[EandM]

Three months ago I cleaned 66 solar panels at a farm near me. The panels are away from any road and have to be accessed by driving across a field. The field is marshy and seems to create a low dust atmosphere. Panels are fixed at a fairly steep angle.
I was interested in the results of the clean as the panels were monitored in real time via on online setup. The panels I cleaned made up one third of the entire system with the monitoring being split into 3 zones with 66 panels in each, meaning that we could accurately measure the before and after outputs of all zones and compare the relative differences. Prior to cleaning, the panels had been installed for about 18 months and had not been cleaned in that time.
The results are in:
The percentage difference between the clean zone and the other two uncleaned zones as accurately measure was: 0%
We have some theories as to why this is but I'd welcome you're thoughts...

[AuRavelling79]

Are the panels "self cleaning" faces?

Does the fact that we had a lot of rain up until 3 months ago mean that there was an element of self cleaning?

Is the measuring accurate?

[Moderator David@stives]

I refer you to googles research

[telfordwindowclnr]

Did the panels look dirty?

[EandM]

The panels were dusty and cleaning them did add some lustre. The output measuring seems accurate enough, the customer is of a scientific background and seems to understand the whole setup. The panels are monitored and results are available on line, in real time - and linked to this are two neighboring farms with their own panel setup. One of these setups was cleaned at a similar time and the resulting output increase was 30% - speculation is that those panels were cited at a shallow angle on a barn roof, overlooking a courtyard where vehicles regularly drive through, many of which are tractors, carrying hay, straw etc and Molasses Animal feed is present at the location. Due to this combination the panels had a sticky residue with a substantial dust covering and caused a marked decrease in output. Presumably then a domestic setup on a house roof and near a road would see a considerable drop in efficiency due to it's location and immediate environmental factors whereas the setup I cleaned is largely self cleaning ?

[Smudger]

Are you going to clean them again or is the owner going to use the guy who got 30% increase ....   


Darran

[telfordwindowclnr]

The panels were dusty and cleaning them did add some lustre. The output measuring seems accurate enough, the customer is of a scientific background and seems to understand the whole setup. The panels are monitored and results are available on line, in real time - and linked to this are two neighboring farms with their own panel setup. One of these setups was cleaned at a similar time and the resulting output increase was 30% - speculation is that those panels were cited at a shallow angle on a barn roof, overlooking a courtyard where vehicles regularly drive through, many of which are tractors, carrying hay, straw etc and Molasses Animal feed is present at the location. Due to this combination the panels had a sticky residue with a substantial dust covering and caused a marked decrease in output. Presumably then a domestic setup on a house roof and near a road would see a considerable drop in efficiency due to it's location and immediate environmental factors whereas the setup I cleaned is largely self cleaning ?

Something is amiss here I'm afraid.  If the panels looked dirty and you cleaned them, they definitely would have increased in generation.

[EandM]

The panels were dusty and cleaning them did add some lustre. The output measuring seems accurate enough, the customer is of a scientific background and seems to understand the whole setup. The panels are monitored and results are available on line, in real time - and linked to this are two neighboring farms with their own panel setup. One of these setups was cleaned at a similar time and the resulting output increase was 30% - speculation is that those panels were cited at a shallow angle on a barn roof, overlooking a courtyard where vehicles regularly drive through, many of which are tractors, carrying hay, straw etc and Molasses Animal feed is present at the location. Due to this combination the panels had a sticky residue with a substantial dust covering and caused a marked decrease in output. Presumably then a domestic setup on a house roof and near a road would see a considerable drop in efficiency due to it's location and immediate environmental factors whereas the setup I cleaned is largely self cleaning ?

Something is amiss here I'm afraid.  If the panels looked dirty and you cleaned them, they definitely would have increased in generation.

Could be that the rain really is keeping them clean and therefore the amount of dirt is negligible and / or not increasing. There are no nearby sources of contamination and as I mentioned the ground around them is fairly wet which should largely eliminate excessive dust. Apparently the he wanted the panels in the field nearest the road but the planners refused so the current location is more chance than anything else. On Friday I cleaned another 15 panels that he has above the stables. These were filthy as they'd been mucking out so it will be interesting to see if anythings changed in the next three months.