Stirling Energy Systems have signed a purchase agreement on Tuesday with Southern California Edison (SEC), to install a 20,000 solar dish array that will cover 4,500 acres that will be capable of generating 500 megawatts of electricity - more than all other current U.S. solar projects combined. The solar installation, 70 miles northeast of Los Angeles, will be the largest in the world. Each collector has a 37-foot-diameter array of mirrors to focus the sun's rays onto a Stirling engine, which turns the heat into rotational torque for electricity generation.