The California Public Utilities Commission approved the utility's proposal to build another 173 miles of new transmission line. The entire line will cover 250 miles and cost $1.96 billion, the utility said.
Once completed in 2014, the Tehachapi Renewable Transmission Project expects to move up to 4,500 megawatts of renewable energy generation to Los Angeles and San Bernardino counties from Kern County, enough to power 3 million homes.
Southern California Edison, part of Edison International, had won approval to build 77 miles of the project, most of which it expects to be on line by the end of 2009.
The utility has contracts for up to 1,800 megawatts of wind power in the Tehachapi region in Kern County.
California has the some of the most aggressive renewable energy goals in the United States, with a target to get a third of its electricity from renewable resources by 2020.
A major hurdle is a lack of transmission lines needed to move electricity from remote areas where solar, wind and other renewable power is produced to cities where it is consumed.