Tuesday, May 12, 2009

The Cleaning and Maintenance of PV Panels and System

One thing that is great about a PV System is that it requires almost no work to get the PV energy. Once it is installed, as long as you do not have to shut it down and move it to another side of the house, you should be OK for a long time. Most of the inverters I have seen have a lengthy warrantee. The panels themselves should outlive the longest investment payback. Most of them are guaranteed for twenty years. I know of panels near here that have been in use longer than twenty years, and are still producing close to what they did initially. Of course, in that same time replacement panels have made real gains in power output and efficiencies. Aside from the panel move earlier this year, we have only had one time our system was “down” for any problems, and that was for a simple part replacement for our inverter. That leaves only one real issue that I have been concerned about, cleaning the panels.

At least once a year, your panels could benefit from a good cleaning, especially if you are in an area that has a lot of dust or windblown pollen. This stuff can get stuck to the panels fairly easily, and although a lot of it is washed away by rain that happens in a time of year you are not really thinking much about production. Therefore, at least once a year, you need to think about cleaning the panels. If you are Ed Begley Jr. or otherwise do not have a problem climbing all over your roof at least once a year, or you have relatively easy access to the panels from the ground, you should have no problems doing your own cleaning. If you fear heights, or simply are older than Ed and your days of roof running are or should be over, what are you going to do?

After the first year of so our panels were up, our neighbor volunteered to clean the panels for us. That was great. It only cost us a six-pack. But, that is not the sort of thing we feel right about asking for repeat service the next year, or the next. I have asked a couple of solar installers in the area for their advice. They either say they do not bother cleaning their own panels, so I should not worry about cleaning mine. Or they say I could try a window washer service. I have not called one yet. Usually my experience asking a company to work outside their specified qualifications has not been good. So, when we moved our array recently, I asked the guys on the roof if they would be interested in making a bit extra money cleaning my panels. They seemed to want to do it when they were here. They told me to call them so we could arrange it. I called. I stopped by the place of business and left a message. I called again. I stopped by the place of business again and talked to the manager to ask if it was appropriate for me to ask. He said as far as he knew, it was something they could arrange to do, or if I wanted, I could contact his installer directly to ask him. I asked the manager to have the installer contact me. That was the last I have heard anything from them.

It seems to me there is a growing demand out there, or there could be a growing demand- for a service company that specializes in PV Systems maintenance. I am not quite up to getting up there and cleaning the panels the right way. The guys who could are missing an opportunity. Or, hopefully they are busy putting in more systems and just can’t get back to me. The thing is, it either forces me to live with dirty panels or to try to do it myself. Either way, the panels are not going to be as clean as they should be. And we will lose a certain amount of production. How much, and is it worth worrying about?

It is odd that I now know the answer to this. I have looked on the internet from time to time trying to find out how dirty PV panels impact production. I have not found it. Maybe I did not know the right terms to search for. What is the answer? What is funny about this is that earlier today, I went out to just hose off my panels. I thought that would help a little anyway. But as I said, it is not a complete cleaning, and there is still residual dirt there blocking my production a bit. I will check later to see if I had much gain over previous days.
Just now, I received a letter in the mail from a person who is doing PV system maintenance in our area. I do not know the cost yet, but he does PV panel cleaning, system module maintenance, system performance overall testing, warrantee troubleshooting and repairs, and will install a security system on the modules. This is just what I had been talking about earlier.

Oh, and the answer for how much dirty panels can cost you come from a study done by PV USA in Davis, Ca. They claim that after a dry rainy season dirty panels can impact your performance by as much as 7%. That seems pretty close to what I have seen here actually. Prior to my neighbor cleaning our panels, we were producing a bit over 9 Kilowatt hours a day. After cleaning, our production went up to a bit over 10 kilowatt hours. I guess it would be up to the individual owner to determine how clean is clean enough. And also it depends on the price of the service. I may call for the free estimate anyway.


  1. Hi,

    We have just started a company that specialise in cleaning solar panels.


  2. there is as well a product Solar Cleaner which is sold in Italy and give great result, I think it can be required online at the web address www.ipannellisolari.com

  3. Vip Clean is the exclusive and innovative line dedicated to glass washing systems and photovoltaic and solar panel cleaning. Our machines guarantee deep cleaning of the photovoltaic solar panel without using soaps, detergents or chemical agents which could damage the panels.