The UK’s National Grid Electricity System

In the electricity sector in the United Kingdom, the National Grid is the high-voltage electric power transmission network serving Great Britain, connecting power stations and major substations. The National Grid network is made of high-voltage power lines, gas pipelines, interconnectors and storage facilities that together enable the distribution of electricity. The Great Britain grid is connected in a wide area synchronous grid nominally running at 50 hertz. There are also undersea interconnections to other grids in the Isle of Man, Northern Ireland, the Republic of Ireland, France, Belgium, the Netherlands and Norway.

Lord Weir, a Glaswegian industrialist, was asked by the British government in 1925 to solve the problem of Britain’s inefficient and fragmented electricity supply industry. Weir consulted with Charles Merz of the Merz & McLellan consulting firm, and the result was the Electricity (Supply) Act 1926, which recommended the establishment of a “national grid” supply system.  The 1926 Act created the Central Electricity Board, which set up the UK’s first synchronised, nationwide AC grid, running at 132 kV, 50 Hz.

Currently, the UK transmission network is owned and maintained by the following regional transmission companies:

-National Grid Electricity Transmission plc (NGET).

-Scottish Power Transmission Ltd.

-Scottish Hydro Electric Transmission.

-Northern Ireland Electricity Ltd.

Offshore transmission networks are subject to a separate competitive tender regime.

There are 14 licensed distribution network operators (DNOs) in Britain. Each is responsible for a particular regional area.

Power outages caused by problems with the grid’s infrastructure or a lack of generation to supply it with enough power are extremely rare. Issues affecting low voltage distribution systems, for which National Grid is not responsible, account for nearly all of the 60 minutes or so of average domestic power outages per year. The majority of these low-voltage distribution interruptions are caused by third parties, such as workmen drilling through street mains (or subterranean higher voltage) cables; this does not happen with major transmission lines, which are mostly overhead on pylons. Since 1990, there have been three power cuts of high national prominence that were linked to the National Grid, two due to generation issues.

The national grid has a stretch goal of becoming carbon neutral or negative by 2033, well ahead of the UK’s national target of 2050. It also intends to achieve zero-carbon status by 2025. In previous years, around 50% of all electricity supplied in the UK was generated by fossil fuels, predominantly natural gas. However, in the second quarter of 2020, 35.1% of UK electricity was generated by fossil fuels (34.4% from natural gas, 0.5% from coal and 2.9% from oil). This was only the second time that UK electricity generation by fossil fuel sources had dropped below 40%, with the UK achieving its first coal-free month of electricity generation between April and June 2020. However, there has been consistent progress toward carbon neutrality, with carbon intensity falling by 53% in the five years leading up to 2020.

Between April and June 2020, renewable energy sources accounted for 44.6% of electricity generation in the UK, up from 35.6% for the same period in 2019. Wind accounted for the vast majority of renewable electricity generation, which saw a 53% rise compared to the same period in 2019. February 2020 was the first month on record when more electricity was produced by wind farms than by gas-fired power stations. Between April and June 2020, the UK also set a new record for the longest period the UK grid has operated without coal. The increased prevalence of renewable generation in the UK energy mix has resulted in the National Grid Electricity System Operator (NGESO) having to spend increased resources on balancing the network.

Despite the fact that solar and wind energy are becoming more affordable, there are still a number of barriers to developing renewable energy in the UK. The following are the primary challenges of transitioning to a low-carbon economy:

Intermittency: The intermittent nature of wind and solar power makes it more difficult to balance supply and demand.

Storage: While advanced storage systems have the potential to provide significant environmental and economic benefits, outdated regulatory policy and a lack of market standardization pose challenges. Regulatory policy is lagging behind current energy storage technology.

Implementing net-zero and changing societal behaviour: The UK’s commitment to net zero will necessitate significant and complicated changes. To achieve that target, electricity production and use would need to increase substantially to meet heating and transport demands, as fossil fuels still account for about 80% of the energy used for heating and transport in the UK.

National Grid has previously stated that it could be ready to implement a zero emissions system as early as 2025 but that this would require significant investment.

This Post was submitted by Climate Scorecard United Kingdom Country Manager Prastuti Saikia


Climate Scorecard depends on support from people like you.

We are a team of researchers providing information on efforts to reduce global emissions. We help make you better informed and able to advocate for improved climate change efforts. Donations of any amount are welcome.