Article written by Arne Jacobson and Stephen Kullmann
Thin film solar photovoltaic (PV) modules are emerging as a lower cost alternative to the more conventional crystalline silicon (c-Si) PV modules. Amorphous silicon (a-Si) PV is the most mature of the thin film technologies and worldwide, a-Si modules make up approximately 15% of total solar PV sales. In some developing country markets, a-Si PV has become the dominant technology.
The growing use of amorphous silicon PV technology has led to a controversy about solar PV module performance ratings. The debate is related to the relative performance of c-Si and a-Si PV technologies. Manufacturers of a-Si modules claim that their products produce 10-15% more electrical energy per rated Watt of power output than c-Si technology. The reason for the variation, the theory goes, is related to the differential influence that real world weather conditions such as temperature have on the performance of the respective module types. With this in mind, a-Si PV manufacturers say that they should be allowed to adjust their power ratings to account for this extra energy production. Manufacturers of c-Si modules dispute this claim.