Oakland firm will design, build installations; sunlight, groundwater will generate power for 375,000 homes
David R. Baker, Staff Writer
San Francisco Chronicle
Pacific Gas and Electric Co. will announce contracts today for three new large solar power plants in the Mojave Desert, whose open spaces and clear skies have placed it at the center of a renewable energy boom.
The three installations, together, will generate enough electricity for more than 375,000 homes. Fields of mirrors at each plant will focus sunlight on centralized towers, boiling water within the towers, creating steam and turning turbines.
"Solar thermal energy is an especially attractive renewable power source because it is available when needed most in California - during the peak midday summer period," said Fong Wan, PG&E vice president of energy purchasing.
All three will be designed and built by BrightSource Energy Inc. of Oakland, with the first plant starting operation as early as 2011. San Francisco's PG&E has signed contracts with BrightSource to buy power from the facilities. The companies won't disclose how much PG&E has agreed to spend.
Dozens of solar projects have been proposed for the Mojave Desert as California tries to fight global warming by expanding the use of renewable energy.
Under state law, all three of California's large, investor-owned utilities have until the end of 2010 to ensure that 20 percent of the power they deliver to their customers comes from such renewable resources as the sun and the wind. So the utilities are turning to the Mojave, which has the strong sunlight and undeveloped land needed for large-scale solar projects.
"It is one of the best spots on planet Earth to put solar power plants," said John Woolard, BrightSource's chief executive officer. "It's a world-class resource."
Two of the company's power plants will be built in the Ivanpah dry lakebed, close to the Nevada border in San Bernardino County. The third will occupy Broadwell Dry Lake, north of Ludlow, also in San Bernardino County.
The Mojave already has several large solar plants that have been generating electricity since the 1980s. Unlike rooftop solar panels, these "solar thermal" plants don't draw energy directly from the sun. Instead, they use curved mirrors to focus sunlight on liquid-filled tubes. The concentrated light heats the liquid, which is used to generate steam and run a turbine.
Several of the people who designed and built the Mojave's earlier generation of solar power plants also founded BrightSource. They have tweaked their technology, hoping to improve each plant's efficiency and lower costs.
Each power plant will use groundwater, which will be recycled within the plant. After spinning the turbines, the water will be cooled through a system much like a car radiator, with the ambient air carrying off the heat. The water will then flow back to the boilers to be turned into steam once again.