On Thursday I cleaned my panels using dishwashing liquid in warm water. I used a 12' pole and window washing pad (sort of like a mop) so I could do this from a 5' step ladder without climbing on the roof. After washing each panel the pad was black, and the water in the bucket quickly turned black as well. Those panels were DIRTY, despite having been rinsed off more frequently than most solar vendors say you need to. (By the way, my roof is pitched at about 20 degrees, which is pretty normal for this area.) The whole job took about 30 minutes for my 12 panel system.
My SolarGuard monitoring reported an 8% increase in output on Friday. Weather was nearly identical (and perfect) on both days, so I think the entire amount of increase was due to the washing, not weather or temperature.
If I can maintain this enhanced production, it will generate about $50-70/year in extra energy.
You can buy the pole and pad at a home improvement store for about $40 and it will pay for itself in less than a year.
1 comment:
Facilities engineers at Google have done a very thorough analysis of the effect of dust on their solar PV system. They found that in only 15 months the output of the horizontally mounted panels was cut IN HALF because they had not been cleaned. See http://googleblog.blogspot.com/2009/07/should-you-spring-clean-your-solar.html for details.
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