Minnesota's largest solar installation begins producing electricity | StarTribune.com
A new system built near Slayton, Minn., with more than 7,000 solar panels is part of the boom in solar installations in Minnesota and across the United States.Flashback: Cold, snow & solar | StarTribune.com
Heavy snows, like the blast that collapsed the Metrodome roof last winter, can cut output dramatically, sometimes to zero. On many arrays, a quirk of the design can halt all electricity production if a portion of the panels is snow-covered, owners say.
"There was a whole week last year when we got dumped with snow and not a single kilowatt was produced from our solar panels," said Seth Nesselhuf of Quality Bicycle Parts, which installed a solar array on its Bloomington headquarters in 2008.
Some homeowners, including the Kubiaks, have purchased long-handled snow rakes with a foam edge to carefully brush away snow from rooftop arrays.
"It's very difficult to use, and I am always nervous that I am going to scratch the glass," said Andy Kubiak, who plans to rake only after the worst snowstorms. "I am just trying to get rid of the bulk, rather than be shut down for days."
Jacò Botha also bought a snow rake to clear the solar panels on his Eagan home. A scientist by training, he calculated that to recoup the $180 he spent on the rake, it would take five winters of raking, assuming he annually saved two weeks of otherwise lost power output.
"It is a lot of work, and if you have a two-story house like I have, you spend a lot of time out in the cold at the end of a very long pole," Botha said. "The conclusion I made after the second winter is that it's not worth the effort."
That benefit can't offset Minnesota's basic problem with winter sun: There's just not enough of it.
For example, the output of the solar array at St. John's Abbey in Collegeville, Minn., peaked last year in July, when daylight typically lasts 14 hours. In the shorter days of December, the output dropped -- by nearly three-fourths.