Counterintuitive Facts on Solar Energy Production

In states like California, Arizona, or Florida, going solar is a no-brainer, but what most people don’t know is that solar is also a great investment in less sunny states. Actually, one of the world’s leaders in installed solar power, Germany, is not exactly known for its long days of sunshine or its tropical climate. Germany only receives about 150 sunny days out of the year, which is substantially less than the national average of 205 days in the United States. Even the least sunny states in the U.S. like Washington or Oregon get more sun than Germany!

1) Solar works in the rain and cloudy or snowy weather

Solar panel production varies depending on weather, and factors such as rain, snow, hail, or clouds will affect your solar panels’ production. On a clear, sunny day, your solar panels will hit their peak performance. The highest energy production will be when it’s the sunniest, with less production in the morning and afternoon. That being said, solar panels still produce energy during rainy or cloudy days. Just like you can get sunburned from being outside in overcast conditions, your rooftop solar array will still convert photons into electric current even if the skies are cloudy and overcast. The sun’s rays that your panels need to produce energy still make their way through rain or clouds, but not as strongly as on a clear day. This means that your panels’ production will not be as efficient or consistent, but they will still produce, nonetheless.

In some cases, however, clouds can even increase the production of your solar panels. Sometimes, individual clouds move slowly across the open sky. These lone clouds reflect direct sunlight, causing more of a higher concentration of light to hit nearby solar panels. So, for a brief amount of time, a residential solar system can produce a burst of extra electricity. This is called the cloud edge effect and commonly occurs during colder fall and winter months of the year. Although homeowners should never depend on lone clouds to boost their energy output, they can have peace of mind knowing that clouds don’t always have such a negative effect on solar production!

2) Solar panels can perform better in low temperatures

Believe it or not, lower temperatures are actually better for your solar panels than extreme heat. High temperatures can cause solar panels to be less efficient—just like a computer or phone, solar panels can overheat. The hotter it is, the worse the panels will perform, so panels are actually more efficient during the colder fall and winter months. Solar industry experts typically test their panels as if they were in a 25 °C or 77 °F environment. The average panel will drop by about 0.05 percent for every degree Celsius over that tested temperature. If panels reach an internal temperature of 35 °C (95 °F), they will produce power with .5% less efficiency than their original grade. For most states, this decrease in efficiency only occurs during the summer months, meaning that panels are technically more efficient during the winter. Temperature plays the biggest effect in hot states like Arizona, California, Florida, or Nevada, where panel temperatures can exceed 95 °F for almost half the year. During the winter, all solar owners will avoid any losses to solar panel efficiency and monthly electricity bill savings independent of the state they live in.

Originally, solar panels performed poorly in freezing temperatures. However, the solar industry was quick to develop a layering design to protect solar panels’ internal temperatures from getting too low. Through the use of tempered glass, aluminum casing, and a steady back sheet, solar panels can stay at the ideal internal temperature of 40 to 55 degrees Fahrenheit even during the coldest winter storms. However, scientists have yet to discover a way to keep panel’s internal temperatures cool during the hotter summer months. Thus, the winter months should not scare homeowners away from going solar, since lower temperatures are actually ideal.