Electricity Interconnectors: How Britain Trades Power With Its Neighbours

Britain's electricity system is physically wired into its neighbours. Ten operational interconnectors, high-voltage cables mostly buried under the sea, give Great Britain 10.3GW of cross-border capacity, enough to move power in or out on the same scale as several large power stations¹. A new link to Germany, NeuConnect, adds 1.4GW and takes the total to 11.7GW¹.

The cables carry electricity in whichever direction the money points. When British wholesale prices are lower than those across the water, traders export; when continental or Nordic power is cheaper, Britain imports. In 2024 total imports rose by 31% to 43.7TWh, and net imports, imports minus exports, reached 33.4TWh, a 40% rise on 2023¹. In 2025 net imports fell back 11% to 30TWh³.

For a household, the practical questions are whether these links make electricity cheaper or dearer, and whether they make supply more or less secure. The short answers: they cut both ways on price, and they add flexibility to the grid without removing Britain's underlying position as a net importer of energy⁴.

What an electricity interconnector is, and why Britain built them

An electricity interconnector is a direct transmission link between two countries' grids, in Britain's case almost always a pair of subsea high-voltage cables running to France, the Netherlands, Belgium, Norway, Ireland or Denmark. Power can flow either way, and the direction at any moment is set by the wholesale price difference between the two markets. When the price gap is large enough to cover the cost of transmission losses and charges, traders buy in the cheaper market and sell in the dearer one, and the cable carries the power.

The reason Britain built them is structural. The British grid has a large and growing share of wind and solar generation, which produces in bursts rather than on demand. Norway's hydro reservoirs, French nuclear output and the continental market can absorb British surpluses when wind output is high, and send power back on cold, still evenings when British generation is stretched. Interconnectors are, in effect, a way of borrowing other countries' flexibility, and of selling Britain's own when it has spare.

They are not a new idea, and they are not only an electricity story. Britain has long traded gas through pipelines with Belgium, the Netherlands and Norway, and interconnector pipeline imports of gas play a key role in balancing supply and demand on cold winter days, though they account for around 1% of gross annual gas supply on the five-year average¹. The electricity links do the same job for power. The parallel story is covered in gas pipelines and interconnectors, and the Irish links, Moyle and East-West, have their own page at the Moyle and East-West interconnectors.

Interconnector capacity today: 10.3GW over ten links

Great Britain currently has 10.3GW of operational electricity interconnector capacity across ten interconnectors¹. The same figure appears in the government's Clean Flexibility Roadmap, which records GB's current interconnection capacity as 10.3GW². Two official documents published within a year of each other agree exactly, which is worth noting because interconnector totals are often quoted inconsistently elsewhere.

To put 10.3GW in scale, it is roughly comparable to the output of several large power stations flowing in one direction, and it sits within a system whose total installed capacity NESO projects will reach 190GW by 2035⁵. The links are not all equal: some are long subsea routes to Nordic hydro, others short crossings to the French and Dutch markets, and their value differs accordingly. A link to Norwegian reservoirs behaves differently from a link to a market dominated by nuclear, because the neighbour's ability to absorb or return power depends on its own generation mix.

Capacity is not the same as delivery. A 10.3GW ceiling is the maximum the cables could carry if every link were importing at full rate at the same time, which does not happen in practice. Actual flows depend on price differences, the availability of generation on both sides, and the state of each cable. The figures on how much power actually moves are smaller, and they are covered below.

Planned capacity of 11.7GW and the outlook beyond

The next step is NeuConnect, a 1.4GW link between GB and Germany, which brings the total to 11.7GW¹. Beyond that, over 6GW of further interconnection projects hold GB regulatory approval². Those are projects that have cleared the regulatory hurdle but are not yet built, so their completion dates and final capacities remain subject to delivery.

