The importance of power
Most of us aren’t really aware of how important power is in our lives unless we’ve gone through a power cut for a few hours and realised we suddenly can’t do 90% of the things we’re used to doing. Everyday actions like turning on the light, charging your phone or keeping food fresh in the fridge are only possible thanks to the power system, which brings electricity to every home. You might think it’s all down to magic and that’s why you don’t have to go to the supermarket every day, but the truth is quite a bit more complex (spoiler alert). If you want to learn a bit about this fascinating topic, I invite you to keep reading.
Table of contents
Traditional fossil-fuel-based production systems vs. renewable systems
Systems based on the mechanical rotation of an alternator vs. photovoltaic energy
Conventional generation systems
Parts of the Electrical Power System
The power system is divided into three clearly differentiated parts: generation systems, consumers, and the distribution grid, which carries power from the generation systems to consumers and is the hardest part to explain. In this post, we’re going to focus on the first element: the generation systems. In this section we’ll look at the main types of power generation systems used for electricity generation today.
Types of power generation systems
There are several ways to classify the different types of power plants:
Traditional fossil-fuel-based production systems vs. renewable systems
You’re probably already familiar with this first distinction. Basically, the systems that come to mind when we talk about generating energy from gas, oil, coal or uranium (a key component for nuclear power plants) are the traditional ones; this is because we’ve been using them for many, many years. As you probably know, using these energy sources has harmful polluting effects on the environment, mainly the emission of huge amounts of CO₂ into the atmosphere.
As the main alternative to traditional energy generation systems, we have renewable systems, which are characterised by using natural resources to generate energy in a sustainable and environmentally friendly way. Hydroelectric plants that use water as their main element, wind turbines driven by the wind or photovoltaic panels that harness the energy of the sun are all examples of renewable energy generation systems.
Systems based on the mechanical rotation of an alternator vs. photovoltaic energy
How do traditional energy sources work?
Most conventional systems, as well as wind turbines and hydroelectric plants (renewable energy), generate power based on the mechanical or rotational movement of a generator shaft. Since the goal of this post is not to make you shut down your computer and hit the bottle, let’s just say that the heat produced by burning gas or oil, or the movement of the blades of a wind turbine, creates motion which, thanks to electromagnetism, ends up producing electric current.
How does a solar panel work?
Photovoltaic energy, on the other hand, doesn’t need a rotating generator. It generates electric current when certain materials (semiconductors such as crystalline silicon or gallium arsenide) are exposed to a light source (the photoelectric effect). Photovoltaic energy is able to convert sunlight (photons) into electrical energy.
All in all, this is the basic categorisation we can apply to each type of power generation system. Now let’s dig a bit deeper into each one, using the first classification: conventional vs. renewable systems.
Conventional generation systems
Among the types of conventional power plants, we can highlight the following:
1)Thermoelectric or thermal power plants: they transform the chemical energy of fossil fuels (heat) into electrical energy. Their operation is very similar regardless of the energy source used.
1.1) Conventional: energy is obtained by burning fossil, non-renewable raw materials such as coal, natural gas, oil or fuel oil.
1.2) Combined cycle: similar to conventional plants, but they only use natural gas. Their operation is more complex, as they have two separate turbines: a gas turbine and a steam turbine that work together. They are more efficient.
1.3) Nuclear: they generate power from the thermal energy produced by fission reactions (splitting of atomic nuclei) in the vessel of a nuclear reactor. The key element in a nuclear plant is the reactor, where the nuclear fuel is housed and where the chain nuclear reactions that release thermal energy take place. As in the plants mentioned above, the heat is used to heat water until it turns into high-pressure, high-temperature steam. This steam drives a turbine, which is connected to a generator that transforms the mechanical energy of the rotating turbine into electrical energy, ready for industrial or domestic use.
Renewable energy systems
When it comes to renewable systems, we have the following:
How does hydropower work?
1) Hydroelectric power: hydroelectric plants use a turbine to convert into electricity the energy carried by water as it falls from a certain height. In this turbine, the water is directed inside so that it hits the blades located on the edge of a shaft connected to an electric generator. The power is determined by the height of the incoming water’s fall. Hydroelectric plants are one of the cheapest energy sources and have very low emissions, mostly linked to the cement and steel used in their construction.
How does a wind turbine work?
2) Wind power: as mentioned earlier, a typical modern wind turbine has three blades mounted on a horizontal shaft, each of them around 60 metres long, which drives an electricity generator. Wind power essentially generates almost no global warming and no pollution; it only has a small amount of associated CO₂ emissions from the fossil fuels used to build and operate wind farms.
How does photovoltaic energy work?
3) Photovoltaic energy: its main energy source is the sunlight we receive every day. Silicon is the main material used in solar panels; the rest is made up of other photovoltaic materials such as gallium arsenide and cadmium telluride.
Solar photovoltaic systems that are already up and running do not produce any pollution or greenhouse gases, and they offer a safe way to generate power. They have no moving parts, which reduces maintenance, and they don’t cause noise pollution or need water (apart from a small amount to clean the panels). Some hazardous materials are used in their manufacture, but in small quantities, along with energy from fossil fuels. However, since panels last thirty years or more, the carbon footprint of the electricity they produce is only around 10% of that of gas turbine power plants.
What alternative energy sources are there?
4) Biomass: by biomass we mean any organic matter that can be used as an energy source. It can come from either animals or plants and can be obtained naturally or through chemical processes carried out in biomass plants. Biomass can be classified into three categories: natural (produced without human intervention), residual (of human origin) and cultivated (energy crops where specific species are grown for energy use).
5) Solar thermal energy: solar thermal, or thermosolar, energy is a type of renewable energy that harnesses the sun’s energy to generate thermal or electrical energy. Unlike photovoltaic panels, which generate electricity directly from light photons, solar thermal systems use radiation to heat a fluid. This hot fluid can then be used for things like heating, domestic hot water and other processes that require heat.
Besides the renewable systems mentioned above, it’s worth highlighting other renewable sources whose contribution may be smaller compared to wind or photovoltaic energy but which, on a small scale or in certain geographical areas, can become more relevant:
6) Tidal energy: energy from the tides.
7) Wave energy: energy from the motion of waves.
8) Geothermal energy: energy from the Earth’s internal heat (limited to regions of the world with high geological activity).
To make things a little easier, we’ve included a visual summary of the main electricity generation sources we’ve been talking about:
Well, that’s it — you’ve made it to the end of this post. Congrats! We hope you enjoyed this post about the different types of electricity generation sources. In the next chapters we’ll keep exploring how you can charge your phone or turn on your computer thanks to the power system.