The modern world runs on Electricity. It is the backbone of the information age that we find ourselves in. Without electricity, you wouldn't be reading these words right now. This raises the question, however, how is electricity generated? On top of that, how do we get electricity out of the raw Materials we have around us and how does it get to our houses? We're going to start discussing answers to these questions right here!
What is the meaning of electricity generation?
Before we do anything else, we should discuss what the words Electricity generation mean. Electricity is a type of energy that occurs due to charged Particles, which can be either Static Electricity or an electrical current. Static electricity is not within the scope of this topic, however, you can read more about it here. Generation is the production or creation of something. Therefore, we can say that electricity generation is the production of charged particles to create an electrical current.
Electricity generation is the production of a current, normally caused by charged Particles moving through a material. In most cases, this material is a wire of some sort.
Sources and Methods of Electricity Generation
Electrical Energy can be generated by multiple different sources, such as oil, gas, nuclear, or solar energy. Some of these are raw Materials, some are other Forms of Energy that are then converted into electrical energy. The next thing we want to look at is the different forms of electricity generation. On Earth, there are two main categories that methods for generating electricity fall into, and you may have heard these terms before. One category is renewable and the other is non-renewable, and both categories have a series of sources or generation methods.
You may have heard the terms clean energy and renewable energy used interchangeably before but we need to make it clear that not all renewable energy is clean. On the other hand, it's also important to note that not all non-renewable sources of energy are dirty. It's much easier to work through each source on a case-by-case basis than to simply say all renewable energy is clean.
Examples of renewable sources of electricity generation
A renewable source of energy is a source of energy that can be replenished over time as it is used. There are four main types of Renewable Energy Sources that you need to know, and they are all discussed below. We should also make the distinction between renewable energy sources and clean energy sources. Just because a source of energy is renewable, that does not necessarily mean that it is clean energy.
Wind Energy
Electricity can be generated via wind power through the use of wind turbines. Turbines are made to rotate by the wind, which is produced as a result of convection currents in the atmosphere. The motion of the wind pushes drive blades on the wind turbine, where the rotation of the blades connects to a system of gears that are linked to a generator. This generator is the part of the turbine that generates electricity. Wind power is a clean form of electricity generation. This method essentially converts the kinetic energy of air into kinetic energy of the blades which is finally converted into Electrical Energy.
A convection current is the motion of a liquid or gas caused by heating in some part of the fluid. In this case, the sun causes these convection currents to occur. Therefore, wind power is a byproduct of solar energy, and as long as the sun is shining, wind power will continue to generate electricity!
Fig. 1: A pair of wind turbines that are using the kinetic energy in wind to generate electricity.
Water Energy
Electricity generated by water comes in several forms, mainly because there are several different ways to convert kinetic energy into electricity via a generator. The three forms of electricity generation via water energy are wave power, tidal power and hydroelectric power. All power generation that uses water is a clean form of electricity generation.
- Wave power generates electricity thanks to the rise and fall of waves on the surface of the ocean. This upwards and downwards motion is a form of kinetic energy, and is used by buoys or pontoons to generate electricity via kinetic movement.
- Tidal power generates electricity from the extremely large amounts of water that move in and out of the mouth of a river during high and low tides. To harness this electricity, a structure called a tidal barrage is built across an estuary, which forces water between small gaps to make use of the kinetic energy of a tidal movement. These gaps in the tidal barrage contain electrical generators, and so they generate electricity.
- Finally, hydroelectric power is where a large damn is built to block the water in a higher up location. hydroelectric dams take advantage of the gravitational potential energy of the water being blocked. This water is forced through a generator, which also generates electricity.
Solar Energy
Electricity generated by solar power is caused directly by the sun shining on solar cells, or photovoltaic cells. Photovoltaic cells convert energy from light waves into electrical energy. Solar power is a renewable source, which means we can continue to generate electricity for as long as the sun is shining. It is also a clean source of electricity.
Solar electricity generation pairs very well when combined with batteries, as photovoltaics cannot generate any electricity overnight.
