Performance loss rate of twelve photovoltaic technologies under field conditions using statistical techniques

Abstract

This paper presents a comparison of the annual performance loss rate (PLR) of twelve different grid-connected photovoltaic (PV) technologies based on outdoor field measurements. The annual DC performance loss rates of the installed PV technologies are obtained by using linear regression and classical series decomposition applied on the monthly DC performance ratio (PR) time series over five years (June 2006–June 2011). The PLR values obtained over the five-year period differ by up to 0.65% per year depending on the selection of the applied analysis method. The choice of the analysis technique affects the resulting PLR value but not the performance loss trend exhibited over the evaluation period for most technologies. Finally, there is evidence that the duration of the data used in the analysis affects the results as the PLR pattern exhibited by the crystalline-silicon (c-Si) and copper indium gallium diselenide (CIGS) technologies demonstrates a gradual convergence towards a steady state value over the five-year period, whereas more time is required to reach steady state for the thin-film technologies of amorphous silicon (a-Si) and cadmium telluride (CdTe).