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Do I need to clean my solar panels to maintain efficiency?

Posted by Chris Rudge on 17 November 2011 at 7:33 am

Q: Research seems to suggest that solar PV panels are not especially durable and suffer from failure. Even if they lasted 25 years of time (and I have not seen one company offering the domestic user anything like that length of guarantee), I have read that they deteriorate in efficiency and need constant cleaning otherwise the output declines significantly. Is this correct? If so, how practical is it for a householder to access the roof to actually clean these panels?

A: Durability and quality, plus of course consistant output of any PV module depends on build quality. On the whole though, unless buying cheap far eastern products with strange brand names, solar PV modules will degrade in output by circa 1% a year. This is the case with most crystalline technology (different with thin film though, which is largely unused in the UK).

The key in choosing PV modules will be check out the data sheet and search online for reports on the product. Good installers will only provide products they know will last the distance, as they are ones to be called back at times of failure.

Regarding cleaning, this is indeed an issue in Southern Europe, North Africa, etc, where the rainfall is quite low and airborne dust high. A layer of dust will build up on the modules causing a drop off in generation. Luckily for us in the UK, we have a good supply of rainfall, just about all year round  at regular intervals. The rain will bring the modules' self-cleaning properties into play, and a good shower will even remove bird droppings. A layer of light dust deposited in most dry periods in the summer will have a negligable effect on generation.

A few of our customers have felt the need to wash their modules this summer, and have reported hardly any change at all in generation after the process.

More information about maintaining solar panels from YouGen

How to keep your solar panels clean

How should I deal with snow on my PV modules?

Why don't PV panels work so well in the heat?

Solar PV information page

Picture by Patrick Feller

About the author: Chris Rudge is a qualified electrician who specialises in renewable energy.

If you have a question about anything in the above blog, please ask it in the comments section below.

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Comments

5 comments - read them below or add one

Clear Nano

Clear NanoComment left on: 19 November 2014 at 8:37 pm

http://www.clearnano.co.uk

 

If you are looking at getting your panels cleaned then look at our product, it keeps your panels clean for a gurenteed 5 years and cost the same as a single clean.

 

 

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Cathy Debenham

Cathy DebenhamComment left on: 30 April 2013 at 4:31 pm

Thanks Sunnyboy - good to hear the results of your labour. I wish mine were more easily accessible.

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Sunnyboy

SunnyboyComment left on: 30 April 2013 at 1:44 pm

I had 9 solar panels installed 2 years ago and have relied on the rain to clean them. Today is sunny with no clouds and at 1pm the panels were generating 1012 watts. I took a bucket of water with just a small squirt of washing up liquid and wiped over the panels [mine are on a flat roof] then dried them. The output had increqased to 1510 watts in the 15 minutes it took to clean them. The water was dirty! So it does pay to clean!

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Explore Solar

Explore SolarComment left on: 5 January 2012 at 2:37 pm

Companies are adding this to the service.

http;//www.exploresolar.co.uk

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Icarus

IcarusComment left on: 23 November 2011 at 10:59 am

I'm amazed that entrepreneurial window cleaners aren't adding this to their services. My man looked bewildered and had no idea of costs or potential.http://www.solarpowerdiary.co.uk/2011/06/pv-panels-and-window-cleaner.html

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