Big solar power plant for California is planned.
PG&E embraces solar thermal power technology
David R. Baker, Chronicle Staff Writer
Monday, November 5, 2007
As California utilities scramble to buy more renewable energy, Pacific Gas and Electric Co. and a Palo Alto startup will announce plans today to build a solar power plant big enough to light more than 132,000 homes.
Ausra Inc. will design and build the plant, which will be located on the Carrizo Plain of eastern San Luis Obispo County and could begin operating as soon as 2010. San Francisco's PG&E has agreed to buy the plant's power for 20 years.
Like the rest of California's big utilities, PG&E faces a state-imposed deadline to derive 20 percent of its power from certain renewable sources by the end of 2010. And like the other utilities, PG&E already has warned that it might not meet that target.
So the company is turning to solar thermal power plants, which can generate large amounts of energy on a reliable basis.
In July, the company agreed to buy power from a solar plant planned for the Southern California desert, which will generate 553 megawatts, enough for more than 414,000 homes. PG&E plans to buy 1,000 megawatts of solar thermal energy within the next five years.
"Solar works best when it's really hot, and that's when we need a lot of power," said Peter Darbee, the utility's chief executive officer. "So solar is something we're exploring more."
Solar thermal plants do not use the solar cells that more Californians are bolting to their rooftops.
Instead, they use the sun's energy to heat liquids that turn turbines and generate power. Ausra's technology uses flat mirrors that focus sunlight on tubes carrying water, which then turns to steam. The plants can produce far more electricity than silicon solar cells provide and at a far lower price.
"If you want to get a lot of megawatts on the grid, solar thermal is the best, scalable technology available," said Bob Fishman, Ausra's chief executive officer.
