Huge amounts of American electricity is generated by polluting coal-fired power generating plants. Electric cars and solar cells on private homes are nice, but what technology exists to replace these antiquated workhorses of the electrical grid?
The answer may lie in a new technology that’s already generating power for 380,000 homes in California and sparking a mad rush for venture capital and land. While photovoltaic cells only capture roughly 20% of the sun’s energy, solar thermal technology can capture upwards of 40%. Total costs for solar thermal technology are rapidly approaching the costs for energy produced through fossil fuels (the stated goal of google.org’s renewable energy program), and a large solar thermal plant can produce similar amount of power as a full-sized coal plant.
In a recent article the New York Times counted 10 plants in development in the Southwest, with 17 or more planned around the world:
On sunny afternoons, those 10 [U.S.] 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.
The technology begins with this map, which shows what any visitor already knows: the American southwest is drenched in high intensity sunlight ideal for solar power generation.
FPL Energy employs giant parabolic mirrors to concentrate the sun’s rays onto a liquid-filled pipe, used to drive a large turbine. Stirling Energy uses parabolic mirrors to focus the sun’s rays onto sealed Sterling engines.
Here is the relatively straightforward plan of an FPL-type concentrating solar thermal plant. While this design contains a supplementary natural gas boiler, new plant designs will feature mechanisms to store energy for cloudy periods or evenings.
The phenomenon is global, and a new solar thermal plan recently came online in Australia, and an Abu Dhabi firm has announced plans to aggressively invest in solar thermal technology across the world’s “sun belt,” with the American Southwest a primary target for investment.
While it sounds promising, can the technology produce enough power to drive both our homes and our cars, even at night? One enterprising California power company thinks so, even though Wired magazine is a bit skeptical of the hype. At the very least, short huge new power lines the cloudy Northeast and Northwest may have to look to other sources. As Wired points out, “There’s a long road from a prototype plant in Bakersfield to providing 90 percent of the nation’s electric needs.”