Turning Glare Into WattsMr. Boucher was battling clouds, timing the operations of his power plant to get the most out of patchy sunshine. It is a skill that may soon be in greater demand, for the world appears to be on the verge of a boom in a little-known but promising type of solar power.
It is not the kind that features shiny panels bolted to the roofs of houses. This type involves covering acres of desert with mirrors that focus intense sunlight on a fluid, heating it enough to make steam. The steam turns a turbine and generates electricity.
The technology is not new, but it is suddenly in high demand. As prices rise for fossil fuels and worries grow about their contribution to global warming, solar thermal plants are being viewed as a renewable power source with huge potential.
After a decade of no activity, two prototype solar thermal plants were recently opened in the United States, with a capacity that could power several big hotels, neon included, on the Las Vegas Strip, about 20 miles north of here. Another 10 power plants are in advanced planning in California, Arizona and Nevada.
On sunny afternoons, those 10 plants would produce as much electricity as three nuclear reactors, but they can be built in as little as two years, compared with a decade or longer for a nuclear plant. Some of the new plants will feature systems that allow them to store heat and generate electricity for hours after sunset.
Aside from the ones in the United States, eight plants are under construction in Spain, Algeria and Morocco. Another nine projects are in various stages of planning in those countries as well as Israel, Mexico, China, South Africa and Egypt, according to a count kept by Frederick H. Morse, formerly in charge of solar energy at the Energy Department and now a consultant.
In Phoenix on Feb. 21, the Arizona Public Service unit of Pinnacle West announced plans for a large plant to be built by a Spanish company, Abengoa, and finished in 2011. That one will store heat so that it can continue to produce power for up to six hours after sunset.
The newest solar-thermal technology involves building a “power tower,” a tall structure flanked by thousands of mirrors, each of which pivots to focus light on the tower, heating fluid. That design can work even in places with weaker sunlight than a desert.
One of the big advantages of these plants is that they can be built with the capacity to store heat in what amounts to a giant Thermos. Experts say that will smooth production and make it easier to integrate the plants into the electrical grid.
If large numbers of plants are built, they will eventually pose some problems, even in the desert. They could take up immense amounts of land and damage the environment. Already, building a plant in California requires hiring a licensed tortoise wrangler to capture and relocate endangered desert tortoises.
Outside, row after row of U-shaped mirrors, covering nearly a square mile, stretched across the desert. In the center of each U, where the force of the sun was magnified 70 times, ran a pipe painted black, and inside it flowed oil that warmed to hundreds of degrees as it collected the heat needed to run a generator.source
My comment: It was high time to see some growth in solar plants. What bothers me is that technology doesn't grow with them. We expand in volume (ok, surface if we have to be more precise),but not in quality and innovations.
But well, better than nothing.