Image-Based PV Soiling Loss Quantification under Laboratory Conditions

In this study, we investigate the use of an image-based metric, black-to-white ratio (BWR), to quantify the soiling loss of a photovoltaic reference cell under different soiling conditions. BWRs extracted from the solar panel image and a surrogate checker pattern are correlated with the PV cell soiling loss measured via short circuit current method. A linear correlation was found between the BWR and the soiling loss of the PV reference cell. In addition, the surface dust loading estimated from the BWR agreed well with the PV reference cell’s soiling loss and dust potency information. However, it was found that BWR extracted from the lab PV cell is subject to over exposure and uncertainty, which calls for using field-size PV panel or the checkered board pattern as a surrogate. The results further demonstrated the utility of image-based soiling quantification and its feasibility for use in the field.