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How We Generate Electricity in The UK

LAST UPDATED FEB 2022

Where Does Our Electricity Come From

The UKs electricity is generated in a variety of ways by a number of companies and managed by ‘National Grid ESO’. It is their job to make sure the electricity supply meets demand wherever and whenever it is needed. 

Historically our electricity was generated by a small number of very large power stations that all ran on fossil fuels. Today we utilise a variety of different types of electricity generation including fossil fuel, nuclear, solar, and wind. The latter are known as ‘renewable’ energy as they are produced using renewable resources like solar, harnessing energy from the sun and wind turbines which harness energy from wind.

There is a huge global effort to move away from fossil fuel electricity generation as it is very polluting producing enormous amounts of carbon dioxide, the main ‘greenhouse gas’ responsible for global warming. The UK Government has committed to producing all of our energy needs from 100% renewable resources by 2035. This is an ambitious target and we can all help achieve this by looking at what we can do to reduce the amount of energy we use.

National Grid ESO publishes data showing how much of our electricity is produced by each type of electricity generation. We have pulled this data into a few charts below to show the % mix of the different types of electricity generation during the last few years and we will keep this post updated on a regular basis. We have also summarised each type of electricity generation further below. 

2020 UK Electricity Generation

2021 UK Electricity Generation

2022 UK Electricity Generation

Combined Cycle Gas Turbines (CCGTs) are currently the largest source of electricity generation in the UK producing over a third of all of our electricity. They combine a gas-fired turbine with a steam turbine and are very efficient. The steam turbine drives a generator and the generator produces electricity. But gas is a fossil fuel and burning it produces a lot of carbon dioxide so this is the main type of electricity generation that we need to move away from. One key aspect of these turbines is they can be brought on or offline very quickly and therefore they are used to balance out renewable technologies, i.e. when it’s not very windy or sunny we use more gas and vice versa.
Wind turbines are very efficient at converting wind power to electricity. They work by harnessing the power of wind to turn the propeller like blades of a turbine, which turns a rotor, which drives a generator, which creates electricity. There is no burning fuel so no pollution or waste which means it is clean and it’s renewable, i.e. it keeps working as long as the wind blows. This does however mean that this source of energy is intermittent, if it’s not windy it doesn’t work. This means we can’t rely on wind turbines by themselves, we will always need another type of electricity generation for those days when there’s not enough wind.

There are a number of on-shore and off-shore ‘wind farms’ across the UK that consist of a large number of turbines grouped together. The Rampion wind farm sits about 8 miles off the coast of Sussex and comprises 116 turbines producing enough electricity for around 350,000 UK homes. That’s about 600,000 tonnes of carbon dioxide emissions saved each year by not burning fossil fuels to generate this electricity.

Wind turbines are currently second to gas in regards to the amount of electricity they generate but this amount can change daily as the wind changes. Over the last couple of years wind turbines have generated over 20% of the UKs electricity peaking in Feb 2022 at almost 40% thanks to three major storms Dudley, Eunice and Franklin. There are significant expansion plans for wind farms as the technology continues to come down in price. Offshore wind farms can be built at large scale so they can easily match the output of gas turbine power stations. The owners of The Rampion wind farm have proposed building an additional 100 new turbines.

There are currently 8 operational nuclear power stations across the UK producing around 15% of our electricity. They generate power through ‘fission’, which is the process of splitting uranium atoms to produce energy. The heat released by fission is used to create steam, which spins a turbine, that drives a generator which generates electricity. Nuclear power stations are expensive to build and maintain but they produce no carbon emissions so the electricity they produce is clean. They do however produce waste which can be dangerous and costly to process and dispose of.

Half of the UKs nuclear power stations are due to be decommissioned within the next 5 years. The UK government is considering building new ones to maintain nuclear power as an important part of the UKs energy make up. They can’t be easily or quickly switched on and off but they can be managed to produce more or less electricity at different times. This will help manage the peaks and troughs of wind power and provide an opportunity to further reduce our reliance on gas.

