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What should I expect of my solar array during the winter?


We all love to look at our solar array production via the handy online applications on our smartphones. But be forewarned: you may drive yourself crazy if you are expecting “normal” production during the Michigan Winters. That is because the Earth has tilted us away from the sun.
In the winter (November through February +/-) the sun’s rays have to penetrate the atmosphere at an increased angle, thus rays go through more atmosphere – dropping solar production significantly. The Earth’s tilt also means the days are shorter and the average hours of sunlight are decreased. Add in the thicker cloud cover on a high number of days per month and it is understandable how Michigan solar arrays only make 10-15% of the annual production over the entire four months of winter.
There are some winter days your array won’t even turn on. Many other days the array just appears to be flaky on your monitoring application. Don’t worry – this is all normal. When we size an array – all of that is taken into consideration. It is normal!
After a large snowfall, brush off and expose a portion of each panel. The panels will begin to produce energy and warm up melting the rest of the snow off the panels. For large or roof-mounted arrays you may want to use a roof snow broom/rake to remove the snow. If the roof rake has a metal end, duct tape a towel around it to protect the glass on the solar panels so they don’t get scratched or cracked when removing the snow. There are also telescoping snow brooms available online that auto dealers use to brush snow off cars that won’t scratch your solar panels.
* Note: Solar panels work best when they are cold.
So, if a period of very cold weather is expected, you will see a large benefit from removing any snow from the panels to maximize your energy production. The best hourly production you will have all year is when it is at or below zero!

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