Posted:
April 2, 2008
Editor’s note: This story by David Baker appeared April 1 in the San Francisco Chronicle.
Pacific Gas and Electric Co. will announce contracts
today (April 1) 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.