Photovoltaic model uncertainties based on field measurements

The purpose of this paper is to compare the combined uncertainties inherent in three PV models the single-point efficiency, the single-point efficiency with temperature correction and the PVUSA. This evaluation was performed using outdoor measurement data from 12 different, 1 kW_p, grid-connected PV systems, operating in Cyprus since June 2006, along with measurement data from the meteorological sensors on-site. The different models were associated with different uncertainties which affected the accuracy of the annual energy yield prediction of the different PV technologies. For the single-point efficiency model, the combined uncertainties on the annual dc energy yield of all PV systems were in the range ±7%, resulting from the name-plate efficiency at standard test conditions (η_STC) and the global irradiation measured on the plane of array (G_POA). By applying temperature correction on the model, the combined uncertainties dropped to an average of ±5.68% over the evaluation period. Lastly, the combined uncertainties for the PVUSA model were even lower, on average ±1.59%.