Although it doesn’t really occur to many people, solar panels can get quite dirty. There are many external influences that can make a panel dirty, including dust, road grime and bird or bat droppings to name a few.
A photovoltaic (PV) system performs best with completely unobstructed access to the sun’s rays for most or all of the day. Even something as seemingly inconsequential as a residue layer can affect the performance of your panels, while bigger spots & obstructions can have a much greater impact that is disproportionate to their size. On top of cleanliness, there are numerous other issues that may crop up over a system’s lifetime that may go unnoticed, especially when seen by an untrained eye. For example, a panel may have developed cracks as a result of hail or other falling objects, or parts of the racking may have come loose.
In the past, it was generally accepted that the rain would clean the panels. More recently, this conventional wisdom has come into question with new discussion and articles on the subject. For reference, there is an interesting article on the analysis of energy losses in photovoltaic modules here. It was conducted for the World Renewable Energy Congress in Sweden. It highlights that dust buildup does have a significant effect on solar energy production – contrary to popular thinking on the matter.
A good analogy is with your car windscreen: If you leave you car sitting outdoors for a few weeks, the buildup on this glass would make it difficult to see through without cleaning it. Even if it has cleaned, you would still need to clean it with the wipers or other means – and even then, with more driving it will get too dirty to see through again. Likewise, having dust, grime or buildup on your panels can reduce your system’s energy yields by up to 25% – and associated reductions in energy bill savings.
In terms of how often the panels should be cleaned or checked, it is often the case that the installation date is the last time a solar system owner ever looks at their panels – until something goes wrong. We at Elite Window Cleaning recommend that panels be cleaned and inspected annually. Cleaning at regular intervals prevents buildup of residue and keeps your panels operating optimally at all times. Regular checks can also prevent cracks or fire risks from developing into something worse – but you’ll need to know what you’re looking for in order to identify these issues in the first place.
Where ever and whenever possible, panels should be cleaned using purified water and a soft brush.
Panels should not be cleaned with a pressure washer, as doing so could result in cracked glass. Abrasives and chemicals should also be avoided, as both can result in ‘rough spots’ on the panels where dirt is likely to accumulate. Also remember that you should never put pressure on the panels by stepping or putting weight on them. The benefits of having your solar panels cleaned by a professional as opposed to cleaning them yourself is that we use a de-ionised water system to give an effectively spot free finish that is more resistant to becoming dirty and will also give you a better result with a longer-lasting impact. Tap water and chemicals can leave a residue on your panels that can inadvertently encourage dirt to accumulate. This is one of the reasons that having your panels cleaned professionally is a good idea. Being a professional window cleaning service provider, we possess all the correct systems and tools to effectively and safely clean solar panels.
Another part of having a trained technician do the job is that they can check other aspects that can affect the health and performance of your system. These include potential fire safety issues, cracks, hot spots and nests from uninvited guests like birds, rats and possums. Detecting issues like crazing (ie. webs of small cracks) and delamination (i.e. peeling off of laminate layer) are also essential to to ensure a system running well.
In addition to keeping your solar panels clean throughout the year, it is equally important to remove built up snow. Systems perform best with completely unobstructed access to the sun’s rays. Having the ability to remove built up snow and ice safely without damage to the panels will prevent energy losses and costly repairs.
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