UPDATE 1-PG&E expands deal with solar company BrightSource

*PG&E, BrightSource expand deal for solar thermal power

*Seven projects to power about 530,000 average homes

LOS ANGELES, May 13 (Reuters) - California utility Pacific Gas and Electric Co on Wednesday announced an expanded agreement with solar thermal power company BrightSource Energy Inc for more than 1.3 gigawatts (GW) of clean, solar energy.

The utility, a unit of PG&E Corp (PCG.N: Quote, Profile, Research), said the new deal supersedes a 900 MW agreement it struck with BrightSource a year ago. It is part of a push by PG&E to comply with a state requirement that at least 20 percent of its electricity supplies come from renewable sources by 2010.

Solar thermal power plants use the sun's heat to create steam that powers a turbine. They are typically much larger than plants made up of photovoltaic solar panels, which use sunlight to create electricity.

The power purchase agreements between PG&E and BrightSource cover seven projects that will generate enough electricity to power about 530,000 homes, the companies said in a statement.

"Today's agreements reflect the technological milestones that the BrightSource Energy team has achieved over the past year," BrightSource Chief Executive John Woolard said.

PG&E's new deal with BrightSource comes three months after another California utility, Edison International (EIX.N: Quote, Profile, Research) unit Southern California Edison, signed a series of contracts with the solar thermal company for 1.3 GW of solar power.

The first, 110 MW solar power plant BrightSource is building will be located in Ivanpah, California, and is contracted to begin operation in 2012. (Reporting by Nichola Groom, editing by Dave Zimmerman)