SFPUC staff outlines steps to enable Potrero Power Plant closure, cites $1–4M transmission fix

San Francisco Public Utilities Commission staff on May 12 presented a plan for how the city might seek near‑term closure of the Potrero Power Plant while preserving electric reliability. Barbara Hale, assistant general manager for power, told commissioners that California Independent System Operator (Cal ISO) studies show a relatively small summer 2010 reliability gap — roughly 25 megawatts in the ISO’s 2010 scenario, dropping in later years — and that modest transmission changes could eliminate the need for continued ‘must‑run’ contracts for Potrero’s units.

Hale said the plant includes Unit 3, a roughly 206‑megawatt natural‑gas unit with once‑through cooling, and three peaker units (Units 4–6) of about 52 MW each. She described a near‑term proposal to install 2 to 4 series reactors on PG&E’s 115‑kV transmission system at substations such as Futuro or Martin. “A 2 to 4 of them would cost $1 to $4 million,” she said, calling it “a very modest change” that could reroute flows and relieve overloaded lines so the ISO would no longer require Potrero to be held for reliability in some scenarios.

The s…