Biggest U.S. photovoltaic power plant announced

Unlike most large-scale solar plants, which use big mirrors to concentrate sunlight, the SunPower project will use the same solar panels that homeowners install on their rooftops.

It will be built in Florida's DeSoto County and will generate up to 25 megawatts of electricity, enough to power 18,750 homes. SunPower also will build a smaller facility, generating 10 megawatts, at Kennedy Space Center.

Both plants will be owned and operated by Florida Power & Light Co., an electric utility. The two companies are not releasing financial details of the deal.

As utilities across the country try to find cleaner sources of power, some are turning to large-scale solar plants. But most of those plants don't use photovoltaic panels, which generate electricity directly from sunlight. Instead, they use mirrors to focus sunlight, heat water, produce steam and turn turbines.

Southern California has several vast solar thermal mirror farms that have been generating electricity since the 1980s.

They are owned by FPL Group, the same company that owns Florida Power & Light. Instead of building a solar thermal plant in Florida, the company chose to use photovoltaic panels.

"Here's a company that knows all about solar thermal," said Julie Blunden, SunPower's vice president for public policy. "And they looked around and said, 'What makes sense for Florida?'"

Most solar thermal plants under development around the country will deliver far more electricity than SunPower's DeSoto plant. But solar thermal technology doesn't work as well in cloudy, humid locations as photovoltaic panels can, Blunden said.

Large-scale photovoltaic facilities also take less time to build, she said.

SunPower built the country's largest existing photovoltaic solar power facility, a 14-megawatt installation at Nevada's Nellis Air Force Base.

Assuming the new projects win regulatory approval, the DeSoto plant is scheduled to open next year, while the facility at Kennedy Space Center will be completed in 2010.