BrightSource Energy employs “power tower” technology, in which a field of thousands of flat mirrors, called heliostats, focuses sunlight onto a boiler mounted at the top of a tower. Steam produced in the boiler is piped to a turbine, which drives a generator to produce electricity. A commercial power tower was recently built in Spain, but only demonstration plants have been built in the United States. In addition, NRG Energy Inc. signed an agreement with eSolar to develop three solar projects totaling as much as 500 MW, also using solar power towers.
For PV power plants, California's Pacific Gas and Electric Company (PG&E) appears to be taking a leadership position, as the utility announced in late February that it plans to develop and own up to 250 MW of solar power facilities, while buying power from another 250 MW of solar power owned by independent developers. The California Public Utilities Commission has also approved two previous large contracts PG&E has signed with solar power developers, including a contract for 550 MW of thin-film solar PV from Topaz Solar Farms on the Carrizo Plain in San Luis Obispo County, as well as another contract with High Plains Solar Farms for 210 MW of silicon solar panels.
SunPower Inc. owns the latter project, and the former project was owned by OptiSolar Inc., but First Solar Inc. just bought out all of OptiSolar's projects, including the PG&E project. In the fourth quarter of 2008, First Solar managed to cut the manufacturing cost for its thin-film solar modules to 98 cents per watt, breaking the $1-per-watt cost barrier. The company's annual production capacity is expected to exceed 1,000 megawatts per year by the end of this year.
While California has a definite lead in solar power development, utilities in other states are now pursuing megawatt-scale solar PV projects. In New Jersey, the Public Service Electric and Gas Company has proposed to spend $773 million to support the development of 120 MW of solar PV power through many projects located throughout its service territory.
In New York, Governor David Paterson announced that the Long Island Power Authority is planning to support 50 MW of new solar power, including 13.1 MW of smaller projects developed by enXco and 36.9 MW to be installed by BP Solar in two large projects at the Department of EnergyÂ’s Brookhaven National Laboratory.
Down in the Sunshine State, Florida Power & Light has just broken ground on the DeSoto Next Generation Solar Energy Center, a 25-MW solar PV facility that should be completed by the end of the year.