A new transmission line that will provide added electric reliability and meet growing demand for electricity in San Francisco and the Peninsula was approved today by the California Public Utilities Commission.

Dubbed the Jefferson-Martin 230-kV Transmission project, the 27.5-mile line will add a transmission line between two substations in San Mateo County. About 24 miles of the line will be placed underground. Construction on the project is expected to begin in December or January once final engineering and permitting are completed, with construction expected to take about one year. The project is expected to cost more than $200 million.

Pacific Gas and Electric Company will build and own the line.

Once finished, it adds an additional 400 MW of capacity to the region, or enough electricity to power about 300,000 homes. Electric demand in the region continues to grow and another transmission line is needed to increase reliability for the cities of Hillsborough, Burlingame, Millbrae, San Bruno, South San Francisco, Brisbane, Colma, Daly City, Pacifica and San Francisco.

The Jefferson-Martin line, along with other transmission projects that are now finished, in the process of being built or currently awaiting CPUC approval, will allow closure of the Hunters Point Power Plant, according to a recent letter from the California Independent System Operator. First built in 1929 in San Francisco, the plant has a current capacity of 210 MW.

In April 2002, the California Independent System Operator's Board of Governors adopted a resolution declaring the need for the line. PG&E filed its initial proposal for the route with the CPUC in September 2002. Under the California Environmental Quality Act, the CPUC performed the environmental review for the project and decided on the route and design. The environmental impact report for the Jefferson-Martin line is the largest one ever done for a transmission line project in California.

The line's route runs primarily beneath major roads in the county, working its way northeast from the Jefferson Substation west of Redwood City to the Martin substation in Brisbane. Some 38 routes were examined by the CPUC, including evaluation of the legal, environmental and technical feasibility of routes.

Planners had to contend with challenges posed by the San Andreas earthquake fault, a pristine watershed hosting rare and endangered plant and animal life that enjoy federal environmental protection, and a densely populated urban area whose demand for electricity continues to grow.

The approved route has the support of environmental groups, local governments, PG&E and the CPUC's environmental consultants. The above ground portion spans just over three miles between Burlingame and San Bruno and will run in an existing overhead transmission line corridor. The route also comes above ground at a small dam crossing near Hillsborough.