Supervisors back transmission-only push to close Potrero power plant; remainder of resolution sent to committee

The San Francisco Board of Supervisors on Tuesday voted to approve a transmission-only portion of a resolution urging the Public Utilities Commission and the city attorney to present to the California Independent System Operator (CAISO) a transmission-only plan to close the entire Potrero power plant.

The measure was divided by Supervisor Daly into multiple questions; the first question, limited to urging a transmission-only solution, passed by a roll call vote of 8 ayes and 3 noes. The board then unanimously agreed, without objection, to refer the remainder of the resolution — which addresses minimum criteria for in-city generation and other production-related provisions — back to committee.

Why it matters: The divided vote separates the board's near-term message to CAISO about transmission from more contentious recommendations about in-city generation standards and new peaking units. Supporters said a transmission-only approach could be a clearer, more broadly acceptable step toward closing Potrero; opponents warned that the resolution's comparisons and assumptions about how frequently retrofit or new generation would run could be misleading.

Supervisor Daly, who asked that the transmission issue be considered separately, said the intent was to "move forward with a transmission-only solution" and to send a signal to CAISO. Daly told colleagues the split would allow the board to act on the transmission request while studying the more controversial generation criteria in a separate question.

Supervisor Maxwell pushed back on portions of the resolution that would alter criteria for local projects, saying she did not "understand the problem of at least meeting the same criteria that was going to be met with our own city peakers." Maxwell said she feared changing standards so they would be less stringent than city projects.

Supervisor Daly and others debated technical claims underlying the generation comparisons. Supervisor Ellsberg raised published statements from an ISO spokesman and a PUC consultant and urged caution, noting that some analyses indicated new combustion turbines would run many more hours annually than retrofit units.

After the first portion passed 8-3, Supervisor Maxwell moved to refer the balance to committee; Supervisor Ellsberg seconded that referral, and the board re-referred the remaining language without objection.

Actions and next steps: The board's formal action sends a clear, transmission-only recommendation to the PUC and city attorney while delaying and subjecting the generation-criteria language to further committee review. The referral means that the city will not adopt the resolution's minimum criteria for in-city generation at this meeting.

Public and procedural context: The measure drew extended debate among supervisors about technical assumptions and the appropriate scope of an advocacy resolution. The record shows both procedural division of the file and unanimous agreement to study the more complex generation language further.

The board will await committee work on the remainder of the resolution before any additional formal action.