FONTANA, Calif. -- Gov. Arnold Schwarzenegger joined Southern California Edison officials Thursday in Fontana to announce the nation's largest rooftop solar installation project ever proposed by a utility company.

The project will place 250 megawatts of advanced photovoltaic generating technology on 65 million square feet of unused commercial buildings' rooftops in Southern California.

That's enough clean power to serve 162,000 average Southern California homes, KNBC's Mary Parks reported.

An Edison spokesman said work will begin immediately on the project. He says it will take five years to finish and cost $875 million.

"These are the kinds of big ideas we need to meet California's long-term energy and climate change goals," Schwarzenegger said. "I urge others to follow in their footsteps. If commercial buildings statewide partnered with utilities to put this solar technology on their rooftops, it would set off a huge wave of renewable energy growth."

This groundbreaking solar installation project, subject to approval by the California Public Utilities Commission, will help California in meeting its goal to achieve 20 percent of its electricity from renewable sources by 2010.