Life Cycle Assessment of Photovoltaics

This chapter presents the most up-to-date estimates of energy payback time (EPBT), greenhouse gas (GHG) emissions, and heavy metal emissions from the life cycles of the currently commercial photovoltaics (PV) technologies. Comparing the GHG emissions from the lifecycle of PV with those of conventional fuel-burning power plants, results reveal the environmental advantage of using PV technologies. The majority of GHG emissions come from the operational stage for the coal-, natural gas-, and oil-fuel cycles, while the material and device production accounts for nearly all the emissions for the PV cycles. The GHG emissions from the nuclear-fuel cycle are mainly related to fuel production, i.e. mining, milling, fabrication, conversion, and the enrichment of uranium fuel. The lower the EPBT, the lower will also be the emissions to the environment, because emissions mainly occur from using fossil-fuel-based energy in producing materials, solar cells, modules, and systems.