall be prohibited in Type
I aquifer recharge areas:
1. Class V injection wells that inject industrial, municipal, or commercial waste fiuids (as
deflned in WAC 173-218-030);
2. Surface impoundments for treating, storing and disposing of dangerous waste (as
deflned in WAC 173-303-040 and 173-304-100);
3. Waste piles for treating or storing solid waste (as deflned in WAC 173-303-040, 173-303-
660 and 173-304-420);
4. Hazardous waste treatment, storage, and disposal (as deflned in WAC 173-303-040);
5. All types of solid waste landfllls (as deflned in WAC 173-304-100);
6. On-site sewage systems (as deflned in Chapter 246-272A WAC) except as related to R-C,
residential conservancy zoned properties and properties located within sole source aquifer
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(community well sites not classifled as groundwater protection areas) flve- and 10-year
time of travel areas. On-site sewage systems may be allowed in instances that there are no
other means of sewage disposal and the applicant can demonstrate to the King County
health department that the system can meet treatment standard N, as provided in WAC
246-272A-0110. Should an on-site sewage system be unable to meet these requirements,
the applicant may apply for a critical areas variance in accordance with this chapter.
7. Recycling facilities that accept, store, or use hazardous substances as deflned in WAC
173-218-030.
8. Underground storage of hazardous substances as deflned in WAC 173-218-030,
excluding the underground storage of petroleum and other substances as regulated by
Chapter 173-360A WAC;
9. Use, storage, treatment, or production of perchlorethylene (PCE) or tetrachloroethylene
(PERC), other than in closed-loop systems that do not involve any discharge of chemicals;
10. Petroleum reflning, reprocessing, and storage, excluding the underground storage of
petroleum products and other substances as regulated by Chapter 173-360A WAC;
11. Petroleum-product pipelines not associated with underground storage of petroleum
and other regulated substances as regulated by Chapter 173-360 WAC; and
12. Storage or distribution of gasoline treated with the additive methyl tertiary butyl ether
(MTBE).
E. Geologically Hazardous Areas.
1. General Standards.
a. The city may approve, condition or deny proposals for the alteration of geologically
hazardous areas, as appropriate, based on the degree to which the signiflcant risks
posed by critical hazard areas to public and private property and to public health and
safety can be mitigated. The objective of mitigation measures shall be to render a site
containing a critical geologic hazard as safe as one not containing such hazard or one
characterized by a low hazard. In appropriate cases, conditions may include limitations
of proposed uses, modiflcation of density, alteration of site layout and other
appropriate changes to the proposal. Where potential impacts cannot be effectively
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mitigated or where the risk to public health, safety and welfare, public or private
property, or important natural resources is signiflcant notwithstanding mitigation, the
proposal shall be denied.
b. When development is permitted in geologic hazard areas by these regulations, an
applicant and/or its qualifled professional shall provide assurances which, at the city’s
discretion, may include one or more of the following:
i. A letter from the geotechnical engineer and/or geologist who prepared the
geotechnical report required by these regulations, stating that the risk of
damage from the proposal, both on site and off site, is minimal subject to the
conditions set forth in the report, that the proposal will not increase the risk of
occurrence of the potential geologic hazard, and that measures to eliminate or
reduce risks have been incorporated into its recommendations;
ii. A letter from the applicant, or the owner of the property if not the applicant,
stating its understanding and acceptance of any risk of injury or damage
associated with development of the site and agreeing to notify any future
purchasers of the site, portions of the site, or structures located on the site of
the geologic hazard;
iii. A legally enforceable hold harmless agreement, which shall be recorded as a
covenant and noted on the face of the deed or plat, and executed in a form
satisfactory to the city, acknowledging that the site is located in a geologic hazard
area; the risks associated with development of such site; and a waiver and
release of any and all claims of the owner(s), their directors, employees, or
successors, or assigns against the city of Auburn for any loss, damage, or injury,
whether direct or indirect, arising out of issuance of development permits for the
proposal; and
iv. Posting of a bond, guarantee or other assurance device approved by the city
to cover the cost of monitoring, maintenance and any necessary corrective
actions.
2. Speciflc Standards.
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a. CriticalClass IV Landslide Hazard Areas. Alteration shall be prohibited subject to the
reasonable use provisions of this chapter.
i. Alterations to landslide hazard areas may be permitted based on the flndings
and recommendations of a geotechnical engineer (report, letter, etc.) that is
prepared consistently with the requirements of this chapter and certifying that
the development complies with the criteria in subsection (1) of this section.
ii. Unless otherwise provided or as a necessary part of an approved alteration,
removal of any vegetation from a critical landslide hazard area or buffer shall be
prohibited, except for removal of dead or diseased trees as verifled by an
arborist that pose danger to life or property or except for removal of tree(s)
within the public right-of-way by order of the City Engineer to address public
safety.
iii. Vegetation on slopes within a landslide hazard area or buffer which has been
damaged by human activity or infested by noxious and invasive weeds may be
replaced with native vegetation pursuant to an enhancement plan. The use of
hazardous substances, pesticides, and fertilizers in landslide hazard areas and
their buffers is prohibited, unless otherwise approved by the director.
iv. All alterations shall be undertaken in a manner to minimize disturbance to the
landslide hazard area, slope, and vegetation, unless the alterations are necessary
for slope stabilization.
b. Critical Seismic Hazard Areas.
i. For one-story and two-story residential structures, the applicant shall conduct
an evaluation of site response and liquefaction potential based on the
performance of similar structures under similar foundation conditions; or
ii. For all other proposals, the applicant shall conduct an evaluation of site
response and liquefaction potential including sufficient subsurface exploration to
provide a site coefficient (S) for use in the static lateral force procedure described
in the International Building Code.
c. Erosion Hazard Areas.
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i. Clearing in an erosion hazard area is not limited to time of year, except when
such restrictions are recommended in the geotechnical report and approved by
the City.
When development is permitted in geologically hazardous areas by these regulations,
an applicant and/or its qualifled consultant shall provide assurances which, at the city’s
discretion, may include one or more of the following:
i. A letter from the geotechnical engineer and/or geologist who prepared the
geotechnical report required by these regulations, stating that the risk of damage
from the proposal, both on site and off site, is minimal subject to the conditions
set forth in the report, that the proposal will not increase the risk of occurrence of
the potential geologic hazard, and that measures to eliminate or reduce risks have
been incorporated into its recommendations;
ii. A letter from the applicant, or the owner of the property if not the applicant,
stating its understanding and acceptance of any risk of injury or damage
associated with development of the site and agreeing to notify any future
purchasers of the site, portions of the site, or structures located on the site of the
geologic hazard;
iii. A legally enforceable hold harmless agreement, which shall be recorded as a
covenant and noted on the face of the deed or plat, and executed in a form
satisfactory to the city, acknowledging that the site is located in a geologically
hazardous area; the risks associated with development of such site; and a waiver
and release of any and all claims of the owner(s), their directors, employees, or
successors, or assigns against the city of Auburn for any loss, damage, or injury,
whether direct or indirect, arising out of issuance of development permits for the
proposal; and
iv. Posting of a bond, guarantee or other assurance device approved by the city to
cover the cost of monitoring, maintenance and any necessary corrective actions.
F. Flood Hazard Areas. Development standards are deflned by Chapter 15.68 ACC. (Ord. 6733 § 3
(Exh. B), 2019; Ord. 5894 § 1, 2005.)
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16.10.110 Mitigation standards, location, and timing, wetland
replacement ratios, and long-term protection
requirements.
A. Mitigation Standards. Adverse impacts to critical area functions and values shall be mitigated.
Mitigation must follow the sequence of avoidance, minimization, rectiflcation/rehabilitation,
reduction of impacts over time, and compensation, in that order. Proposals relying on
compensatory mitigation shall demonstrate Mitigation actions shall generally be implemented
in the preferred sequence identifled in this chapter. Proposals which include less preferred
and/or compensatory mitigation shall demonstrate that:
1. All feasible and reasonable measures as determined by the department have been
taken to avoidreduce impacts and losses to the critical area; including, where applicable;, or
to avoid impacts where avoidance is required by these regulations;
a. Alternative building locations on the property;
b. Adjustments to the project footprint and orientation;
c. Modiflcation of building setbacks where feasible, as a flrst option before encroaching;
into critical areas and/or buffer; and
d. Multi-story design or alternate building design.
2. The restored, created or enhanced critical area or buffer will be as viable and enduring
as the critical area or buffer area it replaces; and
3. No overall net loss will occur in wetland or stream functions and values. The mitigation
shall be functionally equivalent to or greater than the altered wetland or stream in terms of
hydrological, biological, physical, and chemical functions.
4. Mitigation shall occur within the same drainage basin using a watershed approach.
However, when the applicant can demonstrate that a mitigation site in a different sub-
drainage basin is ecologically preferable, it should be used.
B. Location and Timing of Mitigation.
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1. The preferred location of mitigation is on site when ecologically preferable to other
identifled alternatives. Mitigation may be allowed off site when it is determined by the
director that on-site mitigation is not ecologically preferable to other identifled alternatives,
or, in the case of wetlands, where the affected site is identifled as appropriate for off-site
mitigation in the Mill Creek Special Area Management Plan (SAMP), April 2000. The burden
of proof shall be on the applicant to demonstrate that mitigation cannot be provided on
site or is consistent with the SAMP. If it is determined that on-site mitigation is not
ecologically preferable to other identifled alternatives, mitigation shall be provided in the
same drainage basin as the permitted activity on property owned, secured, or controlled by
the applicant, or provided by the applicant using alternative mitigation options such as
mitigation banking or in-lieu fee programs. The mitigation should result in no net loss to
the critical area functions impacted and associated watershed. Where mitigation is
authorized to be located outside the city limits, the applicant shall assure to the satisfaction
of the director that other requirements of this chapter will be met, including but not limited
to, monitoring and maintenance.
2. In-kind mitigation shall be provided except when the applicant demonstrates, and the
director concurs, that greater functional and habitat value can be achieved through out-of-
kind mitigation. All off-site mitigation must provide equivalent or greater ecological
functions and be consistent with the provisions of this chapter. Where mitigation is located
outside the city limits, the applicant shall demonstrate to the satisfaction of the director
that long-term protection, maintenance, and monitoring requirements of ACC 16.10.110
and ACC 16.10.130 will be met
3. When wetland, stream or habitat mitigation is permitted by these regulations, the
mitigation project shall occur near an adequate water supply (river, stream, groundwater)
with a hydrologic connection to the critical area to ensure a successful mitigation or
restoration. A natural hydrologic connection is preferential as compared to one which
relies upon manmade or constructed features requiring routine maintenance. In-kind
mitigation shall be provided unless the applicant demonstrates, and the director concurs,
that on-site mitigation is not feasible and out-of-kind mitigation will result in equal or
greater ecological or habitat function. Out-of-kind mitigation may be approved only where
it provides equal or greater beneflts to critical area functions.
4. Any mitigation plan shall be completed before initiation of other permitted activities,
unless a phased or concurrent schedule that assures completion prior to occupancy has
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been approved by the department. Mitigation for wetlands, streams, and habitat
conservation areas shall occur in a location that has a sufficient and reliable water source,
including surface water or groundwater, with a hydrologic connection to the impacted
critical area. Preference shall be given to locations with natural hydrologic connections over
those that rely on artiflcial or constructed systems requiring regular maintenance.
5. Timing of Compensatory Mitigation. It is preferred that compensatory mitigation projects
be completed prior to activities that will impact wetlands. At the least, compensatory
mitigation shall be completed immediately following wetland impacts and prior to use or
occupancy of the action or development. Construction of mitigation projects shall be timed
to reduce impacts to existing flsheries, wildlife, and fiora.
6. The applicant shall provide documentation demonstrating that the chosen mitigation
location and schedule will achieve no net loss of ecological functions and values and that
the mitigation site will be protected in perpetuity consistent with ACC 16.10.130.
C. Wetland and Buffer Replacement Ratios.
1. Where wetland alterations are permitted by the director, the applicant shall enhance or
create areas of wetlands in order to compensate for wetland losses. The compensation
shall be determined according to acreage, function, type, location, timing factors and
projected success of enhancement or creation. Wetland compensatory mitigation ratios
shall account for the wetland category, the proposed impact area and functions, the quality
and functions of the mitigation site, location factors, and timing of mitigation. To protect
functions and values more fully, and as an alternative to the mitigation ratios found in
Section ACC 16.10.110(C)(2) of this Chapter, the director may allow mitigation based on the
Credit-Debit Method developed by the Department of Ecology in Calculating Credits and
Debits for Compensatory Mitigation in Wetlands of [Western Washington (Ecology
Publication # 10-06-011), see ACC 16.10.110(D) for information on credits from an
approved in-lieu fee program.
2. The following acreage replacement and enhancement ratios shall be implemented;
however, the department may vary these standards if the applicant can demonstrate and
the director agrees that the variation will provide adequate compensation for lost wetland
area, functions and values, or if other circumstances as determined by the director justify
the variation. In no case shall the amount of mitigation be less than the area of affected
wetland. The director may at his discretion increase these standards where mitigation is to
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occur off-site or in other appropriate circumstances. The following acreage replacement
ratios shall be used when impacts to wetlands are permitted. These ratios are based on the
category of the wetland and the type of mitigation proposed. Ratios apply to permanent,
direct impacts to wetlands.
3. Category IV wetlands can be mitigated by either: (a) meeting one of the replacement
ratios listed in the following table; or (b) fllled and mitigated consistent with ACC
16.10.100(A)(3)(d).
Category and Type
of WetlandCategory
of impacted wetland
(based on score for
function)
Creation or
Reestablishment Rehabilitation Preservation* Enhancement
Category I: Bog,
Natural Heritage Site
Not considered
possible
Case by case Case by case
Category I: Mature
Forested
6:1 12:1 24:1
Category I: Based on
Functions
4:1 8:1 16:1 16:1
Category II 3:1 6:1 12:1 12:1
Category III 2:1 4:1 8:1 8:1
Category IV 1.5:1 3:1 6:1 6:1
*Preservation ratios apply only when used in combination with reestablishment or creation at
no less than a 1:1 ratio.
3. Category IV wetlands may be mitigated either by using the replacement ratios
identifled in subsection (2) or, when permitted by state and federal regulatory agencies,
through authorized flll and compensatory mitigation.
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4. Buffer Mitigation Ratios. Impacts to buffers shall be mitigated at a minimum 1:1 ratio.
Compensatory buffer mitigation shall replace those buffer functions lost from
development.
D. In-Lieu Fee (ILF) Mitigation: Credits from an approved in-lieu fee program may be used when
all the following apply:
1. The director determines that it would provide appropriate compensation for the
proposed impacts and on-site mitigation is infeasible.
2. The proposed use of credits is consistent with the terms and conditions of the
approved ILF program instrument.
3. Projects using ILF credits shall have debits associated with the proposed impacts
calculated by the applicant’s qualifled wetland professional using the credit assessment
method specifled in the approved instrument for the ILF program.
4. The impacts are located within the service area specifled in the approved ILF
instrument.
ED. Long-term protection of regulated wetlands, streams, flsh and wildlife habitat conservation
areas, geologically hazardous areas, aquifer recharge areas, and any associated buffer(s) shall
be provided by one of the following methods:
1. For subdivisions, short subdivisions, and binding site plans, the critical area and its
buffer shall be protected long-term by one of the following measures in the following order
of preference:
a. The critical area and its buffer shall be placed in a separate tract on which
development is prohibited and a note shown on the face of the plat indicating that the
homeowners or homeowners’ association is responsible for maintenance of the tract.
If the city agrees to accept dedication of the tract, a city-approved note shall be shown
on the face of the plat indicating that the city is responsible for long-term ownership
and maintenance of the tract and there shall be adequate provisions for city access to
the tract from a public street, as approved by the director.
b. The critical area and its buffer shall be protected by execution of an easement
dedicated to the city, a conservation organization or land trust, or similarly preserved
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through a permanent protective mechanism acceptable to the city. Access to the
easement must be assured from the public street.
2. For all other developments, the critical area and its buffer shall be protected by
execution of an easement dedicated to the city, a conservation organization, or land trust or
similarly preserved through a permanent protective mechanism acceptable to the city. The
legal description, depicted location, limitations associated with the critical area and its buffer,
and access from the public street shall be included within the easement document. The
easement provisions shall be reviewed and acceptable to the city prior to recording with the
King County recorder or Pierce County auditor. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6476 § 1, 2013; Ord.
5894 § 1, 2005.)
3. For any critical area mitigation site required by this chapter, long-term protection shall be
provided using one of the protective mechanisms described in subsections (E)(1) or (E)(2) of this
section and recorded prior to final plat approval or issuance of any occupancy permit.
F. Mitigation Plan Requirements. All required mitigation plans shall meet the requirements of
RCW 90.74.020. When a project involves wetland, streams, and/or buffer impacts, a mitigation
plan prepared by a qualified wetland professional shall be required, meeting the following
minimum standards:
1. The report shall include a written plan and plan sheets that contain, at a
minimum, the elements listed below. Full guidance can be found in Wetland Mitigation in
Washington State–Part 2: Developing Mitigation Plans (Version 1) (Ecology Publication #06-06-
011b, or as revised).
a. The written report shall be prepared by a qualified wetland professional and contain,
at a minimum:
i. The name and contact information of the applicant; the name, qualifications,
and contact information of the primary author(s) of the compensatory mitigation
plan; a description of the development proposal; a summary of the impacts and
proposed compensation concept; identification of all the local, state, and federal
wetland-related permits required for the project; and a vicinity map for the
project.
ii. Description of how the development project has been designed to avoid,
minimize, or reduce adverse impacts to wetlands.
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iii. Description of the existing wetland and buffer areas proposed to be altered.
Include acreage or square footage, water regime, vegetation, soils, functions,
landscape position, and surrounding land uses. Also describe impacts in terms of
acreage by Cowardin classification, hydrogeomorphic classification, and wetland
rating.
iv. Description of the compensatory mitigation site, including location and
rationale for selection. Include an assessment of existing conditions, including
acreage or square footage of wetlands and uplands, water regime, sources of
water, vegetation, soils, functions, landscape position, and surrounding land
uses. Estimate future conditions in this location if the compensation actions are
not undertaken.
v. Surface and subsurface hydrologic conditions, including an analysis of existing
and proposed hydrologic regimes for enhanced, established, or restored
compensatory mitigation areas. Include illustrations of how data for existing
hydrologic conditions were used to determine the estimates of future hydrologic
conditions.
vi. A description of the proposed actions for compensation of wetland and buffer
areas affected by the project. Include overall goals of the proposed mitigation,
including a description of the targeted functions, hydrogeomorphic classification,
and expected categories of wetlands.
vii. A description of the proposed mitigation construction, activities and timing of
activities and where appropriate as determined by the director a description and
documentation of the as-built conditions.
viii. Performance standards (measurable standards for years post-installation)
for wetland and buffer areas, a monitoring schedule, a maintenance schedule,
and actions proposed by year.
ix. A discussion of ongoing management practices that will protect wetlands
after the development project has been implemented, including proposed
monitoring and maintenance programs (for remaining wetlands and
compensatory mitigation wetlands).
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x. A bond estimate for the entire compensatory mitigation project, including the
following elements: site preparation, plant materials, construction materials,
installation and oversight, maintenance at least twice per year for up to ten
years, annual monitoring field work and reporting, contingency actions for a
maximum of the total required number of years for monitoring, and removal of
all non-natural site implements (e.g., irrigation equipment, construction fencing,
plant protectors, weed barrier fabric) by the end of the monitoring period.
xi. Proof of establishment of Notice on Title for the remaining wetlands and
buffers on the development project site (if any) and a legal site protection
mechanism for the compensatory mitigation areas.
b. The scaled plan sheets shall contain, at a minimum:
i. Mapped, ground-verified edges of the existing wetland and buffers, proposed
areas of wetland and/or buffer impacts, and location of proposed wetland
and/or buffer compensation actions.
ii. Existing topography, ground-verified, at two-foot contour intervals in the zone
of the proposed compensation actions if any grading activity is proposed in the
compensation area(s). Also include existing cross-sections (estimated one-foot
intervals) of wetland areas on the development site that are proposed to be
altered and of the proposed areas of wetland and buffer compensation.
iii. Conditions expected from the proposed actions on site, including future
hydrogeomorphic classes, vegetation community types (e.g., Cowardin class),
and future hydroperiods.
iv. Required wetland buffers for existing wetlands and proposed compensation
areas. Also identify any zones where buffers are proposed to be reduced or
enlarged outside of the standards identified in this Chapter.
v. A planting plan for the compensation area, including all species by proposed
community type and hydroperiod, size and type of plant material to be installed,
spacing of plants, typical clustering patterns, total number of each species by
community type, and timing of installation.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
16.10.120 Performance standards for mitigation planning.
The performance standards in this section shall be incorporated into mitigation plans
submitted to the city for impacts to critical areas.
A. Wetlands and Streams.
1. Use plants native to the Puget Lowlands or Paciflc Northwest ecoregion; non-native,
introduced plants or plants listed by the Washington State Department of Agriculture as
noxious weeds (Chapter 16-750 WAC) shall not be used;
2. Use plants adapted to and appropriate for the proposed habitats and consider the
ecological conditions known or expected to be present on the site. For example, plants
assigned a facultative wetland (FACW) wetland indicator status should be used for sites
with soils that are inundated or saturated for long periods during the growing season. Use
nearby reference wetlands or aerial photos to identify plants suitable to the site conditions
and hydrologic regimes planned for the mitigation site. Avoid planting signiflcant areas of
the site with species that have questionable potential for successful establishment, such as
species with a narrow range of habitat tolerances;
3. Utilize plant species’ heterogeneity and structural diversity that emulates native plant
communities described in “Natural Vegetation of Oregon and Washington” (Franklin, J.F.
and C.T. Dyrness, 1988) or other regionally recognized publications on native landscapes;
4. Specify plants that are commercially available from native-plant nurseries or available
from local sources. If collecting some or all native plants from donor sites, collect in
accordance with ecologically accepted methods, such as those described in the
“Washington Native Plant Society’s Policy on Collection and Sale of Native Plants,” that do
not jeopardize the survival or integrity of donor plant populations;
5. Use perennial plants in preference to annual species; the use of annual species should
be limited to a temporary basis in order to provide erosion control, support the
establishment of perennial plants, or if mitigation monitoring determines that native plants
are not naturally colonizing the site or if species diversity is unacceptably low compared to
approved performance standards;
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Chapter 16.10 ACC, Critical Areas Page 59 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
6. Use plant species high in food and cover value for native flsh and wildlife species that
are known or likely to use the mitigation site (according to reference wetlands, published
information, and professional judgment);
7. Install a temporary irrigation system and specify an irrigation schedule and responsible
party to maintain unless a sufficient naturally occurring source of water is demonstrated.
Temporary irrigation facilities shall be removed after the time specifled by the qualifled
professionalconsultant;
8. Identify methods of soil preparation. For stream substrate or wetland soils, at least one
foot of clean inorganic and/or organic materials, such as cobble, gravel, sand, silt, clay,
muck, soil, or peat, as appropriate, shall be ensured. The stream substrate or wetland soils
shall be free from solid, dangerous, or hazardous substance as deflned by Chapter 70.105
RCW and implementing rules;
9. Conflne temporary stockpiling of soils to upland areas. Identify construction access
routes and measures to avoid resultant soil compaction. Unless otherwise approved by the
director, comply with all applicable best management practices for clearing, grading, and
erosion control to protect any nearby surface waters from sediment and turbidity;
10. Show densities and placement of plants; these should be based on the ecological
tolerances of species proposed for planting, as determined by a qualifled
professionalconsultant;
11. Provide sufficient speciflcations and instructions to ensure proper placement and
spacing of seeds, tubers, bulbs, rhizomes, springs, plugs and transplanted stock, and other
habitat features, and to provide a high probability of success, and to reduce the likelihood
of prolonged losses of wetland functions from proposed development;
12. Do not rely on fertilizers and herbicides to promote establishment of plantings; if
fertilizers are used, they must be applied per manufacturer speciflcations to planting holes
in organic or controlled release forms, and never broadcast on the ground surface; if
herbicides are used to control invasive species or noxious weeds and to help achieve
performance standards, only those approved for use in aquatic ecosystems by the
Washington Department of Ecology shall be used; herbicides shall only be used in
conformance with all applicable laws and regulations and be applied per manufacturer
speciflcations by an applicator licensed in the state of Washington; and
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
13. Include the applicant’s mitigation plan consultant in the construction process to
ensure the approved mitigation plan is completed as designed. At a minimum, the
consultant’s participation will include site visits to inspect completed rough and flnal
grading, installation of in-water or other habitat structures, and to verify the quality and
quantity of native plant materials before and after installation;
14. Signs and Fencing of Wetlands and Streams Critical Areas.
a. Temporary Markers. The outer perimeter of the critical area or buffer and the limits
of those areas to be disturbed pursuant to an approved permit or authorization shall
be marked in the fleld in such a way as to ensure that no unauthorized intrusion will
occur, and verifled by the department prior to the commencement of authorized
activities. This temporary marking shall be maintained throughout construction, and
shall not be removed until permanent signs, if required, are in place.
b. Permanent Signs. As a condition of any permit or authorization issued pursuant to
this chapter, the department may require the applicant to install permanent signs
along the boundary of a critical area or buffer. Permanent signs shall be made of metal
face and attached to a metal post, flrmed anchored, or other materials of equal
durability approved by the director. Signs must be posted at an interval of one per lot
or every 50 feet, whichever is less, and must be maintained by the property owner in
perpetuity. The sign shall be worded as follows or with alternative language approved
by the director:
Sensitive Area Boundary
“Help protect and care for this area. Trampling or cutting vegetation, placing flll or garbage,
and any other activities that may disturb the sensitive area are prohibited, as regulated
under Auburn City Code Chapter 16.10.
