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Researchers with the International Potato Center study blight-resistant potatoes bred from wild relatives. Michael Major for Crop Trust / CC BY-ND 2.0

New research presented Tuesday at the IUCN World Conservation Congress in Marseille sounded the alarm that wild relatives of some of the world's most important crops, including potatoes, avocados and vanilla, are at risk of extinction, said The Food & Environment Reporting Network (FERN). The study was published in the journal Plants, People, Planet.

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Wildfires in Russia's Sakha Republic (Yakutia) on July 22, 2021. Russian Aerial Forest Protection / TASS via Getty Images

Smoke from wildfires burning in Siberia's dense boreal forest has reached the North Pole for the first known time in history, NASA satellite images revealed last week.

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MAXSHOT / iStock / Getty Images

Solar panels allow you to harness the sun's clean, renewable energy, potentially cutting your electric bills as well as your environmental footprint. But do solar panels work on cloudy days, or during seasons of less-than-optimal sun exposure? For homeowners who live outside of the Sun Belt, this is a critical question to consider before moving ahead with solar panel installation.

In this article, we'll go over how solar panels work on cloudy days, whether solar panels work at night, and how to ensure you always have accessible power — even when your panels aren't producing solar energy.

How Solar Panels Work on Cloudy Days

Photovoltaic (PV) solar panels can use both direct and indirect sunlight to generate electrical power. This means they can still be productive even when there is cloud coverage. With that said, solar panels are most efficient and productive when they are soaking up direct sunlight on sunny days.

While solar panels still work even when the light is reflected or partially obstructed by clouds, their energy production capacity will be diminished. On average, solar panels will generate 10 to 25% of their normal power output on days with heavy cloud coverage.

With clouds usually comes rain, and here's a fact that might surprise you: Rain actually helps solar panels work more effectively. That's because rain washes away any dirt or dust that has gathered on your panels so that they can more efficiently absorb sunlight.

Do Solar Panels Work at Night?

While solar panels can still function on cloudy days, they cannot work at night. The reason for this is simple: Solar panels work because of a scientific principle called the photovoltaic effect, wherein solar cells are activated by sunlight, generating electrical current. Without light, the photovoltaic effect cannot be triggered, and no electric power can be generated.

One way to tell if your panels are still producing energy is to look at public lights. As a general rule of thumb, if street lamps or other lights are turned off — whether on cloudy days or in the evening — your solar panels will be producing energy. If they're illuminated, it's likely too dark out for your solar panel system to work.

Storing Solar Energy to Use on Cloudy Days and at Night

During hours of peak sunlight, your solar panels may actually generate more power than you need. This surplus power can be used to provide extra electricity on cloudy days or at night.

But how do you store this energy for future use? There are a couple of options to consider:

You can store surplus energy in a solar battery.

When you add a solar battery to your residential solar installation, any excess electricity can be collected and used during hours of suboptimal sun exposure, including nighttime hours and during exceptionally cloudy weather.

Batteries may allow you to run your solar PV system all day long, though there are some drawbacks of battery storage to be aware of:

  • It's one more thing you need to install.
  • It adds to the total cost of your solar system.
  • Batteries will take up a bit of space.
  • You will likely need multiple batteries if you want electricity for more than a handful of hours. For example, Tesla solar installations require two Powerwall batteries if your system is over 13 kilowatts.

You can use a net metering program.

Net metering programs enable you to transmit any excess power your system produces into your municipal electric grid, receiving credits from your utility company. Those credits can be cashed in to offset any electrical costs you incur on overcast days or at night when you cannot power your home with solar energy alone.

Net metering can ultimately be a cost-effective option and can significantly lower your electricity bills, but there are a few drawbacks to consider, including:

  • You may not always break even.
  • In some cases, you may still owe some money to your utility provider.
  • Net metering programs are not offered in all areas and by all utility companies.

Is Residential Solar Right for You?

Now that you know solar panels can work even when the sun isn't directly shining and that there are ways to store your energy for times your panels aren't producing electricity, you may be more interested in installing your own system.

You can get started with a free, no-obligation quote from a top solar company in your area by filling out the 30-second form below.

FAQ: Do Solar Panels Work on Cloudy Days?

How efficient are solar panels on cloudy days?

It depends on the panels, but as a rule of thumb, you can expect your solar panels to work at 10 to 25% efficiency on cloudy days.

How do solar panels work when there is no sun?

If there is literally no sunlight (e.g., at night), then solar panels do not work. This is because the photovoltaic effect, which is the process through which panels convert sunlight into energy, requires there to be some light available to convert.

