[8weekly]

It doesn't load on my ipad.

[telfordwindowclnr]

A 10% loss per year on that site equates to over £20,000.

You don't need to get into complicated maths, to realize its worth while to get them cleaned every 26 weeks.

Hi Alex. You are right. For what the array produces, cleaning is awesome value.  

[telfordwindowclnr]

It doesn't load on my ipad.

It just loaded on mine. 

[Dave Willis]

A 10% loss per year on that site equates to over £20,000.

You don't need to get into complicated maths, to realize its worth while to get them cleaned every 26 weeks.

Hi Alex. You are right. For what the array produces, cleaning is awesome value.  

That's true, but who says it's losing 10%? How is it known? How long does it stay clean? How can it be measured?

[ben M]

you can be proud of yourself steve, very well done mate 

[Alex Wingrove]

A 10% loss per year on that site equates to over £20,000.

You don't need to get into complicated maths, to realize its worth while to get them cleaned every 26 weeks.

Hi Alex. You are right. For what the array produces, cleaning is awesome value.  

That's true, but who says it's losing 10%? How is it known? How long does it stay clean? How can it be measured?

Every 60-120 panels is attached to an inverter, these inverters keep logs, from there its very easy to see, the average hourly output, and then daily, seasonal etc,

For a site this large, you will notice a increase that very day its cleaned. So assuming the weather doesn't go from bright sunshine, to thunderstorm, in the space of 8 hours, you will see an accurate figure

From past experience 10% is a very low average figure, I would be inclined to say between 12-14% increase after cleaning. Ive cleaned sites with over 40% loss.

Also you don't spend £250,000 on monitoring systems, if you haven't got anything to monitor.

Alex

[telfordwindowclnr]

A 10% loss per year on that site equates to over £20,000.

You don't need to get into complicated maths, to realize its worth while to get them cleaned every 26 weeks.

Hi Alex. You are right. For what the array produces, cleaning is awesome value.  

That's true, but who says it's losing 10%? How is it known? How long does it stay clean? How can it be measured?

Hi Dave. I'll try to answer your questions one at a time.

1. 10% at this point is an estimate. Based on experience from other jobs, I know certain parts of the array would have been losing more.
2. The panels under the tree line, will not be clean as the panels in full open sun. As the article states, this is the very first clean on this site, so as yet, we are unsure how long it will stay clean.
3. It can be measured by the monitoring dept at Toyota and British Gas. Both have expensive equipment to measure the performance of the array. This is not, with all due respect, a cheap residential install of a few panels. This cost millions to install. The panels would have been relatively cheap. The monitoring equipment is not. It has been monitored from day 1 until today. I will be sitting down at some point with British Gas and discussing the figures. Believe me, if they are favourable, which I believe they will be, I will be writing another article explaining the real benefits of solar panel cleaning on this specific site.

Do not underestimate these clients. They are no mugs. They are huge, huge companies who do not throw money away. They have whole departments devoted to monitoring. I cannot fool them. Their tech gives them the info, not me.

[telfordwindowclnr]

[ quote author=ben M link=topic=172231.msg1452059#msg1452059 date=1371504223]
you can be proud of yourself steve, very well done mate 
[/quote]
Cheers Ben. 

[spongebob]

So...... how long do you think it will take for the dust to settle again and knock 10% back off the output? About a month I reckon.

bout...........12 weeks, more likely 

That's fine. We are contracted to do it every 6 months.

Steve
Ignore the negative vibes.
If you have a contract thats all that matters. If they decide to not clean them in future they will probably have to pay you to take garden leave anyway.
I like the write up you have put on your link. Milk it for all its worth and ignore anyone who tries to drag you down to their level.
Keep it up

[Tomboler]

So...... how long do you think it will take for the dust to settle again and knock 10% back off the output? About a month I reckon.

bout...........12 weeks, more likely 

That's fine. We are contracted to do it every 6 months.

Steve
Ignore the negative vibes.
If you have a contract thats all that matters. If they decide to not clean them in future they will probably have to pay you to take garden leave anyway.
I like the write up you have put on your link. Milk it for all its worth and ignore anyone who tries to drag you down to their level.
Keep it up

my comment wasn't meant with negative vibes (man) I was just imagining the deal being struck, nice work if you can get it.

also Steve, ideal job for the widest brush possible, which brush do you use ?

[rosskesava]

Good grief.

Well done mate.

I wouldn't bother about all the comments about is it worth it in terms of output and all that stuff. If the customer is happy, that's all that matters.

[robertphil]

leader in your field i would think

[Moderator David@stives]

Research by google says it is not cost effective cleaning solar panels, at least not for them

http://googleblog.blogspot.co.uk/2009/07/should-you-spring-clean-your-solar.html

[Dave Willis]

Negative comments? You halfwits!

That's the very reason I'm asking how it's monitored, how long the clean will last and how these massive companies check the figures. Because no two days are the same it's impossible to get a 100% accurate reading from an inverter.
You can't work out an average - last years would be massively higher - we had a drought right through the spring, wall to wall sunshine, this year has been totally different.
Paint densities on cars can be measured and also ink densities on paper with a densitometer. It may be possible to do something similar in future on a solar panel - maybe reflective light can be measured with a hand held meter.

The figures I've seen so far on peoples websites are wild guesses. Steves estimate is probably one of the lowest I've seen at 10%.

If the figures could be relied on in some way then customers could get a proper figure and see the losses due to dirt and the gains after cleaning.

My own figures on admittedly a much smaller unit show  miniscule gains in productivity after the first year of installation and a covering of dust within a week.

I would expect an increase in productivity on a massive site like that anyway because the days are still getting longer - producing more daylight.

[telfordwindowclnr]

Try leaving your panels for 23 months like this site, then clean them and see if you see an increase. That is the reality of what has happened on Toyota. A 10% loss can cost them thousands every day. For Toyota, it is worth the cleaning.

[Neil Jones]

Well done Steve great job to have. These companies wouldn't have them cleaned if there wasn't a benefit, simple really.
There is also a tool that measure reflectivity, used on hard floors like marble etc

[Dave Willis]

Try leaving your panels for 23 months like this site, then clean them and see if you see an increase. That is the reality of what has happened on Toyota. A 10% loss can cost them thousands every day. For Toyota, it is worth the cleaning.

I agree. It's the methods of measurement that interests me. 10% of my piddly system will be massively different to 16,000 panels.

[bobplum]

its so big it wont load

[jimiwindows]

well done steve it beats doing houses for a tenner

[telfordwindowclnr]

So...... how long do you think it will take for the dust to settle again and knock 10% back off the output? About a month I reckon.

bout...........12 weeks, more likely 

That's fine. We are contracted to do it every 6 months.

Steve
Ignore the negative vibes.
If you have a contract thats all that matters. If they decide to not clean them in future they will probably have to pay you to take garden leave anyway.
I like the write up you have put on your link. Milk it for all its worth and ignore anyone who tries to drag you down to their level.
Keep it up

Cheers spongebob. Spoke to the higher powers at BG today and they are overjoyed with the work.
Some slate what we are doing, I don't bother with them. Some question it, that's fine, I try to answer their questions. If some are interested and even get excited about it, great! If the last group get asked to do such a job, but don't feel they can handle it for whatever reason, hopefully they will recommend me and I will cut them in. But if you don't push the articles and promote a little, no one may ever make a few quid from that job.
Thanks for the encouragement!