Keeping your solar panels clean is much more than cosmetics. Dust and dirt can significantly reduce solar panel efficiency and thus effect the returns from your investments. The operating efficiency of a solar PV panel is dependent on the amount of sunlight that hits it. If trees constantly shade your panels, the amount of electricity they generate will be significantly reduced. Likewise, if your panels are covered in dirt they are going to produce less electricity, so keeping them clean ensures you are maximising your generating potential and returns from NIROCS.
All sorts of things can make your panels dirty – pollen from plants and trees, salt deposits (if you are living near the sea), and maybe just an unfortunate bombing run from a bird. It simply may even be just an accumulation of dust on the panel but any of these can decrease the amount of electricity you are producing.
UK Solar panel cleaning companies have been monitoring the increases in efficiency that cleaning can bring. They have frequently seen sizeable increases of solar efficiency on agricultural sites, of up to 30%. This has been proved by customers who have sent readings to prove solar panel cleaning has increased the output and efficiency of their array. On industrial and commercial sites there has have been increases of up to 60% and on residential arrays of up to 21%.
These findings are confirmed by the World Academy of Science, Engineering & Technology, who say a drop in the efficiency of a solar PV panel is not desired. One of the contributing factors in the drop of efficiency in PV panels is the accumulated dust on the panel. Solar Energy Power Association notes that dirty solar panels can lose 20% of their energy output. The National Renewable Energy Laboratory puts that figure even higher, at 25%. Recent University research has shown that a dirty solar panel can lose 50% of its efficiency compared to a clean panel.