Please contact city of Auburn at 253-931-3090 with questions or concerns.”
c. Fencing.
i. The director shall condition any permit or authorization issued pursuant to this
chapter to require the application to install a permanent fence at the edge of the
critical area or buffer, when fencing will prevent future impacts on the critical area.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
ii. The applicant shall be required to install a permanent fence around the critical
area or buffer when domestic grazing animals are present or may be introduced
on site.
iii. Fencing installed as part of a proposed activity or as required in this subsection
shall be designed so as to not interfere with species migration, including flsh runs,
and shall be constructed in a manner that minimizes habitat impacts.
iv. Fencing shall include a permanent natural wood split-rail fence, such as cedar
or other non-pressure-treated wood, with fence posts set in concrete footings, or
similar, as approved by the director.
B. Wetlands. Do not exceed a maximum water depth of 6.6 feet (two meters) at mean low
water unless approved as part of a planned interspersion of wetland vegetation classes and
deep-water habitats.
1. Do not exceed a slope of 25 percent (4H:1V) in the wetland unless it can be clearly
demonstrated by supporting documentation that wetland hydrology and hydric soils
capable of supporting hydrophytic (wetland) vegetation will be created on steeper slopes;
2. Do not exceed a slope of 25 percent (4H:1V) in the wetland buffer; and
3. Limit deep-water habitat (greater than 6.6 feet at mean low water) in compensatory
wetland to no more than 60 percent of the total area, and approach this limit only when
deep-water habitat is highly interspersed with wetland vegetation classes, including aquatic
bed, emergent, scrub-shrub, and forested.
C. Fish and Wildlife Habitat Conservation Areas.
1. Incorporate relevant performance standards from subsections A and B of this section,
as determined by the director;
2. Include the following additional mitigation measures in mitigation planning:
a. Locate buildings and structures in a manner that minimizes adverse impacts on
critical habitats used by threatened or endangered species and identifled by the
Washington State Department of Fish and Wildlife, NOAA Fisheries, and U.S. Fish and
Wildlife Service;
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Chapter 16.10 ACC, Critical Areas Page 62 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
b. Integrate retained habitat into open space and landscaping;
bc. Wherever possible, consolidate critical habitats into larger, unfragmented,
contiguous blocks;
cd. Use native plant species for landscaping of disturbed or undeveloped areas and in
any habitat enhancement or restoration activities;
de. Create habitat heterogeneity and structural diversity that emulates native plant
communities described in Natural Vegetation of Oregon and Washington (Franklin, J.F.
and C.T. Dyrness, 1988) or other regionally recognized publications on native
landscapes;
ef. Remove and/or control any noxious weeds or exotic animals which are
problematic to the critical habitat area as determined by the director or consultant
hired by the city to review the mitigation plan; and
fg. Preserve signiflcant or existing native trees, preferably in stands or groups,
consistent with achieving the goals and standards of this chapter; the plan shall refiect
the report prepared pursuant to ACC 16.10.070.
D. Geologically Hazardous Areas.
1. Incorporate relevant performance standards from the preceding subsections, as
determined by the director;
2. The following additional performance standards shall be refiected in proposals within
geologically hazardous areas:
a. A geotechnical report shall be prepared to identify and evaluate potential hazards
and to formulate mitigation measures;
b. Construction methods will not adversely affect geologic hazards or will reduce
adverse impacts on geologic hazards;
c. Site planning shall minimize disruption of existing topography and natural
vegetation;
d. Impervious surface coverage shall be minimized;
Page 654 of 758
Chapter 16.10 ACC, Critical Areas Page 63 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
e. Disturbed areas shall be replanted with permanent vegetation as soon as feasible
pursuant to a mitigation or landscape plan;
f. Clearing and grading shall be limited to between April 1st and October 31st unless
the geotechnical report speciflcally addresses measures necessary to perform clearing
and grading during other portions of the year;
g. The limited use of retaining walls that minimize disturbance or alteration of existing
natural slope areas is preferred over graded slopes;
h. Temporary erosion and sedimentation controls, pursuant to an approved plan,
shall be implemented during construction;
i. A drainage plan shall be prepared for large projects as required by the city engineer;
j. Development shall not increase instability or create a hazard to the site or adjacent
properties, or result in a signiflcant increase in sedimentation or erosion.
E. Aquifer Recharge Areas. Protective measures are required of all development except an
individual single-family or two-family (duplex) dwelling unit. Development applications shall
include the following minimum measures and incorporate the appropriate responses:
1. Type I Aquifer Recharge Areas.
a. Indicate how hazardous substances shall be stored and used such that any
unauthorized release or discharge of the hazardous substances is prevented.
b. Specify that pesticides, herbicides, and fertilizers shall be applied in strict
conformance with manufacturer’s instructions and by persons licensed to perform
such applications, if applicable.
c. Document hazardous substances management procedures, including, but not
limited to, operations plans, drawings and as-built diagrams, emergency response and
spill cleanup plans, and employee training documentation. This information can be
provided in the form of copies of permits or other documentation required by other
authorities.
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
d. Indicate that any flll material shall be documented to be free of contaminants that
exceed Method A and Method B soil cleanup standards specifled in Chapter 173-340
WAC prior to placement on the ground, if applicable.
e. Specify that any contaminant release reported to the Washington State Department
of Ecology (Ecology) per Chapter 173-340 WAC shall also be reported to the city of
Auburn public works department concurrent with notiflcation of Ecology.
f. Include a provision that the implementation of the protective measures will be
maintained during the life of the project. Updates shall occur whenever there is a
change in use or business occupancy or when there are signiflcant changes in facility
operations or hazardous substances management. A copy of the plan is to be available
for review by city inspectors at the business or businesses within the development. The
plan should cover the facility site in general as well as have a section(s) speciflc to any
tenants within the development.
2. Type II Aquifer Recharge Areas. Property owners shall implement best management
practices for water resource protection. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 5894 § 1, 2005.)
16.10.130 Monitoring program and contingency plan.
A. For all actions requiring a mitigation plan, a monitoring program shall be prepared and
implemented by the applicant to evaluate the success of the mitigation project and to
determine necessary corrective actions. This program shall determine if the original goals and
objectives are being met. The monitoring program shall be reviewed and approved by the city
prior to implementation. The monitoring program shall include a contingency plan in the event
that implementation of the mitigation plan is inadequate or fails.
B. A performance and maintenance security is required to ensure the applicant’s compliance
with the terms of the approved mitigation plan. The amount of the performance security shall
equal 125 percent of the cost of the mitigation project for to be provided prior to construction
commencing and for the length of the monitoring period after construction is complete; the
director may agree to reduce the security in proportion to work successfully completed over
the period of the security.
C. Incorporate the following into monitoring programs prepared to comply with this chapter:
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
1. Appropriate, accepted, and unbiased qualitative or precise and accurate quantitative
sampling methods to evaluate the success or failure of the project compared to
performance standards approved by the city;
2. Quantitative sampling methods that include permanent photopoints installed at the
completion of construction and maintained throughout the monitoring period and shall
also include permanent transects, sampling points (e.g., quadrants or water quality or
quantity monitoring stations), and wildlife monitoring stations;
3. Clearly stipulated qualitative and quantitative sampling methods that are approved by
the city before implementation by the project proponent;
4. Appropriate qualitative and/or quantitative performance standards that will be used to
measure the success or failure of the mitigation. For wetlands, streams and habitat areas
these will include, at a minimum, standards for plant survival and diversity, including
structural diversity, the extent of wetland hydrology, hydric soils, and habitat types and
requirements as appropriate; all proposed standards are subject to review and approval by
the city or the professional consultant selected by the city to review the mitigation
monitoring plan. The qualitative and/or quantitative performance standards shall generally
address the following subject areas:
a. Requirements for survival of plantings;
b. Requirements for plant density or percentage cover by plants;
c. Requirements for plant diversity (species composition diversity, structural
diversity – tree, shrub, and groundcover layers, deciduous and evergreen, etc.);
d. Requirements that are staged over time so that different performance
standards must be met as the mitigation area matures;
e. Measures to verify that the type and amount of functional areas that are part of the
mitigation plan are successfully established (e.g., identify steps that will be
implemented to conflrm that the amount and type of created wetland meets the
criteria of a wetland);
f. Requirements speciflcally limiting occurrence of exotic and nuisance plant species;
Page 657 of 758
Chapter 16.10 ACC, Critical Areas Page 66 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
g. Requirements for ongoing preservation and protection measures such as
continued existence in good condition of fencing and critical area signage. Also,
avoidance of disturbance, trampling and the accumulation of litter or debris within the
critical area and its buffer.
5. Monitoring programs for a minimum period of flve years for buffer enhancement and
other types of mitigation programs that include, at a minimum, preparation of an as-built
plan upon completion of construction; biannual monitoring and preparation of annual
monitoring reports following implementation; and a maintenance plan. More stringent
monitoring requirements or longer monitoring periods may be required on a case-by-case
basis for more complex mitigation plans (e.g., ten10 years or more when forested or scrub-
shrub wetlands are the intended result);
6. Monitoring reports shall be submitted to the director by December 1st of the year in
which monitoring is conducted. The reports are to be prepared by a qualifled
professionalconsultant and must contain all qualitative and quantitative monitoring data,
photographs, and an evaluation of each of the applicable performance standards. If
performance standards are not being met, appropriate corrective or contingency measures
must be identifled and communicated to the director and upon concurrence, implemented
to ensure that performance standards will be met;
7. Provision for the extension of the monitoring period beyond the minimum time frame if
performance standards are not being met at the end of the initial flve-year period; and
provision for additional flnancial securities or bonding to ensure that any additional
monitoring and contingencies are completed to ensure the success of the mitigation. (Ord.
6733 § 3 (Exh. B), 2019; Ord. 5894 § 1, 2005.)
16.10.140 Procedural provisions.
A. Interpretation and Confiicts. The director shall have the authority to administer the provisions
of this chapter, to make determinations with regard to the applicability of the regulations, to
interpret the intent of unclear provisions, to require additional information, to determine the
level of detail and appropriate methodologies for critical area reports and studies, to prepare
application forms and informational materials as required, and to promulgate procedures and
rules for unique circumstances not anticipated within standards and procedures contained in
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
this section. The director shall also determine whether critical area review is required based on
the presence or proximity of mapped critical areas or indicators on a project site.
Administrative interpretations may be appealed to the hearing examiner as prescribed in ACC
18.70.050.
B. Penalties and Enforcement. Compliance with these regulations and penalties for their
violation shall be enforced pursuant to the procedures set forth in Chapter 1.25 ACC.
C. Appeals of Critical Area Review Decisions. Appeals of critical area review decisions shall be
governed by the procedures set forth in ACC 18.70.050. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 5894 § 1,
2005.)
16.10.150 Reasonable use provision.
A. The standards and requirements of these regulations are not intended, and shall not be
construed or applied in a manner, to deny all reasonable use of private property. If an applicant
demonstrates to the satisfaction of the hearing examiner that strict application of these
standards would deny all reasonable economic use of a property, development may be
permitted subject to appropriate conditions.
B. Applications for a reasonable use exception shall be processed as a Type III decision,
pursuant to ACC 14.03.030 and Chapter 2.46 ACC.
C. An applicant for relief from strict application of these standards shall demonstrate that all of
the following criteria are met:
1. No reasonable use with less impact on the critical area and its buffer is possible.
There is no feasible and reasonable on-site alternative to the activities proposed,
considering possible changes in site layout, reductions in density, conflguration, and/or
building size, that would allow a reasonable and economically viable use with fewer
adverse impacts to critical areas and buffers. and similar factors, that would allow a
reasonable and economically viable use with fewer adverse impacts;
2. The proposed development activities, as conditioned, will result in the minimum
possible impacts to affected critical areas;
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The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
3. All reasonable mitigation measures have been implemented or assured;
4. The proposal is consistent with the general purposes and intent of this chapter and the
public interest.
5The. The inability to derive reasonable use is not the result of the applicant’s actions or
that of a previous property owner, such as by segregating or dividing the property and
creating an undevelopable condition; and
65. The applicant shall demonstrate that the use would not cause a hazard to life, health
or property.
D. Any alteration of a critical area approved under this section shall be subject to appropriate
conditions and will require mitigation construction authorized by an approved mitigation plan.
Any authorization of a reasonable use exception shall be the minimum necessary to allow for
reasonable economic use of the property, and shall include conditions of approval and
mitigation as necessary to protect critical areas and their functions and values to the maximum
extent practicable.
E. The burden of proof shall be on the applicant to provide evidence in support of the
application and to provide sufficient information on which any decision has to be made.
F. Any alteration of a critical area approved under this section shall be subject to an approved
mitigation plan consistent with ACC 16.10.110 and 16.10.120.
GF. Approval of a reasonable use exception shall not eliminate the need for any other permit
or approval otherwise required for a proposal by applicable city codes.
HG. Except when application of this title would deny all reasonable use of a site, an applicant
who seeks an exception from the regulations of the title shall pursue a variance as provided in
ACC 16.10.160. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6442 § 13, 2012; Ord. 5894 § 1, 2005.)
16.10.160 Variances.
Applications for variances to the strict application of the terms of this chapter to a property may
be submitted to the city. Minor variances, deflned as up to and including 10 percent of the
requirement, may be granted by the director as a Type II decision as deflned by Chapter 14.03
Page 660 of 758
Chapter 16.10 ACC, Critical Areas Page 69 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
ACC. Variance requests which exceed 10 percent may be granted by the hearing examiner as a
Type III decision, pursuant to ACC 14.03.030 and Chapter 2.46 ACC. Approval of variances from
the strict application of the critical area requirements shall conform to the following criteria:
A. There are unique physical conditions peculiar and inherent to the affected property which
make it difficult or infeasible to strictly comply with the provisions of this section;
B. The variance is the minimum necessary to accommodate the building footprint and access;
C. The proposed variance would preserve the functions and values of the critical area, and/or
the proposal does not create or increase a risk to the public health, safety and general welfare,
or to public or private property;
D. The proposed variance would not adversely affect surrounding properties adjoining;
E. Adverse impacts to critical areas resulting from the proposal are minimized; and
F. The special circumstances or conditions affecting the property are not a result of the actions
of the applicant or previous owner. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6442 § 14, 2012; Ord. 5894 § 1,
2005.)
16.10.170 Special exception for public agencies and utilities.
A. If the application of this chapter would prohibit a development proposal by a public agency
or public utility, the agency or utility may apply for an exception pursuant to this section.
B. Exception Request and Review Process. An application for a public agency and utility exception
shall be made to the city and shall include a critical area identiflcation form; critical area report,
including mitigation plan, if necessary; and any other related project documents such as permit
applications to other agencies, special studies, and environmental documents prepared
pursuant to the State Environmental Policy Act (Chapter 43.21C RCW and Chapter 197-11 WAC).
The director shall prepare a recommendation to the hearing examiner based on review of the
submitted information, a site inspection, and the proposal’s ability to comply with public agency
and utility exception review criteria in subsection D of this section.
C. Hearing Examiner Review. The hearing examiner shall review the application and director’s
recommendation, and conduct a public hearing pursuant to the provisions of Chapter 2.46 ACC.
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Chapter 16.10 ACC, Critical Areas Page 70 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
The hearing examiner shall approve, approve with conditions, or deny the request based on the
proposal’s ability to comply with all of the public agency and utility exception criteria in
subsection D of this section.
D. Public Agency and Utility Review Criteria. The criteria for review and approval of public agency
and utility exceptions follow:
1. There is no other practical alternative to the proposed development with less impact on
critical areas;
2. The application of this chapter would unreasonably restrict the ability to provide utility
services to the public;
3. The proposal does not pose an unreasonable threat to the public health, safety, or
welfare on or off the development proposal site;
4. The proposal protects critical area functions and values to the extent feasible and
provides for mitigation in accordance with the provisions of this chapter; and
5. The proposal is consistent with other applicable regulations and standards.
E. Burden of Proof. The burden of proof shall be on the applicant to bring forth evidence in
support of the application and to provide sufficient information on which any decision has to be
made on the application. (Ord. 6733 § 3 (Exh. B), 2019; Ord. 6442 § 15, 2012; Ord. 5894 § 1, 2005.)
16.10.180 Severability.
If any provision of these regulations or its application to any person or circumstance is held
invalid by a court of competent jurisdiction, the remainder of these regulations or the
application to other persons or circumstances shall not be affected. (Ord. 6733 § 3 (Exh. B), 2019;
Ord. 5894 § 1, 2005.)
The Auburn City Code is current through Ordinance 6992, and legislation passed August
18, 2025.
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Chapter 16.10 ACC, Critical Areas Page 71 of 71
The Auburn City Code is current through Ordinance 6992, and legislation passed August 18, 2025.
Disclaimer: The city clerk’s office has the official version of the Auburn City Code. Users should
contact the city clerk’s office for ordinances passed subsequent to the ordinance cited above.
City Website: www.auburnwa.gov
Hosted by General Code.
Page 663 of 758
SEATTLE | KIRKLAND | BURLINGTON | WHI D BEY ISLAND | FEDERAL WAY | SPOKANE
facetnw.com
TECHNICAL MEMO RANDUM
Date: February 20, 2026
To: Steven Sturza – City of Auburn
Cc: Alyssa Tatro, Alexandria Teague – City of Auburn
From: Nell Lund, Sr. Ecologist
Project Name: Auburn CAO Update - Streams
Facet Number: 2510.0746.00
CAO Update – Stream Regulations Review
Introduction
The City of Auburn is going through the periodic update process for their Critical Areas Ordinance
(CAO). To align with requirements under the Growth Management Act, the City of Auburn must
include best available science (BAS) when developing policies and development regulations. Based on
comments received from the Washington Department of Fish and Wildlife (WDFW), the City is
conducting a targeted review of proposed draft stream regulations.
The purpose of this memorandum is to provide a high-level summary of stream and riparian BAS,
document the City’s GIS analysis of conditions in Auburn, summarize City proposed stream regulations,
and document how BAS was considered and incorporated in the CAO update.
Best Available Science Review Summary
Streams are a type of Fish and Wildlife Habitat Conservation Area (FWHCA) as defined by the Revised
Code of Washington (RCW 36.70A.030). WDFW provides BAS summary in their publication, Riparian
Ecosystems, Volume 1: Science Synthesis and Management Implications (Quinn et al. 2020). Based on
Volume 1, WDFW provides guidance in Riparian Ecosystems, Volume 2: Management Recommendations
(Rentz et al. 2020). Other cited publications are provided in the reference list.
STREAM & RIPARIAN FUNCTIONS & VALUES
Composition, structure and functions of streams are tied to watershed and riparian conditions. Riparian
ecosystem functions include stream morphology (e.g. streamflow and sedimentation processes),
woody debris recruitment, microclimate and in-stream temperature, pollutant removal, and nutrient
cycling. Streams and their associated riparian areas also provide important habitat for diverse terrestrial
and aquatic wildlife species (Quinn et al. 2020).
Commonly recognized functions and processes that influence the habitat conditions within aquatic
areas are briefly summarized below.
Page 664 of 758
AUBURN CAO UPDATE - STREAMS
TECHNICAL MEMORANDUM / 2
Water Quality: Metrics for water quality include temperature, sediment, and pollutants. Wildlife,
including fish and amphibians, require cool clean water to meet their life history needs.
Riparian vegetation influences stream temperatures and microclimate conditions such as air
temperature, wind, light, and moisture. Factors affecting water temperature and microclimate
include shade, orientation, relative humidity, ambient air temperature, wind, channel
dimensions, groundwater, the hyporheic exchange zone where surface and groundwater
interact (Quinn et al. 2020).
Salmonids and amphibians are relatively sensitive to high temperatures, and have narrow
thermal tolerance (Quinn et al. 2020, Bury 2008).
A 100-foot-wide buffer is estimated to achieve 95 percent pollution removal and approximately
85 percent removal of surface nitrogen (Rentz et al. 2020).
Hydrologic Functions: Streams and riparian areas have complex and extensive connections to other
surface waters and groundwater resources in a watershed (Quinn et al. 2020).
Fish and wildlife are adapted to, and in some instances reliant upon, the natural variability in
seasonal and flood flows within a system.
Riparian vegetation reduces the quantity of surface water runoff through rainwater capture
and evapotranspiration (Wynn and Mostaghimi 2006).
Floodplains, wetlands, riparian vegetation and sinuous stream channels attenuate flood flows,
which protects downstream areas from flooding.
Physical Habitat Characteristics: Riparian microclimate affects many ecological processes and
functions, including plant growth, decomposition, nutrient cycling, succession, productivity, migration
and dispersal of flying insects, soil microbe activity, and fish and amphibian habitat (Quinn et al. 2020;
Brosofske, et al. 1997).
Large woody debris (LWD) plays a significant role in the geomorphic formation of stream
channels and in the creation of diverse channel habitat morphologies (Quinn et al. 2020).
Streams migrate naturally which often results in complex natural geomorphology, floodplains,
and heterogeneous ecosystems (Quinn et al 2020).
URBAN AREA IMPACTS
Water Quality Impacts:
Urban areas tend to contribute a disproportionate amount of sediment and contaminants to
receiving waters (Soranno et al. 1996). Some contaminants have significant effects on aquatic
organisms. For example, coho salmon pre-spawn mortality is caused by a breakdown product
of tire wear, 6PPD-quinone (Tian et al. 2021).
Increased erosion and bank instability coupled with a reduction of forest cover simplify stream
morphology, leading to incised, wider, and straighter stream channels (Konrad and Booth
2005).
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Removal of riparian vegetation impacts water quality by increasing stream temperatures (
Murray et al. 2000, Moore et al. 2005, Gomi et al. 2006).
Hydrologic Function Impacts: Impervious surface area within a watershed impacts hydrologic
functions.
Impervious surface is positively correlated with high flow volumes, daily streamflow variability
and negatively correlated with groundwater recharge rates and summer low flow volumes
(Burges, Wigmosta, and Meena 1998; Cuo et al. 2009; Jones 2000; Konrad and Booth 2005).
Urban development impacts stream flow by changing key metrics, including peak discharge,
lag time, flood frequency and total runoff (Quinn et al. 2020).
Less dynamic stream morphology is linked to accelerated water transport and reduced
temporary instream flood storage capacity (Kaufmann and Faustini 2012).
Habitat Fragmentation & Degradation: Habitat loss, degradation, and fragmentation have profound
impacts on wildlife and their ecosystems (Gaston 2010; Wiegand, Revilla, and Moloney 2005; Young et
al. 2016).
Habitat loss and fragmentation reduce biodiversity (MacArthur and Wilson 1967).
Cumulative impacts of direct and indirect habitat alterations tend to reduce the habitat
functions and values of wetlands and riparian areas (Azous and Horner 2010; Sheldon et al.
2005).
KEY PROTECTION STRATEGIES
Identification, classification, buffering and restrictions on adjacent land use are a common approach to
critical area protections.
Identification: The ordinary high-water mark (OHWM) is typically used to determine the edge of
surface waters for jurisdictional purposes. The OHWM should be determined in the field by a qualified
biologist using appropriate resources.
• Those resources include National Ordinary High Water Mark Field Delineation Manual for
Rivers and Streams (David et al. 2025), Determining the Ordinary High Water Mark for Shoreline
Management Act Compliance in Washington State (Anderson et al. 2016), and A Guide to
Ordinary High Water Mark (OHWM) Delineation for Non-perennial Streams in the Western
Mountains, Valleys, and Coast Region of the United States (Mersel and Lichvar 2014).
Classification: DNR classifies streams and other water bodies using a “water typing system” based on
various characteristics, fish use, and functions of a natural water feature (WAC 222-16-030). This system
was developed by Department of Natural Resources as part of forest management practices. Many
local jurisdictions have previously incorporated use of this water typing system in their CAOs for
applying buffer widths to streams.
The latest riparian management zone guidance from WDFW does not use the water typing system but
instead treats all streams equally and differentiates protection based on soil type and associated
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dominant tree species (Rentz et al. 2020). More information on this approach is summarized under the
Riparian Management Zones header below.
Buffers: Historically, most local jurisdictions in Washington state have managed stream and riparian
habitats using fixed- or standard-width stream buffers. Using this approach, buffer widths have
typically been determined based upon stream type characteristics and site-specific factors following
WAC 222-16-030. The latest WDFW guidance recommends a conceptual shift from the fixed-width
buffer approach regarding the way that streams and riparian areas are protected, as described in the
next section.
