Seasonal variations in performance loss of photovoltaic modules: A case study in Thailand Science Park

Abstract

Performance loss rates of five different photovoltaic (PV) technologies operating under Thailand's climate have been derived from the first 3-year data. Although ambient temperature throughout the year in the tropics is relatively constant, we found remarkable seasonal variations in performance loss of the PV modules. The performance loss rates in rainy and dry seasons were severe, while those in summer were relatively slight. The soiling had great effect on the PV performance in the dry season, while the temperature was a key factor in the summer. The high module temperature in the summer caused high temperature loss but it also provided positive effect of recovering performance of thin film Si modules. In the rainy season, with less amount of irradiance and high humidity at the module surface the PV modules showed the highest performance loss rate. Our findings can be used to develop a better operations & maintenance (O&M) strategy for PV systems in the tropics, e.g., proper cleaning of PV modules during the dry season.