Interconnectors in Europe: a map of the subsea and overland power links

At 19:00 on 10 January 2026, the moment the European Commission uses for its winter snapshot, Luxembourg could import 104.95% of its own installed generating capacity from its neighbours. Ireland and Cyprus could import none. Those two numbers, from the Commission’s electricity interconnection targets page, mark the two ends of a question this directory tries to answer link by link: which grids in Europe can lean on each other, through which cables and lines, and how much power each one can carry.

What is an interconnector, in practical terms? It is the physical link, a subsea cable, a buried cable or an overhead line, that joins the transmission grid of one country to another’s, or joins two power systems that cannot otherwise exchange power. This directory lists 61 links. Of them, 47 cross a border and 14 connect two parts of one country, such as the cables to Sardinia, Crete or Shetland. The map and the table below show every one, with its route, capacity, voltage, status and sources.

What interconnectors do for a market

Interconnectors turn two markets into one, at least for as long as they have capacity to spare. Since the North-Western Europe Price Coupling launched in February 2014, more and more of Europe’s day-ahead markets have been calculated together. ENTSO-E describes the Single Day-Ahead Coupling as a single pan-European cross-zonal day-ahead market, now covering 30 transmission system operators and 16 nominated electricity market operators, with one algorithm, EUPHEMIA, computing prices for every bidding zone and allocating the cross-border capacity at the same time.

The effect is easy to picture. If Norway’s hydropower is cheap and Germany’s prices are high, power flows south through NordLink until either the prices meet or the cable is full. While capacity is spare, the two zones settle at one price. Once it is full, the prices separate, and the gap is a direct measure of how much more trade the market wanted than the link could carry. That gap, multiplied by the flow, is the congestion income the operators collect. Persistent price gaps across a border are usually the strongest argument for building the next link, and the guide to grid congestion looks at what happens when the bottleneck sits inside a country instead.

Security of supply is the second job, and the one that makes headlines. A country short of power during a cold, windless evening can import it; a country hit by a disturbance can draw on its neighbours to restart. The limits of that were tested on the Iberian peninsula, one of the least connected regions in Europe, in the blackout of April 2025. The Baltic states took the opposite step in February 2025, when they synchronised with the continental European grid and the back-to-back converter on LitPol Link at Alytus became redundant.

How capacity on interconnectors is traded

Capacity reaches the market by two routes, explicit and implicit.

Explicit allocation sells the right to use the link separately from the electricity itself. Long-term rights (yearly and monthly) are auctioned on behalf of the TSOs by the Joint Allocation Office under a common rulebook, the harmonised allocation rules for long-term transmission rights. Two kinds of right exist. A physical transmission right entitles its holder to physically transfer a certain volume of electricity between two bidding zones in a specific direction during a set period. A financial transmission right pays its holder the day-ahead price difference between the two zones instead, without any power being moved by the holder. Financial rights let traders hedge the price spread across a border months ahead.

Implicit allocation folds the capacity into the energy trade. In the day-ahead market nobody buys cross-border capacity as such: traders bid for energy in their own zone, and the coupling algorithm uses the available capacity to move power from low-price to high-price zones automatically. This is the more efficient method, because the algorithm always uses the capacity in the direction of the price difference.

HVDC links add a wrinkle. Their converter stations lose a measurable share of the power they carry, and ENTSO-E notes that those losses can either be modelled inside the market coupling algorithm or left out, in which case the TSOs have to buy the lost energy themselves.

Europe’s 15% interconnection target

The European Union measures interconnection with a simple ratio: how much electricity a country can import from its EU neighbours, compared with its own installed production capacity. The first target was 10% by 2020. It has since been raised to at least 15% by 2030.

On the Commission’s January 2026 figures, 16 countries already exceed the 2030 target, two are above the old 10% level but short of 15%, and nine are still below 10%. The Commission complements the headline ratio with three supplementary indicators, based on wholesale price differences and on interconnector capacity relative to peak load and to installed renewable generation. An expert group set up in 2016, with ACER, ENTSO-E and representatives of industry, academia and NGOs, advises on reaching the targets.

