New photovoltaic technologies, such as the recent introduction of thin-film cadmium–telluride (CdTe) materials, have nearly doubled the efficiency of solar cells within the past few years. But the methods of making the materials used for photovoltaic cells, whether from silicon, metal, or other material, have raised doubts about the environmental friendliness of these passive energy collectors. Purifying and producing silicon uses a lot of water and energy, and refining zinc and copper ores to get Cd, Te, and other elements creates metal emissions and an energy sink—all of which increase the technology’s environmental footprint.
Source: Environmental Science & Technology, ACS. See also Scientific American (Jan. 2008).
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