Minnesota winters are long, cold, and dark, and they don't seem to be the best when it comes to saving electricity. However, industry experts agree that even with shorter days, solar power can still be a cost-effective system for residential, commercial, and industrial customers.
The amount of sunlight that reaches the Earth in Minnesota varies seasonally. During the summer solstice in June, the state sees about 15 to 16 hours of sunlight, while during the winter solstice in December, Minnesotans see only eight to nine hours of daylight.
In a situation where both solar energy and cost are rapidly increasing, it is worth considering how short days can affect solar energy. But according to Logan O'Grady, executive director of the Minnesota Solar Industries Association, that's less than expected.
"Do we have sun like Florida?" O'Grady asked rhetorically. "We don't have that many, but in terms of sunny days and hours of sunlight, we're comparable to other states in the South."
Although the National Weather Service no longer tracks the amount of sunlight at its stations during any given time period, a 2004 report from the National Oceanic and Atmospheric Administration (NOAA) reported the percentage of possible sunlight readings in major US cities.
To achieve 100% on the NOAA report, a city must experience almost no cloud cover during the day. According to the report, in the five decades ending in 2004, Minneapolis received 58% more sunlight, compared to cities like Atlanta and Houston. Yuma, Arizona, topped the report with 90%, while Juneau, Alaska ranked last with 30%.
Because southern U.S. cities have more winter days than northern cities, the percentages do not reflect the actual amount of sunlight.
"Certainly, Minnesota isn't the sunniest state in the Union, but we're certainly not the darkest," O'Grady said. "Just because it's cloudy or dark doesn't mean the system won't do well at any time of the year."
In addition to the amount of sunlight in the state, O'Grady said cooler temperatures make solar panels more efficient.
"One thing people don't realize is that winter is good for the sun," he said. "In fact, it's better to keep the panels cool, to keep the infrastructure cool under the panels. It transfers power more efficiently and with less loss."
Most solar companies agree that solar panels are less efficient at temperatures above 27 degrees because energy can flow more freely without overheating.
Whether it's snow, ice, or trees, O'Grady recommends keeping solar panels away from anything that could block sunlight from reaching the array.
"It's very rare that [solar panels] don't work," O'Grady said.
In 2021, solar energy will account for about 3.2% of all electricity generated in Minnesota, enough to power 200,000 homes for a year. Industry experts predict growth in both production and consumption in the coming years.
