Vincent Farnsworth 6:31 p.m., Dec. 4
A study published by UC San Diego engineers recently indicates that there’s little, if any benefit to solar power users to pay firms in the business of cleaning their panels to increase efficiency.
A recent study found that panels that hadn’t been cleaned or rained on for a period of nearly five months lost only 7.4 percent of their efficiency, or about 0.05 percent per day of accumulating dust and grime. For a typical 5 kilowatt residential solar installation, that translates to about $20 in lost energy production for panels that go without cleaning versus those washed halfway through the typical San Diego summer dry season.
“You definitely wouldn’t get your money back after hiring someone to wash your rooftop panels,” Jan Kleissl, a professor of mechanical and aerospace engineering at the university, tells UCSD’s NewsCenter.
“Dust on PV panels does make a difference but it’s not a big enough factor in California to warrant cleaning,” adds Felipe Mejia, another study author.
The study notes that while most residential customers shouldn’t bother with cleaning services, larger industrial arrays, or those soiled with heavy bird droppings or other pollutants from nearby businesses, highways or agriculture might benefit from routine cleaning.