It's no brainer that accumulation of dust on the surface of solar panels, also called 'soiling', is one of the main reasons that affects the efficiency of solar power plants. The dust layer itself can reduce the reflectivity to about 50% in just a few days. Most of the solar power plants employ manual cleaners who brush and clean each panel using de-ionised water and detergent; but it's a very labor intensive and routine task. It also adds to the overall maintenance costs which directly results into elevated cost of solar power generation.
The fix for soiling comes from Oak Ridge National Laboratory. The team at ORNL has developed a budget-friendly, transparent and anti-soiling coats for the solar panels so that they that don't need manual cleaning. The coating is based on superhydrophobic coating technology developed by the laboratory and is capable of rejecting water, viscous liquids, dust particles and sand trying to settle on the surface. The coating can be deposited using regular painting or spraying techniques, using a mix of organics & particles. One big advantage of these coatings is that they can be deployed on already-functional solar panels in the solar power plant without taking them out for maintenance.
Image Credit: Wikipedia
There are several challenges involved in development of such coating. The coat has to be an excellent water repellent to minimise the need of occasional cleaning. It should not affect the scattering of solar radiation in 250 - 3000 nm wavelengths. The coating must be super-thin (a few nm thick) and the embedded particles should be tiny. It should also tolerate the constant UV exposure and erosion due to sand. Thankfully, the research team has arrived at a particular formula that exhibits all of the above characteristics.
ORNL team is currently optimising the coatings and performing various exposure tests. The small-scale field testing is expected to begin soon. We'll promise to keep you posted on the developments.