Performance of single-junction a-Si modules under varying conditions in the field

We report on the actual performance of large-area photovoltaic (PV) modules deployed outdoors, which are representative of single-junction amorphous silicon (a-Si) thin-film technology. They are part of the performance and energy-ratings testbed (PERT) at the Outdoor Test Facility (OTF) and are under continuous measurement and load conditions, as executed by a data acquisition system (DAS). The goals are to analyze and compare energy production and performance for various PV technologies deployed in actual field conditions and to validate the PV energy-ratings methodology being developed for modules. For single-junction a-Si, we found the effective efficiency is very similar to that measured at standard conditions.