Shedding light on solar panel cleaning

Solar panels produce the most electricity and make more money for the owner when they are clean. However, because solar panels are exposed to the elements, they get dirty and have need of cleaning. Solar panels installed in urban, rural and coastal areas all have their own unique reasons for needing to be cleaned. You may think that rain washes off dust and pollutants, but in reality, rain water does not clean solar panels. Ideally, the glass on the solar panel is mounted at a 45 degree angle, similar to your car windscreen. If you didn't clean your windscreen for six months, you would lose a lot of visibility because the rain contains airborne dust particles that settle and attach to the surface after the rainwater evaporates. Solar panels are not mounted in the shade as it inhibits their electricity generation. Left long enough however, the natural build-up of contaminants on your solar panels will put your whole array in the shade. 

Various studies completed by universities in the U.S. have shown that if solar panels aren't kept clean, output can drop by up to 50%. Glyndwr University in North Wales hope to carry out such a study in the near future and Clean Solar Solutions will be involved in this research, which involves taking readings of the solar output before and after cleaning. It is most common to see increases in output of between 20-25%. This has been confirmed by the monitoring departments of Solarsense UK and Mipower.

How are solar panels cleaned? 

The most visually exciting method is seeing an automated robot crawl over the panels, cleaning as it goes. Other methods are sprinklers, electric charge systems and various coatings to make the panels self-cleaning. At the moment, these systems are in prototype or early production and are not fit for mass cleaning. For now, the most efficient, commonly used and cheapest way to clean solar panels is by using ultra-pure water which is fed to a brush head. This wets the panel, agitates and lifts the dirt, then rinses. Tap water is not suitable for cleaning solar panels because it contains mineral deposits which dry, create shade and inhibit output. Ultra-pure water has no impurities and as a result, the residue water that is left on the panels dries clear, with no streaks or spots. For now it is the best tried and tested method that has been used in countries further along their solar journey, such as the U.S., for many years.

Due to where they may be mounted, solar panels are difficult to access and clean yourself. Many window cleaners are adding solar panel cleaning to their list of services, as they have access to pure water and the water-fed poles needed to reach the solar panels. Nevertheless, knowledge about the health and safety implications of cleaning solar panels is required as it carries a different level of risk to window cleaning. For example, there is no electricity flowing through a window whilst it is being cleaned with water. Having all of the right tools for a job does not mean one can carry out the job safely. You may own a set of screwdrivers, but you may not know how to safely re-wire your house. Therefore, it is highly recommended that when you get your solar panels cleaned, you use an experienced, specialist solar panel cleaning company. They will have the health and safety knowledge needed and be insured.

Putting a schedule in place

It has become industry standard in countries such as Germany, Portugal, Spain and the U.S. to have your solar panels cleaned every six months in April and September. The UK is following suit. April is ideal because you know you will be heading into the sunshine months with clean panels. September again is a good time because you are making the most of the last few weeks of sunshine for the year. If you live in a rural area, harvest time would have thrown up a lot of dust that will have settled on your solar panels. Solar panels work more efficiently on cooler days as opposed to the hotter, summer days.

Of course, the cost of cleaning varies depending on how many solar panels are on a site. Be careful though – there are some pretty hefty charges being thrown around. The cost of your solar panel cleaning should not outweigh the financial benefit the cleaning will bring. For example, there is no point spending £200 on solar panel cleaning if it will only bring you an added £100 in electricity. The cost has to be right. Again, specialist solar panel cleaning companies will charge what brings the best value to you.

The future of solar panel cleaning

Technologies are being honed every year, be it the brush heads on the water fed poles becoming more efficient at lifting dirt, robots cleaning with less water or the self-cleaning coatings being developed to make them easier to apply and more efficient on all solar arrays. Years ago, solar power was a thing of the future, but now, the future has arrived and solar panels will continue to produce more and more of our power. This means that solar panel cleaning is here to stay.

Photos courtesy of Clean Solar Solutions www.solar-panel-cleaners.com