Not every part of the world is sunny. Some places, like England and the Netherlands, have notoriously wet weather. Like all things geographic, sunshine is not equally distributed. So, does that mean that these areas will have to forego solar energy? And what does it mean for countries that have a large proportion of cloudy days? One can already picture a worried homeowner looking up at the darkening sky as clouds gather, wondering if their solar panel will become a glorified rooftile for the remainder of the day. This brings us to the question, can your solar panels run on a cloudy day? Solar radiation penetrates clouds, as anyone who has suffered from sunburns on a cloudy day will attest. Therefore, solar panels will most definitely work on cloudy days. We’ll get back to nations where the sun doesn’t shine in just a moment, but first, let us consider how and why solar panels will work on cloudy days.
The answer is fairly simple: solar panels will work, but their efficiency will be drastically reduced with the presence of cloud cover. Depending on cloud cover and the efficiency of the solar panels, output can drop down from 10 – 25% of what you can expect on a sunny day. One thing to keep in mind is that modern solar panels are becoming more and more efficient, and so these numbers will likely increase. Nonetheless, solar energy is very much dependent on the sun’s rays, and any disruption in the access to this vital resource will result in a severely handicapped output. Nonetheless, modern solar panels capture various wavelengths of sunlight, including red and blue wavelengths, making them less susceptible to disruptions in solar radiation. These panels are more efficient on not just cloudy days, but also in areas where trees are likely to block the panel’s access to sunlight during certain times of the day. Another way that modern panels work around reduced sunlight conditions is through the use of bifacial modules. These modules use the backside of the panel as a sort of mirror made of aluminum. This bounces some of the photons that have not been absorbed during their first pass back into the cell again, for a second chance at reabsorption. What this essentially does, is use the same input of sunlight as much as possible by bouncing back its electrons again. So, the precious little solar radiation that does reach the panels is not allowed to go to waste.
Important Facts About Solar Panels on Cloudy Days
Here are a few pointers to keep in mind when considering the performance of solar panels in cloudy or cold places.
- In typically cloudy/cold areas, solar panels can work well enough. Examples of this are New York, San Francisco, Milwaukee, Boston and Seattle. All these areas experience incremental weather, from rain, to fog and even blizzards. Even so, these American cities see some of the most savings from solar energy. The same holds true for Tasmania, which is not one of the sunniest parts of Australia. This hasn’t stopped Tasmanian residents from making the most of solar panel systems. The biggest factor in determining the success or failure of a solar PV system is the cost of electricity and not cloudy days. For example, in New York and San Francisco, electricity prices are very high, and therefore, even a solar panel system operating at suboptimal capacity will likely help residents save money on their energy bills. This alone makes it worth the investment. The same holds true for Australia.
- Solar panels do not actually need hot weather to generate electricity. It just so happens that (because of the nature of energy) areas that receive more sunlight tend to be hotter. Nonetheless, areas that receive sunlight and are actually cooler, are ideal for solar panels. Solar panels tend to work less efficiently when their temperature gets above 25 degrees Celsius. This does not mean that they won’t work in traditionally hot places, like Australia’s sunny state or Phoenix, Arizona. In fact, Phoenix is number six on the list of cities that save the most from solar panels. The key point to remember is that electricity costs and not the weather, determine whether a customer will be saving anything through solar panels. If electricity in your area is dirt cheap, you probably won’t benefit from solar panels.
- Modern solar panels are modular and smart. What this means is that they are far more resistant to shading than before. For example, if 10% of a solar panel system is covered by shade, only that 10% will suffer from diminished generation capacity, and the rest will continue to function as normal. That said, a qualified solar panel installer will make sure that your PV system is installed in a way to minimize or eliminate shading. This is why it is very important to make use of the best solar panel companies in your area. Expertise will go a long way in making your life comfortable.
Now back to the point about countries that tend to be cloudier than others. Well, Germany is not a particularly sunny country and yet it is a leader in renewable energy. Germany alone accounts for about 25% of the world’s solar output. Not to belabor a point, but again, it’s the rising cost of electricity and the urgent need to save our planet that makes solar energy such a vital part of our collective future.
To sum it up, one should not be overly concerned about cloud cover when considering purchasing a solar PV system. There are more important factors to keep in mind, as mentioned above. Modern solar panels are designed to operate in reduced light conditions, and are able to withstand most weather. These panels are made of sturdy materials and designed to reduce microfractures caused by environmental stresses and also able to absorb more wavelengths of sunlight, making them more efficient. In a nutshell, yes, your solar panels can most probably still run on cloudy days and save you money in the process.
