Life Cycle Analysis of High-Performance Monocrystalline Silicon Photovoltaic Systems: Energy Payback Times and Net Energy Production Value

This paper summarizes a comprehensive life cycle analysis based on actual process data from the manufacturing of Sunpower 20.1% efficient modules in the Philippines and other countries. Higher efficiencies are produced by innovative cell designs and material and energy inventories that are different from those in the production of average crystalline silicon panels. On the other hand, higher efficiencies result to lower system environmental footprints as the system area on a kW basis is smaller. It was found that high efficiencies result to a net gain in environmental metrics (i.e., Energy Payback Times, GHG emissions) in comparison to average efficiency c-Si modules. The EPBT for the Sunpower modules produced in the Philippines and installed in average US or South European insolation is only 1.4 years, whereas the lowest EPBT from average efficiency c-Si systems is ~1.7 yrs. To capture the advantage of high performance systems beyond their Energy Payback Times, we introduced the metric of Net Energy Production Value (NEPV), which shows the solar electricity production after the system has “paid-off” the energy used in its life-cycle. The SunPower modules are shown to produce 45% more electricity than average efficiency (i.e., 14%) c-Si PV modules.