Snow on solar panels slices production

solar-panels-snow1A quick winter tip for your home solar system: If you get a dusting of snow, you might want to get up on your roof and sweep the snow off your panels.

I’m sure wishing I’d done that today.

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Last night (Nov. 9, 2010), about one inch of snow fell here in the Denver area.

The snow stuck beautifully to all the three branches – and to our solar system.

When I left the house this morning, I figured a very sunny day would quickly melt the snow off the panels.

Five hours of sun to melt one inch of snow
I was wrong. It took until about 2 p.m. this afternoon for the snow to melt off, even on an almost completely sunny, 40-degree Colorado day, and even on our fully south-facing, un-shaded roof.

We lost nearly 20 kWh of power production thanks to this dusting of snow. That’s 80 miles in an electric car, or about $12 worth of “gasoline” at $3 per gallon and 20 m.p.g.

I’m sure it would have melted off much more quickly if I’d scooted up on the roof and swept it off – being very careful, of course, not to break my neck and not to damage the panels (I’m assuming, hopefully correctly, that a nylon brush broom won’t damage the panels).

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I had no idea it would take five hours to melt the snow off of our 26 solar panels on a bright, sunny Colorado day.

Now that I know how much of a hit snow can make on our 5.59 kW system’s production and how long it can take for even a tiny bit of snow to melt on a sunny day, I’ll be up on the roof after every snow dusting brushing things off – and, once again, being very careful when I do it.

While it’s frustrating that we lost about 20 kWh of energy we could have produced today, it’s definitely not worth breaking an arm – or worse – over.

The plan now:

  1. Check the weather forecast.
  2. If a dusting of snow is going to be followed by a sunny day, get up there and brush it off.
  3. If it’s more than a dusting, and several gray days are forecast, I might wait. Then again, I might just be too impatient to wait.

Solar snow experts who have experience with the home solar system/snow dilemma: What do you do?

Other articles about snow & solar systems on the web–>

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