Investigating crystalline silicon cell-based solar photovoltaic module degradation in the Maltese climate

Abstract

Photovoltaic (PV) modules may experience degradation as soon as they are exposed to outdoor weathering conditions. This occurs from the early stages of installation up to the decommissioning stage. PV degradation exists in many forms, some of which occur during the first few months of exposure, while others depend on the materials’ susceptibility to continuous weathering. The Maltese climate is characterised by high levels of solar radiation, humidity and temperatures. These three factors together with coastal region conditions may affect the performance of the PV module during its lifetime. The aim of this research was to gain an understanding of the visual degradation modes together with the rate of loss in maximum power over a number of years of operation. PV modules operating over a range of one to twenty-eight years were analysed. This would provide a clear picture to the installers and investors on the expected degradation in power per year for warranty and energy yield purposes. The results showed that modules with more than eighteen years of operation experienced a greater degradation rate per year in maximum power, when compared to those up to fourteen years operating under Maltese climatic conditions. This implies that the newer modules use improved materials such as UV-stabilised encapsulation, protection against humidity ingress, among others.