Results of Environmental-Based PV Soiling Models after Extreme Dust Events: The Case of Saharan Dust Intrusions in Southern Spain

Soiling is a major issue that greatly determines the operation and maintenance cost of PV systems. The occurrence of extreme dust events in sites where typically the losses due to soiling are not high can significantly alter the cleaning schedule. In this work, two different environmental-based models are applied to estimate the soiling losses that two recent Saharan dust intrusions caused in a location in southern Spain. During the first one, a peak of PM10 equal to 904 μg/m was reached, and it became the most intense dust event registered in 10 years for both its intensity and its length, as it lasted almost three days. Due to these two factors that led to very low irradiance values during the episode, no measurements from a soiling station installed in the site were available. Therefore, the only approach to quantify the impact of this event was through environmental-based soiling extraction models. The results of these models showed both relatively high differences between them and a strong dependence with the cleaning threshold value. These issues are expected to impact the decision-making about the cleaning of PV modules. For example, non-negligible differences were found when considering a cleaning threshold of 1 mm/day or a cleaning threshold of 10 mm/day. In the first case, only 1 day with significant soiling losses (8.3% using Coello' model) is detected; whereas in the second case, the PV modules are supposed to be notably soiled (losses >=3D 8.3%) during 5 days.