SOLAR energy's prospects are looking brighter.
Public demand for clean energy sources and increased federal support from last year's energy policy act are adding sparkle to an industry that has weathered a decade in the dark.
During the 1980s, the federal government eliminated subsidies for solar power development, forcing solar companies to rethink their strategies. Yet the tough lessons of the marketplace have engendered steady advances in solar photovoltaics.
Photovoltaic solar cells (which convert light directly into electricity) are being tested for large-scale use by utilities to produce electricity to feed into the power grid. Worldwide, about 50 megawatts of photovoltaics are installed each year. (A megawatt is a million watts.)
Last Thursday, a 500-kilowatt array of photovoltaic cells delivered its first kilowatt-hour of power to Pacific Gas & Electric's grid in Kerman, Calif. Demand for electricity has grown dramatically from customers located at the end of an existing transmission line there. So PG&E built the array of solar cells "at the end of a line rather than reinforcing the line and equipment [to push more power through from a central station]," says Stephen Metague, PG&E's manager of electric resources planning.
The cost of photovoltaic-generated electricity has dropped by a factor of three since 1980, according to the American Solar Energy Society in Boulder, Colo. Solar experts say costs will continue to fall as manufacturers gain economies of scale.
Utilities such as PG&E and the Sacramento Municipal Utility District (SMUD) are hoping they can help push the cost of solar power down. "If we can give the industry sizable, steady orders for photovoltaics, the price will come down and by the year 2000 photovoltaics will be very, very competitive," says S. David Freeman, SMUD's general manager.
Photovoltaics for Utility Scale Applications (PVUSA) here in Davis, Calif., was set up to test the performance and reliability of photovoltaic cells and their readiness for large-scale use. PG&E, the Electric Power Research Institute, the California Energy Commission, and the Department of Energy are the main sponsors.
In January, Advanced Photovoltaic Systems (APS) of Princeton, N.J., announced that PVUSA had accepted a 400-kilowatt array of its thin-film photovoltaic cells after a one-year test. Thin-film cells are less expensive (and less efficient) than the crystalline silicon solar cells first developed for the United States space program. The APS panels join seven other modules of photovoltaics being tested by PVUSA, says Tim Townsend, a research engineer. "These systems are big enough to give statistically credi ble results. Utilities know that for photovoltaics, there is a high capital cost but fuel costs nothing and maintenance is low."
For utilities, solar is becoming an increasingly viable option. "We have a heavy reliance on natural gas," PG&E's Mr. Metague says. "It's the highest vulnerability on our system and we would like to have alternatives."