California arrays lose output to dust
Peer-reviewed studies of large California systems measured energy lost to soiling during dry periods, including Kimber et al. (2006) and Mejia & Kleissl (2013) on California PV sites.
Rain is not a cleaning plan
NREL's analysis of soiling station data could not find one rain amount that reliably cleaned panels, and panels did not always return to full output after rain.
Fresno's climate normals show a long, dry summer, which is when dust builds up and the sun is strongest.
What this means for site owners
Check soiling against your production data after the dry months and after nearby harvest or construction. NREL's O&M guide also points to robotic cleaning systems for large arrays. We offer all-electric robotic and traditional cleaning across Fresno, Clovis, Tracy and Manteca.
Commercial solar panel cleaning →
Sources
- Kimber et al., The effect of soiling on large grid-connected PV systems in California and the Southwest (2006)
- Mejia & Kleissl, Soiling losses for solar PV systems in California, Solar Energy (2013)
- NREL, Time series analysis of PV soiling station data (2017)
- NWS Hanford, Fresno climate normals 1991-2020
- NREL et al., Best Practices for O&M of PV and Energy Storage Systems, 3rd ed. (2018), sec. 5.7.1 Cleaning
