Of all the parameters that affect the efficiency of a PV installation, one of the most important, which we can also directly influence, is light transmittance related to the cleanliness of photovoltaic modules. In extreme cases, dirt reduces efficiency by up to 20%. So how can we properly keep the panels clean so that they work at the highest possible speed, can we clean them ourselves and finally: are there self-cleaning panels?
Well, that depends! As we mentioned – for the effective operation of the panels, it is important that they are clean and, if possible, dust-free, so that sunlight can freely penetrate them and be converted into electricity, therefore sand, exhaust gas deposits, plant pollen and possibly moss covering them. However, if you are afraid of electric shock or other accident related to the operation of the installation itself, we offer you comfort – the most difficult thing is getting on the roof, so do not do it yourself if you do not have appropriate protection or conditions to stand stably on the roof without them.
What you should also remember – some photovoltaic panels require the use of specialized cleaning agents, so before starting this activity, read the warranty conditions and cleaning instructions for the model you have chosen.
Cells should be washed with distilled water or rainwater and a soft sponge (e.g. nylon). If the dirt is severe, it is recommended to use soap – a mixture of glass cleaner and wine vinegar. After using soap, always remember to rinse it thoroughly from the surface of the faucet. It is not recommended to use tap water to wash panels – it is often hard and may contribute to the formation of scale deposits, which will reduce the photopermeability of our batteries. It is best to wash in the morning, before the installation has time to heat up from the sun, or simply on a cloudy, cooler day, to avoid possible damage resulting from, for example, using too cold water on hot panels.
The prohibitions are quite simple and rather obvious: under no circumstances should you walk on the modules, as they are not adapted to this type of pressure, and you should absolutely not use pressure washers for cleaning!
Most manufacturers recommend washing the panels at least once a year to maintain their efficiency. The practice is to wash them about twice a year, always taking into account the individual conditions prevailing near our installation. Usually, during periods of heavy rainfall, it is not necessary to wash the panels, but it is good to remove dirt such as bird droppings from them a little more often – as in the case of car bodywork, they may cause corrosion on the panel surface, but this is not necessary if access to the installation is difficult. In this case, thorough cleaning in spring and mid- or late summer will be enough.
This is of course true! In recent years, a system of self-washing panels has been developed. They are equipped with low-pressure sprinklers, and some of them also have containers for cleaning agents. The system first sprays the faucet with soap and then rinses the faucet surface with clean water. However, this method is quite an expensive convenience and does not completely relieve us from cleaning our installation – some dirt must be removed manually anyway. However, the claims regarding self-cleaning surfaces are false or far-fetched – atmospheric precipitation does not always enable automatic cleaning of the batteries, and in the summer it even causes increased settling of characteristic yellow plant pollen on the surface of the panels.
Companies providing this type of services provide them based on two washing systems: ionic-cationic, based on filtering with a mixed bed resin, or reverse osmosis system, which in turn is based on filtering through a membrane filter.
As you have seen, washing the panels yourself is not difficult, so if you can do it in safe conditions while observing occupational health and safety rules, and your faucets do not require the use of specialized, hard-to-find cleaning agents, you do not have to decide to use the services of a professional company. So don’t wait with your decision and start your adventure with green energy this season.
