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ASSESSMENT OF LARGE-SCALE PHOTOVOLTAIC MATERIALS PRODUCTION
Citation:
Gandel, M., P. Dillard, D. Sears, S. Ko, AND S. Bourgeois. ASSESSMENT OF LARGE-SCALE PHOTOVOLTAIC MATERIALS PRODUCTION. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/7-77/087.
Description:
Solar cell production at rates needed to supply continuously 1% of projected U.S. power requirements in the year 2000 is examined. Si and CdS are followed from raw material extraction to finished cell; GaAs is reviewed less thoroughly. Numerical data are developed for air, water, and solid wastes, and compared with corresponding effects of equivalent coal-electric power. Mass and energy balance data are derived from flow sheets developed for this report. For Si, major problems requiring engineering solutions are material and energy inefficiencies. Very large byproduct streams should be eliminated to increase yield by as much as 59% or decrease air pollutant releases by 37% on a process weight basis. Power consumption in cell production creates indirect air pollutant emissions over half as large as those created by the coal-burning plants silicon might replace. CdS and GaAs are not as energy inefficient. Their metallic raw materials are themselves byproducts of other smelting operations. Atmospheric cadmium releases, and the potential for Cd or As spills are major problem areas.