Agenda Item No: K.9
AGENDA REPORT
DATE: September 16, 2025
TO: Mayor and Council
FROM: David Gassaway, City Manager
SUBJECT: Resolution 2025-183 PW Onyx Solar Power Purchase Agreement Amendment
Authorizing the City Manager to Execute Amendment No. 1 to the Agreement Between the City of Fairfield and Onyx Development Group LLC.
Funding Source: N/A
Contact: Michael J. Hether, (707) 428-7485
RECOMMENDED ACTION
Adopt resolution.
STATEMENT OF ISSUE
The proposed amendment will address contract changes resulting from technical, operational, and environmental modifications that have arisen in the design -build process for the provision and operation of a solar field at the Waterman Treatment Plant (WTP) with Onyx Development Group LLC (Onyx).
DISCUSSION
On August 20, 2024, the City Council adopted Resolution No. 2024-213 which authorized entering into a solar power purchase agreement (Solar PPA) with Onyx Development Group LLC (Onyx) for the provision and operation of a solar field at the Waterman Water Treatment Plant (WTP) to design, build, and operate a solar field at the Waterman Water Treatment Plant (WTP). The term of the Solar PPA is 25 years, after which the City assumes full ownership and operation of the solar equipment.
The solar field is being designed and constructed using a design -build process which allows for design flexibility but may also necessitate adjustments to the original agreements based on site conditions and equipment availability. As the project has progressed, several modifications have emerged, resulting in certain components of the original executed Solar PPA no longer aligning with the current project scope such as:
The original battery system no longer being available within an acceptable time frame due to supply chain delays. A different battery system is being considered, which will require changes to the system design.
The vegetation management approach is being continuously revised due to changes in the revised layout , feedback from the Fire Marshall, and changing environmental conditions.
As a result, City staff are seeking approval to amend the Solar PPA with Onxy to reflect on these necessary updates and ensure the agreement remains aligned with t he changing conditions of the project.
FINANCIAL IMPACT
N/A
PUBLIC CONTACT/ADVISORY BODY RECOMMENDATION
N/A
ALTERNATIVE ACTION
The council may delay approval of the amendment to the agreement so that staff can address any council concerns.
COORDINATED WITH
City Attorney’s Office
STAFF CONTACT
Michael J. Hether, Assistant Public Works Director - Utilities (707) 428-7485
[email protected]
ATTACHMENTS
Attachment 2: Proposed Resolution
Attachment 3: Proposed Contract Amendment No. 1
Attachment 4: Resolution 2024-213