Gas domain
How the GB gas system works
Gas heats 23 million homes, generates around 40% of our electricity, and provides essential feedstock for industry. The gas system is the largest energy network in the country by energy throughput, and understanding how it works is essential for anyone thinking about the energy transition.
Gas import terminals and supply routes
Gas enters Great Britain through a distributed network of terminals. Pipeline terminals receive gas directly from the North Sea or continental Europe; LNG terminals import liquefied gas by ship from global suppliers including Qatar, the United States, and Australia.
Interconnectors allow bidirectional flow depending on price and demand. BBL links Bacton to the Netherlands; IUK links Bacton to Belgium.
Terminal capacity and strategic significance
The highest concentration of terminals is in Norfolk and the Thames Estuary (Bacton, Isle of Grain), reflecting historical North Sea production and convenient ship access. The Milford Haven LNG terminals in South Wales are supplied by some of the world's largest LNG vessels and serve as a strategic import point for Mediterranean and Atlantic basin suppliers. South Hook alone has a capacity of 15.6 bcm per year, making it one of the largest LNG regasification terminals in Europe.
How gas flows through the system
Gas enters GB through beach terminals (from the North Sea), LNG import terminals (from global markets), and pipeline interconnectors (from Norway, Belgium, and the Netherlands). It flows through the National Transmission System at high pressure, then steps down through pressure reduction stations into regional distribution networks, and finally into your home at very low pressure through your meter.
Where does our gas come from?
GB gas supply has diversified dramatically since the North Sea peaked in 2000. We now import more than half our gas. Click each source to learn more about it.
Current position
Current official material presents diversified imports, storage, and transmission flexibility as central to GB gas resilience. The remaining exposure is often economic rather than purely physical, which is why wholesale shocks can still affect affordability even when supply continues to flow.
Gas distribution networks
Eight regional Gas Distribution Networks (GDNs) operate the local pipelines that deliver gas from the NTS to your home. They are owned by four companies and regulated by Ofgem under the RIIO-GD2 price control (2021-2026). Their biggest challenge right now is preparing for the transition away from natural gas while continuing to maintain and operate a network that 23 million homes depend on.
How the iron mains replacement programme shapes the transition
GDNs have been replacing old iron gas mains with polyethylene pipes for safety reasons since the 1990s. This programme has an unintended benefit for the energy transition: polyethylene pipes are compatible with hydrogen, while iron pipes are not. By the time the iron mains programme completes (expected around 2032), most of the distribution network will be hydrogen-ready in a physical sense. Whether that matters depends on the strategic decision about hydrogen for heating, which the government has repeatedly delayed.
Linepack and system balance
Unlike electricity, gas can be stored in the pipes themselves. The total volume of gas in the NTS at any given time is called linepack. NESO uses linepack as a buffer to balance supply and demand in real time. If demand exceeds supply, linepack falls and pressure drops. If supply exceeds demand, linepack rises and pressure increases.
On a typical winter day, linepack swings by about 30-40 mcm as morning demand ramps up before supply catches up. On a 1-in-20 peak demand day, linepack management becomes critical. NESO can issue Gas Balancing Notifications (GBNs) to incentivise shippers to increase supply or reduce demand.
How linepack mechanics work in detail
Linepack is essentially the gas stored inside the transmission pipes themselves, using the network as a buffer when demand spikes faster than supply can respond. The NTS operates at pressures between 38 and 85 bar. When morning heating demand ramps up, gas is drawn from the pipes faster than it enters, causing pressure and linepack to fall. Shippers must then balance their inputs and outputs over each gas day (06:00 to 06:00). If aggregate linepack falls below NESO's minimum safe level, the system operator can issue Gas Balancing Notifications and, in extreme cases, invoke emergency procedures. GB's relatively low gas storage capacity (around 1.5 bcm, compared to Germany's 24 bcm) makes linepack management especially important during cold spells.
The future of gas
The gas network faces a strategic transition question: what role does it play in a net zero energy system? There are broadly three possible futures, and the eventual mix will depend on policy, technology costs, and consumer uptake over the next decade.
Hydrogen conversion
Repurpose the gas network to carry hydrogen instead of methane. This is technically feasible for distribution pipes (most are already polyethylene, which is hydrogen-compatible) but requires new transmission infrastructure, hydrogen production at scale, and conversion of every appliance in every home. The government's hydrogen village trial at Redcar was cancelled in 2023, and the 2026 strategic decision on hydrogen for heating has been repeatedly delayed.
Electrification
Replace gas boilers with heat pumps and electrify heating entirely. This is the Climate Change Committee's preferred pathway. It requires massive reinforcement of the electricity distribution network, significant insulation improvements to the housing stock, and consumer willingness to switch from a cheap, familiar technology to an expensive, unfamiliar one. The current heat pump installation rate (about 55,000 per year) is far below the 600,000 per year target for 2028.
Managed decline
Gradually reduce gas demand through efficiency improvements and partial electrification, while keeping the network running for residual industrial and peaking uses. This is the most likely near-term outcome, even if it is not anyone's stated policy. It raises difficult questions about who pays for maintaining a declining network as fewer customers spread the fixed costs.
Programme context
The current position is still transitional rather than settled. Policy work continues to test electrification, hydrogen, and managed-decline pathways, and recent programme changes have made a mixed outcome more plausible in the near term: wider electrification for homes, targeted hydrogen use in industrial settings, and continued gas-system roles in residual and backup use cases.
Methodology and sources
Last reviewed: 17 March 2026
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