The Trans Bay Cable project is a 53-mile, 400MW high-voltage direct current submarine transmission line that can transmit up to 40% of the peak power needs for the city of San Francisco.

Pattern Energy CEO Mike Garland said that the Trans Bay Cable provides a new source of power for the city of San Francisco, helping to lower long-term energy costs, relieve congestion and provide transmission reliability for the entire Bay Area, while shutting down the last remaining old power plant in San Francisco.

In September 2005, the Board of Governors of the California ISO chose the Trans Bay project over several other alternatives as the most feasible and fundamentally-sound energy transmission project to address the load capacity issues of San Francisco and northern San Mateo County, Pattern Energy said.

Pattern Energy is an independent, fully integrated energy company that develops, constructs, owns, and operates renewable energy and transmission assets in the US, Canada and Latin America.