A Method of Calculating the Daily Output Power Reduction of PV Modules Due to Dust Deposition on Its Surface

Compared with the cleaned photovoltaic (PV) modules, the output power of the dusty PV modules decreases. In this paper, the factors influencing dust concentration on the PV module glazing surface are studied and discussed. Based on the optical analysis, a method of calculating the output power reduction of PV modules due to dust deposition on its surface is proposed. According to changes of daily PM10 and rainfall, the output power reduction of PV modules can be calculated, which lays a foundation for the formulation of the cleaning strategy. In addition, experiments of dust deposition on the surface of PV modules are designed in Changzhou and Yantai, China, to verify the theoretical output power calculation model. According to the result of experiment and calculation, not only can this method accurately calculate the daily power loss caused by the dust deposition on PV modules surface, but also it can make up for the large fluctuation of outdoor experiments (measurement of the output power reduction of PV modules due to dust deposition) under the changeable weather of radiation.