Written by David Glenn.
No form of energy takes as much effort to generate as sunlight. To create a single photon of light, the gravitational force at the center of the sun has to create a pressure density of approximately 250 billion times that of the earth’s atmosphere at sea-level. At the same time, the temperature needs to be approximately 16 million degrees Kelvin. This allows some of the hydrogen atoms that make up the sun’s interior to overcome their natural tendency to repulse each other, resulting in hydrogen fusion. The fusion releases an almost unfathomable amount of energy (think E=mc2) in the form of photons. However, the journey doesn’t stop there.
With the incredible density at the center of the sun, and the trillions upon trillions of photons racing about in all directions, it gets pretty crowded. As they bump and bounce off of one another, they very slowly make their way towards the sun’s surface. How slowly? Well, we don’t have all of the facts yet, but it is estimated that the journey of a single photon from creation in the core to expulsion from the solar surface can take anywhere from 100,000 to 1 million years (which means that the stray sunbeam that your house-cat likes to lounge in probably originated back when your cat’s ancestors were still preying on your ancestors). Even after it leaves the sun’s atmosphere, assuming it’s heading in the right direction, it will still take that bit of light another eight minutes to reach the planet earth.
And once it gets here, we generally let it just hit the ground and dissipate as heat. What else can we do? Well, thanks to some very forward-thinking individuals and a little something called the photovoltaic effect, mankind has recently discovered that sunlight can be converted into usable electricity. Silicon solar cells allow their own electrons to be knocked free by the sun’s photons, which can then be turned into an electric current, thus producing a free, clean, and abundant energy source. But let’s take a step back for a moment. What if that photon, after making its 1-million-year (plus eight light-second) journey to earth, never actually reaches the surface and just ends up stuck on the backside of a cloud in the upper atmosphere? How then are we supposed to use it to power our lives?
Solar in the Dark
That’s a question that solar energy enthusiasts are often forced to answer, especially if they live in cloudy or dark climates. Can solar power be used when the sun isn’t shining? What about in colder areas of the world? Let’s take a moment and address these concerns. First and foremost: no, cold weather does not hinder the functionality of solar panels. In fact, the colder it gets, the more freely electricity can flow (thanks to reduced resistance in conductors). So, if the temperatures starts to plummet, solar energy users can keep their homes warm and well-lit, content in the knowledge that their panels are operating at peak efficiency.
Of course, cold weather has some other problems associated with it. If allowed to build up on a solar panel, snow can really hamper energy production by virtue of the simple fact that it prevents sunlight from reaching the panel’s surface. Of course, most panels—if installed correctly—sit at an angle, thus allowing snow to sluff off on its own (or with a little help from a well-placed broom strike). Advances are being made to help keep the paneling clean and unobstructed, such as a miniature, cleaning robots that actually attach to the panels and move freely between them, cleaning up debris and wiping off smudges as they go. So, it’s safe to say that a bit of snow isn’t really worth worrying about.
Creating Solutions for All Climates
And now for the major issue. After all, the sun may shine down equally on both the evil and the good, but it tends to be a bit pickier when it comes to latitude. Depending on the time of year, areas that are far north or far south on the globe may find that the seasons are a bit disproportionate, resulting in nights that can last for over 24 hours at a time, interspersed by only short periods of sunlight. Even locations that are further from the poles can suffer from a lack of sunshine thanks to local weather patterns. Are these locations doomed to rely on conventional energy sources?
Not really. For one thing, the location and angle of a solar panel can go a long way towards making up for lost light. Additionally, motorized panels that adjust to track the sun are also available for cases where it makes financial sense.
At the same time, solar homeowners can use batteries. Batteries allow surplus energy to be stored for use during non-daylight hours. Again, these make sense financially where they beat getting nighttime electricity from the grid. Thanks to falling solar panel prices, falling battery prices, and rising electricity prices, this is an increasingly competitive option. Some think it will be widely competitive within a few years.
Current batteries are always being improved upon, and new designs for flow batteries, hydrogen batteries, and even salt batteries are all being developed in the hopes of increasing our potential energy storage capacity. For longer periods of darkness, many solar energy–powered structures are also hooked into the municipal power grid allowing for conventional energy to be used when necessary. And, as an added bonus, many cities will actually buy back any surplus energy that your panels produce, allowing you to use summer sunlight to make up for low energy production during the winter months. And if your home is located near one of the poles and you’re dreading the long dark nights of winter, just remember that once the earth’s orbit takes it halfway around, you’ll be sitting pretty in long days of pure sunlight—it all evens out in the end.
So, even if you live in a less sun-lit part of the world, there are advantages to solar power. Of course, in the end, the choice is still up to you. You can either use the free photons that fly your way, or you can let a million-year journey go to waste.
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