The potential for further reduction in the embodied carbon in PV solar energy systems

In this study the potential for further reduction in Greenhouse Gas Emissions (GHG) of c-Si, mc-Si and CdTe PV systems are assessed to inform climate change mitigation in the UK. The amount of CO2 equivalent released in grams for each kWh of electricity over the lifetime of the PV system (gCO2-e/kWh) has been assessed using a model to predict the change in GHG as a result of engineering improvements in the PV module and system operation. The scenarios modelled here are for two different locations in the UK (Midlands and South West England) to give a typical range. Similarly a range of carbon intensity in manufacture is considered by taking manufacture in China and the UK. This study considers the impact of; system and inverter lifetimes, continuing trends of increases in module conversion efficiencies and reduction in carbon intensity during manufacture. For most of the scenarios considered the extension of the PV system lifetime to 40 years makes the largest impact while extending inverter lifetime for deployment of thin film PV modules becomes more significant and cannot be ignored. All of the four interventions considered in this paper can significantly contribute to a reduction in the carbon footprint of PV by the near term target of 2020. For all three module systems considered the model shows the potential for the carbon footprint to be reduced to one third of the 2012 values giving a range of 11-38 gCO2-e/kWh, which is within the range of current wind generation in the UK