Rating photovoltaics

The rating of photovoltaic (PV) cells and modules is critical in comparing the performance of the plethora of competing PV technologies. The rating should be easy to reproduce, give a unique value in the absence of measurement error, and, most importantly, be directly related to the expected system performance. PV rating methods have evolved since the first measurement workshop in 1975. Consensus standards exist and the PV community is in agreement on how to rate most PV technologies for terrestrial and space applications. There is still disagreement on the proper probing for Si wafers and how to test low-concentration, bifacial cells. Because of the low demand, there has been little effort to standardize rating PV for indoor or other applications that do not involve bulk power generation as their primary activity.