Fig. 2: A typical solar farm.
Biofuel
The final source of renewable electricity that we need to talk about is biofuel. Biofuel requires burning biological matter such as tree trunks to generate electricity. Burning biofuel is still a dirty process, however, unlike the other three energy sources we have discussed above.
The term biofuel is used as a catchall for any method of generating energy that has a biological material as its fuel source. Therefore biofuel can be used for transportation as well as for generating electricity within a power plant and that electricity can be exported to the grid.
Examples of non-renewable sources of electricity generation
A non-renewable source of energy is any source of fuel that runs out over time. Non-renewable has become synonymous with large scale pollution, however, this is not always the case. For example, electricity generated via nuclear power doesn't emit any harmful emissions. You need to know the difference between non-renewable sources and sources that pollute the atmosphere, as we have stated above.
One of the easiest ways to tell if a fuel source is renewable or not is to figure out where it comes from. If the generation method requires a fuel source (in other words a physical object that can be used to generate heat), then it is probably a non-renewable source of electricity. Another way to think of it is to ask yourself, do I need to build a mine to get fuel?
Fossil Fuels
Multiple fuels fall under the definition of fossil fuels, with the main sources being coal, oil and natural gas. These fuel sources are the byproducts of organisms that lived and died several hundred thousand years ago. They contain a store of chemical energy that when burned becomes heat energy. The main byproduct of this burning process is carbon dioxide, which is an atmospheric pollutant, so we can therefore say that burning fossil fuels is a dirty process.
Fossil fuels are not as prevalent for electricity generation as they once used to be. They are more commonly used to power vehicles (in the form of petrol) and for heating homes (mainly in the form of natural gas), although we know this can be done with electricity as well.
In the United Kingdom, fossil fuels were previously used to make up three-quarters of electricity generation. However, in 2020, renewable clean energy overtook fossil fuels in electricity generation for the first time, marking the first step towards a cleaner energy future.
Nuclear Energy
Electricity generated with nuclear fuel is both clean and non-renewable, we know it is not renewable because we need to mine the fuel, and there is only a finite amount of it. Nuclear fuel sources are very clean in terms of carbon emissions and other atmospheric pollutants. These nuclear reactions generate thermal energy, which is used to create steam from water and drive a turbine, and finally generate electricity.
Electricity generation: transmission and distribution
We've discussed several ways that we can generate electricity, but how does the electricity get to your house? Enter the national grid. The national grid is a massive network of cables and electrical infrastructure across all of Britain with the sole purpose of getting electricity from power producers to your houses so that you can do schoolwork or watch television.
Fig. 3: A map of the UK National Grid power lines.
The map above shows you a network map of the UK national grid with the country's approximate locations of major power lines. Electricity is sent through these overhead cables at 400,000 volts, 275,000 volts or 132,000 volts, compared to the voltage of household electricity, which is usually 230 volts. As well as power cables, electrical distribution networks are also made up of transformers and electricity generation stations, or power stations.
The majority of overhead power cables are made from bare Aluminium. They are also uninsulated because the majority of the insulation comes from the air surrounding the cables. This also means that overhead cables are the cheapest way to transmit massive amounts of electricity over long distances.
Electricity Generation - Key takeaways
- Electricity generation is the process of producing a current within a wire, where the current is generated by the motion of charged particles through the metal.
- There are two main differences between the multiple energy sources, some energy sources are renewable and some sources are non-renewable.
- A renewable energy source is any source of energy that can be replenished over time even whilst it is being used.
- There are four main types of Renewable Energy Sources, wind, solar, water and biofuels.
- There are two main types of non-renewable energy sources, nuclear fuel and fossil fuels.
- Electricity is transmitted across the UK via a nationwide network of cables, power stations and transformers, that is controlled by the national grid.
References
- Fig. 3- UK National Grid power lines (https://www.nationalgrid.com/electricity-transmission/network-and-infrastructure/network-route-maps) by - © National Grid UK
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