Abstract
The degradation of used modules in photovoltaic (PV) systems is a major problem for module manufacturers, owners, and researchers due to their exposure to different climatic conditions, which leads to their degradation, regardless of the type and composition of the module. Therefore, this paper aimed to study a real case to calculate the degradation rate of the modules of a PV system connected to the grid, which was established in the year 2012, which is approximately 11 years ago, and is located in the Libyan Center for Solar Energy Research and Studies (LCSERS) in the city of Tripoli. This study was performed through the methodology of visual inspection of the system, measuring maximum power (Pmax) and other electrical characteristics through indoor and outdoor test devices, and thermography. The results showed that the PV system is operating in good condition and that the Pmax degradation rate of the PV module ranges between 13.95% and 16.75%.