Everything Solar Forum

Is it a good idea to clean (or hire someone to clean) solar PV panels that have been in place for about 12 years in Washington DC?

------------------------------
Richard Reis
Owner
Charles Village Homes LLC
------------------------------

Unless you are in a very, very arid climate and dusty, rain usually does the trick...

A good T-storm cleans off most anything...

------------------------------
william fitch
Owner
www.WeAreSolar.com
------------------------------

It depends on your situation.?? At our church we have panels that have
been installed for 6 years and we have noticed that the out put has been
going down significantly?? over the years. We noticed that they looked
dirty.?? Finally we did some cleaning of a few and found that we were
loosing between 20 and 30% of production.?? Then we got serious and
realized that on some panels we were loosing as much as 85% in the
really dirty panels compared to nearby clean ones. And we are finding
that it is not a trivial chore to really get them clean.?? We have
decided that in our environment once we get them clean we will need to
scrub them at least once a year.

Likely not.  I live in NE Tennessee not a very different climate.  My solar has been on for over 11 years now.  There is an array I can easily reach and one that is hard to get to.  Once I cleaned the easy to reach array and comparing to the string that was not cleaned my production dropped, slightly but it dropped.  It was not pure apples to apples as the tilt and azimuth are slightly different.   Then about two years ago my wife wanted the skylights cleaned so I did a deep cleaning of all panels.  This time I used a site 3 miles away at a similar tilt and azimuth.  Again against the control my production dropped a small 3% as I was out producing 106% and after cleaning 103%.  So I have given up on cleaning and let the rain do its job. 

------------------------------
David Hrivnak
SalesEngineering
EcoLogical part time
------------------------------

It depends on whether your array might collect the occasional dust/dirt that will wash off with periodic rain and snow or if you experience the more problematic pollen that some locations get. Pollen does not easily rinse off. A close up inspection of your array will let you know what you are dealing with. Dirt/dust can easily be removed with a little water and can be confirmed by wiping away the debris with your finger. Pollen will not come off easily. Pollen will take some pre-wetting and then physical action with a broom followed by another rinse. I DO NOT recommend using a pressure washer or any other method that might deliver a lot of force through the front side glass into the more fragile silicon cells underneath. 

------------------------------
Rich Stromberg
ESS Prog Dir / PhD Student
Equitable Solar Solutions / Univ of Alaska Fairbanks
Colorado
------------------------------

I live in northern Delaware and have had an array on my roof for 17 years. I have never cleaned them and my output is degrading annually about 0.45% which is better than expected. So no evidence that they would benefit from a cleaning. Every few years I go up and inspect them and nothing obvious. The only time I have considered it is in the spring when there is a lot of evergreen tree pollen (really bright neon green stuff) which will coat the modules until the next thunderstorm. 

Steve 

------------------------------
Steven Hegedus
Professor and Senior Scientist
University of Delaware
Newark Delaware
------------------------------

Original Message:
Sent: 04-30-2024 11:12 AM
From: Richard Strömberg
Subject: Cleaning panels

It depends on whether your array might collect the occasional dust/dirt that will wash off with periodic rain and snow or if you experience the more problematic pollen that some locations get. Pollen does not easily rinse off. A close up inspection of your array will let you know what you are dealing with. Dirt/dust can easily be removed with a little water and can be confirmed by wiping away the debris with your finger. Pollen will not come off easily. Pollen will take some pre-wetting and then physical action with a broom followed by another rinse. I DO NOT recommend using a pressure washer or any other method that might deliver a lot of force through the front side glass into the more fragile silicon cells underneath. 

------------------------------
Rich Stromberg
ESS Prog Dir / PhD Student
Equitable Solar Solutions / Univ of Alaska Fairbanks
Colorado
------------------------------