A practical method for the energy rating of c‐Si photovoltaic modules based on standard tests

The performance of a photovoltaic module at Standard Test Conditions (STC) is valuable for comparing the peak performance of different module types. It does not, however, give enough information to accurately predict how much energy a module will deliver when subjected to real operating conditions. There are several proposals for an energy rating for PV modules which attempt to account for the varying operating conditions that one encounters in the field. In this paper, we present an approach with the emphasis on simplicity and practicality that incorporates existing standard measurements to determine the energy output as a function of global in‐plane irradiance and ambient temperature. The method is applied to crystalline Si modules and tested with outdoor measurements, and a good accuracy of prediction of energy production is observed. Finally, a proposal is made for a simple Energy Rating labeling of PV modules. Copyright © 2005 John Wiley & Sons, Ltd.