Solar Sells (At Last)
By spring of 2010, each dawn will see a startling robotic performance in the Mojave Desert, north of Los Angeles. Just before sunrise, thousands of broad, mirrored dishes will wake in unison, their faces to the east. Each will be as wide as a school bus is long; arrayed in perfect lines for miles, they will track the sun all day, feeding power to the hungry city. After sundown, the dishes will pivot back to await the next dawn. "It's going to be like a ballet," says Stirling CEO Bruce Osborn, the man responsible for putting the dishes in the desert. "Way cool."
Beyond cool. Revolutionary. For the first time, solar collectors will generate electricity on a scale only coal, gas, or nuclear plants have managed. Not kilowatts or megawatts, but city-sized gulps of power, hundreds of megawatts. "The magnitude of this is mind-boggling," says Osborn.
Stirling, based in Phoenix, appears to have cracked the solar conundrum: how to tap an energy source that's all around us. "This is historic in magnitude," says Gil Alexander, a spokesperson for Southern California Edison, Osborn's first customer (and the beast that sends power to 13 million people in 11 counties, including L.A.). "Assuming Stirling pulls it off—and we believe they will—this facility will be capable of producing more electricity from solar energy than all U.S. solar projects currently in existence combined." San Diego Gas & Electric has also signed up to buy Stirling's solar power.
"The technology works," says Thomas R. Mancini, manager of the federal government's solar power program at Sandia National Laboratories in Albuquerque, New Mexico, where Stirling has a six-dish system up and running. "It's reliable, it's efficient. The question is, How do you make the leap in scale, in manufacturing?"
Osborn plans to quadruple his 30-person staff in the next year and says he's on track to secure land for the dishes—and the hundreds of millions of dollars he'll need for initial installations of 32,000 dishes. Once they are up, he says, the units require little to keep them at maximum production beyond routine engine maintenance and a hose, to rinse desert sand from the mirrors. Unlike coal or gas, he points out, "our fuel is free."
Stirling's mechanism is deceptively simple: Its dishes, each nearly 1,000 square feet, collect and concentrate sunlight to 1,350 degrees Fahrenheit, heating the gas in the four sealed cylinders of what's known as a Stirling engine (it's an old, ingenious design; in this case, each engine is about the size of a motorcycle's). As the gas expands, it drives pistons connected to electrical generators. In other words, the things take in heat and spin out electricity—twice as efficiently as photovoltaic cells. With zero emissions.