A new record has been set for the efficiency of a solar PV cell in the United States.
GOLDEN, Colorado, US, 2001-05-04 <SolarAccess.com> The National Renewable Energy Laboratory has measured a conversion efficiency of 16.4 percent for electricity produced by cadmium telluride solar cells, and the Department of Energy facility says the development could help meet expanding demand for solar systems. The 16.4 percent efficiency exceeded the previous threshold of 15.8 percent, a record that has existed for nine years. The efficiency of a PV cell is calculated as the percentage of sunlight that is converted into electricity. The cadmium telluride process developed by NREL uses new materials that interact chemically with the CdTe to improve adhesion, light collection, and electronic properties. “This technology offers the prospect of getting a better product to customers,” says NREL research manager John Benner. “Our industry partners can use this technology in expanding capacity to meet the rapidly mounting demand for PV.” Last year, the PV industry in the U.S. increased its production by 29 percent while the global industry increased production by 39 percent. The recent cost increase in fuels and the California power crisis have sparked installation of solar electric systems for homes and businesses. Two of the largest PV plants in the U.S. are producing thin-film panels made from cadmium telluride, and could adopt the new NREL process if they expand. Cadmium telluride represents a promising technology for thin-film solar cells, where layers of differing electricity-producing materials are applied sequentially to a glass, plastic or steel backing. Thin-films use materials that are less expensive than the materials used in conventional PV panels. There are several materials that can be used for thin-film panels, but cadmium telluride yields higher wattage per square foot, at a lower price per watt of capacity. Increasing efficiency and lowering costs have been the two goals since the U.S. national lab has been involved in research on photovoltaic systems. This year, NREL embarked on a program to reduce PV prices by 50 percent by the end of this decade. NREL works within the National Center for Photovoltaics. in collaboration with the National CdTe Team that includes scientist from universities and industry. DOE established the National Center at NREL in 1996 to coordinate research on solar electric technologies. Sandia National Lab also participates in the center. NREL is managed by Midwest Research Institute, Battelle and Bechtel. It also undertakes research into wind energy, biomass, geothermal and hydrogen fuel cells.