Net Energy Analysis and Carbon Footprint of Solar Cells

Solar photovoltaics (PV) are known for their contribution to greenhouse gas (GHG) emission reduction. The recent research and development on solar PVs are promising with new materials, structures, and manufacturing processes, which are expected to further increase the technologies' energy efficiency and reduce their GHG emissions. The ''Network 4 Energy Sustainable Transition (NEST)" project, Spoke 1 focuses on the topics of innovative solar PV, solar concentrating power and solar concentrating thermal technologies, with consideration on life cycle assessment and eco-design of the technologies. As a part of the preliminary results of the project, this paper reviews 21 life cycle assessment studies on solar PVs on their net energy and carbon footprint and statistically analysed 13 life cycle assessment studies on their energy return on investment, cumulative energy demand, non-renewable cumulative energy demand, and carbon footprint. It is identified that the energy return on investment of crystalline silicon-based solar cells is in the range of 9.4 and 13.17, which is considerably higher than that of perovskite solar cells, at 3.08. Besides, among the studied solar PVs, perovskite solar cell is a promising technology, with the lowest non-renewable cumulative energy demand and carbon footprint, at 8.15E-03 MJ, and 2.51E-03 kgCO(2)eq per kWh, for perovskite solar cells with graphene electrode. It is followed by organic solar cells and thin film. Crystalline silicon-based solar cells have the highest non-renewable cumulative energy demand and carbon footprint.