NESO's longer-term planning assumes interconnector capacity of 13GW in 2030, 13GW in 2035 and 13GW in 2050, against total installed capacity of 190GW in 2035 and 276GW in 2050⁵. Two things stand out in those numbers. First, interconnection grows from 6GW in 2021 to 13GW, more than doubling, but then plateaus in the planning assumptions. Second, it plateaus while total installed capacity keeps climbing, so interconnectors become a proportionally smaller part of a much larger system. By 2050, 13GW of interconnection sits within 276GW of total capacity⁵.

For households, the significance of the growth from 6GW to 13GW is that Britain is deliberately wiring itself more deeply into the European market as its own generation mix shifts towards weather-dependent sources. That is a choice with consequences in both directions, which the rest of this page sets out.

Daily patterns in electricity flowing in and out

Interconnector flows are not a steady one-way stream. Across a typical day they swing with the wholesale price. When British demand is low, for example overnight or on windy afternoons, British prices can fall below continental ones and the links export. At the evening peak, when British demand rises and wind output may be falling, prices rise and the links import. On some occasions British prices fall so far they go negative, and the dynamics of those hours are covered at negative electricity prices in Great Britain.

The annual totals show how much this two-way trade nets out. Total imports in 2024 were 43.7TWh, while net imports were 33.4TWh, meaning roughly 10TWh of British electricity flowed the other way as exports¹. In 2025 net imports fell 11%, from 33TWh to 30TWh, as reported by the Climate Change Committee in its 2026 progress report³. A fall in net imports can mean more British generation serving British demand, more exports, or both; the net figure alone does not say which.

The trading backdrop matters for understanding these swings. Britain's own generation mix, including nuclear at 12.3% of generation by major power producers in the three months to November 2025⁶, sets the floor of British prices, and the continental and Nordic markets set the alternative. The mechanics of how wholesale prices form on both sides are covered at how the wholesale gas and electricity markets work.

Households with solar panels are part of the same export picture at a much smaller scale. Under the Smart Export Guarantee, small-scale generators exported 443.1GWh of low-carbon electricity in 2024 to 2025⁷, a figure two orders of magnitude below interconnector flows, but flowing through the same principle: power moves towards whoever values it.

The role, and limits, of interconnectors in keeping homes supplied

Interconnectors add flexibility, not self-sufficiency. On a tight winter evening, the ability to import several gigawatts from France, Belgium or Norway widens the gap between available supply and expected demand, and that gap is what stands between a strained system and shortfall notices. How those margins are assessed is covered at electricity margins, shortfall notices and the risk of shortages, and NESO's seasonal view at the NESO Winter and Summer Outlooks.

The limits are just as real. An interconnector is only as reliable as the market at the other end. A cold, still spell that squeezes British wind output often squeezes French and German demand too, because Europe's weather is correlated. In those hours the cables may be importing at full rate, or the price may be too high to make importing worthwhile, or the neighbour may need its own power. Interconnection spreads risk across a continent; it does not abolish weather.

The deeper point for a household thinking about energy security is that interconnectors are a form of dependence, deliberately chosen. Britain is a net energy importer with a high dependence on gas and oil⁴, and a net importer of natural gas, importing more than it exports⁸. Electricity interconnectors add another strand to that import position, even as they give Britain an export route for its wind surplus. What a home can genuinely control, from insulation to its own generation, is set out at energy security and household independence.

How interconnectors fit into the broader network

Interconnectors are one piece of a system that has to balance itself second by second. The links land at substations on the British transmission network, the pylons, cables and converters described at the electricity transmission network, and their power then flows through the regional distribution networks to homes. How the system operator keeps supply and demand matched, with interconnector flows among the variables it must manage, is covered at balancing services and frequency response.

Storage increasingly works alongside the links. Britain's existing pumped hydropower storage stands at 2.8GW, the majority contributed by the Welsh schemes at Ffestiniog and Dinorwig⁹, and grid-scale batteries are growing fast, as described at grid-scale battery storage in Great Britain. The pattern taking shape is one in which interconnectors move power over hours and hundreds of kilometres, storage moves it over shorter distances and times, and demand flexibility shifts household consumption itself, as covered at household demand flexibility and the grid.

