Enhanced photovoltaic soiling in an urban environment
Sarah Toth1,2, Michael Hannigan1, Marina Vance1, Michael Deceglie2
1University of Colorado, Boulder, Boulder, CO, United States
/2National Renewable Energy Lab, Golden, CO, United States

Natural soiling, or the deposition of ambient particulate matter (PM) onto the surface of solar glass, causes losses in PV production around the world. Much work in the PV community has focused on soiling in dusty desert environments. However, PV systems in urban environments are exposed to different contaminants and thus soil differently. We present an analysis of PV soiling in such an urban environment simultaneously considering the impacts of dew and air quality. We present 1 year of results from a soiling station in an urban location in Colorado, co-located with high-quality meteorological and ambient particulate matter instrumentation. We find that soiling occurs during periods of higher particulate matter concentration, but also consider the influence of dew events. Bare glass samples were also exposed outdoors for 11 days alongside the station; results from microscopy and light transmittance measurements show how moisture and dew affect the morphology and optics of contamination on glass. The coupon results also suggest that natural cleanings may not be sufficient to clean solar panels in urban environments.