SAN FRANCISCO, Nov 20 (Reuters) - San Francisco Bay Area cities promised to build the electric car capital of the United States, announcing a plan on Thursday to work with start-up Better Place to put battery-powered autos on the road in 2012.

Mayors of San Francisco, Silicon Valley capital San Jose, Oakland and other cities in the region said they would offer incentives and standardize infrastructure with Better Place, a start-up that aims to offer electric cars as a service, like a cell phone, at prices similar or below standard cars.

The San Francisco Bay Area has the reputation as one of the most liberal and environmentally active parts of the country, and as the economic downturn sweeps through the tech sector it is looking to clean technology for a new source of jobs.

"I'm a guy driving a hybrid, and I don't feel particularly good about it," San Francisco Mayor Gavin Newsom told a news conference, adding that all-electric cars would be a "game-changer" for cutting carbon emissions which cause global warming.

Nissan Motor Co. Ltd (7201.T: Quote, Profile, Research, Stock Buzz) and Renault (RENA.PA: Quote, Profile, Research, Stock Buzz) have signed on with other Better Place projects. Better Place is developing networks in Denmark, Israel, and Australia.

Better Place Chief Executive Shai Agassi in an interview said the network to support the cars with charging stations would cost about $1 billion with a quarter of that needed for a test phase in 2010-2011.

"We've got a year-and-a-half to bring the capital in," he said, acknowledging the tough economic environment and arguing that the network would be a good investment.

He told reporters that he hoped the U.S. "Big Three" automakers, GM (GM.N: Quote, Profile, Research, Stock Buzz), Ford Motor Co (F.N: Quote, Profile, Research, Stock Buzz) and Chrysler, would join the plan. (Reporting by Peter Henderson, Editing Leslie Gevirtz)