The household end of this system is also being wired up. The Data and Communications Company operates the secure national network that connects smart meters across Great Britain¹⁰, the metering layer that makes time-varying prices and flexible consumption workable at home. Interconnectors, storage, flexible demand and smart metering are all parts of the same shift towards a system that moves power to where and when it is worth most.

Who owns, regulates and controls the links

Each interconnector is a commercial asset, built and owned by the companies that financed it, typically partnerships involving network businesses on both sides of the link. What they may charge, how they are treated in the regulatory framework, and whether a project goes ahead at all are decisions taken within the British regulatory system.

Ofgem is Great Britain's independent energy regulator¹¹, and it is the body that grants interconnector projects their GB regulatory approvals, the stage beyond which over 6GW of further projects have so far progressed². Energy infrastructure and regulation more widely is the responsibility of the UK Government¹². Day-to-day, the electricity system is balanced by NESO, whose role is described at NESO: the National Energy System Operator.

For households, the relevant regulatory protections sit at the supply end, not the interconnector end. Around 53.7 million domestic customer accounts exist in Great Britain¹³, all served through licensed suppliers whose conduct Ofgem oversees. Where a dispute with a supplier cannot be resolved, the Energy Ombudsman, approved by Ofgem to handle service disputes in the energy sector, is the escalation route¹⁴. Interconnectors sit behind all of this: a household's contract is with a supplier, and the supplier buys in the wholesale market the interconnectors feed into.

Import prices and their effect on household bills

Interconnectors transmit price, not just power. When Britain imports because continental power is cheaper, that can hold British wholesale prices down. When Britain imports because British generation is scarce, the links connect British buyers to whatever the continental price is, and that can pull British prices up. Exports work the same way in reverse: selling British wind surplus abroad raises the price received for British generation, but on a tight day it can also draw power away from the home market.

The recent record is sobering. UK electricity prices stand 40% higher than in mid-2021, and lower prices elsewhere have meant the UK has been third or fourth highest among the EU countries and the UK over the past two years¹⁵. EU members produce on average almost 50% more electricity than the UK on a per capita basis¹⁶, a gap in domestic generation that interconnectors bridge by trade rather than remove. How global events feed into these prices is covered at how global events move UK energy prices.

What reaches a bill is capped. For the cap period from 1 July to 30 September 2026, a household in the Eastern region on a single-rate meter at 2,500 kWh faced a maximum standing charge of £187.52 and an annual bill of £815.65; in the Midlands, £207.57 and £810.72; in the Northern region, £223.48 and £824.03¹⁷.

All figures are Ofgem's cap levels for 1 July to 30 September 2026¹⁷. The regional differences reflect network costs, not interconnector flows, but they show how the wholesale price set partly by interconnector trade is then layered with network and policy costs on its way to a household bill. Those network charges are unpacked at TNUoS, BSUoS and the network charges behind your bill.

Interconnectors' place in the journey towards energy self sufficiency

Interconnectors occupy an awkward position in the independence argument, and it is better to state it plainly than to resolve it one way. On one side, they let Britain sell its wind surplus rather than curtail it, and buy power rather than build enough firm capacity to cover every extreme on its own. That is why the planning assumptions see interconnection doubling from 6GW in 2021 to 13GW by 2030⁵, and why over 6GW of further projects have already cleared GB regulatory approval².

On the other side, every megawatt imported is a megawatt not generated in Britain, and the UK's overall position is unambiguous: a net energy importer with a high dependence on gas and oil⁴, and a net importer of natural gas⁸. The same pattern runs through the gas system, where Britain depends on Norwegian pipeline supply and LNG shipped from further afield, as covered at where Britain's gas comes from and LNG imports and UK terminals. Electricity interconnectors extend that trading position rather than end it.

For a household, the honest conclusion is that interconnectors make the British system more flexible and more exposed at the same time. They reduce the need for Britain to hold spare capacity of its own, and they tie British prices to continental ones in both directions. What they do not change is the value of what a home controls itself: using less, using it at cheaper times, and generating what it can. The national picture, of which interconnectors are one part, is drawn together at UK energy supply.