Photovoltaic Mileage

New Life-Cycle Assessment Reveals Your Photovoltaic Mileage May Vary

by Jeremy Elton Jacquot, Los Angeles on 02. 9.08

Science & Technology

Not all photovoltaic technologies are created equal; some, in fact, incur quite heavy environmental footprints - producing silicon, for example, consumes a lot of water and energy while refining zinc produces a sizeable chunk of emissions. Environmental Science & Technology's Naomi Lubick reports that Vasilis Fthenakis, a scientist at Columbia University and the Brookhaven National Laboratory, just finished a LCA of some of the leading technologies which determined that new thin-film cadmium-telluride (CdTe) materials - such as the ones we covered here - come out on top.

Benefiting from its highly efficient energy conversion, CdTe photovoltaic systems consumed less energy and produced fewer emissions; in addition, when compared to its multicrystal and ribbon silicon competitors, the CdTe technology had the lowest cost. In order to obtain these results, Fthenakis and his colleagues compared data from more than a dozen solar companies, taking into account the manufacturing process, energy conversion and various components.

Unfortunately, the assessment failed to shed light on the technologies' total environmental impact - "not telling you exactly what your impact is if you were to buy them," as Corinne Reich-Weiser, a graduate student at UC Berkeley, explaine

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d. For instance, she notes that the emissions produced during the transportation of components before production and assembly are only partly taken into consideration; moreover, the assessment is based on idealized European and U.S. grids even though most components are built in China.

Still, it provides an effective means of "easily comparing" all of the available technologies, she says, deeming it "incredibly useful." New and future solar technologies should be able to bridge that emissions gap within the coming years as companies continue innovating and expanding their operations. Fthenakis notes that the one missing element from his assessment he hopes to amend soon is the end-of-life and recycling data; he believes this should help make the technologies' emissions profiles even better.