David R. Baker, San Francisco Chronicle Staff Writer, 10.28.2010

California's long-awaited boom in the construction of large-scale solar power plants has finally begun.

BrightSource Energy of Oakland broke ground Wednesday on its Ivanpah Solar Electric Generating System, which will use fields of mirrors in the Mojave Desert to concentrate sunlight and generate enough power for 140,000 homes. Expected to be fully operational by mid-2013, Ivanpah also received a financial boost Wednesday when power plant operator NRG Energy Inc. agreed to invest $300 million in the project, which will cost roughly $2 billion.

Ivanpah is the first in a spate of massive "solar thermal" power plants due to start construction in California during the next two months, as developers race to qualify for a form of federal stimulus funding that expires at the end of the year.

The projects are critical to California's goal of getting 33 percent of the state's power from renewable sources by 2020. California's two largest utilities, Pacific Gas and Electric Co. and Southern California Edison, have agreed to buy Ivanpah's electricity. About 1,000 people will be needed to build the project.

"Projects like this one are helping us meet our long-term energy and environmental goals, while creating jobs and moving us toward a cleaner, more sustainable future - a future where California leads the nation and the world in a clean energy revolution," said Gov. Arnold Schwarzenegger, who attended the groundbreaking.

Ivanpah will occupy 3,600 acres of land near the Nevada border, southwest of Las Vegas. It will use fields of flat, pivoting mirrors to focus sunlight on central towers filled with water. The intense heat will boil the water and generate steam, which will turn turbines and generate electricity.

The project won major backing from the federal government earlier this year when it qualified for $1.375 billion in loan guarantees. And by starting construction before the end of the year, BrightSource will qualify for a federal grant worth 30 percent of the total project cost, given in lieu of a tax credit of equal size already available to renewable-power developers.

NRG Chief Executive Officer David Crane on Wednesday praised the grant program and urged the federal government to extend it past the year-end deadline. Without it, large solar projects will have a harder time lining up financing.

"You're going to see a rush of projects," Crane said. "Then you're going to hear the sound of silence for a while."

E-mail David R. Baker at dbaker@sfchronicle.com.

This article appeared on page D - 1 of the San Francisco Chronicle