Photovoltaic (PV) technologies have shown remarkable progress in terms of annual production capacity & life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-06, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions & heavy metal emissions from 4 types of major commercial PV systems: Multicrystalline silicon; monocrystalline silicon; ribbon silicon & thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe & the US during the materials & module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.
