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Does Solar Work in Illinois Winters?

snow over solar panels
Solar works during Illinois winters. Deep snow and shorter days can limit their effectiveness, but panels will still produce power throughout winter. (Photo by Jeffrey Gahris)

Does solar work in winter in Illinois? It’s a common question whether solar panels are effective during the winter months, especially in areas prone to heavy snow and long stretches of cloudy days like Illinois. While it is an understandable assumption that snow, consistent cloud cover and shorter days could make solar ineffective, it is also a myth—in fact, solar power still works during the winter.

Solar panels absorb energy from the sun’s light rather than the sun’s heat, so the temperature outside does not play a factor in the amount of electricity a solar panel is able to generate. With the addition of snow in cold weather states such as Illinois, it is even possible for solar panels to generate more electricity. Snow on the ground and clouds in the sky can reflect sunlight onto solar panels (depending on their angle) and can cause an “albedo effect,” which is essentially the amount of energy reflected by a surface. Light surfaces—like snow or clouds—reflect more energy, which can cause a larger output by solar panels.

Extremely heavy snow and ice does present certain issues for solar panels, but new research is showing that panels without frames around them allow for microcracks in those panels in which the snow is able to melt. For the periods of prolonged cloud cover, less sunlight hours or panels being covered in deep snow, energy storage products become the hero, allowing access to power captured when there was sunlight or no snow covering the panel. Additionally, the tilted angle of many solar panels can also allow for snow to slide off easier, but for some this isn’t always an option. 

DuPage Forest Preserve Commissioner and Wheaton resident Jeff Gahris has his own rooftop solar system, which covers about 75% of his electricity needs, and he subscribes to community solar to ensure the rest of his power usage is renewable as well. His home is a ranch style with a flatter roof than some, so it often takes longer for snow to melt off his panels than some of his neighbors with more pitched roofs . “In winter,” Gahris explained, “you need to be a little patient.”

graph of solar panels output by month from 2016 to present
Jeff Gahris' solar output by month from 2016 to present. Although he sees less output in the winter, his panels still generate power for his home every month of the year. (Screenshot via Jeff Gahris)

Gahris has used solar to power his home since 2016 and has charted the solar output of each month ever since. Although his energy output decreases with shorter days and heavier snow, his panels still generate power throughout the winter, with one February even exceeding 200 kilowatt-hours of production. Peak energy output for Gahris usually sits at around 400 kilowatt-hours in the summer, so this is impressive for mid-winter production. Even when snow is completely covering his panels, he can often get some output, as long as the snow is about an inch deep or less and enough sunlight can penetrate through the snow. Additionally, he sees benefits from the albedo effect on cloudy days, although he does not benefit from snow reflections due to his panels' location.

Solar has served as a very cost-effective solution for Gahris; he stated that after only a few years, his solar panels paid for themselves. When production is decreased in the winter, it is offset by sunny days in the summer when he enjoys energy surpluses as his panels produce well above his daily energy needs.

It is clear: Solar works in winter in Illinois. Even in some of the coldest and snowiest places, solar panels continue to generate clean and renewable energy for many. In time and with further technological advancements in solar power, winter months will continue to present less and less of an issue and allow solar panels to generate even more energy. 


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