Ever wondered how your energy actually gets to your home? Well it takes quite a long journey. The gas and electric supply network in the UK is split into 3 stages: generation/production; transmission and distribution. The power distribution - the part that gets the energy through your door - is handled by different companies in different areas of the country. Read on to discover more about the journey your energy takes and find out who your gas and electricity distributors are.
- Electric distribution and transmission network
- Gas transmission and distribution network
- Find your gas and electric distrubuter
GB electric distribution and transmission network
The journey your electricity takes
- Generation: electricity produced from the source e.g. power plants, wind turbines etc.
- In order to reduce resistance in transmission lines, the electricity is passed through a step-up transformer to increase the voltage and reduce the current. This allows the electricity to be transported over large distances without losing as much electricity in the process.
- Transmission: electricity is transmitted across the country through transmission pylons bidirectionally to allow the grid’s needs to be fulfilled.
- The voltage of the electricity in the transmission network is really high so it needs to pass through a step-down transformer to reduce the voltage before it can be distributed to homes and businesses.
- Distribution: electricity is transferred to low voltage distribution lines and transported over small distances (usually within small localities) and into your home.
Electricity in the UK comes from a large variety of sources. Although we are still heavily dependant on natural gas and coal, our energy mix is ever expanding, preventing us from becoming too reliant on any one source.
- Nuclear power
- Fossil fuel
- Renewable energy
15 reactors generate about 21% of the UK’s total electricity production, but the aim is to half this by 2025.
The UK’s reliance on energy generated from fossil fuels, such as coal and gas, has been steadily decreasing. In 2017, around 50% of the total electricity production came from fossil fuels.
Burning fossil fuels is one of the major causes of air pollution as they emit Carbon dioxide (CO2) when they are burned. This is why energy companies in the UK are increasingly turning towards low carbon energy sources, often referred to as renewable energy.
Renewable energy comes from sources such as wind, solar, hydro and biomass. In 2017, around 29% of the UK’s electricity came from renewable sources. The aim is for this figure to be 30% by 2020 so we are nearly there!
Wind is currently the biggest source of renewable energy. Many distributors are investing millions of pounds in offshore wind farms. For example, SSE’s Beatrice offshore windfarm (due to be completed in the summer of 2019) will be the UK’s largest offshore windfarm and will seriously increase SSE’s renewable energy generation.
The UK’s biggest power station and largest emitter of CO2, Drax in Yorkshire, is also working to reduce its carbon emissions by increasing its biomass production. They currently transport 2 meta tons of compressed wood pellets annually from the southern states of America to heat homes in the UK.
Signing up for a renewable energy tariff is a great way to do your part toward reducing air pollution. By having a green tariff you are reducing the amount of non-renewable energy that suppliers need in order to fulfil their supply obligations. This, in turn, reduces their - and your - carbon footprint.
Remember: having a green energy tariff doesn’t change the electricity you get in your house , it just means the source of your electricity is renewable and so much less harmful to the environment.
The transmission stage is how the electricity leaves the power plant and gets transported across the country via transmission pylons; you know, the large, ugly metal structures usually located in big open spaces and next to motorways.
Transmission pylons carry extremely high voltages of electricity up and down the country at high speeds. As they are carrying such high voltages, the pylons need to be tall in order to carry the electricity a safe distance from the ground. In the UK they can be up to 190m high. There are two voltage categories: 50,000V - 200,00V, called high voltage lines; and over 200,000V called extreme high voltage lines.
They use alternating current (AC) as their form of electricity transportation. This means the electricity can travel bidirectionality (in both directions), allowing it to quickly get to where it is needed and reducing the risk of power cuts.
The transmission network in Wales and England is primarily managed by National Grid. Scotland is split into two sections; one managed by SP Energy Networks and the other by Scottish and Southern Energy.
The final stage, the distribution stage, is how the electricity enters your home. Distribution lines are local networks of small, (usually) wooden pylons that distribute lower voltage electricity over shorter distances.
They carry considerably lesser voltage than transmission pylons so are not much more than 10m tall. They also have two voltage categories, 0V - 1000V, called low voltage lines; and 1000V - 50,000V, called medium voltage lines. The voltage that enters our homes in the UK is 230V, which means the entry point comes from a common low voltage line. Just like transmission lines in the UK, distribution lines use AC to transport electricity to your home.
Each area of the UK has its own Network Distribution Operator (DNO) that manages the distribution of electricity to each household under their operation.
GB gas transmission and gas distribution network
The journey your gas takes
- Production: using a boring machine, a large drill bit drills into the earth to try bring petroleum oil hydrocarbon to the surface from within the earth.
- Gas processing plant: natural gas enters the gas processing plant in its pure, raw form. It is cleaned, separating any impurities and non-methane hydrocarbons and fluids to produce a ‘pipeline quality’ dry natural gas.
- Transmission: as it is transported across the transmission network, compressor stations increase the compression to help to keep its transportation smooth and efficient.
- Odorant: natural gas is odorless and potentially deadly so an odor is added to enable leakages to be quickly identified.
- Distribution: at 49 points across the UK, the gas enters the 8 distribution networks. Each distribution company is in charge of ensuring the safe arrival of gas to households and business’.
- Supply: gas is delivered to your home. Each customer opts for one of the many energy utilities to pay for their gas supply. Part of this money is used by the utility to pay their gas distributor and the transmission network.
In the UK, gas is mainly extracted from the Irish and North seas from offshore drilling rigs.
Natural gas is taken from substances beneath the earth's surface, such as: water; oil; and rock. It is then transported on large ships to gas processing plants in the UK. Here the gas is cleaned and separated from the other materials to produce a dry natural gas. It is now ready to be transmitted across the UK.
The transmission stage sees is the natural gas transported at speeds of up to 25mph to one of the 8 area distribution networks. The sole owner of the gas transmission network in the UK is National Grid.
All gas in the UK will pass through the National Grid’s National Transmission System (NTS). The system covers 171,000 miles/ 275,000km (the same distance it would take to travel around the world almost 7 times)!Within this network there are 25 compressors and 25 pressure regulators, which ensure the gas is efficiently compressed (to allow large quantities to be transported) and non-harmful to the piping system.
The gas passes through a compression station every 40-100 miles to make sure it’s pressure and volume are correct. Altering the pressure and volume causes the temperature of the gas to rise quite considerably (from around 5ºC to 48ºC). To counteract this, the gas has to travel through a cooling system to prevent damage to the piping system as it travels to its designated distribution network.
8 Gas Distribution Networks (GDN) are responsible for delivery gas to houses across Britain. Each network serves a different part of the country and is owned by one of the four gas transportation companies: National Grid; Northern Gas Networks; Wales & West Utilities; and SGN. As these companies are regional monopolies, they are regulated to limit profit margins.
When travelling through the distribution network, the gas passed through pressure reduction tiers to slow and disband it. Finally, it will visit a measurement station where the pressure will be reduced further so you can use it for cooking or heating your home.
Below is a map of the area gas distribution network, displaying the borders of control for each of the four companies:
Find your gas and electric distributor
|County||Gas Distributor||Distribution Network Operator|
|East Lothian||SGN||SP Distribution|
|Ross & Cromarty||SGN||SSE|
|West Lothian||SGN||SP Distribution|