Riparian Management Zones: WDFW’s current recommendations for establishing RMZ widths are
based primarily on a site potential tree height (SPTH) framework, where the width of the RMZ would be
equivalent to one 200-year SPTH. The SPTH framework is based on a 1993 model developed by the
Forest Ecosystem Management Assessment Team (FEMAT) to understand how riparian functions
change with distance from a stream channel. This model, or relationship, is known as the FEMAT curves
and it demonstrates that most riparian ecosystem functions occur within one 200-year SPTH (Figure 1).
Figure 1. FEMAT curves figure, reproduced from Quinn et al. 2020 and Rentz et al. 2020.
Based on this model, WDFW recommends using tree height to estimate RMZ widths using their
Riparian Ecosystems and Online SPTH Mapping Tool (WDFW Riparian Ecosystems Maps and
Assistance) or Guidelines for Determining Site Potential Tree Height from Field Measurements (WDFW
January 2025). The intent is to base protections on site potential to perform full riparian ecosystem
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TECHNICAL MEMORANDUM / 5
functions. To manage and protect riparian ecosystems, WDFW recommends measuring the RMZ from
the ordinary high-water mark or channel migration zone, whichever is greater (Quinn et al. 2020; Rentz
et al. 2020).
Other Stream Management Recommendations
The following WDFW riparian management recommendations for urban areas should also be
considered for implementation (Rentz et al. 2020):
maintaining and improving functions through regulatory and voluntary means,
identifying and prioritizing restoration,
maintaining and improving riparian connections, and
applying stormwater management.
Auburn Streams / RMZ Review
ASSESSMENT APPROACH
City of Auburn planning staff and their GIS specialist compared SPTH values to current buffer widths
and potential riparian buffer increases. Since the Green River and White River are regulated under the
Shoreline Master Program (SMP), those waterbodies were excluded from the assessment. Streams
within the City that are not mapped by DNR or are designated ‘unknown’ are presumed non-fish
bearing for this assessment. Mapped wetlands and geologic hazard areas were included to show where
critical area protections overlap.
SPTH VALUES
SPTH values in the City of Auburn range from 94 feet to 227 feet with a mean of 166 feet and a median
of 196 feet (See enclosed ‘SPTH Buffers Map’ exhibit). The distribution of SPTH values is shown in the
pie chart below.
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The SPTH for Mill Creek along State Route 167 is 105 feet for most of the reach, which is mostly
surrounded by wetlands. Green River tributaries on the east side of the City commonly have a SPTH
value of 196 feet and have some overlap with landslide hazard areas. White River tributaries at the
south end of the City are highly variable and range from 105 feet to 204 feet. Som e overlap with
wetlands that are mapped in the White River tributaries.
SPTH values are recommended by WDFW to achieve full riparian function for each stream segment
based on site potential. Currently, stream buffers in Auburn are below the currently recommended
SPTH values for full riparian functions. Non-fish bearing stream (Type Np and Ns) buffers, for example,
are below the 100-foot minimum recommended to support water quality functions.
City P roposed S tream R egulations
The City did not propose substantive changes to stream protections in the October 2025 draft update
of the Auburn Municipal Code (AMC), Chapter 16.10 Critical Areas. However, based on this BAS review
and WDFW SPTH recommendations, the City is now proposing the following:
• Update riparian stream buffer widths as documented in Table 1 below.
• Measure riparian stream buffers from the ordinary high water mark. [Note: The Green River is
regulated by the SMP. This update would only apply to streams regulated under the CAO.]
• Add minimization measures for streams to the code, similar to the wetlands section. These
include directing lights away from the stream, routing untreated runoff away from the stream,
following stormwater best management practices (BMPs), and keeping pets and people out of
the buffer.
• Provide dense native vegetated buffer standards in the code.
• Require stream buffers to meet criteria for vegetation conditions and implement applicable
minimization measures or be subject to a width increase.
• Incorporate the term ‘riparian’ into the stream code section to acknowledge the critical
ecosystem functions riparian buffers provide.
The City plans to retain their existing classification system, consistent with the water typing system
provided in WAC 222-16-030 as Type S, Type F, Type Np or Type Ns (AMC 16.10.080.E). This
classification system is based on presence or absence of fish habitat, flow conditions, and location
relative to shoreline jurisdiction. Note: The current code update does not review shoreline regulations
under the City’s Shoreline Master Program (SMP).
Auburn measures stream buffers from the ordinary high-water mark (OHWM) and assigns stream
buffer widths based on the stream type under AMC 16.10.090.C.2 and 16.10.090.E.2, respectively.
Stream buffers under the current City code and proposed update are summarized in Table 1 below and
in the enclosed exhibits. Under current City code, minimum buffer widths may be increased up to the
maximum buffer value by the Director based on site-specific conditions, such as where endangered,
threatened, or sensitive (ESA-listed) species have a primary association with critical area habitat. The
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City code (AMC 16.10.090.E.2.b) provides a list of enhancement options an applicant can propose to
justify a buffer width less than the maximum. These enhancement options include removal of fish
barriers, adding in-stream log structures and habitat features, stream daylighting, and culvert
improvements for fish passage. Under proposed code changes, minimization measures and vegetated
buffer condition standards would be added to these buffer provisions.
Table 1. Stream Types and buffer widths under current and 10-2025 draft AMC 16.10.080 and 090.
Stream Type
10-2025 Draft Code 02-2026 Proposed Code
Minimum buffer Maximum buffer1 Standard Buffer1 Increased Buffer2
Type S Per SMP Per SMP Per SMP Per SMP
Type F 100 ft 150 ft 150 ft 200 ft
Type Np 50 ft 100 ft 100 ft 133 ft
Type Ns 50 ft 75 ft 100 ft 133 ft
1 Director decision based on site-specific conditions, such as presence of critical habitat for ESA species.
2 In addition to ESA review, an increase applies if the applicant does not implement applicable minimization
measures and does not meet vegetated buffer standards.
Auburn allows stream buffer averaging for Type F and Type Np waters that meet code criteria under
AMC 16.10.090.E.2.d. Buffer averaging requires implementation of one or more stream enhancement
measure, maintains the same total buffer area as the standard buffer, limits reduction at any given
point to 25 percent, and results in equal or greater functions and values. Auburn proposes to retain this
flexibility in their code update. The City adopted Ecology’s 2024 Stormwater Management Manual for
Western Washington and those best practices will be applied to maintain water quality standards.
Newly added provision AMC 16.10.090.E.2.e addresses functionally disconnected buffer areas, to
exclude disconnected or functionally isolated stream buffer areas. A critical areas report is required to
confirm such functional disconnectedness. The functionally disconnected buffer provision will be
retained under the proposed update.
Discussion
As Auburn considers BAS for streams and riparian areas, we recognize stream regulations will be
reviewed from an implementation feasibility perspective and are balanced with other Growth
Management Act requirements. For example, the City considered zoning, existing land uses, and
environmental permit administration when evaluating regulatory options.
The GIS analysis was conducted to support the City’s review of stream / riparian protections relative to
Comprehensive Planning goals and existing land uses (see enclosed exhibits). The proposed 150-foot
Type F stream buffer is 77 percent of the median SPTH value of 196. As the FEMAT curve shows, the
relationship between buffer width and cumulative effectiveness is not linear. The proposed buffer
increase is near the point where width increases start to yield diminished returns in cumulative
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TECHNICAL MEMORANDUM / 8
effectiveness. The minimum 100-foot buffer is proposed for Type Np and Ns streams to maintain water
quality.
Additionally, City of Auburn’s 2024 Comprehensive Plan identifies urban separators. Urban separators
are areas designated for low-density uses and are intended to protect resource lands, rural areas, and
environmentally sensitive areas. Urban separators also create open space and wildlife corridors within
and between communities.
The City of Auburn is incorporating BAS in their proposed CAO Stream update through the following
measures.
• Riparian stream buffer widths are increasing to better align with SPTH values. The 150-foot
riparian buffer for Type F streams is representative of average SPTH values in Auburn and aligns
with highly effective riparian function per the FEMAT curve (see Figure 1 above). A 100-foot
buffer will be applied to non-fish bearing streams to protect water quality consistent with BAS.
• Measure riparian stream buffers from the ordinary high water mark. [Note: Mapped channel
migration zones (CMZ) in Auburn are along the Green River; those areas are regulated by the
SMP.]
• The City plans to add minimization measures to the stream buffer code, by cross referencing or
repeating those listed for wetlands under AMC 16.10.090.E.1.
• Auburn plans to add vegetation condition standards to stream buffer / riparian regulations
under AMC 16.10.090.E.2.
• The City plans to apply a riparian buffer width increase if an applicant’s project does not
implement applicable minimization measures, and/or does not meet vegetation condition
standards for buffers (Table 1 above).
• Where appropriate, use the term ‘riparian’ to document the importance of both in-stream and
riparian areas as an ecosystem.
The following additional BAS-based recommendations for updates to the Auburn CAO are in review.
• Review AMC 16.10 for the use of the terms stream, stream type, stream buffer, riparian, and
riparian management zone. After updates to stream classification (AMC 16.10.080) and stream
buffers (16.10.090) are complete, review use of the above terms throughout the code for
consistency and clarity.
• Cross-reference City stormwater management code requirements where applicable to
strengthen critical area protections. Auburn has adopted Ecology’s 2024 Stormwater
Management Manual for Western Washington.
The proposed updates to Auburn stream regulations are the product of a thorough review of BAS and
City-specific considerations for administration and implementation.
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References
Auburn, City of. 2024. Comprehensive Plan.
Azous, P., and R. Horner. 2010. Wetlands and Urbanization: Implications for the Future. CRC Press.
Brosofske, K., J. Chen, R. Naiman, and J. Franklin. 1997. “Harvesting Effects on Microclimate Gradients
from Small Streams to Uplands in Western Washington.” Ecological Applications 7 (4): 1188–1200.
Burges, S., M. Wigmosta, and J. Meena. 1998. “Hydrological Effects of Land-Use Change in a Zero-Order
Catchment.” Journal of Hydrologic Engineering.
Bury, R. 2008. “Low Thermal Tolerances of Stream Amphibians in the Pacific Northwest: Implications for
Riparian and Forest Management.” Applied Herpetology 5 (1): 63–74.
Cuo, L., D. Lettenmaier, M. Alberti, and J. Richey. 2009. .“.Effects of a Century of Land Cover and Climate
Change on the Hydrology of the Puget Sound Basin.” Hydrological Processes 23:907–9.
Gaston K.J. 2010. Urban Ecology. 1st ed. Cambridge University Press.
https://doi.org/10.1017/CBO9780511778483.
Gomi, T., Moore, R. D., & Dhakal, A.S. (2006). Headwater stream temperature response to clear-cut
harvesting with different riparian treatments, coastal British Columbia, Canada. Water Resources
Research, 42(8), W08437. https://doi.org/10.1029/2005WR004162
Jones, J. A. 2000. “Hydrologic Processes and Peak Discharge Response to Forest Removal, Regrowth,
and Roads in 10 Small Experimental Basins, Western Cascades, Oregon.” Water Resources Research 36
(9): 2621–42. https://doi.org/10.1029/2000wr900105.
Kaufmann, P., and J. Faustini. 2012. “Simple Measures of Channel Habitat Complexity Predict Transient
Hydraulic Storage in Streams.” Hydrobiologia 685:69–95.
Konrad, C.P., and D. Booth. 2005. “Hydrologic Changes in Urban Streams and Their Ecological
Significance.” American Fisheries Society Symposium 47:157–77.
MacArthur, R.H., and E.O. Wilson. 1967. The theory of island biogeography. Princeton University Press.
Mersel, Matthew, and Robert Lichvar. 2014. “A Guide to Ordinary High Water Mark (OHWM)
Delineation for Non-Perennial Streams in the Western Mountains, Valleys, and Coast Region of the
United States.” 14–13. ERDC/CRREL TR. Pacific Coast (U.S.): U.S. Army Engineer Research and
Development Center, Cold Regions Research and Engineering Laboratory.
Moore, R.D., and S. Wondzell. 2005. “Physical Hydrology and the Effects of Forest Harvesting in the
Pacific Northwest.” A Review 41:763–84.
Murray, G.L.D., Edmonds, R.L. & Marra, J.L., (2000). Influence of partial harvesting on stream
temperatures, chemistry, and turbidity in forests on the western Olympic Peninsula, Washington.
Northwest Science, 74(2), 151-164. https://hdl.handle.net/2376/1065
Quinn, T., G.F. Wilhere, and K.L. Krueger. 2020. “Riparian Ecosystems, Volume 1: Science Synthesis and
Management Implications.” Olympia: Washington Department of Fish and Wildlife.
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Rentz, T, Amy Windrope, Terra Rentz, Keith Folkerts, and Jeff Azerrad. 2020. “Riparian Ecosystems,
Volume 2: Management Recommendations.” Olympia, Washington: Washington Department of Fish
and Wildlife. https://wdfw.wa.gov/sites/default/files/publications/01988/wdfw01988.pdf.
Sheldon, D., P. Hruby, P. Johnson, K. Harper, A. McMillan, T. Granger, and E. Stockdale. 2005. “Wetlands
in Washington State, Volume 1: A Synthesis of the Science.” Washington Department of Ecology.
Publication # 05-06-006.
Soranno, P. A., S. L. Hubler, S. R. Carpenter, and R. C. Lathrop. 1996. “Phosphorus Loads to Surface
Waters: A Simple Model to Account for Spatial Pattern of Land Use.” Ecological Applications 6 (3): 865–
78. https://doi.org/10.2307/2269490.
Tian, Z., H. Zhao, K.T. Peter, M. Gonzalez, J. Wetzel, C. Wu, and E.P. Kolodziej. 2021. “A Ubiquitous Tire
Rubber–Derived Chemical Induces Acute Mortality in Coho Salmon.” Science 371 (6525): 185–89.
WDFW (Washington Department of Fish and Wildlife. 2025. Guidelines for Determining Site Potential
Tree Height from Field Measurements. Olympia, WA.
Wiegand, T., E. Revilla, and K.A. Moloney. 2005. “Effects of Habitat Loss and Fragmentation on
Population Dynamics.” Conservation Biology 19 (1): 108–21.
Wynn, T.M. and Mostaghimi, S. 2006. Effects of riparian vegetation of stream bank subaerial processes
in southwestern Virginia, USA. Earth Surface Processes and Landforms, Volume 31, Issue 4: 399-413.
https://doi.org/10.1002/esp.1252.
Young, H.S., D.J. McCauley, M. Galetti, and R. Dirzo. 2016. “Patterns, Causes, and Consequences of
Anthropocene Defaunation.” Annual Review of Ecology, Evolution, and Systematics 47 (1): 333–58.
https://doi.org/10.1146/annurev-ecolsys-112414-054142.
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State of Washington
Department of Fish and Wildlife, Region 4
Region 4 information: 16018 Mill Creek Blvd, Mill Creek, WA 98012 | phone: (425)-775-1311
1
September 12, 2025
City of Auburn
Alyssa Tatro, Senior Planner
25 W Main Street
Auburn, WA 98001
RE: Submittal ID 2025-S-9767, WDFW’s comments for Auburn Critical Area Ordinance
amendments
Dear Ms. Tatro,
On behalf of the Washington Department of Fish and Wildlife (WDFW), thank you for the
opportunity to comment on Auburn’s draft Critical Area Ordinance (CAO) amendments as part
of the current periodic update.
Within the State of Washington’s land use decision-making framework, WDFW is considered a
technical advisor for the habitat needs of fish and wildlife and routinely provide s input into the
implications of land use decisions. We provide these comments and recommendations in
keeping with our legislative mandate to preserve, protect, and perpetuate fish and wildlife and
their habitats for the benefit of future generations – a mission we can only accomplish in
partnership with local jurisdictions.
Table 1. Recommended changes to proposed code language.
Code Section Code Language
(with WDFW suggestions in red) WDFW Comment
16.10.010
Purpose
and intent
A....Such areas within the city
include wetlands, streams, wildlife
habitat fish and wildlife habitat
conservation areas, aquifer
recharge areas, geologic hazard
areas, and...
Jurisdictions are required to address five types of
critical areas in their regulations, as outlined in
WAC 365-196-830. We recommend revising this
section to explicitly list Fish and Wildlife Habitat
Conservation Areas (FWHCAs) to ensure
consistency with state terminology. Because
streams are included under this designation,
there is no need to list them separately within
this section, though jurisdictions may choose to
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2
do so if they wish to emphasize this type of
FWHCA.
16.10.010
Purpose
and intent
B(2.) Streams. Streams and their
associated riparian corridors
Riparian Management Zones
(RMZs) provide important fish and
wildlife habitat; help to maintain
water quality; store and convey
storm water and flood water;
recharge groundwater; recruit
large woody debris to create
habitat structure; provide shade
to maintain water temperatures
and dissolved oxygen levels;
support bank integrity and root
reinforcement to reduce erosion;
and serve as areas for recreation,
education and scientific study and
aesthetic appreciation. Stream
buffers serve to moderate runoff
volume and flow rates; reduce
sediment, chemical nutrient and
toxic pollutants; provide shading
to maintain desirable water
temperatures; provide habitat for
wildlife; and protect stream
resources from harmful intrusion.
As noted above, streams are already included
within the FWHCA designation. The streams and
wildlife habitat sections here (B.2. and B.3.) could
be merged if desired. Additionally, we
recommend substituting stream and stream
buffer terminology throughout this chapter with
‘Riparian Management Zone (RMZ),’ consistent
with WDFW’s Best Available Science (BAS) and
guidance document. RMZs better capture the
ecological scope and functions of these areas,
which extend beyond the stream channel itself
and include the adjacent riparian corridor
necessary to sustain fish and wildlife populations
and overall watershed health. RMZs support five
key ecological functions: (1) recruitment of large
woody debris to create habitat structure, (2)
shading to maintain water temperatures and
dissolved oxygen levels, (3) bank integrity and
root reinforcement to reduce erosion and
maintain habitat quality, (4) filtration of nutrients
and sediments in surface and subsurface flows to
protect water quality, and (5) provision of diverse
riparian habitat for fish and wildlife species.
Updating this terminology will ensure your code
reflects current science and aligns with WDFW
recommendations for protecting Fish and Wildlife
Habitat Conservation Areas .
16.10.010
Purpose
and intent
B(3.) Wildlife Habitat and Wildlife
Habitat Corridors.
We appreciate the language within this section
that references the need for connectivity
between habitat areas and the coordination for
connected open spaces, as required by WAC 365-
196-335. We recommend including Wildlife
Habitat Corridors as a distinguished type of
FWHCA here and later in this chapter to further
align with these requirements.
16.10.010
Purpose
and intent
E. Best Available Science - The city
intends to review and monitor
implementation of its critical areas
regulations and to use an adaptive
management approach. It will
make adjustments to the
regulations, as appropriate, in
response to changing conditions,
new information about best
available science, or empirical
We appreciate the inclusion of adaptive
management in this section. Does the city
currently have a reporting process or adaptive
management plan that tracks the CAO’s
effectiveness in achieving no net loss, evaluates
whether exemptions and variances may
cumulatively affect critical area functions and
values, and measures improvements in permit
implementation? For more info, see Commerce's
Critical Areas Handbook, Chapter 7.
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3
data indicating the effectiveness
of its regulatory program.
Additionally, please see WDFW’s current best
available science standards and management
recommendations (released in 2020) for riparian
management zones (RMZs)
16.10.020
Definitions
“Channel Migration Zone” means
the area within which a river
channel is likely to move laterally
over a specified period (e.g., 100
years).
Local governments should identify and limit
development within Channel Migration Zones
(CMZs)(WAC 173-26-221). Additionally,
identifying CMZs helps guide development away
from high-risk areas and reduces flood hazards.
CMZs are critical for maintaining the dynamic
processes that support riparian ecosystems.
Without addressing CMZs, the CAO may fail to
fully protect the functional riparian areas that
naturally shift over time. We encourage the city
to incorporate this CMZ definition as well as
delineate riparian management zones (RMZs)
from the edge of the CMZ if present.
For further information, please see the WA
Department of Ecology’s (DOE) informational
webpage as well as WDFW’s Riparian Ecosystems,
Volume 2: Management Recommendations.
16.10.020
Definitions
“Ecosystem functions" are the
products, physical and biological
conditions, and environmental
qualities of an ecosystem that
result from interactions among
ecosystem processes and
ecosystem structures. Ecosystem
functions include, but are not
limited to, sequestered carbon,
attenuated peak streamflow,
aquifer water level, reduced
pollutant concentrations in
surface and ground waters, cool
summer in-stream water
temperatures, and fish and
wildlife habitat functions.
We suggest including the adjacent definition of
‘Ecosystem Functions.’ ‘Functions’ as a
standalone term is defined later in this section,
but we suggest alignment with language found in
WAC 365-196-210 (14).
16.10.020
Definitions
“Ecosystem values" are the
cultural, social, economic, and
ecological benefits attributed to
ecosystem functions.
See comment above and WAC 365-196-210 (15).
16.10.020
Definitions
"Fish habitat" or "habitat that
supports fish life" means habitat,
which is used by fish life at any life
stage at any time of the year
including potential habitat likely
to be used by fish life, which could
We recommend that the city include the WAC
220-660-030(52) definition of “fish habitat” to
ensure consistency with state regulations and
provide comprehensive protection of aquatic
ecosystems. “Fish Habitat” is also mentioned
Page 676 of 758
4
reasonably be recovered by
restoration or management and
includes off-channel habitat.
later in this chapter for categorizing “Type F”
streams.
16.10.020
Definitions
“Hazard tree” is considered a
threat to life, property, or public
safety. Due to their high habitat
value, hazard tree removal shall
not adversely affect ecosystem
functions to the extent
practicable, encourage the
creation of snags (Priority Habitat
features) rather than complete
tree removal, involve an
avoidance and minimization of
damage to remaining trees and
vegetation, and require a qualified
arborist to evaluate requests for
hazard tree removal.
We recommend defining “Hazard Tree” in order
to designate regulations that guide removal and
mitigation if necessary.
16.10.020
Definitions
“Monitoring and Adaptive
Management” means the process
of monitoring and improving
permits, regulations, and
programs to ensure the protection
of critical areas.
This definition comes from the Department of
Commerce. See further info in the comments
given above for 16.10.010 Purpose and intent,
section E.
16.10.020
Definitions
“No Net Loss of Critical Areas”
refers to the actions taken to
achieve and ensure no overall
reduction in existing ecosystem
functions and values or the
natural systems constituting the
protected critical areas. This may
involve fully offsetting any
unavoidable impacts to critical
area functions and values
pursuant to the Growth
Management Act, WAC 365-196-
830 ‘Protection of critical areas,’
or as amended.
We recommend including this definition, as it is
referenced throughout this chapter.
16.10.020
Definitions
“Riparian management zone”
(RMZ) means the area that has the
potential to provide full riparian
functions. In many forested
regions of the state, this area
occurs within one 200-year site-
potential tree height measured
from the edge of the stream
channel. In situations where a
We suggest adding ‘Riparian Management Zone’
as its own definition, to replace ‘stream buffer’
terminology. This is especially important when
considering RMZs as a type of critical area and
not buffers to critical areas. For further related
management recommendations, see WDFW’s
Riparian Ecosystems, Volume 2: Management
Recommendations.
Page 677 of 758
5
CMZ is present, this occurs within
one site potential tree height
measured from the edges of the
CMZ. In non-forest zones, the RMZ
is defined by the greater of the
outermost point of the riparian
vegetative community or the
pollution removal function, at 100
feet.
16.10.020
Definitions
“Watershed Plan” means a plan
developed by federal, tribal, state,
and/or local government agencies
and/or appropriate non-
governmental organizations, in
consultation with relevant
stakeholders, for the specific goal
of aquatic resource restoration,
establishment, enhancement, and
preservation. A watershed plan
addresses aquatic resource
conditions in the watershed,
multiple stakeholder interests,
and land uses. Watershed plans
may also identify priority sites for
aquatic resource restoration and
protection.
Including a definition for “Watershed Plan”
provides clarity when referencing locally or
regionally adopted plans that guide aquatic
resource restoration and protection. It helps
ensure consistency in implementation, supports
landscape-scale planning, and allows jurisdictions
to align CAO decisions, such as mitigation,
restoration priorities, and buffer considerations,
with established, stakeholder-informed
watershed efforts. This definition also
acknowledges the role of collaborative, science-
based planning in achieving long-term ecological
outcomes.
16.10.040
Exemption
s and
nonconforming
uses
A(4.) Minor Utility and Street
Projects. Utility or street projects
which have minor or short
duration impacts to critical areas,
as determined by the director in
accordance with the criteria
below, and which do not
significantly impact the functions
or values of a critical area(s);
provided, that such projects are
constructed with best
management practices and
additional restoration measures
are provided.
Critical area reports shall be required for all
projects that impact critical areas in order to
demonstrate that mitigation will reach no net loss
standards. Part A of this section describes no
intent to require a critical area report. A(4.)
indicates allowance for impacts to critical areas
with no formal mitigation plan. This is not in
alignment with no net loss principles and state
requirements (per WAC 365-196-830 and WAC
365-190-080).
