A common question I’ve been asked since launching this blog, is about maintenance of the panels; specifically, do they ever need to be cleaned? Here is the official Sharp literature on the subject (emphasis added):
Sharp PV modules are designed for long life and require very little maintenance. If the angle of the PV module is 5 degrees or more, normal rainfall is usually sufficient to keep the module glass surface clean under most weather conditions. If dirt build-up becomes excessive, clean the glass surface only with a soft cloth using water.
So most likely it’ll be a long time, if ever, that we need to have them cleaned. We’ll have to remember to look up at them from time to time and see if they look dirty; also, with the “Enlighten” monitoring system we’ll be able to see if performance changes — if they start looking dirty and the performance goes down, we’ll know they need to be cleaned.
I asked Joe from Long Island Power Solutions if he had any insights to add based on their experience; he says:
This time of the year, we see a lot of that green pollen. This causes some shading of the cells. Rain will take care of that but between rain, it wouldn’t hurt to hose down the array if it can be done safely from the ground.
My Long Island Solar Energy Story 