Solar Panel Question

Here in WNY we have had several solar farms installed. It is my understanding that they don't generate anything when snow covered. That they have to have the snow swept or shoveled off half of each panel and then they make enough heat to melt the rest. My question, while they are melting the snow off the uncleared half panel, do they make any electricity?

Not trying to start a discussion on the economics behind solar power. I just want to know if they generate anything while melting the snow. I do know they are becoming more efficient in low sunlight areas, like WNY.

Bill

I'm pretty sure they generate some power when there is snow on them, anyone that built snow forts knows that sunlight penetrated snow! I also understand that the panels are more efficient the colder it is. Also in the winter when the sun is at a low angle the panels should be more vertical so the snow may slide off. Our friends in N MN adjust the angle of their panels about 3 times a year, and this winter they didn't have much snow.

My panels are for heating the house. Cool air in and 90 degree air out. I have them next to my porch. The ground is sloped and I will need to remove some dirt this summer so that the snow can slide off the panels. The one end is just too close to the ground. Light dry snow will clear by it's self but the wet stuff will stick to them. If I run my hand along the panels, to remove the snow from the lower half, the upper half will clear by itself.

The act of the solar photovoltaic power generation does not produce heat.
Clearing some of the snow off exposes the panels darkness to the sun allowing the heat of the sun to warm the panel and eventually melt the rest of the snow.

No different than clearing a patch of snow off of a black roof.

I live in the west Michigan snow belt and yes they do produce power when covered by snow. It's not uncommon for us to get a foot and a half of snow in one fall. With the panels in their winter position (nearly vertical) they don't accumulate more than 3 or 4 inches on them no matter how much snow falls. I often check the meter to see how much current I get before and after brushing them off. My system can generate over 90 amps @ 12VDC but with snow on them I typically see about 16 amps. provided it's a sunny day. With clouds or haze it can be even less, rarely is it ever zero. When our battery bank was nearing the end of it's life span I would brush them off because it was more like trying to charge a capacitor than a battery. With the new batteries we bought last summer I don't bother because I usually have plenty of reserve charge, so I just wait for them to shed on there own.

Electrons belong to whomever can capture them!
JD

I drive by a number of them regularly. I have yet to see any snow on them for more than a few hours and have yet to see anyone brushing them off. Maybe they go out before daylight in order to not miss a minute of sun, LOL.

A few years back I went to Martha's vineyard. At one of the restrooms was a small solar panel set up. They show the KW-HR it produced in the past 15 years. I've lost all my pics in my phone. I can tell you no way would it pay the interest on the loan which the electricity it produced. Martha's vineyard has a lot of foggy days. I think there's a lot of SNOW too.
George

Hey there Bill, good questions, here's my opinion based on my experience having used several different makes n models of solar panels over many years:

My question, while they are melting the snow off the uncleared half panel, do they make any electricity?

1) YES depending on the snow and its depth, a solar panel could still produce some degree albeit less, of electricity if partially or fully snow covered. Obviously a dusting is different from a 6 inch covering as if 10% versus 50% is covered. As an example, mine (RV roof mounted) still produce electricity if I'm parked under a full shade cover although not near as much as if I'm parked in bright sunlight. Similar if extremely dirt and dust covered they don't produce as much as if bright n clean, and like almost none at night DUH.

2) Similar, a partial shaded panel obviously cant produce the electricity of one in the clear

3) As far as any heat to melt snow, if a panel is only rated at say 100 Watts to begin with and considering the large surface area coupled with the fact its colddddddddddd outside, much of any heat generated will be transferred to the surroundings IE I don't anticipate very much snow melt caused by the panels operation alone....

NOTE This is my opinion (others may have different opinions) based on personal experience, I have no specs or hard scientific or test data to back it up. If one has the time to dig and research Im sure they could provide more detailed technical information, maybe some fine gentleman here could provide such for you......

Best wishes and God Bless

John T

I wonder how they do with a thick coating of pollen. I have to hose my car every morning if I want to see out the windows. TDF

I read an article about solar cell safety for emergency responders. It stated that moonlight can produce life threatening voltage to responders. So I would think snow covering would still produce power,but less. joe

Jimmydog, If I read your post correctly, snow covered panels produce about 1/5 as much as clear panels. That sounds about right to me. I've a friend is AL who has panels.... no snow but lots of pine pollen. I'll check with him on that. He can operate off the grid for over 24 hours and readily admits he will never see a break even on his investment. The solar farms they are putting in here have a life span of 25 years, I'll bet there in nothing budgeted for disposal.

Bill, yes about 15-20%. Some one mentioned moon shine (not the good stuff either) and I've seen it happen under just the right conditions; clear panels, full moon, and snow on the ground, and I'll see 1 or 2 amps. Not much at all really, but kind of cool.

I could see where pollen would become a problem, might have to wash them from time to time. Me, I've never washed the panels, I have seen the wife do it a couple times over the years but I let nature take care of cleaning them. Not sure what motivates the wife?

ROI wasn't a consideration when I went solar, in fact I kind of fell into it backwards. It's a long story so I won't boor you; but at the time I put my first system in I figured I was spending 11 times as much per Kw (ouch!). When I updated to the system I have now that rate dropped to 3x. With prices as they are now I think it's close to even with grid supplied. Thing about cost comparisons are that system cost is fixed once it's installed but who knows what electricity will sell for in twenty or thirty years? Which brings me to the last point.

I'd bet that decommissioning costs are already figured into the project if it's bonified utility company. It's just normal operating protocol as I understand it. But I could be wrong. The thing about 25 year life span is that panels don't just stop working at the end of their warrantied life time, they just don't out put as much as when their new. So it's quite possible that even after twenty years the powers to be (pun intended) might decide to keep them on line longer depending on what conditions are in the future. As for what to do with them after they're retired? I suspect just like lead acid batteries and aluminum somebody will figure out a way to efficiently recycle them by then. Hope I'm around to say I told you so!

Anyway, nice chatting with you.
JD