16.10.040
Exemption
s and
nonconforming
uses
A(7.) Additions to a legally
established single-family
residential structure in existence
before May 13, 2005, with a
wetland or stream buffer located
within the property, may be
Buffers exist to maintain the ecological functions
and values of a critical area, including water
quality, habitat, and bank stability. Allowing new
impervious surfaces within a buffer directly
undermines these purposes by increasing runoff,
reducing infiltration, and degrading habitat. For
this reason, we recommend removing any
Page 678 of 758
6
permitted if all of the following
criteria are met:
a. The addition is no greater than
500 square feet of building
footprint over that in existence as
of May 13, 2005;
b. The addition is not located
closer to the critical area than the
existing structure;
c. Impacts on critical area
functions are avoided consistent
with the purpose and intent of
this title and as demonstrated in a
critical area report by a qualified
consultant; and
provisions that allow additions of hardscape
within buffers. It is also difficult to track the
cumulative impacts of these incremental
additions of impervious surface over time,
especially given that many properties have
undergone multiple alterations across decades
(often 50+ years), making it challenging to assess
the true extent of buffer loss and ecological
degradation.
At a minimum, we recommend that this section
clearly state that no development or structures
are allowed within 100 feet of a stream, as this is
the minimum width identified by WDFW’s BAS to
effectively filter pollutants if fully vegetated.
16.10.040
Exemption
s and
nonconforming
uses
A(12.) Activities in storm and
water quality basins and
“wetlands” created by poorly
maintained or plugged culverts or
pipes, and artificially created
ditches that are not used by fish
salmonids;
This section currently allows work in areas of
plugged culverts without a permit unless there is
salmonid use. We recommend clarifying that such
activities are not exempt from Hydraulic Project
Approval (HPA) requirements under state law,
and that applicants should contact WDFW to
determine HPA applicability prior to beginning
work. In addition, we suggest revising the
language to reference “fish” rather than
“salmonid” to align with state requirements to
protect all fish species.
16.10.040
Exemption
s and
nonconforming
uses
A(13.) Minor activities not
mentioned above and determined
by the director to have no minimal
impacts to a critical area and will
result in no net loss of ecological
values and functions.
State law requires no net loss of ecological values
and functions to critical areas (per WAC 365-196-
830 and WAC 365-190-080). If impacts are
unavoidable, mitigation must be outlined within a
plan completed by a qualified professional.
16.10.050
Critical
areas maps
General Comment We recommend including WDFW’s 200-year Site-
potential Tree Height (SPTH200) and Riparian
Management Zone (RMZ) Values mapping
resource and WDFW’s PHS map within the city’s
mapping resources.
16.10.070
Critical
area review
process and
application
requirements
C. Consultant Qualifications and
City Review. All reports and
studies required of the applicant
by this section shall be prepared
by a qualified consultant as that
term is defined in these
regulations.
For delineating RMZs, we recommend pointing
the applicant towards the qualified professional
resources in Appendix A of WDFW’s Guidelines
for Determining Site Potential Tree Height from
Field Measurements.
16.10.080
Classificati
E(5.) ...Intentionally created
streams are excluded from
regulation under this section,
It is important to note that all waterways
supporting fish must be protected. Where a
waterway has been intentionally created for
Page 679 of 758
7
on and rating of
critical areas
except manmade streams that
provide “critical habitat,” as
designated by federal or state
agencies, for salmonids, or
streams that contain fish.
Intentionally created streams
must install fish exclusion devices
when applicable to protect fish
life.
irrigation or similar purposes and does not follow
the historic path of natural water flow,
appropriate fish exclusion devices should be
installed, where applicable, to prevent fish from
entering these areas. WDFW is available to plan
and permit new fish exclusion devices.
16.10.080
Classificati
on and rating of
critical areas
F. Wildlife Habitat Classification.
Wildlife habitat areas shall be
classified as critical, secondary or
tertiary according to the criteria in
this section:
Critical areas listed under the FWHCA designation
must be fully protected as critical areas, ensuring
that there is no net loss of ecological values and
functions within these areas. Please review WAC
365-190-130 and incorporate all FWHCA’s
required for protection within this section that
exist within Auburn. We also recommend
including ‘Riparian Management Zones’ and
‘Wildlife Habitat Corridors’ as distinct types of
critical areas under the FWHCA designation.
16.10.080
Classificati
on and rating of
critical areas
F(e.) Riparian Management Zones
Buffers for critical habitat shall be
consistent with Washington
Department of Fish and Wildlife
Riparian Ecosystems.
(f.) Wildlife Habitat Corridors
Although appreciated, this addition seems out of
place. The FWHCA section of the CAO should first
outline the types of FWHCAs and later define the
requirements for protecting each type within
dedicated sections.
16.10.080
Classificati
on and rating of
critical areas
2. “Secondary habitat”
3. “Tertiary habitat”
We do not recommend using ratings to
distinguish different requirements for FWHCAs.
All critical areas are subject to the same
protection standard of no net loss.
16.10.090
Buffer
areas and setbacks
A. General Provisions. The
establishment of on-site buffers,
buffer areas or setbacks shall be
required for all development
proposals and activities in or
adjacent to wetlands, streams,
fish and wildlife habitat
conservation areas, and
geologically hazardous areas...
We suggest aligning this chapter with state
language that describes the five types of critical
areas that require protection, including Fish and
Wildlife Habitat Conservation Areas (FWHCAs).
16.10.090
Buffer
areas and setbacks
C. Buffers shall be measured as
follows:
...2. Stream buffers – the buffer
shall be measured perpendicular
from the channel migration zone if
present. If a channel migration
zone is not present, the ordinary
high water mark shall be used;
Local jurisdictions should identify and limit
development within Channel Migration Zones
(CMZs)(WAC 173-26-221). We encourage the City
to incorporate a CMZ definition as well as
delineate riparian management zones (RMZs)
from the edge of the CMZ if present, as outlined
in WDFW’s Riparian Ecosystems, Volume 2:
Management Recommendations. The CMZ
reflects where the river is most likely to erode
Page 680 of 758
8
banks, flood, or change course. Limiting
development within the CMZ reduces risks to
public safety, property, and infrastructure, while
also protecting riparian functions. If RMZs are
measured only from the ordinary high-water
mark, development may be permitted in areas
highly prone to channel movement and flood
hazards, creating long-term safety and liability
issues for the jurisdiction.
16.10.090
Buffer
areas and setbacks
E(2.) Riparian Management Zones
Stream buffers shall be
established as follows:
WDFW’s BAS and management recommendations
(Riparian Ecosystems Vol. 1 & 2, 2020) emphasize
that riparian areas are not just buffers but critical
habitats in their own right. Although riparian
ecosystems constitute a small portion of the
surface landscape, approximately 85% of
Washington’s wildlife species are known to use
riparian areas associated with rivers and streams.
Of these, 170 species may be riparian obligates,
i.e., require riparian habitat to survive.
Recognizing RMZs as a type of critical area rather
than simply a buffer is necessary to reflect their
ecological importance and align with WDFW’s
BAS.
16.10.090
Buffer
areas and setbacks
2.
Stream Type Minimum
Riparian
Management
Zone Buffer
Width (in feet)
Type S Per SMP
Type F SPTH 100
Type Np SPTH 50
Type Ns SPTH 50
The widths in this table do not represent
sufficient protection standards for riparian areas.
All streams, independent of fish use, shall have
protection measures that ensure no net loss of
ecological values and functions. WDFW’s current
best available science standards and
management recommendations outline the need
to use the Site Potential Tree Height at 200 years
(SPTH200) to measure RMZ widths (see WDFW’s
mapping tool and field delineation guidance).
To stop pollutants from entering streams, RMZs
must be 100 feet wide and fully vegetated at a
minimum. Meeting RMZ standards is especially
critical in highly developed areas like Auburn,
where elevated levels of impervious surface
contribute to increased stormwater runoff and
water quality degradation. The importance of
addressing water quality concerns is
demonstrated by the listing of many water bodies
within the city on Ecology’s 303(d) list, which
outlines a trend of continued degraded biological
integrity over time.
The GMA also requires jurisdictions to give
"special consideration" to conservation or
protection measures necessary to preserve or
Page 681 of 758
9
enhance anadromous fisheries (WAC 365-195-
925) as well as incorporate regulations to address
issues at the watershed scale (WAC 365-196-
830(6)). This is especially relevant to Auburn and
echoes the commitments made by the city in the
WRIA 9 Interlocal Agreement. Stream-related
critical area regulations within Auburn are
instrumental in the recovery of federally listed
Chinook salmon species. As outlined very clearly
in the WRIA 9 Salmon Habitat Plan 2021 Update,
Auburn has many priority projects that, if
completed, would greatly benefit the watershed.
16.10.090
Buffer
areas and setbacks
General comment According to WDFW’s SPTH map, many RMZ
widths look to be around 100 feet within Auburn.
This means that it is likely that only a very small
number of property owners would experience
new critical area restrictions on their properties.
These property owners also have the option to
apply for reasonable use exemptions. We also
recommend adding a section outlining the
allowance for decreased widths for areas that are
isolated from the critical area, similar to the
wetlands section. For instance, Woodinville
outlines “if a portion of a riparian management
zone is determined to be functionally isolated and
physically separated from the watercourse due to
existing, legally established public roadways,
railroads or other legally established structures or
paved areas...the director may exclude this area
from a riparian management zone provided...,”
which can be found in the July 24th, 2025
planning commission packet.
16.10.090
Buffer
areas and setbacks
2(b.) The buffer widths required in
this section may be increased by
the director up to a maximum of
50 percent for Type F and Ns
streams and up to 100 percent for
Type Np streams in response to
site-specific conditions and based
on the report information...
This seems voluntary. We recommend language,
such as “standard RMZ widths are based on the
assumption that the area is densely vegetated
with a native plant community appropriate for
the ecoregion, consisting of an average of 80%
native cover comprised of trees, shrubs, and
groundcover plants. If the existing RMZ is sparsely
vegetated or vegetated with invasive species, the
RMZ must either be enhanced through an
approved mitigation plan or increased by 33%.”
Covington (Planning Commission meeting),
Woodinville (planning commission packet), Skagit
County (meeting agenda packet (14.24.530)), and
other jurisdictions all utilize some version of the
above language to incentivize healthy critical area
buffers.
Page 682 of 758
10
16.10.090
Buffer
areas and setbacks
2(c.)(ii.) For construction of new
public roads and utilities, and
accessory structures, when no
feasible alternative location exists;
or...
See comments for 16.10.040 Exemptions and
nonconforming uses, A(7.) above.
16.10.090
Buffer
areas and setbacks
2(d.) Buffer width averaging may
be allowed for Type F and Type Np
streams only; provided, that all of
the following are demonstrated by
the applicant:
We do not recommend stream buffer averaging.
WDFW has found no scientific evidence
supporting the idea that reducing a riparian
buffer in one area while expanding it elsewhere
achieves no net loss of ecological functions and
values. WDFW’s Riparian Ecosystems, Volume 1:
Science Synthesis and Management Implications
(2020) shows that riparian buffer widths are
established based on the specific ecological
functions they are intended to support, which are
directly tied to the width, continuity, and quality
of vegetation within the buffer.
If buffer averaging is retained, we recommend
adding a provision within this section that no
width can be below 100 feet at any one point to
ensure adequate pollution removal.
16.10.090
Buffer
areas and setbacks
2(e.) Stream buffer widths may be
reduced by the director on a case-
by-case basis by up to 25 percent
if an applicant demonstrates...
See comment above. No RMZ/stream buffer
should be reduced.
16.10.090
Buffer
areas and setbacks
3. Wildlife Habitat Areas.
a. Buffer widths for critical habitat
areas shall be determined by the
director based on consideration of
the following factors: species
recommendations of the
Department of Fish and Wildlife;
recommendations contained in
the wildlife report and the nature
and intensity of land uses and
activities occurring on the site and
on adjacent sites. Buffers shall not
be required for secondary or
tertiary habitat. When designated
Priority Habitat or Species are
present, buffer widths shall
conform to the best available
science guidance in WDFW’s
Riparian Ecosystems, Volume 2:
Management Recommendations
(2020), or as updated. The
director may require a critical area
Riparian protection should be defined in the
section above. Section 3 should be specific to
other wildlife habitats.
Page 683 of 758
11
report prepared by a qualified
professional to document
compliance.
16.10.090
Buffer
areas and setbacks
3(b.) Buffer widths for critical
habitat areas may be modified by
averaging buffer widths or by
enhancing or restoring buffer
quality.
See comments for 16.10.090 Buffer areas and
setbacks. 2(d.) above.
16.10.100
Alteration
or development of
critical areas –
Standards and
criteria –
Prohibited uses
B(3.) Culverts are allowable only
under the following
circumstances:
c. When the following design
criteria are met:
IV. Future climate-related impacts,
such as projected high flows, shall
be considered when reviewing
proposals. This should be done in
accordance with the Washington
Department of Fish and Wildlife’s
guidance document Incorporating
Climate Change into the Design of
Water Crossing Structures: Final
Project Report and the
accompanying Culvert and Climate
Change web application.
It’s important to include climate-related impacts
in Critical Areas development regulations because
projected changes in streamflow, such as higher
peak flows and more frequent flooding, could
directly affect the stability and function of water
crossings and riparian systems. Designing for
future conditions reduces the risk of
infrastructure failure, prevents costly retrofits,
and ensures continued protection of fish habitat
and water quality.
16.10.100
Alteration
or development of
critical areas –
Standards and
criteria –
Prohibited uses
C(2.) Secondary Habitat...
(3.) Tertiary Habitat...
See comments for 16.10.080 Classification and
rating of critical areas, part F, above.
16.10.110
Mitigation
standards,
location, and
timing, wetland
replacement
ratios, and long-
term protection
requirements
1. All feasible and reasonable
measures as determined by the
department have been taken to
reduce impacts and losses to the
critical area, or avoid impacts
where avoidance is required by
these regulations including, where
applicable;
I) Alternative building
locations on the property;
II) Adjustments to the
project footprint and
orientation;
We recommend this section specify the
avoidance measures applicants must consider.
Avoidance of impacts is the most critical step in
the mitigation sequence, and applicants should
be required to demonstrate that they have taken
meaningful steps to avoid impacts. This often
necessitates clear, specific criteria to show that
avoidance was fully evaluated before moving on
to other steps within the mitigation sequence.
Page 684 of 758
12
III) Modification of setbacks,
where feasible, as a first
option before encroaching
into critical areas or their
buffers;
IV) Multi-story design or
alternate building design
16.10.110
Mitigation
standards,
location, and
timing, wetland
replacement
ratios, and long-
term protection
requirements
B(3.) In-kind mitigation shall be
provided unless the applicant
demonstrates, and the director
concurs, that on-site mitigation is
not feasible and out-of-kind
mitigation will result in equal or
greater ecological or habitat
function. Out-of-kind mitigation
may be approved only where it
provides equal or greater benefits
to critical area functions.
For streams, it is essential that ecosystem
functions and values be replaced on-site. The
removal of trees adjacent to a stream can
immediately results in increased water
temperatures, reduced bank stability, and a loss
of habitat complexity, impacts that cannot be
effectively replicated elsewhere. Off-site
mitigation does not restore these site-specific
processes. We recommend that this section
specify off-site mitigation guidance specific to the
critical area type.
16.10.110
Mitigation
standards,
location, and
timing, wetland
replacement
ratios, and long-
term protection
requirements
D(a.) The director determines that
it would provide appropriate
compensation for the proposed
impacts and on-site mitigation is
infeasible.
Including the adjacent edit ensures that in-lieu
fee mitigation is only used as a last resort,
consistent with the mitigation sequence. On-site
mitigation is critical because many ecological
functions cannot be adequately replaced
elsewhere because they support the wider
ecosystem at that specific location. Without this
clause, applicants could more easily bypass on-
site mitigation thereby weakening protections
and undermining no net loss standards.
16.10.110
Mitigation
standards,
location, and
timing, wetland
replacement
ratios, and long-
term protection
requirements
F. Mitigation Plan Requirements.
When a project involves critical
area or critical area wetland
and/or buffer impacts, a
mitigation plan prepared by a
qualified wetland professional
shall be required, meeting the
following minimum standards:
This language should be edited to represent the
requirements to protect all types of critical areas,
including those listed within the FWHCA section.
16.10.110
Mitigation
standards,
location, and
timing, wetland
replacement
ratios, and long-
term protection
requirements
F. Mitigation Plan Requirements. This section should specify mitigation plan
requirements for all critical areas, not just
wetlands. The principle of no net loss of
ecological functions and values applies to every
critical area type, and protections must be
consistent across them.
Page 685 of 758
13
16.10.120
Performan
ce standards for
mitigation
planning
C. Fish and Wildlife Habitat
Conservation Areas.
Edit to align language with state requirements.
16.10.120
Performan
ce standards for
mitigation
planning
C(2.)(b.) Integrate retained habitat
into open space and landscaping;
Open space and landscaping areas should be
planted with native vegetation and designed to
include habitat features. However, the current
language implies that FWHCAs can be treated as
open space or landscaping, which is
inappropriate. FWHCAs must remain distinct and
protected, separate from lawns and other
residential use areas, unless the city protects
open spaces as a type of FWHCA for habitat
connectivity purposes.
16.10.120
Performan
ce standards for
mitigation
planning
3. Where WDFW-designated
critical habitat or Priority
Habitat/Site (PHS) areas are
present adjacent to mitigation
sites, buffer widths must be
consistent with WDFW Riparian
Ecosystems, Volume 2:
Management Recommendations
(2020).
We appreciate this addition and recommend the
stream buffer/RMZ inclusions above to align this
chapter with WDFW’s riparian protection
standards.
16.10.160
Variances
...Minor variances, defined as up
to and including 10 percent of the
requirement, may be granted by
the director as a Type II decision
as defined by Chapter 14.03 ACC...
A 10% variance, such as a 10% reduction of a
critical area buffer, does not align with no net loss
principles required by state law.
Thank you for taking the time to consider our recommendations to better reflect the best
available science for fish and wildlife habitats and ecosystems. We value the relationship we
have with your jurisdiction and the opportunity to work collaboratively with you throughout
this periodic update cycle. If you have any questions or need our technical assistance or
resources at any time during this process, please don’t hesitate to contact me or the Regional
Land Use Lead, Morgan Krueger (morgan.krueger@dfw.wa.gov).
Sincerely,
Marcus Reaves, Regional Habitat Program Manager (Marcus.Reaves@dfw.wa.gov)
Page 686 of 758
14
CC:
Kara Whittaker, Land Use Conservation and Policy Section Manager (Kara.Whittaker@dfw.wa.gov)
Marian Berejikian, Land Use Conservation and Policy Planner (Marian.Berejikian@dfw.wa.gov)
Stewart Reinbold, Assistant Regional Habitat Program Manager (Stewart.Reinbold@dfw.wa.gov)
Julian Douglas, Habitat Biologist (Julian.Douglas@dfw.wa.gov)
Region 4 Southern District Planning Inbox (R4SPlanning@dfw.wa.gov)
Eric Guida, WA Department of Commerce (eric.guida@commerce.wa.gov)
Page 687 of 758
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PA C I F I C
PA C I F I C
P I E R C E
C O U N T Y
P I E R C E
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S U M N E R
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A L G O N A
A L G O N A
E D G E W O O D
E D G E W O O D
E x i s t i n g S t r e a m B u f f e r s
Information shown is for general reference purposes
only and does not necessarily represent exact
geographic or cartographic data as mapped. The
City of Auburn makes no warranty as to its accuracy.
Printed On: 2/17/2026
Map ID: 6366Streams
Landslide Hazard
Fish Bearing Streams WDFW 100 Feet Buffer
Non Fish Bearing Streams Ecology 50 Feet Buffer
Wetlands
Estuarine and Marine Deepwater
Estuarine and Marine Wetland
Freshwater Emergent Wetland
Freshwater Forested/Shrub Wetland
Freshwater Pond
Lake
Other
Riverine
¬
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WESTVALLEYHWYS24TH ST E
SE 274TH ST
PACIFIC AVE SJOVITABLVD
E 132ND AVE SEELLINGSON RD SW
SE 272ND ST
8TH ST E
140TH AVE E136TH AVE EWESTVALLEYHWYS 272ND ST
108TH AVE SEMI
L
I
T
ARY
RDS WEST VALLEY HWY NWSTEWART RD SW
VALENTINE AVE SEWESTVALLEYHWYES
E
K
E
N
T
-KA
N
G
LEYRD68TH AVE S124TH AVE SE116TH AVE SESTEWART RD SE A ST SEWESTVALLEYHWYSSE 272ND ST
S 277T H S T
124TH AVE SE12TH ST EMILITARY RD SAUBURN-BLACKDIAMONDRDSE182ND AVE E9THST E
S 288TH ST
210TH
AVE
E
16TH ST E
S
2
72NDW
AY
214TH AVE EAUBURN WAY NMILITARYRDSA ST SEI ST NEB ST NWC ST SWAUBURN WAY NR ST SE124TH AVE SEWEST VALLEY HWY NS 277TH ST
M ST SEC ST NW15TH ST SW
E MAIN ST 132ND AVE SE51ST AVE S29TH ST SE
L A K E T A P P S P K W Y S E
SE 312TH ST
K
E
R
S
E
Y
W
AY
SE
8TH ST NE
L
A
K
ELANDHILLSWAYSEORAVETZRDSESE 320TH ST
15TH STNW
104THAVESEA ST NWAUBURNWAYSRONCROCKETTDRNWWESTVALLEYHWYSS 316TH ST
D ST NEEAST VALLEY HWY E37T H ST NE
30TH ST NE
SE304THWA Y
W MAIN ST
37TH ST NW
S E 3 0 4 TH ST
6TH ST SE
A ST SESE 304TH ST
W MAIN ST
25TH ST SE
D ST SE56TH AVE S110TH AVE SES T U C K R IV E R D R S E51ST AVE SN ST NEO ST NEW ST NWS 287TH ST
SCENIC
D
RS
E55TH AVE S58TH AVE SK ST SES 328TH ST
C ST SET ST SEMONTEVISTADRSE57THPLS144TH AVE SEH ST SEPIKE ST NEG ST SEFOSTER AVE SEE ST SE140TH AVE SEMSTNE4TH ST SE52ND AVE S56TH ST SEB ST SES 305TH ST
SE290TH ST
54TH AVE SJ ST SE47TH ST SE 130TH AVE SE3 5 T H W A Y S E
E MAIN ST
26TH ST SE
S E 3 1 8 T H W A Y
36 T H S T S E
OLIVE AVE
SE
SE 287THST
24TH ST SE
SE 298TH PL
FOREST R I D G E D R S E2 3 RD S T S E
22ND ST SE
S 292ND ST
O ST SESE 282ND ST
17TH ST S
E111THP LSE5 1 S T ST S E
1 0 8 THAVESES
E
295TH ST
20TH ST SE
54TH ST SE
SE 286TH ST
29T
H
S
T
S
E104
T
HPLSESKYWAY L
N
S
E49TH AVE S3 7 T H W A Y SE16TH ST SE
148TH AVE SESE 294TH ST
T ST NW73RD ST SE
57TH ST SE
1 4 2 N D A V E S E
SE312
THWAYELMSTSESE 285TH ST
62ND ST SE PEARL AVE SE6 7THL
N
S
E
15TH ST SE T ST NE118TH AVE SE6 5 THAVESS 303RD PL
14TH ST SE
63RD ST SE
SE 290TH PL
S
E289TH S T
19TH ST SE
SE 297TH ST
MAPLE DR SE
21ST ST SE
33RD ST SE
WARD AVE SE42ND ST NE
55TH
WAYSE
S 302
N
D
S
T
S 288TH ST
OLYMPIC ST SE43RD ST NE
59THAVES133RD AVE SEJASMINE AVE SER ST NESE 314TH PL 121ST PL SESE 293RD ST
C PL SES 321ST ST
S 329TH PL
34TH ST SE
65TH ST SEJ PL NE114TH PL SE108TH AVE SE57TH ST SEGSTSESE 293RD ST
15TH ST SE
K ST SE16TH ST SE
SE
2
9
8
T
H
P
L
57TH PL S118TH AVE SE33RD ST SEH ST SEK E N T
K E N T
K I N G
C O U N T Y
K I N G
C O U N T Y
PA C I F I C
PA C I F I C
P I E R C E
C O U N T Y
P I E R C E
C O U N T YS U M N E R
S U M N E R
E D G E W O O D
E D G E W O O D
A L G O N A
A L G O N A
S P T H B u f f e r s
Information shown is for general reference purposes
only and does not necessarily represent exact
geographic or cartographic data as mapped. The
City of Auburn makes no warranty as to its accuracy.
