Sun in the Forecast.(Brief Article)

High in the Mojave Desert, 130 miles northeast of Los Angeles, lies a vast field of mirrors. Crisscrossing rows of glass and metal, glinting in the sunlight, cover a full square mile of dirt. It's not some bizarre fun-house experiment or a grotesque exhibit of Hollywood vanity. It's a fully operational array of power plants churning out an average of 180 megawatts of electricity, and offering a glimpse of a world in which the grid's electricity comes from the sun.

Most people think of solar power as a flat panel on every rooftop. But photovoltaic panels, which convert sunlight to electricity, have limitations. They work fine when the sun is strong, but when the clouds roll in you'd better have batteries to run the TV and dishwasher. And even on the sunniest days the panels aren't very well suited for cities, where roof space is limited. For decades, engineers have been working on ways to catch the sun over a broad area, concentrating it and using it to produce electricity on the same scale as centralized coal, hydro or nuclear power plants--hundreds of megawatts at a time. Several pilot plants have been operating in California, some for decades, but so far they haven't had enough volume to force costs down to competitive levels.

That may soon change. Spain is drawing up plans for a pioneering 15- megawatt plant. South Africa, Italy, Australia and India are expected to follow with much larger plants capable of generating more than 100 megawatts each. If at least some of these projects are completed, costs could come down from the current 15 cents a kilowatt-hour for the Mojave plant to 8 cents per kwh in the next eight to 10 years, says Bill Gould, project manager for energy systems at Nexant, a renewable- energy firm. That would go a long way toward closing the gap with gas and oil, which now cost as little as 4 cents per kwh. "The first plants will be expensive," says Craig Tyner of Sandia National Laboratories. "But as we build them the costs will come down."

The Mojave plant, owned by Kramer Junction Company (KJC), is one of the world's first commercial solar power plants, with five Solar Electric Generating Systems (SEGS) supplying electricity to southern California. The basic component of a SEGS plant is a row of parabolic mirrors that reflect sunlight onto a pipe filled with oil. The oil heats up and is used to produce steam, which turns an electrical turbine. Assemble a few dozen rows of these trough-mirrors, and you've got capacity to generate 30 ...