Southern California Edison (SCE) has signed a contract to procure an additional 245 megawatts of solar power for its customers with Pasadena, Calif.-based eSolar in the nation's first commercial effort using power tower solar thermal technology.

The project, which will be built in the Lancaster area of California, is expected to begin delivering energy in 2011, with a total of 105 megawatts of renewable solar power by 2012, ramping up to 245 megawatts by 2013. SCE is currently the nation's leading purchaser of solar energy, buying more than 90 percent of U.S. production.

"Solar is the great untapped energy resource for California - it's renewable and plentiful," said Stuart Hemphill, SCE vice president, Renewable and Alternative Power.

"We rely on innovative companies such as eSolar to help expand our industry-leading portfolio and to secure access to the most promising technology solutions."

Each pre-fabricated module consists of several solar towers each associated with thousands of heliostats, or mirrors. The mirrors precisely track the sun over the course of the day and reflect light to a receiver at the top of each tower.

The concentrated light boils water in a central receiver, routing the steam to a traditional turbine to produce electricity.

eSolar's solar thermal technology is unique in that it uses shorter towers, small mass-manufactured mirrors and advanced tracking software, achieving economies of scale within a minimal footprint and easy connection to transmission lines.