The ratio favours small countries surrounded by large ones. Luxembourg (104.95%), Estonia (89.04%) and Slovenia (74.75%) top the table; Denmark, with links to Norway, Sweden, Germany, the Netherlands and Great Britain, stands at 35.46%.

Where Europe is least connected

The bottom of the table is more interesting than the top. Ireland shows 0% although it has two HVDC links, because both, the East–West Interconnector and, since early 2025, Greenlink, run to Great Britain, which left the EU in 2020 and so does not count towards the target. The Celtic Interconnector to Brittany will be Ireland’s first direct link to another EU state. Cyprus has no link to anywhere, and its hope rests on the Great Sea Interconnector to Crete, whose works stalled in 2025.

Spain, at 3.11%, is the starkest case among connected countries. The Pyrenees have always been a barrier, and the two underground circuits of INELFE raised commercial exchange capacity between France and Spain from 1,400 to 2,800 MW when they entered service in 2015. The Bay of Biscay Interconnection, now under construction, is designed to take it to 5,000 MW, with two 1,000 MW links and around 300 km of subsea cable. Italy (5.13%), Poland (5.06%) and France (5.44%) sit only slightly higher: large systems with plenty of generation of their own, where even several big links move the ratio only a little.

Subsea interconnectors and overland links

Geography decides the route. Of the 61 links in this directory, 22 run entirely under the sea and 30 combine subsea and land sections. Across the North Sea, the Baltic and the Mediterranean there is no alternative to a cable, and almost every long subsea interconnector uses HVDC, for reasons the HVDC explainer sets out. The exceptions in the directory, the AC cables from Sicily to Malta and from the Peloponnese to Crete, carry a few hundred megawatts over 95 and 132 km of seabed. North Sea Link between Norway and England runs 720 km; Viking Link between Denmark and England, at 765 km, is the longest operating link in the directory.

Overland interconnectors are more varied. Some are ordinary AC overhead lines, like the Aurora Line between Sweden and Finland, which entered service on 13 November 2025, and the North South Interconnector across the Irish border, now under construction. Others are buried DC cables, chosen where an overhead line would never get permission: INELFE through the eastern Pyrenees and ALEGrO between Belgium and Germany both run fully underground.

A subsea interconnector is harder to protect than a line you can walk along. Cable faults are permanent until a repair ship lifts the cable, and Estlink 2 was out of full service for about six months after an anchor dragged across it at Christmas 2024. How these cables are laid, buried and mended has its own page, on subsea power cables and their installation.

Reading the map of interconnectors

The line between what is an interconnector and what is simply a long cable inside one country is blurrier than it looks. The Western HVDC Link, rated 2,250 MW along the west coast of Britain, never crosses a border, yet it moves more power than most interconnectors in Europe, and the Tyrrhenian Link will tie Sicily, Sardinia and the Italian mainland into one DC network. The directory keeps both kinds, and the map and table mark which links cross a border and which stay inside one country, so the internal ones can be filtered out when only cross-border trade matters.

Three habits help when reading the figures. The end points on the map are approximate landing, converter or substation sites, drawn for orientation; where a site is not fixed yet, the marker shows only the region. Capacity is the figure the owner or builder publishes, which is not always the same as the capacity offered to the market: Kriegers Flak, for example, trades 400 MW through a converter rated slightly higher. And where two sources disagree, as they do on the length of Viking Link (765 or 767 km) or the voltage of NordLink, the directory uses one value and records the source behind it. Where no source states a figure, the field stays empty.

Interconnectors under construction in Europe

This directory lists 11 links under construction: seven cross-border interconnectors and four internal links. Five are due in 2028: Celtic, NeuConnect between Great Britain and Germany, the Bay of Biscay link, the Tyrrhenian Link inside Italy and SuedLink, Germany’s north–south DC corridor. The two Eastern Green Links along Britain’s east coast and SACOI 3 to Corsica and Sardinia follow in 2029, and the North South Interconnector is expected in 2031. The second Malta–Sicily cable has no confirmed in-service year, and the Great Sea Interconnector has no firm date at all.

Celtic is the one to watch. Its offshore cable laying began in August 2025 and EirGrid expects commissioning in spring 2028. With it, Ireland’s interconnection figure should finally move off zero.