Research Goal: Solar-Powered 21st Century
Concerns about conventional sources of energy spur efforts to find cost-efficient, environmentally safer alternatives. RENEWABLE ENERGY
WILL sunlight be a central source of United States energy for the 21st century? Here at the sprawling, low-rise campus of the Solar Energy Research Institute (SERI), the answer is a resounding ``Yes.''Skip to next paragraph
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Politically, the answer may be coming just in time. Conventional sources of power generation - coal, oil, and natural gas - are coming under increasing fire from an environmentally conscious public concerned about global warming, acid rain, and air pollution. Also of concern: The national security implications of dependence on oil, nearly 40 percent of which is imported.
But nuclear energy, once touted as an environmentally clean alternative, is suffering from continuing revelations following the explosion of a Soviet nuclear reactor at the Chernobyl power station in 1986. The political difficulties surrounding the start up of the Seabrook Nuclear Power Plant in New Hampshire are seen by many as a portent of greater challenges facing nuclear-energy installations in the future.
Can sunlight fill the gap?
``The progress in the last decade has been truly remarkable,'' says Robert Stokes, deputy director of research for SERI, a 13-year-old research facility owned by the US Department of Energy. SERI is currently budgeted at $100 million a year. ``We believe that the government is now set up on a course that will gradually increase the research and development investment in renewable energy to the point that many of these technologies will become cost-effective,'' Mr. Stokes says.
Researchers at SERI, taking an expanded view of the word ``solar,'' use it to cover any of the alternative energy resources that ultimately derive their energy from the sun - including wind power, combustion of organic (biomass) products, wave- and tidal-power, thermal gradients in the ocean, and a number of other technologies.
Already, say researchers, some of these technologies are cost-effective for certain applications. ``We're very much closer today than we were eight or 10 years ago to eventual economic parity with a variety of other energy technologies,'' says Tom Bath, manager of SERI's Analysis and Evaluation Office. Among the cost-effective technologies:
Photovoltaics (PV), the direct conversion of sunlight into electricity using solid-state ``photo-cells,'' has been powering satellites since Vanguard I was launched in 1958. It is already the technology of choice for small applications far from conventional power grids - rural water pumps, communication relay stations, vaccine refrigerators in third-world nations - and is even competitive for some remote homes in the United States. ``If you are more than a third of a mile from the grid,'' Dr. Bath says, ``it pays you to buy PV and batteries today rather than try to hook up.''
Solar thermal power plants like the Luz International plant at Kramer Junction, Calif., use acres of trough-shaped mirrors to focus the sun's rays on vacuum-insulated tubes of oil. Heated to 735 degrees F, the oil is used to generate superheated steam that drives a turbine generator. At a cost of less than 8 cents per kilowatt hour, say plant officials, their power is already cheaper than nuclear power and is becoming competitive with oil and coal. Now producing 274 megawatts of power in southern California, Luz will reach almost 680 megawatts by 1994 - enough to meet the entire residential needs of a city the size of San Francisco or Phoenix.
Wind power, typically generated at windmill farms located in high mountain passes in the West, is already a viable industry. In California alone, nearly 16,000 wind turbines generate nearly 2 billion kilowatt hours each year - as much energy as a medium-sized nuclear plant. Because they are nonpolluting, says Paul Gipe of the American Wind Energy Association in Tehachapi, Calif., these turbines alone offset 1.8 billion pounds of greenhouse gases that would otherwise pour into the atmosphere from conventional power plants.