AN EMPIRICAL PERSPECTIVE ON THE ENERGY PAYBACK TIME FOR PHOTOVOLTAIC MODULES

摘要

Energy payback time is the energy analog to financial payback, defined as the time necessary for a photovoltaic panel to generate the energy equivalent to that used to produce it. This research contributes to the growing literature on net benefits of renewable energy systems by conducting an empirical investigation of as-manufactured photovoltaic modules, evaluating both established and emerging products. Crystalline silicon modules achieve an energy break-even in a little over three years. At the current R&D pilot production rate (8% of capacity) the energy payback time for thin film copper indium diselenide modules is between nine and ten years, and in full production is just under two years. Over their lifetime, these solar panels generate nine to seventeen times the energy required to produce them. Energy content findings for the major materials and process steps are presented, and important implications for current research efforts and future prospects are discussed.