PVSMS: A system for quantifying soiling effects and optimizing cleaning schedule in PV solar plants

Abstract

Soiling of photovoltaic (PV) installations is an efficiency-limiting factor. It induces considerable energy losses and can even make PV projects economically unviable. A priori knowledge about the soiling phenomenon at a given site provides more guidance to PV project owners for effectively designing the solar field and accurately predicting the yield and profitability of the solar project. Soiling information can also improve the performance analysis of operational solar power plants. Recovering soiling losses begins with the installation of a reliable soiling monitoring system, followed by the implementation of optimized soiling mitigation or cleaning policies. In light of these facts, this work aims to provide a reliable and low-cost soiling monitoring station, named PVSMS (Photovoltaic Soiling Monitoring System). The working principle and detailed description of the hardware design are presented. The field validation of the proposed approach was performed by comparing the soiling loss data provided by PVSMS and the soiling loss on a real PV array, and it shows stable operation of the PVSMS and good agreement between the PVSMS data and the soiling losses quantified through the real PV array. A specialized soiling data analysis software tool has been developed to automate the soiling data analysis procedure and to assist operations and maintenance (O&M) teams in deciding on optimal cleaning dates. Furthermore, PVSMS has been used in a feasibility study of a large-scale PV project in a mining site. The result of this application demonstrates that PVSMS can provide valuable insight into soiling behavior and can also be used to optimize cleaning strategy, estimate its related costs and economic benefits.