CO2 Emissions of Silicon Photovoltaic Modules - Impact of Module Design and Production Location

CO2 emissions of two different module designs (conventional glass-backsheet or novel frameless glass-glass modules) produced at three different locations (China, Germany or the European Union, EU) are determined and compared in a life cycle assessment (LCA), using current inventory data and differentiated electricity yields of the modules. The results show that lower environmental impacts are obtained for glass-glass compared to glass-backsheet modules and for a production in the EU and Germany compared to China. Glass-backsheet (glass-glass) modules produced in China, Germany or the EU are linked to 810 (750), 580 (520) and 480 (420) kg CO2-eq/kWp, respectively. This corresponds to CO2 emission reductions of 30% for Germany and 40% for the EU compared to Chinese production, and 8% to 12.5% reduction in glass-glass compared to glass-backsheet modules. The CO2 emissions of the produced electricity, excluding balance of system (BoS), amounts to 13-30 g CO2-eq/kWh, depending on the production location and electricity yield of the modules which is based on warranty yield calculations with longer lifetimes for glass-glass than glass-backsheet modules. It is shown that module efficiency, energy requirements, silicon consumption and electricity mix used at the production location are significant levers for future reductions of environmental impacts. Furthermore, it is emphasized that up-to-date inventories and differentiated electricity yield calculations as well as current modelling of electricity mixes are important to incentivize the development of sustainable module designs.