Comparative Analysis of Methods to Extract Soiling Losses: Assessment with Experimental Measurements

The impact of soiling on the energy yield of PV systems has recently become a major concern for PV owners, as soiling losses have reduced significantly the revenues of several PV sites. However, a large number of PV plants still lack the equipment to monitor these losses. An appropriate knowledge of soiling losses in PV modules can significantly increase the economic profits, even if possible without any specific soiling monitoring system. In this study, a first comparison of different analytical methods to extract losses due to soiling from PV performance data, without the need for specific soiling sensors, is presented. The study is based on outdoor PV power, irradiance and module temperature measurements. The experimental campaign is conducted in a low-moderate soiling location. The first results show that two of the methods assessed in this work can estimate soiling trends with a relative high accuracy, thus allowing planning adequate cleaning schedules.