The consequence of soiling on PV system performance in Arizona; Comparing three study methods

We study the consequence of soiling on different flat-plate photovoltaic modules in Tucson, Arizona. We compare three different methods of study. These methods include (1) a comparison of energy yields between strings of PV modules, held at MPP, that are regularly cleaned and naturally soiled, (2) measurement I-V curves from individual PV modules in the field before and after cleaning, and (3) measurement I-V curves from individual PV modules in the laboratory before and after cleaning using a flash tester. All methods indicate an approximate 1% performance enhancement from cleaning. Laboratory I-V curve measurements provide the most precise results.