A dirty solar panel won’t achieve its optimum power generation – but is it worthwhile to go to the trouble and expense of having them professionally cleaned? A team of engineers at the University of California, San Diego thinks not.
In what is claimed to be the largest survey quantifying losses of electricity output due to dirty solar panels conducted to date, the researchers determined panels that hadn’t been cleaned or rained on for nearly 5 months during a summer drought in California lost only 7.4 percent of their efficiency.
Jan Kleissl, a professor of mechanical and aerospace engineering at UC San Diego, believes the cost involved with hiring solar panel cleaning services simply isn’t worth it when it comes to small solar power systems.
“You definitely wouldn’t get your money back after hiring someone to wash your rooftop panels,” he said.*
While for larger commercial rooftop systems the financial losses are larger, the loss is “still rarely enough to warrant the cost of washing the panels”.
With regard to utility scale solar power systems; Professor Kleissl says economies of scale may mean washing panels is worth the time/expense.
However, the study also determined solar panels mounted at an angle of less than five degrees resulted in bigger losses in efficiency as dirt will tend to slip off panels installed at a steeper angle. The nature of good quality solar panel glass is such that it tends to repel dust and wind will assist with the process.
The researchers also point out panels spattered with bird droppings should be cleaned as the bird poop will block out all sunlight – and once dried, it’s unlikely it will be washed away when it rains.
* Editors note: Electricity in California is substantially cheaper compared to Australia.
Related:
Tips For Cleaning Solar Panels
