Solar energy is an important part of modern renewable electricity. It’s being used to power everything from homes, to planes, to space stations. It produces no exhaust fumes or gases and uses no fuel. It’s quickly becoming a huge part of energy production around the globe and is expanding at an exponential rate.
Solar energy is produced by photovoltaic cells, which have been around for much longer than you might imagine. The first solar cells were created in the 1840s, and though they were incredibly inefficient by modern standards we still use the same principals today.
How Do Solar Panels Work?
To us non-scientists, the process of turning sunshine into electricity can be baffling. Solar panels don’t appear to do anything; they just sit in the sun and generate power. So how do they do it?
- Firstly, we take two thin sheets of silicon and lay them on top of each other (we leave a tiny gap between them, but it’s so small you can hardly tell).
- Secondly, we give them different charges; one positive, and one negative. This creates a very slight amount of tension between them.
- Now we expose the sheets to sunlight. Photons from the sun pour in and knock electrons from the top sheet of silicon. Because of the tension between the two sheets, all the electrons are dragged in one direction.
- We’ve created a flow of electrons; this is DC (direct current) electricity. Now all we must do is send it through an inverter to turn it into AC electricity, and we can use it in our homes.
The very first solar cells used this same concept to create energy, and the basic idea remains the same even today. However, there have been enormous advances in efficiency in recent years, which allow us to generate usable amounts of solar power relatively easily.
What Are The Advantages Of Solar Energy?
We can use as much sunlight as we want, and it’ll never run out. The Earth receives enough sunshine to produce almost 10,000 times the planet’s entire energy consumption every year, so there’s no shortage of “fuel”.
The sun shines on every part of the planet, which means solar power can be used by anyone, anywhere. Unlike localised energy sources such as tidal and geothermal power, which require specific conditions, any country can make use of solar energy.
There are no byproducts of solar energy - no exhaust, no fumes, and no chemicals.
While there are plenty of “solar farms” around the world where thousands of panels are installed, solar panels can also be fitted on roofs, in gardens and in fields. This lets everyday people generate their own power at home.
Drawbacks To Solar Energy
Pollution During Construction
Like all electronics, creating solar cells requires the use of highly poisonous materials and chemicals. While solar energy doesn’t create any pollution while it’s working, the manufacturing process can often create nasty byproducts.
Unpredictable Power Source
It’s impossible to predict how much energy you’ll generate from a solar cell; if it’s a cloudy day, power will drop off significantly. This makes it hard to rely on solar power alone for generating electricity.
Expensive To Manufacture
Solar panels have long been expensive to manufacture, although there have been significant reductions in cost over the last decade.
The Different Types Of Solar Cell
There are many different types of solar panel around these days. They’re usually separated into three generations, each of which has different strengths and capabilities.
First Generation Solar Panels
These cells are created by carefully slicing a single large silicon crystal. These crystals are very expensive and difficult to make, so these panels typically cost a lot. However, they are the most popular and efficient panel in use today. Solar Impulse 2, the world’s first solar-powered airplane to circumnavigate the globe, uses more than 17,000 of these solar cells along its wings and tail structure.
Rather than one single crystal, these cells are created from several different ones. They’re cheaper, but a little less efficient than single-crystal cells.
Amorphous Silicon Cells
These cells use silicon in the same way that a calculator display does. They’re highly flexible and can even be rolled up and put away. They’re only about half as efficient as polycrystalline cells, although they perform better in low-light conditions.
Recent experiments have combined amorphous and polycrystalline cells into a single unit. These perform well in many different conditions and could prove a useful step forward.
Second Generation Solar Panels
Second generation solar cells are generally grouped together because they’re extremely thin. This group consists of the amorphous silicon cells we’ve already looked at, as well as cells created with other elements. Ultra-thin monocrystalline silicon cells have also recently been developed, which promise to improve the efficiency and reliability of second-generation solar panels.
Ultra-thin solar cells can be extremely useful and are often used in applications where solar panels must be extremely light, compact, or fitted to a curved surface.
Third Generation Solar Panels
The third generation of solar panels is mostly confined to the lab and consists of experimental new technologies that could revolutionise solar energy. Research includes constructing solar cells from carbon nanotubes, solar ink, conductive plastics, silicon wiring and organic materials.
Key goals for third generation solar cells are to harness a wider spectrum of light energy (such as infrared), improve efficiency of existing technologies, and to make solar cells cheaper and easier for people to install.
What Does The Future Hold For Solar Energy?
Solar energy is growing incredibly quickly; 74 gigawatts of new solar energy plants were created in the year 2016-17, a staggering 50% increase in total worldwide capacity. Much of this growth is in China, which uses about half of the world’s solar energy.
However, solar power has been growing quickly all around the world; Germany supplies about 7% of its total electricity usage through solar energy alone, and the UK produces about 3.4% (the UK specialises in tidal energy; read more about the UK’s position as a global front-runner here).
Solar panel technology has advanced significantly in recent years, leading to massive improvements in efficiency and reductions in price. Unlike fossil fuels, solar energy technology has only relatively recently become the focus of major scientific research, and there are plenty more breakthroughs to come. The future truly is bright for solar energy.
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