Printed On: 2/17/2026
Map ID: 6368
¬
Streams
Landslide Hazard
Streams SPTH 94 Feet Buffer
Streams SPTH 100 Feet Buffer
Streams SPTH 105 Feet Buffer
Streams SPTH 111 Feet Buffer
Streams SPTH 187 Feet Buffer
Streams SPTH 196 Feet Buffer
Streams SPTH 202 Feet Buffer
Streams SPTH 204 Feet Buffer
Streams SPTH 215 Feet Buffer
Streams SPTH 225 Feet Buffer
Streams SPTH 227 Feet Buffer
Wetlands
Estuarine and Marine Deepwater
Estuarine and Marine Wetland
Freshwater Emergent Wetland
Freshwater Forested/Shrub Wetland
Freshwater Pond
Lake
Other
Riverine
Page 689 of 758
S 277TH ST
WESTVALLEYHWYS24TH ST E
SE 274TH ST
PACIFIC AVE SJOVITABLVD
E 132ND AVE SEELLINGSON RD SW
SE 272ND ST
8TH ST E
140TH AVE E136TH AVE EWESTVALLEYHWYS 272ND ST
108TH AVE SEMI
L
I
T
ARY
RDS WEST VALLEY HWY NWSTEWART RD SW
VALENTINE AVE SEWESTVALLEYHWYES
E
K
E
N
T
-KA
N
G
LEYRD68TH AVE S124TH AVE SE116TH AVE SESTEWART RD SE A ST SEWESTVALLEYHWYSSE 272ND ST
S 277T H S T
124TH AVE SE12TH ST EMILITARY RD SAUBURN-BLACKDIAMONDRDSE182ND AVE E9THST E
S 288TH ST
210TH
AVE
E
16TH ST E
S
2
72NDW
AY
214TH AVE EAUBURN WAY NMILITARYRDSA ST SEI ST NEB ST NWC ST SWAUBURN WAY NR ST SE124TH AVE SEWEST VALLEY HWY NS 277TH ST
M ST SEC ST NW15TH ST SW
E MAIN ST 132ND AVE SE51ST AVE S29TH ST SE
L A K E T A P P S P K W Y S E
SE 312TH ST
K
E
R
S
E
Y
W
AY
SE
8TH ST NE
L
A
K
ELANDHILLSWAYSEORAVETZRDSESE 320TH ST
15TH STNW
104THAVESEA ST NWAUBURNWAYSRONCROCKETTDRNWWESTVALLEYHWYSS 316TH ST
D ST NEEAST VALLEY HWY E37T H ST NE
30TH ST NE
BOUNDARY BLVD SW SE304THWA Y
W MAIN ST
37TH ST NW
S E 3 0 4 TH ST
6TH ST SE
A ST SESE 304TH ST
W MAIN ST
25TH ST SE
D ST SE56TH AVE S110TH AVE SES T U C K R IV E R D R S E51ST AVE SN ST NEO ST NEW ST NWS 287TH ST
SCENIC
D
RS
E55TH AVE S58TH AVE SK ST SES 328TH ST
C ST SET ST SEMONTEVISTADRSE57THPLS144TH AVE SEH ST SEPIKE ST NEG ST SEFOSTER AVE SEE ST SE140TH AVE SEMSTNE4TH ST SE52ND AVE S56TH ST SEB ST SES 305TH ST
SE290TH ST
54TH AVE SJ ST SE47TH ST SE 130TH AVE SE3 5 T H W A Y S E
E MAIN ST
26TH ST SE
SE 288TH ST
S E 3 1 8 T H W A Y
36 T H S T S E
OLIVE AVE
SE
SE 287THST
24TH ST SE
SE
2
9
8
T
H
P
L
FOREST R I D G E D R S E2 3 RD S T S E
22ND ST SE
S 292ND ST
O ST SESE 282ND ST
17TH ST S
E111THP LSE5 1 S T ST S E
1 0 8 THAVESES
E
295TH ST
20TH ST SE
54TH ST SE
SE 286TH ST
29T
H
S
T
S
E104
T
HPLSESKYWAY L
N
S
E49TH AVE S3 7 T H W A Y SE16TH ST SE
148TH AVE SESE 294TH ST
T ST NW73RD ST SE
57TH ST SE
1 4 2 N D A V E S E
SE312
THWAYELMSTSESE 285TH ST
62ND ST SE PEARL AVE SE6 7THL
N
S
E
15TH ST SET ST NE118TH AVE SE6 5 THAVESS 303RD PL
63RD ST SE
SE 290TH PL
S
E289TH S T
19TH ST SE
SE 297TH ST
MAPLE DR SE
21ST ST SE
33RD ST SE
WARD AVE SE42ND ST NE SE 286TH PL
55TH
WAYSE
S 302
N
D
S
T
S 288TH ST
OLYMPIC ST SE43RD ST NE
59THAVES133RD AVE SEJASMINE AVE SER ST NESE 293RD ST
C PL SES 321ST ST
S 329TH PL
34TH ST SE
65TH ST SEJ PL NE114TH PL SE57TH ST SEGSTSEH ST SE118TH AVE SEB ST SESE 293RD ST
57TH PL S108TH AVE SE33RD ST SE
K E N T
K E N T
K I N G
C O U N T Y
K I N G
C O U N T Y
PA C I F I C
PA C I F I C
P I E R C E
C O U N T Y
P I E R C E
C O U N T YS U M N E R
S U M N E R
E D G E W O O D
E D G E W O O D
A L G O N A
A L G O N A
P r o p o s e d S t r e a m B u f f e r s
Information shown is for general reference purposes
only and does not necessarily represent exact
geographic or cartographic data as mapped. The
City of Auburn makes no warranty as to its accuracy.
Printed On: 2/17/2026
Map ID: 6367
¬
Streams
Landslide Hazard
Non Fish Bearing Streams 100 Feet Buffer
Fish Bearing Streams 150 Feet Buffer
Wetlands
Estuarine and Marine Deepwater
Estuarine and Marine Wetland
Freshwater Emergent Wetland
Freshwater Forested/Shrub Wetland
Freshwater Pond
Lake
Other
Riverine
Page 690 of 758
S 277TH ST
WESTVALLEYHWYS24TH ST E
SE 274TH ST
PACIFIC AVE SJOVITABLVD
E 132ND AVE SEELLINGSON RD SW
SE 272ND ST
8TH ST E
140TH AVE E136TH AVE EWESTVALLEYHWYS 272ND ST
108TH AVE SEMI
L
I
T
ARY
RDS WEST VALLEY HWY NWSTEWART RD SW
VALENTINE AVE SEWESTVALLEYHWYES
E
K
E
N
T
-KA
N
G
LEYRD68TH AVE S124TH AVE SE116TH AVE SESTEWART RD SE A ST SEWESTVALLEYHWYSSE 272ND ST
S 277T H S T
124TH AVE SE12TH ST EMILITARY RD SAUBURN-BLACKDIAMONDRDSE182ND AVE E9THST E
S 288TH ST
210TH
AVE
E
16TH ST E
S
2
72NDW
AY
214TH AVE EAUBURN WAY NMILITARYRDSA ST SEI ST NEB ST NWC ST SWAUBURN WAY NR ST SE124TH AVE SEWEST VALLEY HWY NS 277TH ST
M ST SEC ST NW15TH ST SW
E MAIN ST 132ND AVE SE51ST AVE S29TH ST SE
L A K E T A P P S P K W Y S E
SE 312TH ST
K
E
R
S
E
Y
W
AY
SE
8TH ST NE
L
A
K
ELANDHILLSWAYSEORAVETZRDSESE 320TH ST
15TH STNW
104THAVESEA ST NWAUBURNWAYSRONCROCKETTDRNWWESTVALLEYHWYSS 316TH ST
D ST NEEAST VALLEY HWY E37T H ST NE
30TH ST NE
BOUNDARY BLVD SW SE304THWA Y
W MAIN ST
37TH ST NW
S E 3 0 4 TH ST
6TH ST SE
A ST SESE 304TH ST
W MAIN ST
25TH ST SE
D ST SE56TH AVE S110TH AVE SES T U C K R IV E R D R S E51ST AVE SN ST NEO ST NEW ST NWS 287TH ST
SCENIC
D
RS
E55TH AVE S58TH AVE SK ST SES 328TH ST
C ST SET ST SEMONTEVISTADRSE57THPLS144TH AVE SEH ST SEPIKE ST NEG ST SEFOSTER AVE SEE ST SE140TH AVE SEMSTNE4TH ST SE52ND AVE S56TH ST SEB ST SES 305TH ST
SE290TH ST
54TH AVE SJ ST SE47TH ST SE 130TH AVE SE3 5 T H W A Y S E
E MAIN ST
26TH ST SE
SE 288TH ST
S E 3 1 8 T H W A Y
36 T H S T S E
OLIVE AVE
SE
SE 287THST
24TH ST SE
SE
2
9
8
T
H
P
L
FOREST R I D G E D R S E2 3 RD S T S E
22ND ST SE
S 292ND ST
O ST SESE 282ND ST
17TH ST S
E111THP LSE5 1 S T ST S E
1 0 8 THAVESES
E
295TH ST
20TH ST SE
54TH ST SE
SE 286TH ST
29T
H
S
T
S
E104
T
HPLSESKYWAY L
N
S
E49TH AVE S3 7 T H W A Y SE16TH ST SE
148TH AVE SESE 294TH ST
T ST NW73RD ST SE
57TH ST SE
1 4 2 N D A V E S E
SE312
THWAYELMSTSESE 285TH ST
62ND ST SE PEARL AVE SE6 7THL
N
S
E
15TH ST SET ST NE118TH AVE SE6 5 THAVESS 303RD PL
63RD ST SE
SE 290TH PL
S
E289TH S T
19TH ST SE
SE 297TH ST
MAPLE DR SE
21ST ST SE
33RD ST SE
WARD AVE SE42ND ST NE SE 286TH PL
55TH
WAYSE
S 302
N
D
S
T
S 288TH ST
OLYMPIC ST SE43RD ST NE
59THAVES133RD AVE SEJASMINE AVE SER ST NESE 293RD ST
C PL SES 321ST ST
S 329TH PL
34TH ST SE
65TH ST SEJ PL NE114TH PL SE57TH ST SEGSTSEH ST SE118TH AVE SEK ST SEB ST SESE 293RD ST
57TH PL S108TH AVE SE33RD ST SE
K E N T
K E N T
K I N G
C O U N T Y
K I N G
C O U N T Y
PA C I F I C
PA C I F I C
P I E R C E
C O U N T Y
P I E R C E
C O U N T Y
S U M N E R
S U M N E R
E D G E W O O D
E D G E W O O D
A L G O N A
A L G O N A
P r o p o s e d I n c r e a s e d S t r e a m B u f f e r s
Information shown is for general reference purposes
only and does not necessarily represent exact
geographic or cartographic data as mapped. The
City of Auburn makes no warranty as to its accuracy.
Printed On: 2/18/2026
Map ID: 6369
¬
Streams
Landslide Hazard
Fish Bearing Streams 200 Feet Buffer
Non Fish Bearing Streams 133 Feet Buffer
Wetlands
Estuarine and Marine Deepwater
Estuarine and Marine Wetland
Freshwater Emergent Wetland
Freshwater Forested/Shrub Wetland
Freshwater Pond
Lake
Other
Riverine
Page 691 of 758
AGENDA BILL APPROVAL FORM
Agenda Subject: Meeting Date:
Downtown Design Standards and Code Update
Staff Introduction/Presentation (Tatro)
Staff will provide an update on the public outreach conducted for the draft
Downtown Design Standards and provide an overview of the changes made
to Chapter 18.29 ACC.
March 3, 2026
Department: Attachments: Budget Impact:
Community Development Planning Commission
Memorandum, Attachment 1 -
Chapter 18.29 ACC Text
Amendment, Attachment 2 - ACC
Section 18.02.070 Text
Amendment, Attachment 3 -
DUC Zoning Districts Map
Administrative Recommendation:
Background for Motion:
Background Summary:
See attached Planning Commission Memorandum
Councilmember: Staff: Jason Krum
Page 692 of 758
PLANNING COMMISSION MEMORANDUM
TO: Judi Roland, Chair Planning Commission
Bill Stewart, Vice Chair Planning Commission
Planning Commission Members
FROM: Alyssa Tatro, Senior Planner
Dept. of Community Development
DATE: February 18, 2026
RE: ZOA26-0003 – Chapter 18.29 DUC Downtown Urban Center District Update
I. BACKGROUND & PURPOSE
The City of Auburn is currently undertaking a comprehensive update of the Downtown Urban Center
Zoning Code (Chapter 18.29 ACC) and the Downtown Design Standards in association with the recently
adopted Downtown Subarea Plan. The Downtown Urban Center zone establishes the land use
framework, development standards, and district structure for downtown Auburn. These regulations are
intended to support a concentration and mixture of commercial, residential, civic, and industrial uses,
consistent with the vision set forth in the Downtown Subarea Plan. The zoning development standards
are intended to support business and economic development and a connected, pedestrian -focused
environment.
In December 2025, the City adopted the updated Downtown Subarea Plan. The plan establishes a long -
term vision for downtown as a walkable, economically vibrant, and people-centered hub. The code
update is intended to align the Downtown Urban Center zoning district with the land use framework,
development patterns, and policy direction of the Subarea Plan.
The purpose of this memorandum and the Planning Commission meeting is to introduce the draft code
amendment and receive feedback prior to a future public hearing. Feedback from the Commission will be
used to refine the draft code as necessary. An update on public engagement for the Downtown Design
Standards will also be provided at this meeting.
II. SUMMARY OF PROPOSED CODE CHANGES
At a high level, the proposed Downtown Urban Center zoning code update:
• Aligns zoning districts and development standards with the recently adopted Downtown Plan;
• Updates use regulations to better reflect intended land use patterns within each district;
• Revises parking standards to reduce minimum requirements;
• Clarifies applicability;
Page 693 of 758
Staff Member: Tatro Date: Feb. 17, 2026
2
• Adds a new Planned Action Standards section to implement the Downtown Subarea Planned
Action Environmental Impact Statement (EIS); and
• Includes overall changes to ensure clarity and consistency with state law.
III. KEY CHANGES FROM THE EXISTING CODE
1. Expanded and Refined Implementing Districts
The Downtown Urban Center remains a single zone, but the proposed revisions refine the implementing
district structure. These districts are more clearly defined with specific purposes and development
expectations. Each district now includes clearer intent language and specific density and height limits,
helping align zoning with the Downtown Plan’s land use framework.
2. Updated Use Regulations by District
The existing code generally prohibits a list of uses across the entire Downtown Urban Center. The
proposed code reorganizes use limitations so that prohibited uses are identified by district rather than
applied uniformly. The update also adds a new section for uses requiring a Conditional Use Permit.
3. Revisions to Parking Standards
The proposed code significantly updates parking requirements across the Downtown Urban Center.
Changes include:
• Reducing or eliminating minimum parking requirements for several residential uses;
• Establishing no minimum parking requirements for affordable housing, senior housing, and
small commercial uses; and
• Eliminating parking requirements for ground-floor nonresidential uses in mixed-use buildings.
4. District Development Standards
The proposed code reorganizes development standards so that they are clearly applied by district. For
example:
• Core districts continue to use the FAR-based system with bonuses;
• The Neighborhood Residential district includes minimum density, lot size, and setback
standards tailored to middle housing; and
• Commercial and industrial districts include standards that address compatibility with adjacent
residential areas.
5. Addition of Planned Action Standards
The proposed code adds a new section establishing Planned Action Standards for the Downtown Urban
Center. This text is taken directly from the Planned Action Ord. (No. 7006) adopted by Council on
December 15, 2025. The purpose of adding the text in code is for ease of access for staff and the public.
This section implements the Downtown Subarea Planned Action EIS and allows qualifying projects to rely
on the existing environmental review rather than completing separate SEPA review.
6. Minor Text and Process Updates
Additional updates include:
Page 694 of 758
Staff Member: Tatro Date: Feb. 17, 2026
3
• Updating references and internal cross-references;
• Adjusting applicability and exemption language;
• Ensuring compliance and consistency with state law; and
• These changes are primarily administrative and intended to improve clarity and consistency.
IV. RELATIONSHIP TO THE DOWNTOWN PLAN
The Downtown Plan establishes the long-term vision and policy direction for downtown Auburn. The
Downtown Urban Center zoning code is one of the primary regulatory tools used to implement that vision.
The updated Downtown Design Standards and the zoning code revisions are intended to ensure that
future development reflects the community’s vision for a walkable, vibrant, and economically strong
downtown.
V. ATTACHMENTS
1) Chapter 18.29 ACC Text Amendment
2) ACC Section 18.02.070 Text Amendment
3) DUC Zoning Districts Map
Page 695 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 1 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Chapter 18.29
DUC DOWNTOWN URBAN CENTER DISTRICT
Sections:
18.29.010 Intent.
18.29.020 Scope.
18.29.030 Process.
18.29.040 Definitions.
18.29.050 Use limitations.
18.29.053 Uses/activities requiring an administrative use permit.
18.29.054 Uses/activities requiring a conditional use permit.
18.29.055 Deviation from development standards.
18.29.04557 Implementing districts.
18.29.060 Development standards.
18.29.070 Design standards.
18.29.080 Planned action standards.
18.29.010 Intent.
The downtown urban center zone is intended to create a distinct and strong identity for
downtown Auburn by establishing land use and design standards for review of development
proposals within the core area of the city of Auburn’s designated urban center, in order to
implement the city of Auburn downtown plan and the goals, policies and objectives of the
Auburn comprehensive plan. The downtown urban centeris zone is intended to produce a
concentration and mixture of commercial, office, medical, retail, residential and civic uses
within the downtown area; to encourage private and public investment, attract shoppers and
visitors, and appeal to existing and new residents; to provide a development pattern that
supports pedestrian movement, bicycles and use of public transit; and to provide opportunities
to increase the city’s tax base, thereby helping to fund public improvements and public services.
(Ord. 6071 § 6 (Exh. A), 2007.)
ATTACHMENT 1
Page 696 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 2 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.29.020 Scope.
A. AThe downtown urban center district zone may be applied to any property designated as
“Downtown” on the Auburn comprehensive plan map.
B. Site plan and building design review and approval shall be required for all public and private
development activities requiring permits within athe downtown urban center districtzone
unless exempted under subsection C of this section. The planning and development director is
given the authority to require building design and site plans consistent with the design
standards contained or referenced herein and to require revisions as necessary in order to
ensure development is consistent with the purpose of this chapter.
C. The following activities, as determined by the director, shall be exempt from the provisions
of this chapter if the property has frontage on a pedestrian street as defined in the downtown
urban center design standards:
1. Interior alterations that do not alter the exterior appearance of a structure or modify an
existing site condition;
2. Normal or routine building and site maintenance/repair that is exempt from permit
requirements; and
3. Any remodeling or expansion of existing single-unit detached residences and middle
housing developments. with no change in use or addition of dwelling units involved.
D. The following activities, as determined by the director, shall be exempt from the provisions
of this chapter if the property does not have frontage on a pedestrian street as defined in the
downtown urban center design standards:
1. Interior alterations that do not alter the exterior appearance of a structure or modify an
existing site condition;
2. Site and exterior alterations that do not exceed 10 percent of the assessed valuation of
the property (building or land) per the most recent county records;
3. Building additions that are less than 10 percent of the existing floor area of the existing
building(s). Any cumulative floor area increase (from the adoption date of the ordinance
codified in this chapter) that totals more than 10 percent shall not be exempt; unless the
Page 697 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 3 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
director determines compliance with these standards would be unfeasible and/or
unreasonable;
4. Normal or routine building and site maintenance/repair that is exempt from permit
requirements;
5. Any remodeling or expansion of existing single-unit detached residences with no
change in use or addition of dwelling units involved. (Ord. 6959 § 1 (Exh. A), 2024; Ord. 6287 § 2,
2010; Ord. 6230 § 1, 2009; Ord. 6071 § 6 (Exh. A), 2007.)
18.29.030 Process.
A. Compliance with all development and design standards contained or referenced herein
shall occur in conjunction with any required permit process. The director shall provide
appropriate forms that shall accompany a permit application. The director may approve,
approve with conditions, or deny a building or site development permit application to ensure
compliance with these standards. Any decision regarding a permit application shall be set forth
in writing and contain findings of fact and conclusions that support the decision made.
B. The decision of the director shall be final unless the applicant or any affected party appeals
the decision to the hearing examiner. All appeals shall be in accordance with ACC 18.70.050(B)
through (E). (Ord. 6071 § 6 (Exh. A), 2007.)
18.29.040 Definitions.
These words shall have the following meanings for the purposes of this chapter:
A. “Canopy” means a cover over a sidewalk providing protection from the rain, which is
constructed of durable, permanent materials.
B. “Director” means the director of the Auburn dDepartment of Community planning and
dDevelopment.
Page 698 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 4 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
C. “Green roof” means a roof designed with principles of environmental sustainability,
involving the use of vegetation and storm water collection and cleaning. It may or may not be
accessible.
D. “Health club” means a use that offers exercise and recreational activities for tenants and/or
the general public, either with or without a fee.
E. “Parking, below grade” means any portion of a structure containing parking that is located
below the average finished grade around a building.
F. “Parking, structured” means parking contained within an enclosed building, designed to
appear like it is part of the larger building complex, or a freestanding structure devoted
exclusively to above-grade parking.
G. “Performing space” means any interior or exterior area designated for live performing and
entertainment.
H. “Public art” means any form of painting, mural, mosaic, sculpture, or other work of art, so
long as it can be appraised as a work of art and its value as such documented, displayed on the
exterior of a building, at or near the pedestrian entrance, or on a public plaza, and visible to
users of the public right-of-way at all times.
I. “Public meeting room” means a space that can be used by the general public and having a
capacity of at least 50 people. It may operate under a reservation or nominal fee system and
must be easily accessible from a lobby or plaza.
J. “Public plaza” means an open space that is visible and accessible to the public at all times,
predominantly open to the sky, and for use principally by people, as opposed to merely a
setting for the building.
K. “Street level retail” means uses providing goods and services, including food and drink,
adjacent to, visible from, and directly accessible from the public sidewalk.
L. “Water feature” means a fountain, cascade, stream, fall, pond of water, or combination
thereof, that serves as a focal point, located outside of a building, publicly visible and accessible,
and active during daylight hours. (Ord. 6287 § 2, 2010; Ord. 6071 § 6 (Exh. A), 2007.)
Page 699 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 5 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.29.050 Use limitations.
Hereafter, all buildings, structures or properties may be used for any use, unless specifically
prohibited herein. Ground floor retail, restaurants and/or office use is required for all building
frontages facing Main Street. All uses shall be subject to review and approval by the director.
A. The following uses are prohibited in all DUC zoning districts:
A. Sexually oriented businesses as defined in Chapter 18.74 ACC.
B. All industrial uses as defined in the North American Industrial Classification System
(2022 Edition), categories 48 through 49 (transportation), 31 through 33 (manufacturing)
and 42 (wholesale trade).
C. Outdoor storage of materials and equipment (except during active construction
projects).
D. New automobile maintenance and repair businesses.
E. Work release facilities; secure community transition facilities.
F. Wrecking yards.
G. Solid waste transfer stations.
H. Car washes.
I. New gasoline stations.
J. Street-level ministorage.
K. Outdoor sales of vehicles, boats or equipment.
L. Drive-in/drive-through facilities with direct vehicular driveway access onto Main
Street.
M. All marijuana-related businesses and marijuana cooperatives.
N. New single-unit detached dwellings; except for DUC neighborhood residential
district.
1. Battery Energy Storage Systems, Tier III.
2. New motor freight terminals.O. Other uses may be prohibited by the director if the use
is determined to be inconsistent with the intent of this zone or is of the same general
character of the other prohibited uses listed in this section. (Ord. 6959 § 1 (Exh. A), 2024;
Ord. 6642 § 10, 2017; Ord. 6071 § 6 (Exh. A), 2007.)
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 6 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
3. Other uses may be prohibited by the director if the use is determined to be inconsistent
with the intent of the downtown urban center or is of the same general character of the
other prohibited uses listed in this section.
4. Solid waste transfer stations.
5. Use as dwelling units of (1) recreational vehicles that are not part of an approved
recreational vehicle park, (2) boats, (3) automobiles, and (4) other vehicles.
6. Work release facilities; secure community transition facilities.
B. The following uses are prohibited in the DUC Core 75, Core 125, and H-W Districts:
1. All industrial uses as defined in the North American Industrial Classification System
(2022 Edition), categories 48 through 49 (transportation), 31 through 33 (manufacturing)
and 42 (wholesale trade), except wine production facility, small craft distillery, small craft
brewery with a tasting room and/or tourism.
2. All marijuana-related businesses and marijuana cooperatives.
3. Car washes.
4. Drive-in/drive-through facilities with direct vehicular driveway access onto Main Street.
5. New automobile maintenance and repair businesses.
6. New fueling stations.
7. New single-unit detached dwellings.
8. Outdoor sales of vehicles, boats or equipment.
9. Outdoor storage of materials and equipment (except during active construction
projects).
10. Sexually oriented businesses as defined in Chapter 18.74 ACC.
11. Street-level ministorage.
12. Wrecking (tow) yards.
C. The following uses are prohibited in the DUC N-R District:
Page 701 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 7 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
1. Agricultural enterprises.
2. All industrial uses as defined in the North American Industrial Classification System
(2022 Edition), categories 48 through 49 (transportation), 31 through 33 (manufacturing)
and 42 (wholesale trade).
