Do Solar Panels Need Direct Sunlight?
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The short answer is no — while solar panels need direct sunlight to work best, it isn’t required to generate electricity. In fact, solar panels are gaining popularity in all-weather states, including those where the sun doesn’t shine as often.
Residential solar — once considered a novelty energy source — has become widespread across the United States. Today, Americans have tapped into federal tax credits and rebates to offset the cost of installation and reap the benefits of reduced energy bills.
One of the greatest myths surrounding solar energy is that they only work in sunny states like California, Florida, Arizona, Texas, and Nevada. The idea makes sense — why would solar panels function in places with months-long snowfall, rain, and cloud coverage? Surely, Seattle residents — receiving nearly 156 days of rain annually — would find little use or savings from solar panels.
So, how well do solar panels work on a cloudy day, and in which all-weather states are solar panels booming?
How Does Solar Work on Cloudy Days?
Photovoltaic (PV) solar panels are most commonly used on residential rooftops. When sunlight hits the solar panels, the PV cells absorb energy and generate electricity to power your home.
Many people store excess solar energy with net metering — a connection to the electricity grid providing credits for nighttime power consumption when solar panels require daytime sunlight. Net metering ensures round-the-clock access to electricity.
Alternatively, some homeowners have solar batteries that store energy during the day, eliminating reliance on the grid.
PV panels will still absorb energy for electricity from indirect sunlight. According to EcoWatch, panels generate 10% to 25% of their energy output when it’s cloudy or rainy. That’s because light still gets reflected from or breaks through the clouds.
While solar panels need direct sunlight to function at total capacity, homeowners continue to save at reduced operations.
Solar Power in Rain or Shine
Suppose you live in one of the Northwestern states where it rains nearly half the year. You might be surprised to learn that solar panels work exceptionally well. Rainfall keeps solar panels clean, washing away leaves, debris, and air pollution so they can absorb more light.
Even panels installed on New England homes operate efficiently with snowfall — as the snow melts, it washes dirt away. Of course, experts warn that heavy snow accumulation could lead to microcracks and less energy absorption in the PV panels. Nevertheless, New England has added 3.8 gigawatts (GW) of solar capacity since 2016.
The Pacific Northwest has undergone a solar boom in recent years — and projections show a continuous upward trend. Although solar power accounts for only 3.18% of Oregon’s electricity generation, there’s enough solar energy to power 170,446 homes.
Meanwhile, Puget Sound Energy reported 2,000 new solar installations in Washington State in 2021 and expected another 3,000 in 2022.
Should notoriously cloudy-weather states like Oregon and Washington continue to see a rise in residential and commercial solar, it could significantly reduce greenhouse gas emissions. According to Project Sunroof, 85% of Seattle’s rooftops have solar potential — about 149,000 roofs. If Seattle were to max out its solar potential, it could avoid 1.5 million metric tons of carbon dioxide, equal to 325,000 passenger cars removed from roadways for an entire year.
Solar Saves the Day for Thousands of Texans
Even sunnier states have cloudy weather, and as climate change ramps up, unlikely rain and winter storms become more commonplace. In January 2023, Texas experienced a disaster ice storm that sent almost 325,000 electricity customers into darkness amid a failed electrical grid. The state deployed over 100 utility crews to remove downed trees and powerlines following the storm but still struggled to restore power promptly.
Prolonged power outages can be detrimental to communities and individuals. In addition to emergency communication disruptions, power outages can lead to food spoilage, contamination, and the inability to use medications and medical equipment essential for life. Power outages especially put elderly populations at an even greater risk of death, particularly in freezing conditions where they cannot use their home heating systems.
Following the Texas ice storm, the Solar Energy Industries Alliance (SEIA) highlighted that renewable outputs dropped only 1% as thermal power plant output decreased by 25%. Differences like this are notable, considering intense weather patterns will likely increase nationwide.
As for residential solar, homeowners fared well during the ice storm. Even with 0.69 inches of ice accumulation, Tesla’s Powerwall panels kept the lights on for 3,700 solar owners — that was with cloudy weather and heavy precipitation. It should be no surprise that Tesla’s solar products are as durable as they are. A Florida home’s Tesla Solar Roof tiles endured 155 mile-per-hour (mph) winds and a 10-foot storm surge during Hurricane Ian. The Powerwall batteries also worked efficiently after sitting in water.
Texans with residential solar also avoided the spike in electricity prices due to the supply and demand issues after the storm. As a result, people have been blunt about their dissatisfaction with the electrical grid, demanding improved energy infrastructure and greater resilience against inclement weather conditions. Many have taken matters into their own hands by tapping into federal and state solar incentives for more reliable, clean, and self-power generation.
The week following the Texas ice storm, PV installer Sunrun saw a 350% increase in online traffic from Texas, with residents inquiring about rooftop solar installations.
If You Thought Solar Panels Need Direct Sunlight, Think Again
Those living in states with cloud coverage and stormy weather might have thought solar panels wouldn’t make a difference. However, solar panels work just as well in regions where the sun isn’t shining all the time.
Residents of Seattle or Portland benefit from solar energy savings, while people in New England and Texas can keep the power on during snowy, icy conditions. Therefore, it’s likely that solar panels will be right for you wherever you are.
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About the author
Rachel serves as the Assistant Editor of Environment.co. A true foodie and activist at heart, she loves covering topics ranging from veganism to off grid living.