“Two Southern California utility companies are planning to develop a pair of sun-powered power plants that they claim will dwarf existing solar facilities and could rival fossil-fuel-driven power plants.
“Instead of using panels of photovoltaic cells — solar power’s mainstay technology for decades — Stirling Energy Systems uses 40-foot-tall curved dishes that focus the sun’s energy onto Stirling engines.
“Also called an external heat engine, the Stirling engine is a completely sealed system filled with hydrogen. Its design dates to 1816, and it’s named for its inventor, a Scottish minister named Robert Stirling. The focused solar energy, which can reach 1,350 degrees Fahrenheit, heats the hydrogen, making it expand and drive the engine’s four pistons.
“The first phase of the SoCal Edison project will be to build a 1-megawatt test site using 40 dishes, which should be complete by spring 2007. Construction on the full, 500-megawatt facility is expected to begin in mid-2008, and should take three to four years. Each dish can produce up to 25 kilowatts, and the site will eventually have 20,000 dishes stretching across 4,500 acres of desert.”