Quantifying the Energy Impact of Soiling—Thanks to the Tool SoilRatio

Herein, a soiling measurement tool, termed “SoilRatio,” and its software is presented. The originality of this fully integrated device lies in its standalone feature and its sensors on a module scale. It is able to quantify precisely, quickly, and regardless the type of soiling, the production loss of a photovoltaic plant. Most soiling measuring devices consist of two similar modules mounted side by side, one is cleaned frequently and the other is left soiled. Other systems use a photodiode optical sensor that has to be calibrated according to the type of soiling targeted or a cell protected and another exposed as sensors. The sensor surface is too small to generate results representative of commercial modules and should therefore, be processed and interpreted. The concept chosen by the CEA is to use a pair of modules and cover one of them to keep it clean. In this way, it does not require any cleaning, which ensures better accuracy and lowers operating costs. Various experiments are performed to assess its performance and improve the SoilRatio device. The specifications document of the next version is already written to integrate modules with multiple measurement areas so as to identify the soiling patterns.