New performance data from commercial solar specialist Absolar suggests dirty solar panels could be costing UK businesses thousands of pounds in lost electricity generation every year. With routine cleaning, output could be increased by up to 16.6%.
Image Credit: Absolar
Absolar is currently carrying out its annual maintenance program and its engineers say they are seeing a marked build up of grime, air borne pollution and bird droppings on commercial systems that have not been serviced. The resulting solar soiling can reduce energy generation long before it becomes obviously visible.
At Southampton restaurant M Dim Sum, Absolar recorded a 16.6% increase in electricity generation after cleaning a 32 panel rooftop solar installation. After adjusting for solar radiation using independent weather data, the improvement remained around 10%.
Dr Victoria Aragon, renewable energy specialist at Absolar, comments, "Most building owners assume solar panels just get on with the job once they're installed, but our engineers see the reality every time we're out on a roof. Bird droppings, dust, pollen and general soiling build up gradually and most people never notice the drop in output because there's no obvious sign. That is, until you compare the numbers before and after a clean and see a double digit swing. That's revenue a business is simply leaving to rot on the roof."
Absolar says the case for regular servicing rests on more than just cleaning. Dr Aragon continues: “We carry out full system inspections, so every maintenance visit includes a check of component condition, service logs and system efficiency. This helps us to catch early signs of wear or faults before they become costly problems.
Absolar's engineers use deionized water, which dries spot free and leaves no mineral deposits on the panel surface, combined with a cleaning robot to safely reach areas of a roof that would otherwise be difficult to access. Every Absolar installation comes with a 4 year service and maintenance package, with engineers returning to carry out cleaning and inspections rather than leaving it to the customer to remember.
The findings come as Absolar's teams work through this year's maintenance round, with reports showing some of the worst soiling seen at sites that back onto trees or are near bird roosting spots including one system in Ipswich visibly marked by bird droppings across a significant portion of the panelling.
"Businesses invest in solar to cut energy costs," says Dr Aragon. “Our findings suggest many could improve returns simply by making sure their systems are properly maintained. So, whether that's with Absolar or another provider, it's a conversation worth having."