Shining a light on solar
To put solar into perspective, the amount of energy from the Sun that hits the Earth in just one hour is enough to meet the planet’s requirements for a year! With so much energy coming from the Sun, it may be surprising that 2016 was the first time that solar power generation overtook coal power generation.
In this blog post we will discuss the mechanics of solar energy and compare it to other renewable options. We also give a glimpse into the future of exciting new solar tech and have a handy key word guide (words in italics are defined in the key words section).
How does the sun create solar energy?
The Sun creates energy through a process called nuclear fusion; the huge pressure caused by gravitational forces pushes hydrogen atoms, which make up the Sun, so tightly together that they combine to make helium atoms. Einstein’s famous equation (E=mc2) allows some of the hydrogen mass to be converted into energy during this process, predominantly heat and light. The light then travels 148 million kilometres to us, where we can capture it using solar panels.
How do solar panels work?
You may have seen PV mentioned alongside solar in the past. PV stands for photovoltaics and is the word used to describe the conversion of light energy into electricity using semiconducting materials, silicon in this case. Two layers of silicon are sandwiched together in a panel and both are treated. The top layer facing the Sun is treated to have electrons added and the bottom layer is treated to remove them. Silicon atoms like to have a specific number of electrons, so the top layer wants to lose its excess electrons and the bottom layer wants to gain some. When sunlight strikes electrons in the top layer it knocks them out and they go straight into the bottom layer, resulting in a flow of charge. When the layers are connected by a conductive wire the circuit is complete and you get a current – electricity!
How does solar compare?
Solar power has an obvious environmental advantage over fossil fuels as it doesn’t produce greenhouse gases, but how does it compare to other renewable electricity sources?
For one, solar panels are one of the easiest renewable energy sources to maintain, especially when compared with something like biomass power plants. Secondly, solar energy is the most readily available renewable electricity source for domestic use and its portability allows applications anywhere from calculators to space stations. Unlike wind energy, which requires certain wind speeds, solar power does not need direct sunlight to function. The panels will still generate electricity all year round even when it’s overcast or raining, although it will produce less electricity in these conditions.
Despite the many advantages of solar energy, it may not always be the best renewable option. For example, the space that solar panels take up due to their comparatively low efficiency (22%) is larger than many other renewables. A 2MW solar farm will occupy about five acres of land, whereas a 2MW wind turbine would require just 1.5 acres.
On the flip side, this 22% efficiency is expected to improve due to the continuous investment into renewables and their research. There are also projects such as Riding Sunbeams which mitigate the sizeable land usage by installing solar panels on land that would not have another purpose, such as areas running alongside train tracks. Two other space saving ideas include placing panels on your roof or companies creating floating solar farms – more on that in the upcoming tech section.
We mentioned earlier that solar has huge environmental benefits over fossil fuels. However, it is not perfect in this respect. The materials used to make solar panels are difficult to recycle and can include toxic elements like lead and cadmium. To move to a more sustainable future we need to consider how to reduce the use of these non-recyclable materials and harmful chemicals.
Thinking of getting solar panels for your home?
If you’re thinking about buying solar panels for your home and skipped straight to this section, have a read of our above comparison as a lot of it is applicable here.
Solar panels can save you money in a couple of ways. You don’t have to purchase the energy that your panels generate from your supplier as it goes straight to your home, reducing the amount of usage you’re charged for on your electricity bill. There is a large up-front initial cost, but the solar panels will pay for themselves in 9-10 years for an average household. You can even make money from solar, as many energy suppliers have smart export tariffs that pay you for any energy you export to the grid – this will happen when you are producing more electricity than you are using. Alternatively, you can purchase solar batteries to store any energy you don’t use for future use, but these are currently quite expensive.
Another thing to consider is aesthetics – this is obviously a highly subjective matter and where many enjoy having solar panels as a feature, others find them unattractive. There are some solutions to this which we will discuss below.
Exciting solar tech
One of the most exciting recent developments in solar (and wind) energy is floating farms. These farms allow panels to be placed on water, solving the large space requirement issue. The panels can be placed on floating platforms in any body of water, if the water is not too turbulent. One possible application of this is upgrading a hydro power station by adding a floating solar farm to the reservoir.
We also mentioned potential aesthetic issues associated with having panels on your roof. To combat these, several new technologies are being developed. Solar Skins give panels the same design as your roof, allowing them to blend in, and BIPV (building-integrated photovoltaics) are photovoltaic materials that can actually replace conventional building materials such as windows and roof tiles.
There are all sorts of other wild and fantastic new technologies out there. Solar fabrics are a particular favourite of ours; energy absorbing clothing – how futuristic!
- Nuclear fusion – the fusion of smaller atoms to make larger atoms.
- PV (photovoltaics) – the word used to describe the conversion of light energy into electricity using semiconducting materials.
- Semiconductor – a material that doesn’t conduct as well as a conductor (a material that allows heat or electricity to flow, e.g., most metals), but conducts better than an insulator (a material that does not allow heat or electricity to flow, e.g., plastic).
- Electron – a tiny, particle that spins around an atom’s nucleus (centre) like a planet spins around the Sun. Electrons are responsible for the flow of electricity.
Check out our Jargon Explainer to clear up any more energy lingo confusion.