Abstract. Accurate PV power production modelling requires precise knowledge of the distribution of solar irradiance among its direct and diffuse components. Since this information is rarely available, this requirement can be addressed through the use of diffuse fraction models. In this study, we try to quantify the errors in PV modelling when measurements of the diffuse solar irradiance are not available. For this purpose, we use total and diffuse solar irradiance data obtained from ground-based measurements of BSRN to simulate the PV electric output using GSEE. We have chosen five sites in Europe and North Africa, with different prevailing conditions, where BSRN measurements are available. GSEE incorporates an implementation of the Boland-Ridley-Lauret (BRL) diffuse fraction model, along with a Climate Data Interface that enables simulations across different time scales. We evaluate the capability of BRL in providing accurate estimations of the diffuse fraction under diverse atmospheric conditions, with particular attention on the presence of clouds and aerosols and assess the extent to which its associated errors propagate to energy production modelling. Furthermore, we compare GSEE outputs when using CAMS radiation time-series as input instead of ground-based measurements, to quantify the impact of the CAMS radiation product uncertainties in PV modelling.
Papadimitriou et al. (Thu,) studied this question.