Update of energy payback time and greenhouse gas emission data for crystalline silicon photovoltaic modules

Results of a recent photovoltaic energy life cycle study are presented. The focus lies on the energy payback time (EPBT) and the CO2 emission rate achievable with state-of-the-art industrial production chains for conventional monocrystalline and multicrystalline silicon modules. The data have been provided by European manufacturers and represent the processes in their European-primarily German-production sites. The analysis covers all steps from metal grade silicon refinement down to assembled modules as shipped to the customer. Balance of system contributions have not been included in the analysis and in the result figures, both for EPBT and CO2 emissions. The resulting EPBT values for the modules only are 1.09 and 0.93 years for monocrystalline and multicrystalline silicon, respectively, both under southern European conditions. CO2 emission rates strongly depend on the scenario considered, ranging from 18 g/kWh in southern Europe to 60 g/kWh in northern Germany under worst-case conditions for useful lifetime and degradation. Copyright (C) 2014 John Wiley & Sons, Ltd.