Economical evaluation of PV system losses due to the dust and pollution

The continuously increasing number of Photovoltaic (PV) plants has stimulated the research in order to increment their overall efficiency. Usually, the efforts have been focused on the research of innovative materials and in general on the optimization of the photovoltaic conversion. Pollution due to the traffic, to the industrial activities or to the residential heating can reduce the efficiency of the PV plant. However, this phenomenon has been rarely investigated. It is important to highlight that these losses may have a significant impact in PV module and plant performances thus reducing the financial incomes in a nonnegligible way. This paper present and discuss a method which allows to choose the optimal maintenance interval for a PV plant. The method, starting from the costs related to the cleaning of the panels, compares them to the economic losses due to the decrease of the efficiency.