Do Solar Panels Work On Cloudy Days? Yes – And Here’s Why
4 - Minute Read
Jun 22, 2022
Do solar panels work on cloudy days? That’s a common question from homeowners thinking about adding a solar panel system to their home.
Here’s the good news: A homeowner with a grid-tied photovoltaic (PV) system won’t be left in the dark on a cloudy day – or even at night. Let’s take a look at how a solar-powered home gets power when it doesn’t have sunshine beaming down on it.
How Solar Panels Work
To generate renewable energy, solar modules collect sunlight as direct current (DC) electricity. This current runs to the system’s inverter, which converts the DC power into alternative current (AC) that the home and its appliances can use.
Most homes that produce solar energy are still connected to the grid, aka “grid tied.” As the system generates electricity, excess power beyond the home’s current needs goes into the grid. When there’s no sunlight, the home will pull power from the grid to supplement their energy needs. This is how solar-powered homes stay functional at night.
A Note On Net Metering And Using Grid Power
In many cases, utility companies use a payment system called net metering to reward solar-powered homes. In short, they credit homeowners who produce electricity for excess power output. Utility companies typically balance that amount with what the homeowner pulls from the grid at night or other times when their consumption is greater than their production.
Some utility companies do charge a connection or service fee to homeowners with solar panels. They may also charge a “demand fee” for power used during times of peak energy demand – usually in the morning and after the workday.
Does Solar Power Work On Cloudy Days?
Unlike nighttime, solar panels continue getting at least some sunlight when the skies are cloudy. Think about being outdoors on a cloudy day – if you don’t apply sunscreen, you’re likely to get burned even with the cloud cover.
Solar panels can turn indirect sunlight into power, though they won’t generate as much power as they will with direct sunlight. On a partly cloudy day, a home rooftop solar array might operate at up to 80% of its typical capacity.
In the U.S., states like New Jersey, Massachusetts and New York rank highly for the number of residential PV systems installed. Though they typically have far fewer sunny days than places like Arizona or Texas, the cooler temperatures allow solar panels to work more efficiently because they’re in a more optimal temperature range.
What Does Indirect Sunlight Mean For Solar Power?
Indirect sunlight is sunlight that’s somehow being filtered or blocked. Sunlight going through curtains, tinted windows and even trees are examples of indirect sunlight. Sunlight going through clouds also counts as indirect sunlight.
Indirect sunlight still includes photons, which solar panels turn into DC electricity.
Rain And Solar Panels
Solar panels produce power in cloudy weather, but what about rainy days?
Your system will produce power as long as some amount of sunlight, even indirect sunlight, reaches the solar panels. There’s also another benefit to rain: A good rain shower will help clean accumulated dust, pollen, bird droppings, leaves and other debris from your solar panels.
Rain isn’t the perfect way to clean solar panels since raindrops are not always pure water. Even if you live in a rainy area, it’s still smart to periodically clean your solar modules.
Will My Power Go Out On A Cloudy Day?
As mentioned, homeowners with grid-tied solar panels won’t have to worry about losing power on a cloudy day or at night. This is because grid-tied systems will automatically pull power from the utility grid as needed.
Off-grid homes could have a more difficult time, however. Because they can’t draw energy from a utility company, off-grid homes need more solar panels to ensure they can generate extra power, which they can then store in a solar battery system. This will keep the electricity flowing on cloudy days and at night.
Keep in mind that a bigger PV array and enough solar battery storage to keep the power on also mean a higher upfront cost.
Do Batteries Make Sense For Grid-Tied Systems?
Backup batteries aren’t just for off-grid homes. Some homeowners with grid-tied systems use them to store energy in the middle of the day when their solar panels produce more power than they’re consuming.
Their home then switches to battery power at night or during times of high demand, helping the homeowner avoid demand charges.
Grid-tied homes with batteries are also very beneficial for the electric grid because they reduce power demand during the “duck curve” part of the day – when people get home from work, turn their lights on, flip the TV on and start dinner.
Homes using batteries for power can reduce strain on the grid, and homeowners can save money on their electric bill by avoiding demand charges. A solar installer should be prepared to explain what hardware and software can work with the battery to power the home during peak demand hours.
Does Cold Weather Affect Solar Panels?
Solar panels work their best in colder weather. Think of computer servers – information technology professionals keep them as cool as possible to maximize performance. Solar panels also work better at cooler temperatures.
It’s not surprising, therefore, that solar cells keep working in snowy conditions. A light coat of snow on solar panels does little to slow energy production. Even heavy snowfall rarely sticks to the surface very long before sliding off (often taking dust and other particles along with it).
What Are The Best Solar Panels For Cloudy Days?
If you live in a cloudy climate, you might consider getting the most-efficient solar panels available. Panels that operate at 19 – 21% efficiency are widely available, and some models and brands are even approaching 23%. During the earliest days of solar power, the cells only converted about 6% of the sunlight they received into power.
Solar technology is evolving rapidly. A new material called perovskite has pushed solar cell efficiency to 25 – 30%, but this innovation is not widely available yet.
The Bottom Line: Cloudy Days Aren’t An Obstacle For Solar Power
Solar panels continue to produce energy even on cloudy days. When your production falls below your consumption, grid-tied homes will automatically pull power from the grid to keep your home and appliances running. The cool weather that often accompanies cloud cover can also improve your system efficiency.
Want to know more about how to ensure solar panels are working efficiently? Here’s some valuable info on cleaning solar panels.