Interconnectors domain
How does GB trade electricity across borders?
Subsea cables and overhead lines link GB to six neighbouring countries. Electricity flows whichever way the price signal and system conditions dictate. As of 2025, 10.3 GW of operational interconnector capacity can meet roughly 30% of average demand, but relying on imports is not the same as having domestic supply.
Where do the cables run?
Ten operational links connect GB to France, the Netherlands, Belgium, Norway, Denmark, and Ireland. Four more are under construction or planned. The map below shows each cable's landing points and rated capacity.
What does the interconnector portfolio look like?
Each link connects GB to a specific country via high-voltage direct current cables. They are owned and operated by a mix of transmission owners, independent developers, and joint ventures. All require an electricity interconnector licence from Ofgem.
| Name | Country | Capacity | Length | Commissioned | Status |
|---|---|---|---|---|---|
| IFA | France | 2,000 MW | 70 km | 1986 | Operational |
| IFA2 | France | 1,000 MW | 240 km | 2021 | Operational |
| ElecLink | France | 1,000 MW | 51 km | 2022 | Operational |
| BritNed | Netherlands | 1,000 MW | 260 km | 2011 | Operational |
| Nemo Link | Belgium | 1,000 MW | 140 km | 2019 | Operational |
| NSL | Norway | 1,400 MW | 720 km | 2021 | Operational |
| Viking Link | Denmark | 1,400 MW | 765 km | 2023 | Operational |
| Moyle | Ireland (NI) | 500 MW | 63 km | 2001 | Operational |
| EWIC | Ireland (RoI) | 500 MW | 261 km | 2012 | Operational |
| Greenlink | Ireland (RoI) | 500 MW | 190 km | 2024 | Operational |
| NeuConnect | Germany | 1,400 MW | 720 km | ~2028 | Construction |
| GridLink | France | 1,400 MW | 210 km | ~2028 | Planned |
| LirIC | Ireland | 700 MW | ~260 km | ~2030 | Planned |
| Tarchon | Germany | 1,400 MW | ~620 km | ~2030 | Planned |
Why does France have three separate links?
IFA was built in 1986 and remains the highest-capacity single link. IFA2 added diversity by landing at a different point on the south coast. ElecLink runs through the Channel Tunnel infrastructure, which gives it a distinctive cost and risk profile. Three separate cables to the same country reduces the chance that a single fault takes out all French interconnection at once.
What is the cap and floor regime?
Ofgem's cap and floor provides interconnector investors with a minimum revenue guarantee (the floor) and caps upside (the ceiling). If congestion revenues fall below the floor, consumers top up the difference. If revenues exceed the cap, the surplus is returned to consumers. This reduces investment risk while protecting consumers from excessive rents. Most new interconnectors since 2014 have been developed under this regime.
How do interconnectors actually work?
Electricity flows through interconnectors from the lower-priced market to the higher-priced market. When electricity is cheaper in France than GB, IFA imports French power. When GB has surplus wind pushing prices down, power flows the other way.
Capacity allocation
Interconnector capacity is sold through explicit auctions (annual, seasonal, monthly, daily, and intraday) run by the Joint Allocation Office. Traders bid for the right to flow power in a specific direction at a specific time. Since Brexit, GB is no longer part of the EU's coupled day-ahead market, which makes allocation less efficient than it was.
Revenue model
Interconnector owners earn revenue from the spread between wholesale prices in the two connected markets. When the price difference is large, revenues are high. When prices converge, revenues fall. The cap and floor regime smooths this for most newer links.
System security
NESO treats interconnectors as both a supply source and a contingency risk. If a 2 GW link trips during high import, the system loses a large block of power instantly. NESO must hold sufficient reserve to cover the largest single loss, and the cost of that reserve is factored into balancing costs.
Post-Brexit trading
Before Brexit, GB participated in the EU's single day-ahead coupling mechanism, which optimised cross-border flows automatically. Since January 2021, GB has used explicit auctions instead. Ofgem estimated the efficiency loss at 17 to 38 million pounds per year. Discussions about multi-region loose volume coupling continue, but implementation remains incomplete.
What is the difference between HVDC and HVAC interconnection?
All long-distance subsea interconnectors use high-voltage direct current because AC cables generate reactive power over distance, which limits practical cable lengths to roughly 50 to 80 km without compensation. HVDC avoids this and allows precise control over power flow direction and magnitude. The converter stations at each end are expensive, but for cables longer than about 80 km the economics favour DC.
Can interconnectors provide frequency response?
Modern HVDC converters can provide synthetic inertia and frequency response services, which makes them more valuable than older links that simply transferred bulk energy. Viking Link and NSL both have technical capability to support GB frequency management, although the commercial and regulatory arrangements for these services are still maturing.
Why do interconnectors matter for Clean Power 2030?
The Clean Power 2030 plan relies on interconnectors to help balance a system with very high wind and solar penetration. When the wind is not blowing across north-west Europe, interconnectors can import from hydro-rich Norway or nuclear-heavy France. When GB has excess wind, they can export to avoid curtailment.
The diversity argument
Weather patterns across Europe are not perfectly correlated. When it is calm in the North Sea, it may be windy in the Bay of Biscay. When it is cold and still in GB, Norwegian hydro reservoirs may be full. The more interconnected GB is, the less domestic backup capacity is needed. But this creates a dependency on the political and market conditions of neighbouring countries.
The limits of import reliance
Interconnectors help, but they do not replace the need for domestic networks, firm capacity, or local flexibility. If GB itself is tight and so are its neighbours, imports will not materialise at any price. The planned pipeline adds about 5 GW, but not all projects will reach final investment decision.
Methodology and sources
Last reviewed: 17 March 2026
Content sourced from the React page component at commit e19c4d6. The cable map shows all operational and planned interconnectors with verified capacity figures. Supporting sections cover portfolio detail, market mechanics, and the Clean Power 2030 context.
| Source | Ofgem interconnectors — current interconnector estate and regulatory context. |
| Source | Cap and floor handbook 2024 — investment framework and regulatory treatment. |
| Source | Elexon BMRS — live flow data and system context. |
| Source | NESO ETYS — system planning and interconnector capacity projections. |
Voltage: the stepping-down hierarchy
Follow the voltage cascade from 400 kV transmission to 230 V at your socket.