How solar energy works on cloudy days

How solar energy works on cloudy days

Read Time: 5 Minutes

Does solar work when the clouds are out? That’s a question many ask when thinking about adding solar panels to their home or business. While some may dismiss that solar works on cloudy days, we have two real-life examples that show otherwise.

1. Remember the last time you got a sunburn on a cloudy day? Bet you didn’t apply sunscreen thinking that those UV rays wouldn’t get through. And I bet it hurt!
2. Those with transition lenses in their glasses know that they darken even on cloudy days.

While solar does work best in full sun, these examples show that your home will also benefit from solar production even on cloudy days. Here are some important takeaways about how solar works on cloudy days.

3 things to consider about solar during cloudy days

  1. Solar power can work well in locations known for cloudy, cold weather. Consider San Francisco, New York, Milwaukee, Detroit, Seattle and Boston. These cites often have less-than-optimal weather, from blizzards to rain and fog. However, each of these cities can benefit from 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 77 degrees.
  3. Although partial shading or cloudy weather will 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?

It’s a fair question to wonder whether it’s worth going solar when living in a location known for cloudy weather. However, POWERHOME SOLAR customer Jill Barnes, who lives in Lima, Ohio, dispels the myth that solar is poor in cloudier climates.

Let’s break down how solar works in cloudy states by comparing two states from our 10-state market, North Carolina and Michigan. Michigan produces 2,300 hours of sunlight a year. North Carolina produces 2,600 hours of sunlight per year. Although North Carolina produces nearly 13% more sunlight a year than Michigan, that doesn’t mean that Michigan is not ideal for solar. The current price of electricity in Michigan is around $0.16 per kWh, while North Carolinians see their electricity cost at around $0.11 per kWh. Because the electricity cost in Michigan is about 45% higher, and you’re receiving only 13% less sun in Michigan than North Carolina, you see that going solar in the Wolverine State could be more beneficial to your pocketbook.

Even better news is that the solar panels POWERHOME SOLAR installs come with approximately 19 percent efficiency, meaning that homes that get fewer hours of peak sunlight than 5 per day still end up having enough roof space for solar to be viable.

Electricity grid usage and cloudy days

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 more energy than your home needs at any one time, the excess you don’t use can be fed back into the grid or stored in a battery. Net metering programs vary depending on the state, but many utility companies offer a credit that you can use to offset your grid energy consumption when your system doesn’t generate enough power.

Our solar installation specialists will determine the correct number of solar panels for your needs.

Key takeaways: When will solar perform best?

So, we’ve established that solar panels won’t work at optimally when clouds block 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 you.

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?

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 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.

Curious about solar production in your city?

Reviewing solar production on an annual basis as opposed to a day-to-day basis is essential. Energy production can fluctuate much like the stock market. Some days there is high production, others there is lower production. One week could be low production due to rain and clouds the next week could be your best yet. Give us a call at 1-800-POWER-90 so we can get you started on saving money on your electric bill.