It is important to model the probability distribution of solar power to draw conclusions for installing a solar plant. The amount of solar power is depending on solar radiation. In this paper, we deal with the statistical distribution of the power generated by a system of PV modules subject to failure. We obtain some characteristics of the system considering the reliability of modules. We model the mean power and provide the optimum number of PV modules that need to be installed on the power plant. We present a real data analysis for a specific location in Izmir, Türkiye.