Abstract
The aim of this work is to improve knowledge about the observed seasonal behavior of CdTe modules under real operating conditions. The study consists of a characterization of the CdTe photovoltaic (PV) technology based on the application of the Sandia Array Performance Model (SAPM) to two PV fields in Italy (Viterbo and Bolzano) and two PV modules in Spain (Madrid and Jaén). SAPM is a very accurate semi-empirical power estimation model that takes into account the four main phenomena that affect the Performance Ratio (PR) of PV plants or modules: temperature, angle of incidence, irradiance and spectral effects. New outdoor experimental procedures were set up at the ESTER station of University of Rome Tor Vergata to validate the temperature coefficients, the angle of incidence coefficients and the spectral mismatch coefficients of CdTe modules to be used in the SAPM model implementation. A detailed analysis of the deviation between the experimental PR data and the modeled PR estimated by SAPM revealed that it was possible to characterize the residuals and attribute them to phenomena not considered by the model.