What is ‘The Great Grid Update’ and what does it mean for the UK’s plan to decarbonise electricity by 2030?

Zara Pashov
Mar 11
6 min read

UK National Gridlines (Independent 2020)

11th of March 2025

By Zara Pashov (Head Net Zero Research Analyst, UCL Green Economy Society)

Established in 1926 [i], the National Grid is the United Kingdoms’ high voltage, power transmission network.

It supplies electricity reliably, efficiently, over long distances from power generation stations to consumers. Balancing energy supply and demand in real time, the grid serves as the United Kingdoms’ energy backbone, crucial for any industrial, business or home activity.

To meet the UKs’ goal of carbon neutral electricity production by 2030, the grid must undergo a much-needed update. The planned projects will construct fivefold more electricity transmission infrastructure in the next five years than have been constructed in the past thirty years, boosting energy security, reducing reliance on imports, and contributing to lower energy bills in the long term.

Set to be completed by 2029, it has been named ‘the Great Grid Update’.

Why is this important?

With increasing attention turned to our energy systems to produce carbon neutral electricity and with electricity demand in the Uk set to rise, our transmission grids stand at the forefront of the green transition.

With decarbonization, comes large scale electrification; the UK is expecting a 200% increase in electricity demand by 2050 [ii]. This is mainly fueled by the implementation of low-carbon electric based heating systems like heat pumps, transitioning from fossil-fueled cars to electric cars, electrifying heavy industry through electrical energy intense processes like hydrogen production [iii] and finally but not limited to; the growing demands of artificial intelligence technology.

Current analysis for the UK to meet carbon neutral electricity production goals by 2035, and in anticipation of the increase in demand; carbon brief estimates requirements of 12GW of offshore wind, 8GW of onshore wind, and 22GW of solar, totaling an added 42GW [iv]. Our transmission systems are often overlooked but are a crucial bottleneck to large scale electrification of our societies. Any move away from fossil fuel centralized power station production to more-localized distributed renewable energy production requires a newer, better connected and more reliable National Grid.

There is now an established, ‘connection queue’ where renewable energy projects are waiting to be connected to the National Grid and are unable to sell their produced energy. Over the last 5 years, projects awaiting connection have grown 10 fold [v]. Considering the National Grid is already at full capacity, these projects must wait longer to make returns on their investments.

These risks reducing investor sentiment and deterring investment into upcoming renewable energy projects. With many new projects in the pipeline; investment is key for their implementation and upscaling. This conveys the urgency of a larger capacity and more robust electricity grid.

What does the great grid update entail?

Comprised of 17 major infrastructure projects, this initiative will modernise existing networks and build new transmission infrastructure to carry clean energy, such as offshore wind power from the North Sea.

With the UK targeting 50GW of offshore wind capacity by 2030, a third of the UK's electricity demand [vi], the upgrades will ensure the grid has sufficient capacity to transport this renewable energy to consumers. These projects take the form of building transmission lines, (most notably from offshore wind plants), increasing the number of pylons, laying transmission marine cables and installing high voltage conductors. The chief executive of National Grid has reported these projects will,

"Double the amount of energy that can be transported around the country and support the electrification of the industries of today and tomorrow." [vii]

The National Grid has also been key drivers in the innovation of our changing energy systems. As part of the update, National Grid has partnered up with companies such as Linevision, which enhance renewable energy integration in the grid by highlighting spare capacity on overhead power lines. This technology allows better energy censoring and data analytics, estimated to optimise the grid and unlock 0.6GW, saving consumers an estimated 1.4m pounds in the first year of operation. [viii]

The Great Grid update will not only accelerate the UK to their energy targets but is it estimated that the projects £30 billion investment, will create over 55,000 UK jobs and add £14.5 billion annually to the economy [ix]. Importantly, the large investments required for this update show that a green energy transition, if executed right, can provide many jobs, reduce energy costs and boost the economy.

What would the future look like without grid modernisation?

The government have reported that without an expansion and modernisation of the electricity grid there are substantial risks that would "hold back our energy security, economic growth and other important infrastructure with lengthy delays".

Firstly, there is a large risk of curtailment, a situation where renewable energy generation is wasted or must be turned off, even when ideal conditions like strong sun or wind exist, because the grid cannot handle the excess supply. Curtailment is directly tied to rising “constraint costs,” which occur when the grid cannot transport clean energy to where it is needed.

This can happen for a few reasons; some being inefficient transmission capacity or localised demand supply imbalances. These costs are already high, at £2 billion per year in 2022, and are projected to quadruple to £8 billion annually, or £80 per household, by the late 2020s if no action is taken. [x]

Considering the National Grid financed a part of this large update from shareholder investment, and many private companies have invested into renewable energy projects; not delivering this Great Grid Update could create stranded assets. This may negatively effect the investment sentiment for renewable energy projects; slowing our transition to a greener future.

What are some of the risks of relying on purely renewable energy for electricity generation?

Although renewables offer carbon neutral (not counting the lifecycle CO2 of the technology) and abundant energy sources; they doesn't come without significant risk.

As mentioned before, curtailment can also occur when energy generating technology must be turned off as the grid cannot handle the excess supply. Due to the nature of these renewable technologies, this may happen more often if the grid's energy share is too reliant on solar.

This is because on the sunniest days int he UK, energy demand is the lowest; this is also when the solar panels are most productive. Rushing into decarbonsation strategies and relying too heavily on solar in the energy mix, may increase the occurrence of curtailment, leading to not only ‘lost’ energy but also economic losses.

Another risk is grid instability, if there is an increase in produced electricity and there are sudden surges during windy and sunny times of years, the frequency and voltage can become imbalenced, destabilising and causing blackouts.

Alongside enhancing real-time monitoring and management technologies, the National Grid aims to limit both curtailment and grid instability risks by use of batteries. They plan to connect over 19 energy storage projects totaling a storage capacity of 10GW. [xi]

This will address another often-overlooked bottle neck to large scale electrification. By storing excess energy generated during peak production times, these systems can release power during periods of high demand or low renewable output.

Final comments and future steps

After the Labour parties' manifesto to,

‘make Britain a clean energy superpower…with cheaper, zero-carbon electricity by 2030‘

they may well be on their way, showing other nations decarbonising energy system is a fathomable target.

Recent headlines reported that wind energy generation has overtaken natural gas derived electricity as the largest source of electicity for the first time [xii]. According to the National Energy System Operator, NESO, offshore windpower is projected to make up 50% of electricity generation in the UK by 2030 and is considered to become the backbone of the UK’s low carbon energy system [xiii].

Considering the modernisation of the grid is the largest update since 1950, it's a huge feat. The National Grid must work closely with the government to avoid any bureaucratic delays, such as planning permission. It is therefore important that the planning process is improved, and the National Grid continues and increases engagement with local communities to deliver this project on time.

The update to the National Grid is, as mentioned previously, a critical bottleneck to large scale decarbonisation of the network. Without it, the UK threatens our legally binding pledges to decarbonize electricity by 2030, our energy security and higher energy costs.

As impressive and needed as this grid update is; the modernisation and increase in National Grid capacity and storage should have been identified earlier on as a limiting factor for the UK’s move away from fossil fuels and electrification. Other countries now have the opportunity to look at their own energy systems and use the UK’s great grid update to make their grids future-robust.