Comparison of module performance characterization methods

The rating and modeling of photovoltaic (PV) module performance has been of concern to manufacturers and system designers for over 20 years. Both the National Renewable Energy Laboratory (NREL) and Sandia National Laboratories (SNL) have developed methodologies to predict module and array performance under actual operating conditions. This paper compares the two methods of determining the performance of PV modules. The methods translate module performance to actual or reference conditions using slightly different approaches. The accuracy of both methods is compared for both hourly, daily, and annual energy production over a year of data recorded at NREL in Golden, CO, USA. The comparison of the two methods is presented for five different PV module technologies