3. All marijuana-related businesses and marijuana cooperatives.
4. Apartments (more than 20 units).
5. Battery Energy Storage System, Tier II.
6. Café, or coffee shop over 4,000 sf in floor area.
7. Car washes.
8. Civic, social and fraternal clubs.
9. Co-living (more than 80 sleeping units).
10. Commercial over 4,000 sf in floor area.
11. Convenience store over 4,000 sf in floor area.
12. Drive-in/drive-through facilities with direct vehicular driveway access onto Main Street.
13. Group residence facilities (7 or more residents).
14. Hospitals (except animal hospitals).
15. Library, museum.
16. New automobile maintenance and repair businesses.
17. New fueling stations.
18. Outdoor sales of vehicles, boats or equipment.
19. Outdoor storage of materials and equipment (except during active construction
projects).
20. Nursing homes.
21. Sexually oriented businesses as defined in Chapter 18.74 ACC.
22. Street-level ministorage.
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 8 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
23. Use as dwelling units of (1) recreational vehicles that are not part of an approved
recreational vehicle park, (2) boats, (3) automobiles, and (4) other vehicles.
24. Wrecking (tow) yards.
D. The following uses are prohibited in the DUC M-1 District:
1. Apartments, standalone.
2. Live/work unit, standalone.
3. Manufacturing, assembling and packaging – Heavy intensity.
4. Marijuana cooperative.
5. New single unit detached dwellings.
6. Nursing home, assisted living facility.
7. Pharmacies.
8. Senior housing, except developments vested prior to Resolution No. 5187.
9. Work/live unit, standalone.
10. Youth community support facility.
E. The following uses are prohibited in the DUC C-1 District:
1. All industrial uses as defined in the North American Industrial Classification System
(2022 Edition), categories 48 through 49 (transportation), 31 through 33 (manufacturing)
and 42 (wholesale trade).
2. All marijuana-related businesses and marijuana cooperatives.
3. Ambulance, taxi, and specialized transportation facility.
4. Apartment units, as part of a mixed-use development.
5. Apartments, standalone.
6. Building and landscape materials sales.
7. Car washes.
Page 703 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 9 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
8. Commercial recreation facility, outdoor.
9. Construction and heavy equipment sales and rental.
10. Drive-in/drive-through facilities with direct vehicular driveway access onto Main Street.
11. Equipment rental and leasing.
12. Heliport.
13. Kennel, animal boarding.
14. Mobile home, boat, or RV sales
15. Nursery.
16. Outdoor sales of vehicles, boats or equipment.
17. Outdoor storage of materials and equipment (except during active construction
projects).
18. Regional retail establishment.
19. Senior housing, except developments vested prior to Resolution No. 5187.
20. Sexually oriented businesses as defined in Chapter 18.74 ACC.
21. Sports and entertainment assembly facility.
22. Street-level ministorage.
23. Vehicle services – Repair/body work
24. Wrecking (tow) yards.
F. The following uses are prohibited in the DUC C-2 District:
1. All marijuana-related businesses and marijuana cooperatives.
2. Apartments, standalone.
3. Building contractor, heavy
4. Construction and heavy equipment sales and rental
5. Live/work unit, standalone.
6. Manufacturing, assembling and packaging – Heavy intensity.
7. New single unit detached dwellings.
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 10 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
8. Nursing home, assisted living facility.
9. Pharmacies.
10. Senior housing, except developments vested prior to Resolution No. 5187.
11. Warehousing and distribution.
12. Work/live unit, standalone.
13. Wrecking (tow) yards.
14. Youth community support facility.
G. The following uses are prohibited in the DUC F-R District:
1. All marijuana-related businesses and marijuana cooperatives.
2. Apartments, standalone.
3. Battery Energy Storage System, Tier II.
4. Co-living units, more than 80 sleeping units.
5. Live/work unit, standalone.
6. Manufacturing, assembling and packaging – Heavy intensity.
7. Mixed-use, more than 20 units.
8. Nursing home, assisted living facility.
9. Pharmacies.
10. Senior housing, except developments vested prior to Resolution No. 5187.
11. Work/live unit, standalone.
12. Wrecking (tow) yards.
13. Youth community support facility.
18.29.053 Uses/activities requiring an administrative use permit.
Page 705 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 11 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
A. The following uses/activities may be permitted in the DUC Core 75, Core 125, and H-W
Districts when an administrative use permit has been issued pursuant to the provisions
of Chapter 18.64 ACC:
1. Animal daycare businesses that feature outdoor exercise areas and/or kennels.
2. Battery Energy Storage System, Tier II.
3. A. Expansions of existing automobile maintenance and repair businesses.;
4. B. Expansions of existing gasoline (fueling) stations.;
1. C. Animal daycare businesses that feature outdoor exercise areas and/or kennels;
1. D. Wine production facility; small craft distillery; small craft brewery; and a tasting
room is an outright allowed use in the DUC zone. (Ord. 6368 § 8, 2011; Ord. 6269 § 32, 2009.)
B. The following uses/activities may be permitted in the DUC N-R District when an
administrative use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Government facilities.
2. Grocery or specialty food store.
3. Neighborhood recreational buildings and facilities owned and managed by the
neighborhood homeowners’ association.
4. Personal service shop, over 4,000 sf in floor area.
5. Privately owned and operated parks and playgrounds and not homeowners’
association-owned recreational area.
6. Religious institutions, less than one acre lot size. Reference ACC 18.31.165 for
standards related to homeless encampments hosted by a religious organization.
7. Restaurant.
C. The following uses/activities may be permitted in the DUC M-1 District when an
administrative use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 12 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
1. Any commercial use abutting a residential zone which has hours of operation
outside of the following: Sunday: 9:00 a.m. to 10:00 p.m. or Monday – Saturday: 7:00
a.m. to 10:00 p.m.
2. Battery Energy Storage System, Tier II.
3. Conference/convention facility.
4. Construction and heavy equipment sales and rental.
5. Entertainment, commercial.
6. Government facilities; this excludes offices and related uses that are permitted
outright.
7. Indoor emergency housing or shelter. Reference ACC 18.31.160 for specific
standards.
8. Kennel, animal boarding.
9. Library, museum.
10. Lodging – Hotel or motel.
11. Religious institutions, lot size less than one acre.
12. Religious institutions, lot size more than one acre.
13. Sports and entertainment assembly facility.
14. Supportive housing (permanent). Reference ACC 18.31.160 for specific standards.
15. Transitional housing. Reference ACC 18.31.160 for specific standards.
16. Utility transmission or distribution line or substation.
17. Wrecking (tow) yard.
D. The following uses/activities may be permitted in the DUC C-1 District when an
administrative use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Animal daycare (excluding kennels and animal boarding).
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 13 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
2. Any commercial use abutting a residential zone which has hours of operation
outside of the following: Sunday: 9:00 a.m. to 10:00 p.m. or Monday – Saturday: 7:00
a.m. to 10:00 p.m.
3. Auto parts sales with installation services.
4. Auto/vehicle sales and rental.
5. Automobile washes (automatic, full or self-service).
6. Battery Energy Storage System, Tier II.
7. Drive-through espresso stands.
8. Drive-through facility, including banks and restaurants.
9. Entertainment, commercial.
10. Fueling station.
11. Government facilities; this excludes offices and related uses that are permitted
outright.
12. Library, museum.
13. Printing and publishing (of books, newspaper and other printed matter).
14. Private school – Specialized education/training (for profit).
15. Repair service – Equipment, appliances.
16. Utility transmission or distribution line or substation.
E. The following uses/activities may be permitted in the DUC C-2 District when an
administrative use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Ambulance, taxi, and specialized transportation facility.
2. Any commercial use abutting a residential zone which has hours of operation
outside of the following: Sunday: 9:00 a.m. to 10:00 p.m. or Monday – Saturday: 7:00
a.m. to 10:00 p.m.
Page 708 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 14 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
3. Battery Energy Storage System, Tier II.
4. Commercial recreation facility, outdoor.
5. Conference/convention facility.
6. Government facilities; this excludes offices and related uses that are permitted
outright.
7. Kennel, animal boarding.
8. Library, museum.
9. Manufacturing, assembling and packaging – Medium intensity.
10. Senior housing, except developments vested prior to Resolution No. 5187.
11. Sports and entertainment assembly facility.
12. Utility transmission or distribution line or substation.
F. The following uses/activities may be permitted in the DUC F-R District when an
administrative use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Civic, social and fraternal clubs.
2. Commercial retail establishment, over 4,000 sf in floor area.
3. Government facilities.
4. Grocery or specialty food store, over 4,000 sf in floor area.
5. Religious institutions, less than one acre lot size. Reference ACC 18.31.165 for
standards related to homeless encampments hosted by a religious organization.
1.6. Restaurant, café, or coffee shop, over 4,000 sf in floor area.
Page 709 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 15 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.29.054 Uses/activities requiring a conditional use permit.
A. The following uses/activities may be permitted in the DUC N-R District when a
conditional use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Religious institutions, one acre or larger lot size. Reference ACC 18.31.165 for
standards related to homeless encampments hosted by a religious organization.
2. Transmitting towers.
3. Utility facilities and substations. Excludes all public and private utility facilities
addressed under ACC 18.02.040(E).
B. The following uses/activities may be permitted in the DUC M-1 when a conditional use
permit has been issued pursuant to the provisions of Chapter 18.64 ACC:
1. Heliport.
2. All marijuana-related businesses.
C. The following uses/activities may be permitted in the DUC C-2 District when a
conditional use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Heliport.
2. Marijuana retailer.
D. The following uses/activities may be permitted in the DUC F-R District when a
conditional use permit has been issued pursuant to the provisions of Chapter 18.64
ACC:
1. Hospitals (except animal hospitals).
2. Nursing homes.
3. Religious institutions, one acre or larger lot size. Reference ACC 18.31.165 for
standards related to homeless encampments hosted by a religious organization.
4. Transmitting towers.
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 16 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
5. Utility facilities and substations. Excludes all public and private utility facilities
addressed under ACC 18.02.040(E).
18.29.055 Deviation from development standards.
Any development project that seeks to deviate from any development standard listed in ACC
18.29.060 must be granted an administrative variance or variance, depending on the threshold
of relief, pursuant to the provisions of Chapter 18.70 ACC. (Ord. 6959 § 1 (Exh. A), 2024; Ord. 6269
§ 12, 2009; Ord. 6071 § 6 (Exh. A), 2007.)
18.29.04557 Implementing districts.
Downtown urban center zone is intended to create a distinct and strong identity for downtown
Auburn by establishing land use and design standards for review of development proposals
within the core area of the city of Auburn’s designated urban center. This zone is intended to
produce a concentration and mixture of commercial, office, medical, retail, entertainment,
residential and civic uses within the downtown area; to encourage private and public
investment, attract shoppers and visitors, and appeal to existing and new residents; to provide
a development pattern that supports pedestrian movement, bicycles and use of public transit;
and to provide opportunities to increase the city’s tax base, thereby helping to fund public
improvements and public services. In order to implement the city of Auburn Downtown Plan
and the goals, policies and objectives of the Auburn Comprehensive Plan, the zone downtown
is divided into the following districts:
A. DUC Downtown Core -125 District. DUC-The Core 125 district is implemented only in the
downtown urban center and is intended for higher density residential and mixed-uses and
commercial activity. Storefronts in this district that are located on a Pedestrian I street are
required to contain retail, residential, or personal services uses. The DUC Core is subject to
uses and development standards of this chapter and the downtown urban design guidelines.
Development in the DUC downtown Core 125 district shall not exceed 125 feet in vertical height
and is subject to other applicable height restrictions found in Chapter 18.38 ACC.
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 17 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
B. DUC Downtown Core -75 District. The DUC downtown coreCore -75 district zone is consistent
with requirements described in the DUC downtown cCore -125, except a maximum 75-vertical-
foot height limit shall apply.
C. DUC Downtown Core-55 District. The DUC downtown core-55 zone is consistent with the
requirements described in the DUC downtown core-125 except a maximum 55-vertical-foot
height limit shall apply.
D. DUC N-R Neighborhood Residential District. The N-R district overlaps with residential areas of
downtown and is intended to support moderate density residential housing types such as
fourplexes, sixplexes, townhomes, and small apartment buildings. The N-R district allows for
middle housing options, which are designed to support gradual infill development. The district
does allow for limited non-residential uses. This district is subject to uses and development
standards of this chapter and the downtown urban design guidelines. R-2 uses per ACC Table
18.07.020 allowed subject to the development standards of this chapter and the downtown
urban design guidelines.Development in the N-R district shall not exceed 45 feet in vertical
height.
CE. DUC H-W Health and Wellness District. This districtzonedistrict is to be used exclusively for
the hospital area, located in the vicinity of 2nd Street NE and Auburn Avenue, and is intended to
be used for medical and related uses and those uses compatible with the medical community.
Residential may be included as part of vertical mixed-use development with medical being the
primary development use. Storefronts in this district that are located on a Pedestrian I street
are required to contain retail, residential, or personal services uses. This district is subject to the
uses and development standards of this chapter and the downtown urban design guidelines.
Developments in the DUC H-W district shall not exceed 125 feet in vertical height.
EF. DUC M-1 Light Industrial District. The DUC M-1 district is intended to accommodate a variety
of light to medium intensity industrial and manufacturing uses. The primary goal of the district
is to preserve land for industrial use; however, some commercial uses are also allowable. While
allowed, outdoor storage will be regulated in a manner that mitigates visual impacts, taking
surrounding uses and vehicular corridors into consideration. This district is subject to uses and
development standards of this chapter and the downtown urban design guidelines. M-1 zone
uses allowed per ACC Table 18.23.030, subject to the development standards of this chapter
and the downtown urban design guidelines. Developments in the DUC M-1 45 feet in vertical
height.
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 18 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
F. DUC C-1 Light Commercial District. The DUC C-1 district is intended for lower intensity
commercial uses that are adjacent and compatible with residential neighborhoods. This district
represents the primary commercial designation for small- to moderate-scale commercial
activities that are developed in a manner which is consistent with and attracts pedestrian-
oriented activities. This district encourages a broad mix of small-scale uses that are conducive
to attracting shoppers and pedestrians. This district is subject to uses and development
standards of this chapter and the downtown urban design guidelines. Developments in the
DUC C-1 district shall not exceed 45 feet in vertical height.
G. DUC C-2 Heavy Commercial District. The DUC C-2 district is intended to allow for medium-to-
high intensity commercial uses, primarily uses that are oriented to automobiles. The uses in
this classification may be larger in scale and building size and have more potential for impacts
to surrounding properties and street systems than those uses permitted in the more restrictive
commercial classifications. This district is subject to uses and development standards of this
chapter and the downtown urban design guidelines. Developments in the DUC C-2 district shall
not exceed 75 feet in vertical height.
HG. DUC F-R Residential-Flex Residential District. The DUC F-R is districtzone is intended to
promote craft industrial /commercialand commercial uses that are compatible with residential
areas (i.e., workshop, brewery, etc.). This district is subject to uses and development standards
of this chapter and the downtown urban design guidelines.R-F zone uses allowed per ACC Table
18.07.020, subject to the development standards of this chapter and the downtown urban
design guidelines. Developments in the DUC F-R district shall not exceed 45 feet in vertical
height. (Ord. 6959 § 1 (Exh. A), 2024.)
18.29.060 Development standards.
A. The following zoning development standards apply to the DUC Core 75, Core 125, and H-W
Districts:
1. A. Minimum lot area: none.
2. B. Minimum lot width: none.
3. C. Minimum lot depth: none.
4. D. Floor Area Ratio. Floor area ratio is the cumulative amount of floor area within a
building as a multiple of the lot area.
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The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Floor Area Ratio (FAR)1
Basic Allowable “As of Right” Maximum Allowable Wwith Bonuses
Nonresidential2 Residential2 Nonresidential Residential3 Combined4
3.0 2.0 4.0 3.5 5.0
1 Floor area is measured to the inside face of exterior walls. The following shall be excluded from floor area
calculation:
a All space below finished grade.
b Space dedicated to structured parking.
c Space used for any bonus feature listed in subsection E of this section.
2 Minimum required FAR is 0.75; basic allowable FAR is 1.0.
3 Hotels, nursing homes, assisted living centers, etc., shall be considered residential for the purpose of
calculating FAR.
4 Allowable FAR for nonresidential and residential uses may be added together within a project, for a
combined total.
5 FAR for the DUC H-W district based on mixed use development.
1.5. E. Bonus Features Allowing Increased Floor Area Ratio. An applicant may be
required to provide a legally binding agreement or easement to ensure any of the below
features is maintained over the life of the project.
Page 714 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 20 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Feature Additional Gross Floor
Area for Each Feature
Street level retail 100 sf of floor area for
each linear foot of retail
frontage
Restaurant 100 sf of floor area for
each linear foot of
restaurant frontage
Public plaza 5 sf of floor area for
each sf of plaza
Widening public
sidewalk
4 sf of floor area for
each sf of sidewalk
made available for
public use
Canopy 4 sf of floor area for
each sf of canopy
Daycare 104 sf of floor area for
each sf of daycare
Health club 2 sf of floor area for
each sf of health club
Performing space 2 sf of floor area for
each sf of performing
space
Public meeting room 25 sf of floor area for
each sf of meeting
room
Page 715 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 21 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Feature Additional Gross Floor
Area for Each Feature
Public art (arts
commission approval
required)
10 sf of floor area for
each $100 of valuation
Water feature 10 sf of floor area for
each $100 of valuation
Structured parking 10.5 sf of floor area for
each sf of required
parking above grade
Below grade parking 1 sf of floor area for
each sf of required
parking below grade
(including half-level
plate below grade)
Green roof 2 sf of floor area for
each sf of green roof
Public restrooms 10 5 sf of floor area for
each sf of public
restroom
Contribution to a public
park or cultural facility
such as a library,
museum or theater
within 0.5 miles of the
DUC zone; also, any
project including a
performance or
entertainment venue is
eligible for these
10 sf of floor area for
each $100 of
contribution towards
acquisition or
development. This can
be used to exceed both
maximum FAR and
maximum building
height by up to 25%.
Page 716 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 22 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Feature Additional Gross Floor
Area for Each Feature
bonuses, based upon
the value of
construction
Development of open
space such as open
roof decks, balconies,
lanais or parts of the
building and improved
for outdoor living;
including rooftop
daycare play areas, dog
walking areas, etc.
5 10 sf of floor area for
each sf of open space
F. Maximum Building Height. Maximum building height within the DUC zone shall be
based on each zoning district 75 feet, unless bonus height is permitted per subsection E
of this section.
1. If retail uses occupy the ground floor, the minimum height for that floor shall be 14 feet.
2. Mechanical penthouses, stair/elevator overruns, and antennas may be
excluded from building height calculation, provided they extend no more than
20 feet above the roof deck.
3. Maximum building height may be increased by up to 20 percent if the top is
designed as a nonhabitable, architectural element. This element may extend above
the increased height limit.
6. G. Minimum Building Height. The minimum height for any new structure shall be two
stories for the full extent of the building footprint.
7. Signs. The design of all signs shall be in conformance with the design standards
referenced in ACC 18.29.070. Any permanent or permanently affixed sign that projects
into the public right-of-way is subject to a right-of-way use permit. Allowable types,
numbers and sizes of signs shall be as follows:
Page 717 of 758
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The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
a. Freestanding: not allowed, except for monument signs as described within the
downtown Auburn design standards; no more than one per street frontage;
maximum size: 64 square feet, calculated at a rate of one square foot of sign area
per lineal foot of site frontage; minimum entitlement shall be 32 square feet;
maximum height: five feet.
b. Wall signs: maximum area of 150 square feet per building facade, calculated at a
rate of one square foot of sign area for every lineal foot of facade; minimum
entitlement shall be 16 square feet.
c. Suspended signs: attached under a marquee or canopy: one double-faced sign, no
greater than three square feet per face allowed for each building entrance;
minimum clearance above grade: eight feet.
d. Portable Signs: may be allowed for each business entrance, subject to the following:
i. Signs may be placed within the public right-of-way, within 12 feet of a business
entrance, subject to the guidelines provided by the director in consultation with
the city engineer such that sign placement does not interfere with pedestrian or
vehicular traffic, does not create a sight hazard, and conforms to the
requirements of the Americans with Disabilities Act. Additional portable signage
may be authorized in order to support downtown events that are permitted or
sanctioned by the city.
ii. The sign shall be in accordance with the provisions of ACC 18.56.030(L).
iii. The sign area cannot exceed 42 inches in height, 32 inches in width, and be
limited to two faces.
iv. Portable signs are not permitted to be affixed to city infrastructure located
within the right-of-way (e.g., street lights, fire hydrants, public art). This includes
a prohibition of chaining or otherwise securing portable signs to such
infrastructure.
v. Signs may be displayed during business hours and shall not be displayed when
the business is closed.
vi. No landscaping may be covered, cut, damaged, or modified to accommodate a
portable sign. The city may require replacement of any damaged landscaping
pursuant to Chapter 18.50 ACC.
vii. All portable signs shall have the permit number affixed to the back of the sign.
e. Temporary signs: allowed subject to the provisions provided in ACC 18.56.030(B).
Page 718 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 24 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
B. The following zoning development standards apply to the DUC N-R District:
1. Minimum lot area: new lots shall be a minimum of 2,000 square feet.
2. Minimum density: 7 units or lots per acre.
3. Minimum lot width: 20 feet, 35 for corner lots.
4. Minimum lot depth: none.
5. Maximum impervious surface: 75%.
6. Setbacks:
a. Front: 10 feet.
b. Front, garage: 20 feet.
c. Side, street: 10 feet.
d. Side, interior: 5 feet.
e. Rear: 5 feet.
f. Rear, garage: 20 feet.
7. Units per lot: subject to the standards contained in ACC 18.07.030(D)(1), (2), and (3).
8. Signs: subject to the signs standards contained in ACC 18.56.040(A).
C. The following zoning development standards apply to the DUC M-1 District:
1. Minimum lot area: none.
2. Minimum lot width: none.
3. Minimum lot depth: none.
4. Maximum impervious surface: none.
5. Setbacks:
a. Front: none.
b. Side, street: none, subject to the Engineering Design Standards.
c. Side, interior: none, 25 feet when adjacent to a residential zone.
d. Rear: none, 25 feet when adjacent to a residential zone.
6. Apartment buildings and mixed-use developments: subject to the zoning development
standards of ACC 18.29.060(A).
1.7. Signs: subject to the signs standards contained in ACC 18.56.040(D).
Page 719 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 25 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
D. The following zoning development standards apply to the DUC C-1 District:
1. Minimum lot area: none.
2. Minimum lot width: none.
3. Minimum lot depth: none.
4. Maximum impervious surface: none.
5. Setbacks:
a. Front: none.
b. Side, street: none, subject to the Engineering Design Standards.
c. Side, interior: none, 25 feet when adjacent to a residential zone.
d. Rear: none, 25 feet when adjacent to a residential zone.
6. Apartments buildings and mixed-use developments: subject to the zoning development
standards of ACC 18.29.060(A).
7. Signs: subject to the signs standards contained in ACC 18.56.040(B).
D. The following zoning development standards apply to the DUC C-2 District:
1. Minimum lot area: none.
2. Minimum lot width: none.
3. Minimum lot depth: none.
4. Maximum impervious surface: none.
5. Setbacks:
a. Front: none.
b. Side, street: none, subject to the Engineering Design Standards.
c. Side, interior: none, 25 feet when adjacent to a residential zone.
d. Rear: none, 25 feet when adjacent to a residential zone.
6. Apartments buildings and mixed-use developments: subject to the zoning development
standards of ACC 18.29.060(A).
7. Signs: subject to the signs standards contained in ACC 18.56.040(E).
E. The following zoning development standards apply to the DUC F-R District:
Page 720 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 26 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
1. Minimum lot area: new lots shall be a minimum of 3,000 square feet.
2. Minimum density: 7 units or lots per acre.
3. Minimum lot width: 20 feet, 35 for corner lots.
4. Minimum lot depth: none.
5. Maximum impervious surface: 75%.
6. Setbacks:
a. Front: none.
b. Side, street: none, subject to the Engineering Design Standards.
c. Side, interior: none.
d. Rear: none, 25 feet when adjacent to a residential zone.
7. Units per lot: see R-F zone under ACC 18.07.030.
8. Mixed-use developments: subject to the zoning development standards of ACC
18.29.060(A).
1.9. Signs: subject to the signs standards contained in ACC 18.56.040(B).
F. The following zoning development standards apply to all DUC districts:
1. Maximum Building Height. Maximum building height within the DUC shall be based
on each zoning district, subject to the airport overlay and Part 77 Surfaces, unless
bonus height is permitted per subsection E of this section.
a. Mechanical penthouses, stair/elevator overruns, and antennas may be excluded
from building height calculation, provided they extend no more than 20 feet
above the roof deck.
a.b. Maximum building height may be increased by up to 20 percent if the top is
designed as a nonhabitable, architectural element. This element may extend
above the increased height limit.
