Impact of thermoelectric coal-fired power plant emissions on the soiling mechanisms of nearby photovoltaic power plants in the Atacama Desert

Soiling of photovoltaic modules is a problem that causes production and economic losses and is highly dependent on local environmental conditions. Photovoltaic plants' operators need to develop operation and maintenance strategies to balance the investment in cleaning procedures with these economic losses, especially in industrial areas. This paper analyses the impact of coal-fired power plants on the soiling mechanisms in photovoltaic plants in Atacama Desert. For that, the accumulated dust on the modules and its effect on the PV plant performance is analysed and compared in three different places in Atacama Desert. Two of them are in the coastline, one close to thermoelectric coal-fired power plant and another in the inner desert. The adhesion mechanism of deposited material and the impact of soiling on energy generation in photovoltaic modules installed within the coal-fired power plant are analysed. Our results show that calcite, used in the sulphur gas reduction process at the power plant, generates synthetic gypsum (FDG), which facilitates dust cementation on photovoltaic modules. Furthermore, our results indicate that the effects of the power plant's activity are noticeable up to 9 km away, becoming particularly evident in areas with high humidity, where the solubility of materials enhances the recrystallization and consolidation of dust on module surfaces. Specifically, the impact of the coal-fired power plant on the modules installed within its premises shows that after five months of exposure, the deposited dust reaches a maximum of 1.63 mg/cm2, with a soiling rate up to six times higher compared to other studied locations, resulting in a 23 % reduction in photocurrent.