solar in the snow


I am in the midst of researching information for a house my Dh and I plan to build in Northern Idaho in a few years. Because it is likely we will not have municipal utilities available and I would prefer to avoid fossil fuels as much as possible, I am on a solar research quest. I have read quite a bit of infomation and it was suggested to me to look here. Having lived in coastal Southern California my entire life, I understand the theory of how solar works and the more I read, the more I wonder why it is not used more extensively here. The area seems perfect for solar energy.

In Idaho however, there is snow and cloudy days and winter is long and cold and snowy and I do not understand how solar can work under such conditions. I have spent a few hours reading the archives as related to this concern and what I have discovered is that one arranges the panels so they can be bursh clear of snow.

That's it?!? Is that how it works??? To use solar in a place with lots of snow, one much be able to brush the accumulated snow from the panels???? If that is the case, then I presume that the panels are not mountedon the roof.

I have gathered information from the area in which we intend to move from various sources and it looks like it would cost approximately 15k to set up a system from the ground up when we build the house. That is certainly preferable to the 90K+ for bringing in electrical power to the acreage we are considering. I like the idea of not being dependent upon a grid system and I love the concept of conservation oand stewardship to the earth - I also like lights int he house as well.

What's the catch - how does solar work in the snow under non-sunny conditions? I don't get it. :?


  • rplarryrplarry Solar Expert Posts: 203 ✭✭✭✭✭
    Re: solar in the snow

    Solar doesn't work worth a poop when there is no sun, thats why most people have back up generators, either wind, water or fossil fuel. When the sun is out then it is great, and when it is cold the pv's put out even more. You'll be happy that you set up an off grid house.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: solar in the snow

    $15k is a good start for you and you may wish to expand upon it later so deseign with possible expansion in mind. this will save you troubles later. batteries are a sticky subject in expansion though and i hope you've read about all of this in the forum too.
    anyhow, on the subject of snow, it is a thorn in our sides for those of us that deal with it. we do like to have it tilted more to allow the snow to not accumulate as well or as fast. pvs are darker in color too so when the sun hits it the heat melts the snow a bit faster than other surfaces. in the most stubborn cases we have to either brush it off as you've mentioned or let it lie there. i don't recommend that heavy amounts of snow (measured in feet) be allowed to stay on the pvs very long because of the added weight. this is true of the roof surface as well and yes we are talking of roof mounted pvs too. nobody said nothing difficult would ever be easy. the bottom line is that no sun = no power no matter the cause of no sun.
  • System2System2 Posts: 6,290 admin
    Re: solar in the snow

    I've played around a bit with mine. So far, they are at the Summer cottage, but eventually will be moved to the house. I have GE 110 watt panels. What I've found:
    1) the PV is made up of 2 series strings, running the long way (length) of the PV, so, mount them on their side and as the snow slides down, it uncovers the (now) top string and you get half power, until the whole thing is clear. Mounted lengthwise up and down, and you get nothing until the whole PV is clear.
    2) Here in Nova Scotia, with snow on the ground and the sun shining, I get excellent results with the PV's mounted straight up at 90*. The sun hits them along with the reflected sun off the snow, AND best of all, the snow doesn't stick for long, if at all, on a vertical surface. (depends on snow conditions)
    3) Only on heavy overcast days do I get no power at all. There are lots of brighter cloudy days that still produce a fair amount of power that helps to keep things going. Granted, it's not the power of a bright sunny day, but that's why I have more PV's than I would need if the sun was on them every day.
    I'm still trying things, still learning and will never know it all, not in this life.
    Cheers Wayne
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: solar in the snow

    you would do better to have them angled some as you will still get the reflected light off of the snow even with say 70 or 80 degrees instead of your 90 degrees. this will give you the better angle on the direct sunlight while still allowing the reflected light at an ok angle and letting the snow slide off too. this assumes it's aimed southerly as pvs aimed too much towards the east or west will get nothing but the reflected and ambient light in the dead of winter.
  • System2System2 Posts: 6,290 admin
    Re: solar in the snow

    Yeah, what you say makes sense, it's just that I was playing around with my amp meter on them and found little if any difference between 90and 70 or 80. In fact I was surprised that the output didn't really drop at 90*. But this was done during the shortest days of Winter, when the sun was at it's lowest on the horizon and that angle would NOT be good during late Winter, or any other time of year. Also remember that I'm north of the USA, so the sun is lower in Winter, except for Alaska of course.
  • nielniel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: solar in the snow

    yes the sun is a few degrees lower to the horizon there than where i'm at, but do realize that i'm not in the south as the canada is about 150 miles north of me. you are right that at winters peak or antipeak for the the sun is the lowest point the sun shall be and is higher before and after that point. that means you may have to change to an angle other than 90 before or after that point with adverse weather possibilities.
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