The Economics of Solar Farm Cleaning
Why scheduled cleaning is the highest-ROI O&M action available to a solar farm operator.
Soiling losses on a solar farm compound into very real revenue lost every billing cycle. The cleaning ROI on most San Diego County sites is well under 90 days.
Typical soiling rates in San Diego County
Inland San Diego County solar farms typically measure 0.3–0.8% soiling loss per week during dry season, peaking at 12–22% before the first material rain. Coastal and ag-adjacent sites run worse — agricultural dust and pesticide drift are particularly stubborn.
Cleaning cost vs. recovered revenue
A scheduled cleaning on a 5MW San Diego solar farm typically prices in the low five figures per cleaning. At PPA rates of $0.06–$0.09/kWh, a 15% production lift on that array over even a single quarter generates more than the cleaning cost — often by a factor of three.
Optimal cadence by site profile
Most San Diego solar farms land on a 2–3 cleaning per year cadence with a deep cleaning ahead of the highest-irradiance summer months. Sites near agricultural operations or active construction often benefit from a quarterly schedule. We model the math from site-specific weather and irradiance data.