In many countries, solar panels face the realities of northern climates - snow. Snow covers things, including solar panels. The thing about solar panels is that they cannot function when they are covered up. It is their uncovered space that is what absorbs the energy of the sun.
If you have rooftop solar panels, mounted on your barn or house roof, snow will accumulate just as it does on any other roof. The steeper the roof, the more likely the snow is to slide off. If your slope is less steep, you might not have use of your panels in the winter (although with a long broom and a ladder, you might be able to keep them partially clear most of the winter).
Even if your roof is quite steep, the snow might not always slide off or it might take many days before it does - depending on the temperature. Solar panels are generally black, so they absorb the sun's heat and melt the snow, but if the snow is thick enough on them, the sun won't get through and no black surface will be created. Yes, that is why a ladder and broom to at least clear part of the panels is worthwhile - if you can safely mount a ladder in winter.
Uneven patterns of snow falling and melting means that you might find your rooftop panels generating power for only part of the winter.
With ground-mounted solar panels and a pivot-and-swivel tracking system, you *should* never have to worry about snow. Of course, "should" and "reality" often disagree on the details.
Our installation has this little tray that detects when snow is accumulating on it. When snow weighs it down, it sends a signal to the position controls to raise the panels to their most upright position. The snow would of course slide right off the panels.
But reality doesn't quite cooperate.
Snow sometimes falls and sticks and even at their most upright position, sometimes more than an inch of snow will stubbornly stick.
In theory, the sun will melt the snow and before long it will slide off. But with no black surface to absorb the sun's rays, on a cold day, you could easily miss two-thirds of your generating hours before the panels start to clear. Imagine also if the panels are already upright and facing the west from the previous night's sunset, and snow covers them in the night. The sun won't even shine on them directly until the afternoon.
Snow could stick to the panels for a couple days, even fairly sunny days. That is a fair amount of earning power lost to snow.
So get out there armed with a long-handled broom and an ice scraper (one you would use on your car windshield. If you get most of the snow off the panels, the sun will shine through. Even with an inch of snow, the sun shines through a bit. If you can remove most of the snow, a thin layer of ice will let much of the sun's radiation through, and provide a somewhat black surface to help melt what is left. A long-handled broom (and maybe a step stool) can help you reach most of the panels. The ice scraper can be used on the lower panels to help break through the ice faster. The result could be an extra day or two of earning power.
A broom is a worthwhile investment.
David Leonhardt recently installed solar panels and is learning the ropes. Before you invest in solar power generation, read his " solar Ontario " blog. For instance, learn what a kilowatt hour actually is.
