​How solar energy works on cloudy days

​How solar energy works on cloudy days

Last Updated: December 16th, 2019 at 5:17 pm
Read Time: 5 Minutes

3 important facts about ​how solar energy works on cloudy days

  1. Solar power can work well in locations known for cloudy, cold weather. Consider San Francisco, New York, Milwaukee, Seattle and Boston. These cites often have bad weather, from blizzards to rain and fog. However, each of these cities tops the list of those that see major savings due to solar panel installations. The cost of electricity, not how many cold, cloudy or sunny days, is a key factor in how much solar power can save on your electric bill. And remember, electric bills typically go up, not down, so investing in solar panels may benefit you in the long run.
  2. Solar panels don’t need hot weather to create electricity. Sunny, cool weather is actually the best weather for solar panels to work at peak efficiency. They tend to work less efficiently when the temperature rises above approximately 77 degrees.
  3. Although partial shading or cloudy weather can decrease the amount of energy your solar panels generate, modern solar panel systems are engineered to prevent these conditions from causing all energy production to cease.

Do solar panels work on cloudy days?

In the end, it isn’t seasonal cloudy days or even the occasional one, but the average yearly amount of sunshine you get. Although some states get more annual sunlight than others, the entire U.S. receives enough sun to power solar panel systems. Here’s a quick look to see how the numbers work.

Even with 15 percent efficiency, let’s look at an article written by UC San Diego professor Tom Murphy that beautifully breaks down why the number is plenty good enough for solar to be feasible. He writes:

A typical location within the U.S. gets an annual average of 5 full-sun-equivalent hours per day. This means that the 1000 W/m² solar flux reaching the ground when the sun is straight overhead is effectively available for 5 hours each day. Each square meter of panel is therefore exposed to 5 kWh (kilowatt hours) of solar energy per day. At 15 percent efficiency, our square meter captures and delivers 0.75 kWh of energy to the house. A typical American home uses 30 kWh of electricity per day, so we’d need 40 square meters of panels. This works out to 430 square feet, or about one sixth the typical American house’s roof (the roof area of a two-car garage). What’s the problem?

Even better news is that the solar panels POWERHOME installs come with approximately 18 percent efficiency, meaning that homes that get fewer hours of peak sunlight than 5 still end up having enough roof space for solar to be viable.

Of course, seasons and geographical location will determine how much sunlight you get. Cloudy days will lower the output, but not completely. On an overcast day, solar panels can produce energy, just less. But, in most areas, they will overproduce in the summer. While your electric bill may be higher in the winter, that will be offset by lower bills in the summer. And, with net metering, you may get a credit for any energy you feed back into the grid.

Electricity grid usage

When your solar panel system is installed, your house is not separated from the electric grid. Your house uses the energy produced by your solar panels first and will draw on electricity from the power grid if needed. This means you won’t have to worry about getting enough energy for your home on cloudy days, though you may see a slightly higher electric bill during months that have cloudy days.

The benefit of remaining connected to the power grid is that when it is sunny and your solar panels are producing plenty of energy, any energy you don’t use can be fed back into the grid. Net metering programs vary depending on the state, but most offer a credit that you can use to offset your energy usage when your system doesn’t generate enough power.

Our solar installation specialists will determine the correct number of solar panels for your needs. The grid connection means that any energy from the grid that you use on cloudy days can be canceled out by the energy your system feeds into the grid on sunny days.

Key takeaways: When will solar perform best?

So, we’ve established that solar panels won’t work at peak efficiency when clouds are blocking the sun. However, whether you have cloudy or sunny weather, your solar panels will produce electricity that can lower your electric bill. This is why the average annual sunlight you get is important. By calculating your average annual sunlight, you can determine the right solar panel installation for your home.

ves enough sun to power solar panel systems. Here’s a quick look to see how the numbers work.

Even with 15 percent efficiency, let’s look at an article written by UC San Diego professor Tom Murphy that beautifully breaks down why the number is plenty good enough for solar to be feasible. He writes:

A typical location within the U.S. gets an annual average of 5 full-sun-equivalent hours per day. This means that the 1000 W/m² solar flux reaching the ground when the sun is straight overhead is effectively available for 5 hours each day. Each square meter of panel is therefore exposed to 5 kWh (kilowatt hours) of solar energy per day. At 15 percent efficiency, our square meter captures and delivers 0.75 kWh of energy to the house. A typical American home uses 30 kWh of electricity per day, so we’d need 40 square meters of panels. This works out to 430 square feet, or about one sixth the typical American house’s roof (the roof area of a two-car garage). What’s the problem?

Even better news is that the solar panels POWERHOME installs come with approximately 18 percent efficiency, meaning that homes that get fewer hours of peak sunlight than 5 still end up having enough roof space for solar to be viable.

Of course, seasons and geographical location will determine how much sunlight you get. Cloudy days will lower the output, but not completely. On an overcast day, solar panels can produce energy, just less. But, in most areas, they will overproduce in the summer. While your electric bill may be higher in the winter, that will be offset by lower bills in the summer. And, with net metering, you may get a credit for any energy you feed back into the grid.