Wildfire-damaged transmission and generation restored to San Francisco municipal customers

Crews from the San Francisco Public Utilities Commission (SFPUC) have returned to service 230-kV transmission lines and two generators at the Kirkwood powerhouse on the Hetch Hetchy power system that were damaged by an out-of-control wildfire burning in wooded land east of the San Francisco Bay area.

At a Sept. 3 news conference at the facilities in the town of Moccasin, Calif., some 135 miles east of San Francisco, San Francisco Mayor Edwin Lee announced that the damaged facilities had been tested over the Labor Day weekend and returned to service, generating approximately 110 MW between the Kirkwood and the undamaged Mocassin powerhouses. A third generating facility, the Holm powerhouse, is still undergoing repairs that are expected to take a few weeks, the SFPUC said in a statement.

The Rim Fire, which started Aug. 17, damaged the Kirkwood powerhouse and the roof of the Holm powerhouse and knocked out of service a 12-mile stretch of 230-kV transmission that carries the power generated by the power system to the utility and its customers.

Approximately 50 crew members worked to repair the damage to the powerhouses and equipment. The utility replaced the power from the facilities that were, and continue to be, out of service by accessing power in an existing power bank and purchasing power on the open market. All of San Francisco’s municipal electric customers continue to be fully supplied with no service interruption, SFPUC said.

The Rim Fire also forced Pacific Gas & Electric (PG&E) to deenergize one 12-kV distribution line for the safety of firefighters and others in the area. It has also damaged some components of PG&E’s infrastructure.

The fire itself had blackened more than 235,000 acres of brush, oak, and pine by 6 a.m. Sept. 3 and was approximately 75% contained, prompting the Tuolumne County Sheriff’s Office to lift all evacuation advisories countywide. Despite the progress made from the 30% containment reported on Friday, Aug. 30, officials estimate the fire will not be fully contained until Sept. 20.

PG&E is a subsidiary of PG&E Corporation (NYSE:PCG).