Clean Power SF details 69 MW "Tumbleweed" battery, urges chance to seek EV funds under AB 1814

Clean Power SF Director Mike Himes told the San Francisco Local Agency Formation Commission on Feb. 18 that the agency is moving forward with long‑duration energy storage and legislative engagement to expand transportation‑electrification programs.

"Assembly Bill 1814 would authorize CCAs to also apply to the California PUC for ratepayer funding to administer their own transportation electrification programs in their service areas," Himes said, summarizing the legislation authored by Assemblymember Tim Grayson. Himes said the bill could be heard in committee on March 10.

Himes described a CC Power‑approved project called the Tumbleweed Project, a 69‑megawatt lithium‑ion battery sited near Rosamond in Kern County. "The target commercial operation date is June first of 2026, and the contract term for the project would be 15 years from the commercial operation date," he said. The developer was identified in the presentation as LS Power (also referenced as Rev Renewables). Himes said the project was procured through a joint powers agency process and that CC Power members, including Clean Power SF, must secure approvals from their governing bodies before execution.

Himes walked commissioners through three contract documents the CC Power JPA will use: a coordinated operations agreement defining operations coordination; a project participation share agreement allocating benefits and obligations among participants; and a buyer‑liability pass‑through agreement that limits Clean Power SF's guarantee to its share of the project and addresses CC Power's limited credit as a new entity.

On technology life span and maintenance, Commissioner Jackie Fielder asked whether the Tumbleweed battery had an expected lifetime and how maintenance would work. Himes said 15 years is the current estimate for the contract term and that plant owners are responsible for ongoing maintenance. "If the battery wasn't performing or was degrading, they would add cells to the battery to maintain the capacity level," he said.

Himes also said the California Public Utilities Commission had issued a procurement order in 2021 requiring procurement of long‑duration storage and that CC Power's solicitation was one response to that order. He said Clean Power SF participated in the joint request for offers and that CC Power approved the Tumbleweed project on Jan. 19; the agency plans to seek its own internal approvals next week and the Board of Supervisors' approval in March.

Himes ended with updates on customer programs and procurement: Clean Power SF is launching heat‑pump water‑heater and green‑tariff programs, preparing RFPs for an energy‑services company and for community solar (which drew no bids on the first solicitation), and planning a local renewable solicitation by midyear.

Public commenters responded: Eric Brooks of Our City SF urged LAFCO to formally support AB 1814, saying investor‑owned utilities often get first access to program funds and that CCAs need parity to deliver local transportation‑electrification measures. Other callers raised accountability and transparency concerns about Clean Power SF and SFPUC operations.

Next steps: Clean Power SF staff said they will keep LAFCO informed as AB 1814 moves through committee and as CC Power member agencies take approvals; the Tumbleweed project requires further governing‑body signoffs and execution of the three project agreements before commercial operations.