Evaluation of the environmental performance of sc-Si and mc-Si PV systems in Korea

摘要

In this study, environmental issues associated with silicon-based photovoltaic (PV) systems in Korea are investigated using life cycle assessment (LCA). The target PV systems are single-crystalline silicon (sc-Si) and multi-crystalline silicon (mc-Si) modules with a power conditioning system (PCS) and balance of system (BOS). In order to identify the environmental benefits and key environmental issues associated with the deployment of these systems, the global warming potential (GWP), fossil-fuel consumption (FFC), CO_2 payback time (CO_2PBT), and energy payback time (EPBT) of the target PV systems throughout their life cycles are analyzed. The LCA results show that sc-Si and mc-Si PV systems are superior to the current grid mix in Korea with respect to GWP and FFC. For the current conversion efficiency, the mc-Si PV system has lower values of GWP and FFC. With the predicted improvements in conversion efficiency, the GWP results associated with the construction phase of sc-Si and mc-Si PV system will be offset by electricity generated in 1.66 and 1.53 years, since then 1470 and 1477 tonne CO_2 equiv. of GHGs are reduced during its lifetimes, respectively. In addition, the energy inputs during sc-Si and mc-Si PV system's construction phase will be offset in 3.11 and 2.97 years, since by then 10.15 and 10.20 TJ of net energy benefit will have been obtained, respectively. Considering the planned deployment of PV systems in Korea and the expected improvements in PV module efficiencies, the net CO_2 reduction and net energy benefit between 2010 and 2030 were calculated. If 0.45% of the Korean grid mix was substituted with mc-Si PV systems, and a conversion efficiency of 20.30% were attained, the net CO_2 reduction would be a 69.8 Mtonne CO_2 equiv. The supply plan is achieved using sc-Si PV systems, which achieve a conversion efficiency of 27.60%; the net energy benefit would be 410.6 TJ, which is equivalent to 4.3% of the total primary energy supply in 2009. It is shown that sc-Si and mc-Si PV systems would be suitable solutions to reduce energy consumption and CO_2 emissions if they replaced non-renewable energy sources in Korea.