Google just did a study of their own solar panels (they’ve got a lot installed on their roofs). They compared the efficiency of the flat solar panels versus the ones that were installed at an angle.
Guess what? The flat solar panels had a lot of dirt on them. The sloped ones did not (except in the corners).
After the flat ones were cleaned, power output doubled. These panels had not been cleaned for 15 months. Read that again. The power output was cut in half from dust accumulation.
There was also dust on the angled solar panels, but just in the corners. So the efficiency gains from cleaning them weren’t as great.
Google now has plans to do regular cleaning of their flat panels.
What does this mean for you?
If you have solar panels installed flat on your roof, you need to get up there and clean them regularly. Probably every few months is good, though you’ll need to pay attention to any seasonal effects such as high pollen.
If you haven’t yet installed solar panels, this information should lead you toward installing them at an angle so that rainfall can wash them clean. This will save you a lot of maintenance time, and will keep your power generation at maximum efficiency.
Dirty solar panels at Google headquarters
You can get a link to the original google blog post at goodcleantech.
