Science Energy Do Solar Panels Work on Cloudy Days? At Night? By Katherine Gallagher Katherine Gallagher Writer Chapman University Katherine Gallagher is a writer and sustainability expert. She holds a B.A. in English Literature from Chapman University and a Sustainable Tourism certificate from the GSTC. Learn about our editorial process Updated October 28, 2022 Fact checked by Elizabeth MacLennan Fact checked by Elizabeth MacLennan University of Tennessee Elizabeth MacLennan is a fact checker and expert on climate change. Learn about our fact checking process Jose Camilo Lopez Perez / Getty Images Energy Renewable Energy Fossil Fuels In This Article Expand How Do Solar Panels Work? Do Solar Panels Work on Cloudy Days? Solar Panels in Cloudy Climates Do Solar Panels Work at Night? Advances in Solar Technology Frequently Asked Questions Solar panels may generate more energy with direct sunlight, but they can use indirect light to generate power. This means that solar panels will still generate electricity on cloudy days and at night. But that doesn't mean solar customers go without power on bad weather days. Solar battery storage and net metering ensure consistent access to electricity. How Do Solar Panels Work? Solar panels convert sunlight to direct current (DC) electricity, most of which is inverted into alternating current (AC) to power electronics in the home. On exceptionally sunny days, excess power produced by solar systems can be sold back to the public utility power grid. Net metering programs give solar system owners credit for the excess power they generate. They can use this to compensate when the system produces less energy during cloudy weather. Do Solar Panels Work on Cloudy Days? Clouds make solar panels work less efficiently. Panels under 0%-30% shade can produce 30%-40% less power. Net metering laws help improve solar system stability and can help account for weather fluctuations, but may vary depending on the state. Many utility companies will also offer them to make solar more affordable. This is where net metering comes in. These programs are designed to give solar system owners credit for the excess power they generate, which they can then draw on when their system is producing less energy due to cloudy weather. Net metering laws may vary depending on your state, and many utility companies will offer them either voluntarily or due to local legislation. Solar Panels in Cloudy Climates Some of the most popular regions for solar power are also some of the most overcast. Mild temperatures help solar efficiency, as excess heat reduces solar system output. Portland, Oregon and Seattle, Washington are some of the most popular locations for solar installations. Rain can help keep solar panels running efficiently by washing off dust and dirt. Dust accumulation on solar panels can reduce efficiency by up to 50%. Do Solar Panels Work at Night? tzahiV / Getty Images Solar panels can produce small quantities of energy at night with direct moonlight. But most nighttime solar energy comes via battery backup systems or net metering credits. Advances in Solar Technology Even now, breakthroughs in solar energy are happening all the time. For instance, researchers are working on thermoradiative solar cells that would heat up and draw energy from the cold night sky. Nighttime photovoltaic cells could potentially keep generating power continuously without needing to rely on solar batteries or power grids. Prototypes already produce 50 watts of electricity per square meter, which is about 25% of what traditional solar panels are able to generate during the day. To improve solar efficiency on cloudy days, researchers are leveraging E. coli bacteria. The bacteria naturally converts sunlight into energy. To improve solar efficiency, the organic material is coated with metallic nanoparticles before introducing it into an energy-producing electrode. The project is still in its experimental phase but has the potential to compete with conventional solar panel systems. Frequently Asked Questions How do you know if your solar panels are working? You can verify that your panels are actually generating electricity by checking your meter. Green lights are an indicator that the panels are functioning properly. A red light could indicate a reduction in solar production—whether due to a problem with the panels themselves or your inverter. How much less efficient are solar panels on cloudy days? The efficiency of solar panels roughly correlates with the percent of sunshine they receive. They should charge at full capacity in full sun or 60% to 70% in 20% to 30% shade. How do you know if your climate is suitable for solar? Solar panels are most efficient when they receive about five to six hours of full sun per day; however, that isn't to say solar isn't suitable for rainier, cloudier conditions. The rain can, in fact, be beneficial for solar panels because it naturally cleans them, therefore allowing them to capture more UV light. View Article Sources Anand, V.P., et al. "Experimental Investigation of the Shading Losses on Solar Module System Performance." IEEE Xplore, 2014., doi:10.1109/ICAEE.2014.6838548 Pforzheimer, Adrian, et al. "Shining Cities 2020." Environment America Reserch and Policy Center and Frontier Group, 2020, pp. 38. Deppe, Tristan and Jeremy N. Munday. "Nighttime Photovoltaic Cells: Electrical Power Generation by Optically Coupling with Deep Space." ACS Photonics, vol. 7, no. 1, 2020, pp. 1-9., doi:10.1021/acsphotonics.9b00679 Srivastava, Sarvesh Kumar, et al. "A Biogenic Photovoltaic Material." Small, vol. 14, no. 26, 2018, pp. 1800729., doi:10.1002/smll.201800729