SFPUC describes multi-day Treasure Island outage traced to damaged underwater cable; fuel and generator issues complicated response

San Francisco ' The San Francisco Public Utilities Commission reviewed an outage that left Treasure Island and Yerba Buena Island without grid power in mid-November and described recovery steps and follow-up work.

Barbara Hale, Assistant General Manager for Power, said crews determined the outage originated on the Oakland side of the systems serving both islands, on an underwater cable that feeds from a Port of Oakland substation. Staff followed an emergency protocol with the Treasure Island Development Authority and transferred customers to on-island generators. An initial generator fuel shortfall led staff to intentionally cycle the Treasure Island generator overnight to conserve fuel; subsequently the Treasure Island generator failed.

Hale said crews were able to switch residential customers on Treasure Island to the generator on Yerba Buena Island, and an independent generator was connected to critical facilities such as the Department of Labor Job Corps dormitories. SFPUC called for mutual-assistance crews from Hetch Hetchy and Modesto Irrigation District for repairs and ultimately restored power to both islands. Hale said the likely cause was an excavation that damaged the underground cable and that staff will conduct an after-incident review with city emergency management and the Treasure Island Development Authority to identify lessons, including fuel logistics, generator sufficiency and permitting coordination with the Port of Oakland.

Commissioners asked whether permit/inspection protocols were followed where the cable was dug and whether the city should require different inspection or enforcement procedures when work is done near critical buried infrastructure. Staff said those lines may be under Port of Oakland jurisdiction and pledged to follow up on responsibilities and any corrective actions.