Mathematical models of photovoltaic modules degradation in desert environment

The lifetime of a photovoltaic module operating in natural environment may never be known. It is useful to look for mathematical laws that are reliable in predicting the approximate warranty and performance times of these instruments before they fail. Literature is rich of many laws (parametric, semi-parametric or non-parametric) that have a high efficiency in all scientific branches. Parametric laws are used more than others in the branches of electronics. In this paper, we examined the validity of some reliability laws (15 models) to simulate the degradation of the maximum electrical power of crystalline silicon photovoltaic modules and to estimate their lifetimes when exposed to Saharan environments (especially the Sahara of Adrar in the South West of Algeria and the desert of California in the United States of America) where the climate is generally warm and dry during half a year. A genetic algorithm (a method of artificial intelligence) has been used here to calculate the parameters of each tested model. The modified Weibul model is the most adequate one compared to the other parametric models tested. In this study, the average lifespan of photovoltaic modules in the desert of California has been estimated to approximately 30 years (29 years for Adrar) for which the electrical energy supplied reaches 46% of its initial value. The prediction results must be taken into consideration for any construction study of a solar station in desert environments.