Biomass is a term used to describe plant based materials that are used to produce either heat or electricity. The most common type of Biomass used in the UK to produce electricity is wood pellets, most of which are imported from the US and Canada. These pellets are burned in converted coal power stations to produce steam which spins a turbine which drives a generator which generates electricity.

There is significant debate as to exactly how ‘green’ biomass energy is as burning wood pellets does produce greenhouse gases like carbon dioxide. But Biomass is considered a renewable form of energy production when managed properly. The trees and crops that eventually become wood pellets remove carbon dioxide as they grow, so it has been called a carbon neutral fuel – we put back in through burning what was taken out through growth. If we plant more trees than what we eventually burn Biomass energy can help to reduce the amount of greenhouse gases entering the atmosphere.

Its success therefore relies on a number of things. It takes trees a long time to grow so the positive effect of removing carbon dioxide takes time and we will always need to plant more than what we intend to burn. Critics claim we are not doing enough of this and we need to increase the volume of trees that we plant to make it really successful. We also need to take into account the pollution produced from transporting Biomass long distances. The UK government has committed to increasing properly managed Biomass energy production as part of a long term plan to use a combination of different types of electricity generation including WInd, Solar and Nuclear.

Solar PV or Solar Photovoltaic panels convert sunlight into electrical energy. It is estimated that every couple of hours, enough sunlight hits the surface of our world to provide the entire world’s energy consumption for a year. The difficulty is harnessing all of that energy. Solar PV is an intermittent source of renewable energy, if it’s not sunny it doesn’t work and therefore despite significant improvements in technology over the last few decades, it still does not generate electricity as efficiently as other technologies.

Different types of energy production are compared by using what is known as a Capacity Factor. This is a rating that describes how much energy an electrical power station of any type actually produces versus what it is technically capable of producing. Nuclear power has a Capacity Factor of around 93%, in other words nuclear power stations on average are producing electricity 93% of the time, the other 7% when they are not producing electricity is during maintenance and refueling. Gas power stations have a Capacity Factor of around 55% and wind farms have a Capacity Factor of around 35%.

Solar PV has the lowest Capacity Factor of all UK electrical power production at around 24%. Quite simply we don’t get enough sun in the UK to get more out of the technology and there are a number of factors that can influence its success. The UK gets less sun than most European countries and some parts of the UK get more sun than other parts. The direction the Solar PV panels face is another key factor, panels facing directly south will perform much better than those that don’t.

The solution is to build a large number of very large Solar PV farms so they are financially viable or utilise a lot more rooftops across the UK. The downside is that large scale Solar PV farms require a lot of land and residential rooftop arrays are expensive, potentially taking up to 20 years to recoup their cost. Commercial rooftops are more cost effective for Solar PV and this market is growing. The UK government does include Solar PV as part of its commitment to reduce carbon emissions by moving away from fossil fuels to renewable energy.

Up until the 1990’s over 80% of the UKs electricity came from coal fired power stations. Today, Feb 2022, only 2% of our electricity comes from burning coal. This dramatic shift was due to the increase in use of Gas and Nuclear and renewable energy sources like Wind and Solar.

Coal is formed over millions of years and there are vast deposits across the globe. It has been used as a fuel for thousands of years in a very limited way, until the industrial revolution and the invention of the steam engine. Coal use increased more and more rapidly, providing power for iron and steel production, manufacturing and transportation, heat for domestic properties and power for electricity generation.

Coal is by far the dirtiest fuel that we use. As our awareness of the impact of pollution from burning coal has increased and new technologies have become available, our reliance on coal has dropped but it is still widely used. In 2020 coal supplied a third of the world’s electricity emitting 14 billion tonnes of carbon dioxide into the atmosphere, a quarter of all greenhouse gas emissions for the year. China was the biggest importer and consumer followed by India and Indonesia, Australia and Russia were the biggest exporters.

Most coal fired power stations in the UK have either been decommissioned or converted to burn Biomass which is considered a renewable fuel when managed properly.