Influence of climatic data and degradation factor on the efficiency of the photovoltaic modules

The power output of photovoltaic modules operating under certain field conditions decreases over the time. The photovoltaic module degradation factor depends not only by the physical properties of the material but also by the change of parameters of the environment where the PV panels operate. The change of the PV modules degradation factor over the time reflects on the power output which is in a close relation with revenues from the purchased electricity produced by the modules.The process of PV modules degradation is a normal process accompanying the operation of the panels. This process is a result of increased losses in linear connections; increased relative humidity of the ambient air, and the process of moisture evaporation; limitation of possibilities of the p-n junction; and destruction of protective coating. The first above mentioned of losses generally depends on the local atmospheric conditions where the panels operate. At higher local values of the average temperature and relative humidity of the air the rate of degradation increases. An analysis about the degradation rate of the PV modules operating under specific field conditions here is made.