Material and environmental implications of ultra high efficiency solar cells

If electricity generation by photovoltaics (PV) is to expand to a scale comparable with conventional power generation, then PV production on the scale of Gigawatts will be required. For many power production applications high efficiency is important and it is likely that multi-junction devices will be used in these applications. A target of the Japanese PV Programme is to construct flat plate modules of multi-junction cells composed of III-V and Si materials (AlGaAs/GaAs/Si, GaP/GaAs/Si, InGaP/InGaP/Si) with efficiencies of 40% by the year 2010. This paper discusses the implications of the production of 40% efficient cells at the rate of 1 million/m² per year, i.e. a production rate of 400 MW/year. It analyses the range of environmental and health impacts which might arise from a production facility of this scale and discuss the choice of flat plate versus concentrator systems