Will dirt/dust diminish output?

[LenCuff]

I've got PV panels laying almost flat on a garage roof. Works well but looking at them today I've noticed dirt/dust at the edges.
Is it best to hose the dirt off or doesn't it make any difference? New to all of this as I've had themjust over a month. There is a small angle on the panels to allow rain to drain off.

 

[johnb2713]

Yes it will make a difference, clean them if you can, take care not to damage them.

 

[LenCuff]

Yes it will make a difference, clean them if you can, take care not to damage them.

Thanks, I'll give them a quick spray with the hose to get the dirt off and then keep an eye on them.

 

[binky]

I have a very similar array. In theory it will output 90% of perfect pitch due south array, in reality it gathers bird poo, dust, and leaves, so does benefit from regular cleaning.

 

[LenCuff]

I have a very similar array. In theory it will output 90% of perfect pitch due south array, in reality it gathers bird poo, dust, and leaves, so does benefit from regular cleaning.

As they are easy to get to I've just given them a quick spray with the hose and see what tomorrow's generation is!

 

[binky]

I use a window cleaning pole, wet the panels, use the pole to move stuck on dirt and rinse. Mine are 10 years old now, so algae tends to build up on the panel edges, which hosing doesn't move on it's own.

 

[Murdoch]

I noticed yesterday that our PV output at noon is running at about 60% which is odd given the clear sunny days

from the ground they do appear to have sand or dust on them. Would this explain the drop off of the output?

 

[Murdoch]

According to the BBC weather tonight at 10.30 “Sahara” sand blocked out the sun to some extent today

so maybe it’s both of these factors

 

[simonstroud1970]

Seeing similar, my 4kW array is only peaking at 3kW over the last few days. It's only been up 6 months, should I be concerned? Is it a time of year thing?

 

[Murdoch]

Seeing similar, my 4kW array is only peaking at 3kW over the last few days. It's only been up 6 months, should I be concerned? Is it a time of year thing?

Not sure TBH - I only noticed it because I looked at the PV monitor when I popped in yesterday lunchtime

 

[binky]

According to the BBC weather tonight at 10.30 “Sahara” sand blocked out the sun to some extent today

so maybe it’s both of these factors

The most annoying thing is when it rains and deposits even more Saharan sand on the panels .

Down yer in the SW , there's been a lot of high level thin cloud, plus the dust, plus the sun is a little lower in the sky, which all adds up to lower outputs despite the heat.

 

[offgridAndy]

Heat can “severely reduce” the ability of solar panels to produce power, according to CED Greentech, a solar equipment supplier in the United States.
Depending on where they’re installed, hot temperatures can reduce the output efficiency of solar panels by 10%-25%, the company says.
According to the American renewable energy website EnergySage, solar panels are tested at 25°C (77°F) and generally have a temperature range of between 15°C and 35°C. Solar cells – the electronic devices that convert sunlight into electricity that are connected together to build solar panels – produce solar power most efficiently within this range.
But solar panels can get as hot as 65°C (149°F), EnergySage says. This can affect the efficiency of solar cells.

 

[johnb2713]

Seeing similar, my 4kW array is only peaking at 3kW over the last few days. It's only been up 6 months, should I be concerned? Is it a time of year thing?

Temperature may be a factor in this, my panels peform much better when it's cooler but clear skies. Moisture in the atmosphere can also absorb some of the solar energy. What sort of peak reading have you had before?

 

[Oldman22]

https://www.walesonline.co.uk/news/wales-news/saharan-dust-plume-forecast-uk-27653350 Its across the UK so dont expect good numbers this week.

 

[Murdoch]

2.42 kwh peak today with full sun out of our 4 kwh system.

 

[binky]

Heat can “severely reduce” the ability of solar panels to produce power, according to CED Greentech, a solar equipment supplier in the United States.
Depending on where they’re installed, hot temperatures can reduce the output efficiency of solar panels by 10%-25%, the company says.
According to the American renewable energy website EnergySage, solar panels are tested at 25°C (77°F) and generally have a temperature range of between 15°C and 35°C. Solar cells – the electronic devices that convert sunlight into electricity that are connected together to build solar panels – produce solar power most efficiently within this range.
But solar panels can get as hot as 65°C (149°F), EnergySage says. This can affect the efficiency of solar cells.

it's called heat saturation. Wedon;t get much of that in the UK, but the current hot spell is likely to see the panels get too hot. The only panels which don't suffer from this is Panasonic, which is hybrid amorphous thin film silicone combined with silicone wafers, but you don't see those very much anymore, and they are relatively expensive.

 

[Kot]

Seeing similar, my 4kW array is only peaking at 3kW over the last few days. It's only been up 6 months, should I be concerned? Is it a time of year thing?

And soon it will be winter lol here is a good description of irradiance etc https://ratedpower.com/blog/solar-i...tion is the process by,area, measured in W/m2

 

[wc1966]

Pretty certain the heat this week has been reducing output a bit, my panels have been hitting 55c.

That said there’s been so much solar this week it doesn’t matter, been averaging 40kwh gen per day off 8kw / 5kw inverter

The dust will soon wash off when usual weather resumes. Think a good clean a couple of times a year has to be a good idea, once you get lichen on panels you’ll struggle to shift it.