2. H.Parking Ratios. The following parking standards shall apply within the a DUC
districtzone in lieu of any standard noted in ACC 18.52.020 or provision of ACC
18.52.030:
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Chapter 18.29 ACC, DUC Downtown Urban Center District Page 27 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Use Type Minimum Required
Maximum
Allowed for
Surface
Parking Lots
Retail 2 stalls/1,000 nsf 4 stalls/1,000
nsf1
Office 2 stalls/1,000 nsf 4 stalls/1,000
nsf
Residential (mixed-use,
apartment, live/work,
work/live)
0.51 stall per dwelling
unit
2 stalls per
dwelling unit
Residential (middle housing) 1 stall per dwelling
unit outside of one-
half mile walking
distance of a major
transit stop
2 stalls per
dwelling unit
outside of
one-half mile
walking
distance of a
major transit
stop
Residential (single unit
detached) over 1,200 nsf
1 stall per residence N/A
Residential (single unit
detached), 1,200 nsf and
under
0 N/A
Affordable housing units 0 N/A
Senior housing 0 1 stall per unit
Child care centers (including
home based daycares)
0 N/A
Page 722 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 28 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Use Type Minimum Required
Maximum
Allowed for
Surface
Parking Lots
Commercial (nonresidential
business purposes, including
retail, office, wholesale,
general merchandise, and
food services) over 3,000 nsf
2 stall per 1,000 nsf 4 stalls per
1,000 nsfa
Commercial (nonresidential
business purposes, including
retail, office, wholesale,
general merchandise, and
food services) 3,000 nsf and
under
0 N/A
Ground floor nonresidential
in mixed use buildings
0 N/A
Restaurant 0.5 stall per 4 seats 1 stall per 4
seats
Industrial 0.5 stall per 1,000 nsf N/A
1 nsf = net square feet
a. 1. Parking requirements for uses not listed shall be determined by a study of
parking demand for that use, as prepared by a qualified professional and as
accepted by the director.
2. Retail and restaurant uses less than 3,000 nsf in area shall be exempt from
parking requirements.
b. 3. Uses sharing a common parking facility may reduce the required number of
stalls by 25 percent.
c. 4. Required parking may be located off site, so long as it is: (a) located within the a
DUC zonedistrict, (b) within 1,000 feet of the property, (c) connected to the property
by streets improved with sidewalks or walkways, and (d) tied to the site by a
Page 723 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 29 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
contractual agreement reviewed and approved by the city attorney that is filed with
the city and deed of record at the county.
5. On-street parking that is located directly adjacent to a development site may be
used to satisfy minimum parking requirements and shall not be included in
determining maximum surface parking allowances.
d. 6. If subject to the standards provide in ACC 18.29.060(A), Ddedicated off-site
parking provided within a parking structure may be used to provide FAR bonuses
for a project on a separate site, provided the parking structure is located consistent
with this chapter.
e. 7. The maximum standards noted in the table above may be exceeded if all stalls
above the maximum limit are provided within a parking structure.
f. 8. Compliance with these standards is not required for a change of use within an
existing building or whenever there is an expansion of an existing building or a new
building replaces an existing building that does not increase the floor area by more
than 25 percent.
9. In lieu of providing the minimum parking required by this section, an applicant may
request to pay for each required parking stall into a special fund that will be used to
provide and upgrade municipal parking to serve the DUC zone. The per-stall fee shall be
as specified in the city’s fee schedule.
I. Signs. The design of all signs shall be in conformance with the design standards
referenced in ACC 18.29.070. Allowable types, numbers and sizes of signs shall be as
follows:
1. Freestanding: not allowed, except for monument signs as described within the
downtown Auburn design standards; no more than one per street frontage; maximum
size: 64 square feet, calculated at a rate of one square foot of sign area per lineal foot of
site frontage; minimum entitlement shall be 32 square feet; maximum height: five feet.
2. Wall signs: maximum area of 150 square feet per building facade, calculated at a
rate of one square foot of sign area for every lineal foot of facade; minimum entitlement
shall be 16 square feet.
3. Suspended signs attached under a marquee or canopy: one double-faced sign, no
greater than three square feet per face allowed for each building entrance; minimum
clearance above grade: eight feet.
4. Portable Signs. Portable signs may be allowed for each business entrance, subject to
the following:
Page 724 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 30 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
a. Signs may be placed within the public right-of-way, within 12 feet of a business
entrance, subject to the guidelines provided by the director in consultation with the
city engineer such that sign placement does not interfere with pedestrian or
vehicular traffic, does not create a sight hazard, and conforms to the requirements
of the Americans with Disabilities Act. Additional portable signage may be
authorized in order to support downtown events that are permitted or sanctioned
by the city.
b. The sign shall be in accordance with the provisions of ACC 18.56.030(L).
c. The sign area cannot exceed 42 inches in height, 32 inches in width, and be
limited to two faces.
d. Portable signs are not permitted to be affixed to city infrastructure located
within the right-of-way (e.g., street lights, fire hydrants, public art). This includes a
prohibition of chaining or otherwise securing portable signs to such infrastructure.
e. Signs may be displayed during business hours and shall not be displayed when
the business is closed.
f. No landscaping may be covered, cut, damaged, or modified to accommodate a
portable sign. The city may require replacement of any damaged landscaping
pursuant to Chapter 18.50 ACC.
g. All portable signs shall have the permit number affixed to the back of the sign.
3. J. Landscaping. Landscaping shall be provided as defined in the downtown Auburn
design standards, except for development subject to the middle housing and single
unit detached design standards.
4. Fences: Fencing shall be subject to the standards in ACC 18.31.020(A) through (F);
except for the DUC M-1 district in which the standards of ACC 18.31.020 (G) and (H)
also apply. Where there is a conflict between ACC 18.31.020 and the downtown
design standards shall govern.
5. Outdoor lighting: Outdoor lighting shall be subject to the standards in Chapter 18.55
ACC. Where there is a conflict between Chapter 18.55 and the downtown design
standards shall govern.
18.29.070 Design standards.
Page 725 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 31 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Adopted by reference are the downtown Auburn design standards and the Auburn Junction
design standards, a copy of which shall be maintained by the city clerk. These documents
contain standards for development of the built environment in the DUC zoning districtse. The
director shall have the authority to apply the standards to specific development proposals.
These standards may be amended upon approval by the community development director.
(Ord. 6828 § 1 (Exh. A), 2021; Ord. 6532 § 29, 2014; Ord. 6419 § 2, 2012; Ord. 6287 § 2, 2010; Ord. 6190 § 1,
2008; Ord. 6071 § 6 (Exh. A), 2007.)
18.29.080 Planned action standards.
A. Purpose of the planned action. The purpose of this section is to:
1. Set forth a procedure designating certain project actions within a specific subject site
as “planned actions” consistent with state law, RCW 43.21C.031; and
2. Provide the public with an understanding as to what constitutes a planned action
and how land use applications which qualify as planned actions will be processed by
the city; and
3. Streamline and expedite the development review process for this designated
planned action by relying on completed and existing detailed environmental analysis
for the subject site; and
4. Combine environmental analysis with land use planning; and
5. Apply the city’s development regulations together with the mitigation measures
described in the environmental impact statement (EIS) and this chapter to address
the impacts of future development contemplated by the planned action.
B. Findings. The city council makes the following findings:
1. The City is subject to the requirements of the GMA (Chapter 36.70A RCW) and is
applying Planned Action to an Urban Growth Area (UGA).
2. The procedural requirements of Chapter 36.70A RCW have been complied with.
3. The procedural and substantive requirements of SEPA (Chapter 43.21C RCW) have
been complied with.
Page 726 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 32 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
4. The City has an adopted Comprehensive Plan complying with the GMA and is
replacing the 2001 Auburn Downtown Plan with the 2024 Auburn Downtown
Subarea Plan.
5. An EIS has been prepared for the Planned Action Area and the City Council finds that
the EIS adequately identifies and addresses the probable significant environmental
impacts associated with the type and amount of development planned to occur in
the designated Planned Action Area.
6. The 2024 Auburn Downtown Subarea Plan and Planned Action EIS, together with
adopted City development and environmental regulations, will adequately mitigate
significant impacts from development within the Planned Action Area.
7. The regulation of land and development is subject to the authority and general
police power of the City, and the City reserves its powers and authority to
appropriately amend, modify, and revise such land use controls in accordance with
applicable law.
8. The 2024 Auburn Downtown Subarea Plan and EIS identify the location, type, and
amount of development contemplated by the Planned Action.
9. Essential public facilities defined in RCW 47.06.140 are excluded from the Planned
Action and are not eligible for review or permitting as Planned Action Projects unless
they are an accessory to or part of a project that otherwise qualifies as a planned
action.
10. The Planned Action is located entirely within a UGA and applies to a defined area
that is smaller than the overall City boundary.
11. Public services and facilities are adequate to serve the proposed Planned Action with
implementation of the City’s adopted Engineering Design Standards and the
Comprehensive System Plans.
12. The City has provided several opportunities for meaningful public involvement in the
2024 Auburn Downtown Subarea Plan and EIS including a community meeting
consistent with RCW 43.21C.440, and has considered all comments received, and, as
appropriate, has modified the proposal or mitigation measures.
13. Future projects that are implemented consistent with the Downtown Subarea
Planned Action EIS and mitigation measures will protect the environment, benefit
the public, and enhance economic development.
C. Applicability of the Planned Action.
Page 727 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 33 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
1. Planned Action Area. This section applies to approximately 360 acres included in the
Auburn downtown subarea project area as described in the Downtown Subarea
Planned Action EIS issued by the City on January 22, 2025 (and any addenda thereto)
and shown in Exhibit A of Ord. No. 7006 are designated as the Downtown Planned
Action Area.
2. Environmental Document. A Planned Action Project determination for a site-specific
project application within the Downtown Planned Action Area shall be based on the
environmental analysis contained in the Downtown Subarea Planned Action EIS. The
mitigation measures contained in this section, as well as Exhibit B of Ord. No. 7006, are
based upon the findings of the Downtown Subarea Planned Action EIS and shall, along
with adopted City regulations, provide the framework the City will apply appropriate
conditions on qualifying Planned Action Projects within the Downtown Planned Action
Area.
3. Planned Action Designated. Uses and activities described in the Downtown Subarea
Planned Action EIS (and any addenda thereto), subject to thresholds (ACC 18.29.080(D))
and the mitigation measures contained in this section, are designated Planned Action
Projects pursuant to RCW 43.21C.440. A development application for a site-specific
project located within the Downtown Planned Action Area that meets the criteria in ACC
(ACC 18.29.080(D) and (E) may be designated a Planned Action Project pursuant to the
process in ACC 18.28.080(I).
D. Planned Action Thresholds. Subject to the zoning regulations for the site and the mitigation
measures described in this chapter, the maximum levels of development described below have
been evaluated in the Downtown Subarea Planned Action EIS, as described in the EIS (and any
addenda thereto), and are planned actions pursuant to RCW 43.21C.031. In order to qualify as a
planned action, total cumulative development within the Downtown Planned Action Area that
has been permitted under this chapter shall meet all of the following criteria:
1. Land Use. The following general types of land uses are considered Planned Actions:
a. Single-unit detached housing and middle housing;
b. Multi-family housing (apartments and co-living housing);
c. Mixed-use (vertical or horizontal);
d. Retail, commercial, office, services;
e. Restaurants and bars;
Page 728 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 34 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
f. Craft industry/light industrial, small food production;
g. Arts/entertainment (gallery, theater, fine arts studios);
h. Medical offices and hospital;
i. Open space, passive or active parks, trails, recreation;
j. Civic, cultural, government, and utility facilities as identified in the Plan and
allowed in the Auburn Zoning Code;
k. Uses allowed in the Zoning Code provided for each implementing district (Chapter
18.29 DUC);
l. Other uses applicable to the 2024 Auburn Downtown Subarea Plan that are similar
to uses listed above as determined by the Community Development Director or
designee;
m. Multi-modal transportation improvements consistent with the Comprehensive
Transportation Plan and the Planned Action EIS; and
n. Enlargement or intensification of uses existing at the time the Planned Action Area
is approved, so long as such enlargement or intensification complies with the
Zoning Code to the extent practical.
2. Planned Action Uses. A land use shall qualify as a Planned Action Project land use
when:
a. It is within the Downtown Planned Action Area; and
b. It is within one or more of the land use categories described above; or
c. It is a common accessory use or appurtenance to a permitted use.
3. A Planned Action Project may be a single Planned Action land use, or a combination
of Planned Action land uses in a mixed-use development.
4. Development Thresholds. The following amount of new various land uses are
contemplated by the Planned Action (Table 2 Ord. No. 7006):
Page 729 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 35 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
a. Shifting development amounts between land use identified above may be
permitted provided the transportation thresholds are not exceeded and the
development impacts identified in the Downtown Subarea Planned Action EIS are
mitigated consistently with the mitigation measures.
b. Further environmental review may be required pursuant to WAC 197-11-172, if
any individual Planned Action Project or combination of Planned Action Projects
exceed the development thresholds specified above and/or alter the assumptions
and analysis in the Downtown Subarea Planned Action EIS.
5. Transportation Thresholds.
a. Level of Service Threshold. The City uses an LOS rating system to evaluate the
operations of its roadway system. LOS is a concept used to describe traffic
operations from the driver’s perspective. LOS ratings are defined by intersection
delay in seconds—LOS ranges from LOS A, which signifies no congestion and little
delay, to LOS F, which signifies substantial congestion and delay. All intersections
currently meet the City’s minimum LOS standards. As of Dec. 2025, one
intersection does not meet the City’s minimum LOS standards: C Street NW & 3rd
Street NW – LOS F. This intersection is currently identified in the Comprehensive
Transportation Plan and 6-Year Transportation Improvement Plan for future
mitigation.
b. Concurrency. All Planned Action Projects shall meet the City's transportation
concurrency requirement standards and the level of service thresholds according
to the Comprehensive Transportation Plan and Engineering Design Standards.
Applicants shall be required to document that the project meets concurrency
standards.
c. Impact Fee. In order to mitigate transportation related impacts, all Planned Action
Projects shall pay impact fees, with adjustments made for any applicable credits.
d. Mitigation. Each Planned Action Project shall provide its proportionate share of
transportation capital improvements analyzed in the Planned Action EIS. The City
Engineer shall have the discretion to adjust the allocation of responsibility for
required improvements between individual Planned Action Projects based on
their identified impacts.
Page 730 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 36 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
e. Discretion. The City Engineer shall have discretion to determine incremental and
total trip generation, consistent with Chapter 19.04 ACC for each Planned Action
Project proposed under this Planned Action.
E. Elements of the Environment and Degree of Impacts. A Planned Action Project that would result
in a significant change in the type or degree of adverse impacts to any element(s) of the
environment analyzed in the Planned Action EIS will not qualify as a Planned Action Project.
F. Changed Conditions. Should environmental conditions change significantly from those
analyzed in the Downtown Subarea Planned Action EIS, the City’s SEPA Responsible Official or
designee may determine that the Planned Action designation is no longer applicable until
supplemental environmental review is conducted.
G. Review Criteria for Planned Actions. The City’s SEPA Responsible Official or designee may
designate projects as “Planned Action Projects”, pursuant to RCW 43.21C.030, applications that
meet the following conditions:
1. The proposal is located within the Planned Action Area identified above.
2. The proposed uses and activities are consistent with those described in the
Downtown Subarea Planned Action EIS and this Section.
3. The proposal is within the Planned Action thresholds and other criteria of this
Section.
4. The proposal is consistent with the Auburn Comprehensive Plan and the 2024
Auburn Downtown Subarea Plan.
5. The proposal’s significant adverse environmental impacts have been identified in the
Downtown Subarea Planned Action EIS.
6. The project’s significant impacts will be mitigated by application of the measures
identified ACC 18.29.080(J) and other applicable City regulations, together with any
conditions, modifications, variances, design review, or special permit that may be
required.
7. The project complies with all applicable local, state, and/or federal laws and
regulations, and the SEPA Responsible Official or designee determines that these
laws and regulations constitute adequate mitigation.
Page 731 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 37 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
8. The project is not an essential public facility as defined by RCW 36.70A.200 unless
the essential public facility is an accessory to or part of a development that is
designated as a Planned Action Project.
H. Effect of Planned Action Designation. Designation as a Planned Action Project by the City’s SEPA
Responsible Official or designee means that a qualifying proposal has been reviewed in
accordance with this Section and found to be consistent with the development parameters and
thresholds established herein and with the environmental analysis contained in the Downtown
Subarea Planned Action EIS
I. Planned Action Permit Process. Applications for Planned Action Projects shall be reviewed
pursuant to the following process:
1. Development applications shall meet all applicable requirements of the Auburn
Municipal Code and this Section in place at the time of the Planned Action Project
application.
2. Applications for Planned Action Projects shall:
a. Be made on forms provided by the City;
b. Include the SEPA checklist in WAC 197-11; and
c. Meet all applicable requirements of the Auburn Municipal Code and this Section.
3. The City’s SEPA Responsible Official or designee shall determine whether the
application is complete as provided in Title 14 ACC.
4. If the application for a project within the Planned Action Area, as defined in Exhibit A
of Ord. No. 7006, then the application will be reviewed to determine if it is consistent
with the criteria of this ordinance and thereby qualifies as a Planned Action Project.
5. The decision of the City’s SEPA Responsible Official or designee determining if a
project is a Planned Action Project is a Type 1 decision. The City’s SEPA Responsible
Official or designee shall notify the applicant of their decision in writing to the
applicant or project representative, as listed on the application, and federally
recognized tribal governments and agencies with jurisdiction over the Planned
Action Project pursuant to RCW 43.21C.440.
6. If the project is determined to qualify as a Planned Action Project, it shall proceed in
accordance with the applicable permit review procedures specified in Title 14 ACC,
Page 732 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 38 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
except that no SEPA threshold determination, EIS, or additional SEPA review shall be
required.
7. Notice of application for a Planned Action Project shall be consistent with Title 14
ACC.
8. If notice is otherwise required for the underlying permit, the notice shall state that
the project has qualified as a Planned Action Project. If notice is not otherwise
required for the underlying permit, no special notice is required by this Ordinance.
9. To provide additional certainty about applicable requirements, the City or applicant
may request consideration and execution of a development agreement for a
Planned Action Project, consistent with RCW 36.70B.170.
10. If a project is determined to not qualify as a Planned Action Project, the City SEPA
Responsible Official or designee shall notify the applicant and prescribe a SEPA
review procedure consistent with the City’s SEPA regulations and requirements of
state law. The notice shall describe the elements of the application that result in
failure to qualify as a Planned Action Project.
11. Projects that fail to qualify as Planned Action Projects may incorporate or otherwise
use elements of the Downtown Subarea Planned Action EIS, as well as other relevant
SEPA documents, to meet their SEPA requirements. The City SEPA Responsible
Official or designee may limit the scope of SEPA review for the non-qualifying project
to those issues and environmental impacts not previously addressed in the
Downtown Subarea Planned Action EIS.
J. Planned Action Mitigation Measures. The planned action mitigation measures set forth in
Exhibit B attached to Ord. No. 7006 and codified in this chapter and incorporated herein by this
reference shall apply to the project identified therein. Exhibit B shall not be codified with the
provisions of this chapter but shall be on file and available for review in the office of the city
clerk.
K. Amendments. Amendments to this chapter may be initiated by the city, the proponent, or the
proponent’s successor, and shall occur as follows:
1. The director may interpret the words and meaning of certain conditions in order to
resolve conflicts in implementation. All words in the ordinance codified in this
chapter shall carry their customary and ordinary meaning.
Page 733 of 758
Chapter 18.29 ACC, DUC Downtown Urban Center District Page 39 of 39
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
2. If changes to the language of the ordinance codified in this chapter are required,
such proposed changes shall be reviewed by the director. If, in the estimation of the
director, the proposed change is minor, then the proposed change shall be
forwarded directly to the city council for its consideration. If, in the estimation of the
director, the change is major, the proposed change shall be referred to the planning
commission which shall conduct a public hearing and make a recommendation to
the city council.
Page 734 of 758
ACC 18.02.070, Establishment of zones Page 1 of 2
The Auburn City Code is current through Ordinance 7008, passed November 17, 2025.
18.02.070 Establishment of zones.
A. The city is divided into the following classes of zones:
1. RC, residential conservancy zone (one dwelling unit per four acres);
2. R-1, residential one unit per acre zone;
3. R-2, residential low zone;
4. R-3, residential moderate zone;
5. R-4, residential high zone;
6. R-MHC, manufactured/mobile home community zone;
7. R-F, residential flex zone;
8. R-NM, residential neighborhood mixed-use zone;
9. C-1, light commercial zone;
10. C-2, heavy commercial zone;
11. C-AG, auburn gateway zone;
121. M-1, light industrial zone;
132. M-2, heavy industrial zone;
143. L-F, airport landing field zone;
154. P-1, public use zone;
165. UNC, unclassified use zone;
176. I, institutional use zone;
187. DUC, downtown urban center, 125 District;
198. DUC, downtown urban center, 75 District;
19. DUC, downtown urban center, 55 District;
ATTACHMENT 2
Page 735 of 758
ACC 18.02.070, Establishment of zones Page 2 of 2
The Auburn City Code is current through Ordinance 7008, passed November 17, 2025.
20. DUC, neighborhood residential district;
21. DUC, health and wellness district;
22. DUC, residential-flex district;
23. DUC, light commercial district;
24. DUC, heavy commercial district;
25. DUC, light industrial district;
26. OS, open space zone.
B. The zones set out in subsection A of this section are established as the designations,
locations, and boundaries thereof as set forth and indicated on the zoning map.
C. The intent statement for each zone set forth in this title shall be used to guide the
application of the zones to all lands in the city of Auburn. The intent statements shall guide
interpretation and application of land use regulations within the zones, and any change to the
range of allowed uses within each zone through amendment to this title. (Ord. 6959 § 1 (Exh. A),
2024; Ord. 6885 § 1 (Exh. A), 2022; Ord. 6677 § 1, 2018; Ord. 6245 § 2, 2009.)
Page 736 of 758
CSTSWASTSEAUBURN AVE3RD ST SW
8TH ST NE
4TH ST SE
E MAIN ST
3RD ST NE
A ST SW4 T H S T NE
W MAIN ST
2NDSTSW AUBURN WAY N2ND ST SE
AUBURN WAY S1ST ST SW
3RD ST SE
1ST ST SE
3RD ST NW
4THSTSW SDIVISIONSTBSTNWC ST NWD ST NEA ST NE9THST
N
E
10TH ST NW
ASTNWCROSS
S
T
S
E
10TH ST NE
City of Auburn Downtown Urban Center Zoning Districts
0 0.13 0.25
Miles
DUC - Core 125
DUC - Core 75
DUC - FR Flex Residential
DUC - Health & Wellness
125
DUC - C-1 Light
Commercial
DUC - C-2 Heavy
Commercial
DUC - M-1 Light Industrial
DUC - NR Neighborhood
Residential
DUC - Downtown Urban
Center
C-AG - Auburn Gateway
C-1 - Light Commercial
C-2 - Heavy Commercial
I - Institutional
M-1 - Light Industrial
M-2 - Heavy Industrial
LF - Airport Landing Field
OS - Open Space
P-1 - Public Use
Planned Unit Development
District
R-1 - Residential 1 DU/Acre
R-2 - Residential Low
R-3 - Residential Moderate
R-4 - Residential High
Lakeland Hills PUD
R-MHC - Residential
Manufactured/Mobile Home
Community
R-NM - Nieghborhood
Mixed-Use
RC - Residential
Conservancy
R-F - Residential Flex
Terrace View District
Unclassified Use District
Information shown is for general reference purposes
only and does not necessarily represent exact
geographic or cartographic data as mapped. The
City of Auburn makes no warranty as to its accuracy.
Map ID: 6356
Printed On: 1/8/2026
Updated On: 12/30/2025
Downtown Urban Center
ATTACHMENT 3
Page 737 of 758
AGENDA BILL APPROVAL FORM
Agenda Subject: Meeting Date:
Citywide Design Standards and Code Update
Staff Introduction/Presentation (Reed)
Staff will provide an update on the public outreach conducted for the draft
Citywide Design Standards and provide an overview of the associated code
updates.
March 3, 2026
Department: Attachments: Budget Impact:
Community Development Attachment 1 - ACC Section
18.31.200 Text Amendment,
Attachment 2 - ACC Section
18.23.040 Text Amendment,
Attachment 3 - ACC Section
18.07.030 Text Amendment,
Memorandum
Administrative Recommendation:
Background for Motion:
Background Summary:
See attached Memorandum
Councilmember: Staff: Jason Krum
Page 738 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 1 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.31.200 Architectural and site design review standards and
regulations.
A. Intent and Purpose. The architectural and site design regulations provide an administrative
review process for evaluating the design and arrangement of development. The architectural
and site design regulations are intended to be consistent with and implement the policies of
the comprehensive plan. The purposes of these design review regulations are to:
1. Foster good decision-making for development through architectural and site design
within the context of the community’s built and natural environmental character, scale and
diversity;
2. Promote the use of appropriate scale of buildings and the configuration of open space
and parking areas for development to safely and comfortably accommodate pedestrian
activities;
3. Coordinate the interrelationship of buildings and public and private open space;
4. Discourage monotony in building design and arrangement, while promoting harmony
among distinct building identities; and
5. Mitigate, through design and site plan measures, the visual impact of large building
facades, particularly those which have high public visibility (encourage the creative use of
architectural and landscape features in order to reduce the actual and perceived scale and
bulk of structures).
