California Energy Commission.

California regulators have licensed what is for the moment the world’s largest solar thermal power plant, a 1,000-megawatt complex called the Blythe Solar Power Project to be built in the Mojave Desert.

By contrast, a total of 481 megawatts of new solar capacity was installed in the United States last year, mostly from thousands of rooftop solar arrays, according to the Solar Energy Industries Association, a trade group.

“Given the challenge of climate change at this time, it is very important to reduce fossil fuel use by moving forward with the largest solar project in California,” Robert Weisenmiller, a member of the California Energy Commission, said at a hearing Wednesday in Sacramento after a unanimous vote to approve the Blythe project.

“We’re taking a major step toward reducing the threat of future climate change impacts on the state, and at the same time the other real challenge for the state is the economy,” he added, referring to 604 construction jobs and 221 permanent jobs that the Blythe project would create in an area of California where the unemployment rate was 15 percent this summer.

After years of environmental reviews, the California Energy Commission has in the past three weeks licensed solar thermal farms that would generate 1,500 megawatts of electricity when completed.

A commission spokeswoman said the commissioners anticipated making licensing decisions by the end of 2010 on additional solar projects that would produce another 2,829 megawatts. At peak output, those solar farms would generate the equivalent electricity produced by several large nuclear power plants.

Developers are racing to start construction before federal tax incentives for big renewable energy projects expire at year’s end.

If all the projects are built, they would create 8,000 construction jobs and 1,000 permanent jobs, according to the energy commission.

At peak operation, the Blythe solar complex would supply enough electricity for 800,000 homes, said Karen Douglas, the energy commission’s chairman. The multibillion-dollar project will be built in four 250-megawatt phases.

It is notable for being the first big solar project to be licensed that would be built on federal land. The United States Bureau of Land Management is expected to decide by the end of October whether to approve the Blythe complex.

The project will be constructed by Solar Millennium, a German developer, and will cover 9.3 square miles in Riverside County in Southern California with long rows of parabolic troughs. The solar reflectors focus the sun on liquid-filled tubes suspended over the mirrors to create steam that drives an electricity-generating turbine housed in a central power block.

Many proposed solar power plants are planned for federal land, and the need to undergo federal environmental review has complicated the licensing process as disputes have arisen over the industrial projects’ impact on endangered wildlife like the desert tortoise and on scarce water supplies.

On Wednesday, Karen Douglas, chairman of the California Energy Commission, praised the Blythe developers for selecting a site with less intractable wildlife issues and for agreeing to use a cooling technology that sharply reduces the amount of water consumed by the power plant.

“Of course, it’s impossible to build a project of this magnitude without causing any environmental impacts,” Ms. Douglas said. “But I’m convinced the substantial benefits of this project definitely outweigh those impacts that can’t be mitigated.”

The developer’s next major hurdle will be to secure a federal Energy Department loan guarantee to allow it to obtain financing to build the power plant.

Solar Millennium, whose United States operations are based in Oakland, Calif., has two other solar power plants that would generate a total of 734 megawatts undergoing licensing in California, as well as projects in Nevada.

“The Blythe Solar Power Project will help build the bridge for renewable energy here in California,” Alice Herron, a senior director at Solar Millennium, said at Wednesday’s meeting. “It will take renewable energy from a small portion of our energy base to becoming the backbone of the state’s power base.”