Clean to Be Greener (cleaning PV panels to maintain output)

Daox · 02-19-15, 09:30 AM

This is a nice quick article from HomePower on the benefits (or lack there of depending on conditions) of cleaning your panels. I'd never have thought that you could loose up to 30% of your power generation from dirty panels!

BACK PAGE BASICS: Clean to Be Greener | Home Power Magazine

Quote:

The newly updated PV energy calculator PVWatts assumes that module soiling can cause a 2% reduction in array energy output—making losses over the array’s lifetime add up. In some locations that are particularly dusty and have little rainfall, losses in dusty or heavily industrial areas could easily be 25% to 30% of the array’s potential output. On the other hand, if you have no local industrial polluters, but have regular rainfall—*and your PV modules are at a steep-enough angle to allow rain to wash down the glass*—the effects of soiling on the system’s output could be minimal, and not worth worrying about.

where2 · 02-19-15, 10:39 PM

I seem to fall into this category: "If you have no local industrial polluters, but have regular rainfall—*and your PV modules are at a steep-enough angle to allow rain to wash down the glass*—the effects of soiling on the system’s output could be minimal, and not worth worrying about. "

I washed 2 of my panels after the first 12 months, and 6 months later you can hardly determine which two I washed looking at daily microinverter outputs. Used a sponge mop on them even... Today was a beautiful solar day, and I collected 1.25kWh from two adjacent panels (one washed, one not). I collected 1.28kWh and 1.27kWh out of two that have never been washed.

Daox · 02-20-15, 08:12 AM

I assume those worst case scenarios are like the picture shown. The panels are completely horizontal, and in a dusty non-windy environment. I wouldn't imagine that there are too many installations like that. Its good to know that under more normal (IMO) conditions, its not an issue.

grad · 07-19-15, 06:01 PM

It is no surprise for me - if you dirty panels, there would be less sunlight going through it.

02-20-15, 08:12 AM	#3
Daox Administrator Join Date: Aug 2008 Location: Germantown, WI Posts: 5,525 Thanks: 1,162 Thanked 374 Times in 305 Posts	I assume those worst case scenarios are like the picture shown. The panels are completely horizontal, and in a dusty non-windy environment. I wouldn't imagine that there are too many installations like that. Its good to know that under more normal (IMO) conditions, its not an issue. __________________ Current project - To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts. & To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.

07-19-15, 06:01 PM	#4
grad Lurking Renovator Join Date: Jul 2015 Location: USA Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	It is no surprise for me - if you dirty panels, there would be less sunlight going through it. __________________ easysolar.co - revolutionizing app for photovoltaic builders!

02-19-15, 10:39 PM	#2
where2 DIY Geek Join Date: Apr 2013 Location: Sunny Florida Posts: 401 Thanks: 74 Thanked 83 Times in 73 Posts	I seem to fall into this category: "If you have no local industrial polluters, but have regular rainfall—and your PV modules are at a steep-enough angle to allow rain to wash down the glass—the effects of soiling on the system’s output could be minimal, and not worth worrying about. " I washed 2 of my panels after the first 12 months, and 6 months later you can hardly determine which two I washed looking at daily microinverter outputs. Used a sponge mop on them even... Today was a beautiful solar day, and I collected 1.25kWh from two adjacent panels (one washed, one not). I collected 1.28kWh and 1.27kWh out of two that have never been washed.