B. Applicability. The following land uses, types of development activities, including all related
site improvements, and geographic areas, are subject to the architectural and site design
standards and the processes and regulations for conducting design review contained in this
chapter:
1. Apartment buildings, s (Formerly Multiple-Family) and Mixed-Use Developments, Congregate
living development, and Non-residential development. The following land uses and types of
development are subject to the city’s apartment and mixed-use design standards
document unless addressed by a different set of architectural and site design standards
applicable to a specific geographic area:
ATTACHMENT 1
Page 739 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 2 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
a. Apartment buildings, containing seven or more units on a single lot, development
inclusive of seven or more units in all zones in the city where permitted outright or as a
conditional useallowed and not otherwise addressed through the city’s residential infill
development standards (Chapter 18.25 ACC); and
b. Mixed-Use Residential Development. Mixed-use development containing residential
living units in all zones in the city where allowed permitted outright or as a conditional
use; and
c. Retirement apartments, congregate living facilities and senior housing complexes in
all zones in the city where permitted outright or as a conditional useallowed; and
d. Non-residential development, except for development within the M-1 and M-2
zones.
2. Downtown Urban Center. The following locations of development activities are subject to
the city’s downtown urban design standards document:
a. Properties located within the boundaries of the DUC, downtown urban center
zoning district boundary, as identified on the comprehensive zoning map.
3. Auburn Junction. The following locations of development activities are subject to the
city’s Auburn Junction design standards document:
a. Properties located within the boundaries of West Main Street, 2nd Street SE/SW, A
Street SE, and A Street SW as identified with ACC 18.29.070, downtown urban design
standards.
4. Northeast Auburn Special Planning Area. The following locations of development activities
are subject to the city’s Auburn Gateway architectural and site design standards document:
a. Properties located within the boundaries of the Auburn Gateway Project as defined
by the development agreement approved by city Resolution No. 4756, or as may be
subsequently amended. The Auburn Gateway architectural and site design is
addressed in Section 4 of that resolution and provided as Attachment 4 to the
resolution.
C. Exemptions. The following activities as determined by the community development director
shall be exempt from the provisions of the design standards:
Page 740 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 3 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
1. Any building activity that does not require a building permit; or
2. Interior construction work which does not alter the exterior of the structure; or
3. Normal or routine building and site maintenance/repair that is exempt from issuance of
a permit, including the repair or maintenance of structural members; or
4. Interior alterations that do not modify an existing site condition.; or
5. Site and exterior alterations that do not exceed 10 percent of the assessed valuation of
the property building or land per the most recent county records; or
6. Building additions that are less than 10 percent of the existing floor area of the existing
building. Any cumulative floor area increase from the adoption date of the ordinance
establishing the architectural and site design standard that totals more than 10 percent
shall not be exempt unless the community development director determines compliance
with these standards would be infeasible and/or unreasonable.
D. Design Standard Documents. Adopted by reference are the following architectural and site
design documents, copies of which shall be maintained by the city clerk. These documents
contain the standards for the design and development of the built environment. The
community development director or designee shall have the authority to apply the standards to
specific development proposals. The following specific architectural and design standards
documents may be amended upon approval by the community development director:
1. Mixed-use and apartment (formerly multiple-family) developmentCitywide design
standards.
2. Auburn Gateway architectural and site design standards.
3. Downtown urban design standards.
4. Auburn Junction design standards.
E. Timing of Administrative Design Review.
1. Design review shall be conducted by the community development director or designee
prior to or concurrent with the processing of building permits and/or review of
discretionary land use approvals/permits.
Page 741 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 4 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
2. The decision on the administrative design review shall be issued prior to issuance of the
building permits and/or issuance of discretionary land use approvals/permits.
F. Pre-Application Meeting Recommendation with– When Required Associated With a Design Review.
A pre-application conference is recommended for all other projects subject to the city’s
architectural and site design review but is not required.
1. A pre-application conference is requiredstrongly recommended for the following
instances:
a. For aApartments in the R-3 and R-4 residential zonesbuildings; and
b. For mMixed-use development; and containing residential living units located within
R-3 and R-4 residential zones; and
c. For mixed-use development containing residential living units located within
commercial zones; and
cd. For retirement apartments, congregate living facilities and senior housing
complexes. located within R-3 and R-4 residential zones, and all commercial zones.
2. A pre-application conference is strongly recommended for all other projects subject to
the city’s architectural and site design review but is not required.
G. Design Review Submittal Requirements. In addition to any other documentation required for
submittal of a complete application for building permit or discretionary land use
approvals/permits, the following items shall be required for the architectural and site design
review:
1. Elevation drawings prepared by an architect licensed in the state of Washington of all
proposed construction, including dimensional drawings at one-eighth inch equals one foot
or comparable scale showing the type of exterior materials, color (where applicable),
exterior finishes for buildings and accessory structures, location and elevations of exterior
lighting for buildings, the type, style and model of exterior lighting fixtures (where
applicable), parking areas, and fenestration details;
2. A to-scale landscape plan prepared by a landscape architect licensed in the state of
Washington showing existing vegetation to be retained and proposed vegetation to be
Page 742 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 5 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
installed inclusive of the common and botanical name of all vegetation, the location and
quantity of vegetation, the initial planting size and methods of irrigation;
3. A context vicinity map that shows all structures on the property and within 200 feet in
each direction of the subject property drawn approximately to scale;
4. A neighborhood circulation plan consistent with the provisions of Chapter 17.16 ACC
(Neighborhood Circulation Plan); and
5. Conceptual plans for any public infrastructure, including roads, water, sewer, and storm
facilities.
H. Interpretations.
1. The community development director shall be authorized to interpret the meaning of
words, phrases and sentences which relate to the implementation of the specific
architectural and design standards document. Any interpretations regarding
implementation of the specific architectural and design standards document shall be made
in accordance with its intent or purpose statements and the intent and purpose statements
of this chapter. For interpretations, life safety and public health regulations shall be given
priority over all other regulations.
2. Administrative interpretations may be appealed to the hearing examiner as prescribed
in ACC 18.70.050.
I. Design Review DeparturesAdjustments.
1. Authority for Design Review DeparturesAdjustments. The community development director
or designee shall have the authority, subject to the provisions for departures within design
standard documentsof this section and upon such conditions as the community
development director or designee may deem necessary to comply with the provisions of
this section, to approve design departures or alternative design treatments. adjustments as
follows:
a. An adjustment to architectural or site design requirements such that no more than
two of the total number of required menu items in the city of Auburn apartment and
mixed-use design standards are out of compliance.
Page 743 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 6 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
b. An adjustment to required building wall and roof modulation standards, as
contained in the city of Auburn apartment and mixed-use design standards, up to 20
percent of the amount of any quantified standards contained therein.
c. An adjustment to the architectural or site design requirements that remains
consistent with the purpose and intent of the architectural and site design standards.
2. Required Findings to Grant Design Review DeparturesAdjustments. Each determination
granting a departurean adjustment by the community development director or designee
shall be supported by written findings showing specifically wherein all of the following
conditions exist:
a. That the granting of such departure adjustment meets the purpose of the
standards and any other applicable departure criteria that applies to the specific
standarddoes not constitute a grant of special privilege inconsistent with the
limitations upon uses of other properties in the vicinity and/or zone of the subject site;
and
b. That the granting of such departure adjustment will not adversely affect the
established character of the surrounding neighborhood, discourage maintenance or
upgrades on surrounding properties nor result in perpetuation of those design
qualities and conditions which the comprehensive plan intends to eliminate or avoid ;
and
c. That the project incorporates alternate design characteristics that are equivalent or
superior to those otherwise achieved by strict adherence to the standard. stated menu
options; and
3. Public Notification and Action on Design Review Adjustment Applications. Upon the filing of
a properly completed application and associated request for a design review adjustment,
the community development director or designee shall comply with the city’s Type II land
use review requirements for issuance of a properly noticed and appealable land use
decision.
34. Appeal of Director’s Decision on Design Review Departures. Adjustment
a. If a written objection to the initial determination notice is filed within 14 business
days of said notification, the community development director or designee shall
Page 744 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 7 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
reconsider the initial determination in light of the objection(s) as raised and render a
final decision on the permit. This final decision shall result in either the community
development director’s affirmation of the original determination of approval, the
approval with additional modifications or denial.
b. Upon completion of the community development director’s reconsideration, all
parties notified of the original determination shall receive notification of the
community development director’s final decision. Any party aggrieved by the
community development director’s final decision may file an appeal of that decision to
the hearing examiner in accordance with the city’s land use appeal provisions. Such
appeals for hearing examiner review must be filed within 14 business days from the
date the written decision was made and shall include the following:
i. The appeal shall be filed on forms provided by the department of planning and
development.
ii. The appeal shall clearly state the decision being appealed, setting forth the
specific reason, rationale, and/or basis for the appeal.
iii. Fees associated with the appeal shall be paid to the city upon filing of the
appeal in accordance with a fee schedule established by resolution.
5. Upon filing of a timely and complete appeal, the hearing examiner shall conduct a
public hearing to consider the merits of the appeal. This hearing shall be subject to the
city’s public noticing and public hearing requirements and shall include notification of all
parties notified of the community development director’s final decision. The hearing
examiner may affirm the community development director’s decision or may remand the
matter to the community development director for further review in accord with the
examiner’s direction.
6. If no written objection is filed to the initial determination within the specified time limits,
the community development director shall render a final decision on the permit in accord
with the initial determination.
J. Approval Criteria for Design Review. The community development director or designee may
approve, modify and approve, or deny an application for an administrative design review. Each
Page 745 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 8 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
determination granting approval or approval with modifications shall be supported by written
findings showing the applicant satisfies all the following criteria:
1. The plans and supplemental materials submitted to support the plan meet the
requirements of the specific architectural and site design documents; and
2. The proposed development is consistent with the comprehensive plan.
3. The proposed development meets required setback, landscaping, architectural style
and materials, such that the building walls have sufficient visual variety to mitigate the
appearance of large facades, particularly from public rights-of-way, single-unit detached
dwellings and middle housing.
4. In addition to the criteria in subsections (J)(1) through (J)(3) of this section, for
apartments and retirement apartment projects, the director or designee must determine
that the following key review criteria have been met:
a. The proposed development is arranged in a manner that either:
i. Provides a courtyard space creating a cohesive identity for the building cluster
and public open space furnished to facilitate its use; or
ii. Possesses a traditional streetscape orientation that provides clearly identifiable
and visible entries from the street, views from residential units onto the street and
reinforces pedestrian-oriented streetscape characteristics (e.g., building edge
abutting sidewalk, entries onto the street); or
iii. Faces and facilitates views of a major open space system;
b. The proposed development provides a variety in architectural massing and
articulation to reduce the apparent size of the buildings and to distinguish vertical and
horizontal dimensions;
c. The proposed development contains a combination of elements such as
architectural forms, massing, assortment of materials, colors, and color bands
sufficient to distinguish distinct portions and stories of the building;
Page 746 of 758
ACC 18.31.200, Architectural and site design review standards and regulations Page 9 of 9
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
d. Residential buildings in large apartment projects or mixed-use projects are
physically integrated into the complex possessing sufficiently different appearance or
placement to be able to distinguish one building from another;
e. Unit entrances are individualized by use of design features that make each
entrance distinct or which facilitate additional personalization by residents;
f. Areas dedicated to parking are sufficiently visually broken up and contain a
complement of vegetative materials to project a landscaped appearance;
g. Where applicable, a transition is created that minimizes impacts from apartments
and mixed-use development projects on neighboring lower density residential dwelling
units; and
h. Where applicable, in cases of granting density or height bonuses, the project has
provided community benefits, facilities or improvements above and beyond those
required in the municipal code and supports the goals, objectives and policies of the
comprehensive plan. (Ord. 6959 § 1 (Exh. A), 2024; Ord. 6728 § 4 (Exh. D), 2019; Ord. 6408 § 1,
2012; Ord. 6287 § 2, 2010; Ord. 6245 § 15, 2009.)
Page 747 of 758
ACC 18.23.040, Development standards Page 1 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.23.040 Development standards.
A. Hereafter, no use shall be conducted and no building, structure and appurtenance shall be
erected, relocated, remodeled, reconstructed, altered or enlarged unless in compliance with the
requirements in Tables 18.23.040A (C-1, C-2, and C-AG Zone Development Standards) and
18.23.040B (M-1 and M-2 Zone Development Standards) and in compliance with the provisions
of this title, and then only after securing all permits and approvals required hereby. These
standards may be modified through either an administrative variance or variance, subject to
the procedures of Chapter 18.70 ACC.
Table 18.23.040A. C-1, C-2 and C-AG Zone Development Standards
Development Standard
Requirement by Zone
C-1
Light Commercial
C-2
Heavy Commercial
C-AG
Mixed-Use
Commercial
Minimum lot area None None None1
Minimum lot width, depth None None None
Maximum lot coverage None None None
Minimum setbacks Minimum setbacks required for structures. See also ACC 18.31.070 for
specific exceptions to these setback standards.
Front 20 ftNone4 20 ftNone4 20 ft
Side, Interior None2 None2 None2
Side, Street 15 ft 15 ft 15 ft
Rear None2 None2 None2
Height limit Maximum allowable height of structures. See also ACC 18.31.030
ATTACHMENT 2
Page 748 of 758
ACC 18.23.040, Development standards Page 2 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Development Standard
Requirement by Zone
C-1
Light Commercial
C-2
Heavy Commercial
C-AG
Mixed-Use
Commercial
(Height limitations – Exceptions) for specific height limit exceptions.
Maximum height 45 ft3 75 ft 75 ft
Additional development standards None None None
Fences and hedges See Chapter 18.31 ACC
Landscaping See Chapter 18.50 ACC
Parking See Chapter 18.52 ACC
Signs See Chapter 18.56 ACC
Lighting See Chapter 18.55 ACC
Nonconforming structures, land and
uses
See Chapter 18.54 ACC
Notes:
1 Residential uses: no minimum lot size; provided, that residential density does not exceed 20 units per gross
acre (this includes privately owned open space tracts but excludes dedicated public roads).
2 A 25-foot setback is required when adjacent to a residential zone.
3 Buildings within the Auburn north business area, as established by Resolution No. 2283, may exceed 45 feet
if one additional foot of setback is provided from each property line (or required minimum setback) for each
foot the building exceeds 45 feet in height.
4 In addition to meeting setback requirements, all structures must meet sight distance requirements in
accordance with city engineering design and construction standards.
Page 749 of 758
ACC 18.23.040, Development standards Page 3 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Table 18.23.040B. M-1 and M-2 Zone Development Standards
Development Standard
Requirement by Zone
M-1
Light Industrial
M-2
Heavy Industrial
Minimum lot area None None
Minimum lot width, depth None None
Maximum lot coverage None None
Minimum setbacks Minimum setbacks required for structures. See also ACC 18.31.070 for
specific exceptions to these standards.
Front 20 ftNone 30 ft
Side, Interior None1 None1
Side, Corner 20 ft 30 ft
Rear None1 None1
Height limit Maximum allowable height of structures. See also ACC 18.31.030 (Height
limitations – Exceptions) for specific height limit exceptions
Maximum height 45 ft2 45 ft2
Additional development standards None None
Page 750 of 758
ACC 18.23.040, Development standards Page 4 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Development Standard
Requirement by Zone
M-1
Light Industrial
M-2
Heavy Industrial
Fences and hedges See Chapter 18.31 ACC
Landscaping See Chapter 18.50 ACC
Parking See Chapter 18.52 ACC
Signs See Chapter 18.56 ACC
Lighting See Chapter 18.55 ACC
Nonconforming structures, land and
uses
See Chapter 18.54 ACC
Notes:
1 A 25-foot setback is required when adjacent to a residential zone.
2 Buildings may exceed 45 feet if one foot of setback is provided from each property line (or required
minimum setback) for each foot the building exceeds 45 feet.
(Ord. 6959 § 1 (Exh. A), 2024; Ord. 6885 § 1 (Exh. A), 2022; Ord. 6728 § 3 (Exh. C), 2019; Ord. 6433 § 26, 2012.)
Page 751 of 758
ACC 18.07.030, Development standards Page 1 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
18.07.030 Development standards.
Table 18.07.030. Residential Development Standards
Standard RC R-1 R-2 R-3 R-4 R-NM R-F
A Minimum density units
or lots per acre (lot area
per unit)1, 5
0.25
(174,000
sf of lot
area per
unit)
1 (43,500
sf of lot
area per
unit)
7 (6,222
sf lot area
per unit)
12 (3,630
sf lot area
per unit)
16 (2,723
sf lot area
per unit)
30 (1,452
sf lot area
per unit)
7 (6,222
sf lot area
per unit)
B Minimum lot size
(square feet)8
174,000 43,500 4,400 2,700 2,200 2,200 4,400
C Minimum lot width
(feet)2, 5, 7
125 125 40 20 for
interior
lots; 35
for
exterior
lots
20 for
interior
lots; 35
for
exterior
lots
20 for
interior
lots; 35
for
exterior
lots
40
D Units allowed
1 Base units allowed per
lot 6
4 4 4 4 4 4 4
2 Base units per lot
allowed with transit or
affordability bonus 6
6 6 6 6 6 6 6
3 Lot area per unit above
base (B1 or B2 as
applicable) allowance
(square feet) 6
X X 1,250 750 N/A N/A 1,250
4 Maximum units per lot 6 6 6 6 20 N/A N/A 6
ATTACHMENT 3
Page 752 of 758
ACC 18.07.030, Development standards Page 2 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Standard RC R-1 R-2 R-3 R-4 R-NM R-F
E Minimum setbacks
(feet)2, 3, 10
1 Residence front
setback3
35 35 10 109 10None 10None 109
2 Garage (minimum front
setback required from
street access)3
20 20 20 20 20 20 20 unless
alley-
loaded
then 15
provided
there are
20 feet
from any
garage
3 Setback to any property
line for barns, stables,
or similar structures for
enclosure of large
domestic animals
For other animals, see
the supplemental
development standards
for animals in ACC
18.31.220
75 X X X X X X
4 Setback to any property
line for any corral,
exercise yard, or arena
for large domestic
animals
For other animals, see
the supplemental
development standards
for animals in ACC
35 X X X X X X
Page 753 of 758
ACC 18.07.030, Development standards Page 3 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Standard RC R-1 R-2 R-3 R-4 R-NM R-F
18.31.220
5 Interior side setback 20 10 5 5 5 5 5
6 Street side setback3
In all zones, 20 feet
minimum street side
setback required from
street access.
35 20 10 10 10 10 10
7 Rear setback3 35 20 15 15 10 10 15
8 Rear setback, detached
structure3, 8
In all zones, 20 feet
minimum street side
setback required from
street access.
15 15 10 5 5 5 10
F Maximum impervious
area (%)
25 50 75 80 90 90 75
G Maximum building
height (feet)
35 35 35 45 75 75 45
H Maximum height of
accessory buildings and
structures
354 35 24 24 24 24 24
I Minimum front setback
area landscape strip
(feet)
N/A N/A N/A 5 10 10 N/A
J Minimum side setback
area landscape strip
N/A N/A N/A 5 10 10 N/A
Page 754 of 758
ACC 18.07.030, Development standards Page 4 of 4
The Auburn City Code is current through Ordinance 7002, passed October 6, 2025.
Standard RC R-1 R-2 R-3 R-4 R-NM R-F
(feet)
K Minimum landscaped
open space (%)
N/A N/A See
Chapter
18.50 ACC
See
Chapter
18.50 ACC
See
Chapter
18.50 ACC
See
Chapter
18.50 ACC
N/A
1 See Chapter 18.32 ACC for calculating density.
2 All minimum lot widths, setbacks, and landscaping strips are subject to demonstration to the satisfaction of
the city engineer that all required utility infrastructure, access requirements, and street elements can be
accommodated in accordance with the city engineering design standards and construction standards.
3 In addition to meeting setback requirements, all structures must meet sight distance requirements in
accordance with city engineering design and construction standards.
4 Barns and other specialized structures used for agricultural purposes may exceed the height limits.
5 Provision applicable to residential subdivision.
6 See ACC 18.02.067 for calculating units allowed per lot.
7 Applies to new parent lots within a unit lot subdivision.
8 When abutting an alley, detached accessory dwelling units are allowed within the rear setback.
9 Non-residential, mixed use, and apartment buildings may have either no or a reduced front setback if the
applicable Citywide “Storefront” design standards are met.
10 Minimum setbacks required for structures. See also ACC 18.31.070 for specific exceptions to these setback
standards.
(Ord. 6959 § 1 (Exh. A), 2024; Ord. 6661 § 3, 2018; Ord. 6600 § 10, 2016; Ord. 6245 § 5, 2009.)
Page 755 of 758
1
Memorandum
TO: Judi Roland, Chair, Planning Commission
Bill Stewart, Vice Chair
Planning Commission Members
FROM: Alexandria Teague, Planning Services Manager
Dinah Reed, Senior Planner
Department of Community Development
DATE: February 18, 2026
RE: ZOA26-0002 – Design Standards Related Standards Code Update
I. BACKGROUND & PURPOSE
House Bill (HB) 1293, an Act relating to streamlining development regulations for design review, was
passed by the Legislature in the 2023 Regular Session. HB 1293 requires counties and cities planning
under RCW 36.70A.040 to have clear and objective development regulations governing the exterior design
of new development.
On the February 3rd regular meeting staff introduced the revised Citywide Design Standards (formerly the
Multifamily and Mixed-Use Design Standards). The purpose of this memorandum and the March 3rd
Planning Commission meeting is to introduce the draft code amendment and receive feedback prior to a
future public hearing. Feedback from the Commission will be used to refine the draft code as necessary.
An update on public engagement for the Downtown Design Standards will also be provided at this
meeting.
II. SUMMARY OF PROPOSED CODE CHANGES
Section ACC 18.31.200 Architectural and site design review standards and regulations
The purpose of the revisions in this section are as follows:
1) ACC 18.31.200(B)(1) clarifies for the types of new development that are applicable to the design
standards
2) ACC 18.31.200(B)(1)(a), (b), (c), (d) defines apartment buildings, mixed-use residential
development, retirement apartments, congregate living facilities and senior housing are no longer
subject to conditional use permits, and non-residential development, except for development
within the industrial zones.
3) ACC 18.31.200(B)(3) removes Auburn Junction as a design review document. Auburn Junction is
a specific area defined in the downtown area. The Downtown Urban Center Design Standards
have largely superseded the Auburn Junction Design Standards and they are no longer needed.
4) ACC 18.31.200(C) removes standard (5) and (6) related to the threshold of a site and exterior
alteration. The specific threshold or levels of site and exterior alteration that would trigger design
review are now contained in the Citywide Design Standards.
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5) ACC 18.31.200(F) pre-application meetings are no longer mandatory (required) but are
recommended. This update is related to HB 5290 in which cities should no longer make pre -
application meetings mandatory.
6) ACC 18.31.200(I) updates the requirements for design review departures (formerly called
adjustments). The Citywide Design Standards now contain specific departures for specific design
standards. The proposed standard-specific departures will allow for flexibility for each
development, while ensuring that the overall design of the development meets the purpose and
intent of the design standards. Applicants are still required to make findings (explain) why the
departure is necessary. This section also removes the requirement for public notice for
departures. Public notice is only required when a design review application triggers a state
environmental policy act review or exceeds 40 units. Therefore, it should not be triggered for a
design review departure.
7) ACC 18.31.200(J) updates the approval criteria for design review applications. The specific
standards listed in this section are no longer necessary. The proposed development must be
consistent with the standards contained in the Citywide Design Standards in order for it to be
approved.
Section ACC 18.07.030 Development standards (Residential Zones)
The proposed revision to ACC 18.07.030 is to reduce the front setback in the R-4, Residential High and R-
NM, Residential Neighborhood Mixed-Use zones to zero to allow for the “Storefront” option in the
Citywide Design Standards. This update allows for a storefront for a mixed-use or non-residential use in
the R-4 and R-NM zones to abut public sidewalks help to create vibrant and active pedestrian-oriented
shopping and dining areas within Auburn. Note – that a zero front lot line is allowed only if all structures
must meet sight distance requirements in accordance with city engineering design and construction
standards.
Section ACC 18.23.040 Development standards (Commercial & Industrial Zones)
These revisions reduce the front setback in the C-1, Light Commercial, C-2, Heavy Commercial, and M-1,
Light Industrial zones to zero to allow for the “Storefront” option in the Citywide Design Standards.
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III. TEXT AMENDMENT
The text amendment is shown by strikeout/underline and is attached to this memo as Attachments 1
through 3.
IV. COMMENTS FROM PUBLIC OPEN HOUSE
On February 4th, staff held an open house at the Auburn Resource Center from 4pm to 6pm. The open
house was well attended; approximately 11 people signed in. Staff did not receive formal comments at
the open house, and as of the date of this memo, no written comments have been received.
V. STAFF REQUEST
To move forward with the proposed Citywide Design Standards and associated text amendments to ACC
18.31.200, ACC 18.23.040 and ACC 18.07.030 to a public hearing on April 7, 2026.
VI. ATTACHMENTS
1 ACC Section 18.31.200 Text Amendment
2 ACC Section ACC 18.23.040 Text Amendment
3 ACC Section 18.07.030 Text Amendment
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