How Much do Clouds Affect My Solar Power?


Okay, so we know that solar panels need sunlight to produce energy – it’s literally in their name. The thing is, not everyone lives in perpetual sun. Even those of us who live in near perpetual sun do on occasion have a rainy day where clouds block out the sunlight. Do solar panels still work then?

Because solar panels work best in direct sunlight, you can expect your production to drop 10 to 15 percent on a partly cloudy day and 70 to 90 percent on completely overcast days.

Despite this, even if you do live in a place where it constantly rains – yes Washington, I am looking at you – you should still consider getting solar panels for your home. Thanks to modern science, solar panels are becoming more and more efficient and capable of producing energy even under cloudy skies.

Best Solar Panels for Cloudy Climates

In case you didn’t know, there are many different types of solar panels, and not just whether or not they go on your roof or are mounted to the ground. And as with everything, not all solar panels are created equal. Here we will give you some options of different types of solar panels so you can determine what will work best for your needs.

Monocrystalline Solar Panels

Monocrystalline solar panels are black tinted and have the highest efficiency rate on the market – 20 percent. While these solar panels tend to be more on the expensive side – they are the most efficient, what did you expect? – they also have the added benefit of having maximum performance, so you won’t have to worry too much about cloud coverage.

Polycrystalline Solar Panels

These solar panels tend to be blue-tinted and have an efficiency rate of 15 percent. These are cheaper than the monocrystalline and other panels. While still fairly efficient, these solar panels are more sensitive to high temperatures. This means that as they overheat, their efficiency declines. However, if you live in a more temperate location – which a lot of cloudier climates tend to be – this might be a good choice for you. With it being so efficient, having cloud coverage shouldn’t be too much of a problem.

Thin Film Solar Panels

So these solar panels tend to be the least efficient of all solar panels at only 10-11 percent efficiency rates. However, they do have the benefit of also being one of the cheapest types of solar panels. They also have the added bonus of being specifically designed to work better in warmer temperatures and will lose efficiency in higher temperatures slower than the polycrystalline panels will. So if you’re worried about losing efficiency from your solar panels overheating, this is may be a good option for you.

Overcast Winners

If you’re still feeling unconvinced that solar panels will ever do any good in your ever cloudy climate and are hesitant to move forward in getting them, perhaps you’d be interested to know that some of the top producers in the United States of solar electric power come not only from the very sunniest places in the country but from some of the very cloudiest.

Portland, Oregon, the city that has the second most cloudy days in a year ranks in the top 20 cities for solar energy. This is possible because while it does get a lot of cloud coverage, Portland’s temperatures also tend to be more temperate. During the summertime when Portland sees the most sunlight, the temperatures are ideal for peak efficiency. Other places around the country may have more sunlight, but often with the added downfall of high temperatures that decrease the efficiency of the solar panels.

While not ranking as highly, in Seattle Washington, the most cloudy city in the country, it is also becoming increasingly popular to install solar panels. Like Portland, its temperatures are more moderate and ideal for peak efficiency when full and direct sunshine is available.

If we leave the United States for a moment, looking at the country of Germany, they produce 45.9 GW to every 49.6 GW the US produces. This is quite a feat, especially considering that Germany is overall cloudier and much smaller than the United States, yet they are still almost able to match us in solar power production.

The nice thing about keeping solar panels in a place where there is frequent rain is that you won’t generally have to worry about cleaning them. The rainwater will help wash off any dirt and dust that may try to cover your panels, which causes them to decrease in efficiency. While it’s always a good idea to keep an eye on your panels for any muck that might stick to your solar panels, at the very least you won’t have to worry about dirt building up over time.

If you only live in an area where it gets occasional rainy days but frequently has partly cloudy days, you don’t have to worry too much about that hurting your efficiency. Firstly, the amount of efficiency lost due to partial cloud coverage is much more minimal than with total coverage. Secondly, there’s a chance, even if it’s small, that it might even make your energy output greater for a few minutes. Does that seem too good to be true? Well, you better believe it because it actually happens!

This phenomenon is nicknamed the “edge of cloud” effect. On days when you see fluffy cumulus clouds passing by, your solar panels have the chance of experiencing a brief increase in electrical production. This happens when the light of the sun reflects off of clouds in a way that they become focused on the light receptors of your solar panels. Similar to burning ants in the sun, this acts as a sort of magnifying glass for the sunshine, intensifying the rays of light in a way that benefits you. Just don’t expect this every day when there are clouds out. While this phenomenon isn’t necessarily uncommon, it also doesn’t happen every time you see a fluffy white cloud pass you by.

Overall, you shouldn’t let cloud coverage get in your way of purchasing solar panels. While it is true that your efficiency will drop when the solar panels aren’t in direct sunlight, they still produce some energy. As the world goes on, we’re going to need to harness any renewable energy that we can so our reliance on fossil fuels goes down and our ability to “be green” goes up.

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