However, you can potentially use surplus solar power that you've stored in a battery. Also note that solar panels can work with indirect light, meaning they can function even when the sun is obscured by cloud coverage.

Do solar panels work on snowy days?

If there is cloud coverage and diminished sunlight, then solar panels will not work at their maximum efficiency level on snowy days. With that said, the snow itself is usually not a problem, particularly because a dusting of snow is easily whisked away by the wind.

Snow will only impede your solar panels if the snowfall is so extreme that the panels become completely buried, or if the weight of the snow compromises the integrity of your solar panel structures.

Will my solar panels generate electricity during cloudy, rainy or snowy days?

Cloudy days may limit your solar panel's efficiency, but you'll still be able to generate some electricity. Rainy days can actually help clean your panels, making them even more effective. And snowy days are only a problem if the snow is so extreme that the panels are totally submerged, without any part of them exposed to the sun.

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Ron Goodman and his boss were training a new volunteer ranger at the North Etiwanda Preserve, a lush and rocky landscape in the foothills of the Cucamonga Wilderness, roughly 50 miles east of Los Angeles. They were looking out over an area of burn scar when Goodman spotted three men with duffle bags among the sand-colored boulders. He knew exactly what they were doing and took off running in their direction.

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Wild horses roam on BLM land along the Pony Express Trail on Oct. 15, 2020 outside Dugway, Utah. George Frey / Getty Images
The plight of the roughly 95,0000 wild horses that roam public lands across the Western United States is both complicated and controversial. This year, unprecedented widespread drought is exasperating the issues the horses face.
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The kiwikiu, or Maui parrotbill, is an endangered species and is endemic to the island. Maui Forest Bird Recovery Project
A golden, thick-billed bird thought to have died more than 1.5 years ago was seen alive on the slopes of a Maui volcano last Wednesday. The discovery is giving researchers hope for the critically endangered species, Newsweek said.
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A pyrocumulus cloud from the Bootleg Fire drifts into the air near Bly, Oregon on July 16, 2021. PAYTON BRUNI / AFP via Getty Images
As the Bootleg fire in Southern Oregon rages on, the massive wildfire is creating its own weather systems.
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An aerial view of droughts effect at Hemenway Harbor, Lake Mead, which is at its lowest level in history since it was filled 85 years ago, Monday, June 28, 2021. Allen J. Schaben / Los Angeles Times / Getty Images

The federal government is expected to declare a first-ever water shortage in the Colorado River basin by next year at the latest –some believe the call could come this summer. The declaration would implement mandatory water cuts in Lower Basin states, three of the seven in the Colorado River Compact, Newsweek and NPR reported.

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"Justice for Berta Caceres is justice for Honduras," reads a placard below the image of the environmental activist on July 5 2021 in Tegucigalpa, Honduras. Delmer Membreno / picture alliance via Getty Images

Roberto David Castillo Mejía, a former top executive of a Honduran construction firm Desarrollos Energéticos (DESA), was the eighth person charged with the 2016 murder of environmental activist Berta Cáceres, Reuters reported.

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Extinction Rebellion protesters block the roads outside the Bank of England on Oct. 14, 2019 in London, England. John Keeble / Getty Images

After six months of deliberation, an international panel of 12 legal experts has drafted an official definition of ecocide.

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The Goldman Environmental Prize recognizes grassroots activists from six continents who have moved the needle on environmental issues their communities face. 2021 Goldman Environmental Prize Virtual Award Ceremony / YouTube

Nicknamed the "Green Nobel Prize," the prestigious Goldman Environmental Prize recognizes grassroots activists from six continents who have moved the needle on environmental issues their communities face. This year's recipients led the charge on environmental justice, wildlife and rainforest conservation, plastic pollution, dams and coal projects.

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A bdelloid rotifer feeding on algae and other microorganisms, seen under a microscope. Eduardo Baena / iStock / Getty Images Plus

Scientists in Russia have revived a bdelloid rotifer — a type of multicellular microorganism that's accustomed to wet environments — after the invertebrate spent 24,000 years frozen 11 feet beneath the Siberian permafrost.

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Linda Lucas and her granddaughter Lilly Malinowski plant tomatoes in the shadow of GenOns Cheswick Power Station, which still burns coal to produce 637 megawatts of electricity, on June 7, 2021 in Cheswick, Pennsylvania. Scientists reported that despite a year-long pause in much of the economy due to the COVID-19 pandemic, levels of atmospheric carbon dioxide reached the highest levels since accurate measurements began 63 years ago. Jeff Swensen / Getty Images

Last month, EcoWatch reported that atmospheric carbon dioxide (CO2) levels this year were expected to climb to beyond 2019 levels, despite falling during the pandemic. Now we know just how much.

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