Milk the Sun has recently begun a field trial to show whether the cleaning of photovoltaic outdoor installations is economically worthwhile for operators.
At Intersolar Europe, the online platform presented the first interim results. Modules with an output of about 30 kilowatts have been cleaned by hand at 17 solar parks in Germany, mainly located in Bavaria, Eastern and Northern Germany. These were monocrystalline, polycrystalline and thin-film modules in solar parks that were put into operation between July 2007 and October 2013.
The yields of the purified module areas would have subsequently increased by up to 5.2 percent compared to a reference group located next to it. The highest result was achieved in a photovoltaic system with cadmium telluride thin film modules in Bavaria. For two of the plants, no cleaning effect has yet been determined, as the interim report shows. In the majority of the photovoltaic plants, the surplus yield was between 0.5 and 2.0 percent.
The investigation that Milk the Sun and Meteocontrol are carrying out continues until the end of September. The results are then to be evaluated and published in a study. The modules are cleaned by hand with a rotating brush using exclusively demineralised water.