Under construction · HVDC · underground
SuedLink
Two buried DC cables meant to carry northern German wind power to the industrial south, fully permitted in October 2025.
Route drawn between the landing points; outlines: Natural Earth.
- Route
- within Germany
- From
- Brunsbüttel / Wilster, Schleswig-Holstein
- To
- Großgartach (Leingarten), Baden-Württemberg
- Length
- 700 km
- Capacity
- 4,000 MW
- Voltage
- 525 kV
- Type
- HVDC · VSC · underground cable
- Status
- Under construction (checked September 2026)
- Expected
- 2028
- Operators
- TenneT, TransnetBW
- Built by
- Siemens Energy (Brunsbüttel–Großgartach converters); Hitachi Energy (Wilster–Bergrheinfeld converters)
Near Glückstadt, SuedLink will pass under the Elbe in a 5.5 km tunnel. Further south, between Bad Friedrichshall and Leingarten, 16 km of it will run through a working salt mine owned by Südwestdeutsche Salzwerke. Those two sections, described by the Bundesnetzagentur, give a sense of how far the planners have gone to keep this line out of sight.
SuedLink is two direct-current connections in one corridor. One runs from Brunsbüttel in Schleswig-Holstein to Großgartach, in Leingarten, near Heilbronn in Baden-Württemberg. The other runs from Wilster, also in Schleswig-Holstein, to Bergrheinfeld in Bavaria. Each carries 2 GW at 525 kV, and together they span about 700 km. TenneT builds the northern part and TransnetBW the southern.
The reason is Germany’s split geography. SuedLink connects the wind-rich north with Bavaria and Baden-Württemberg in the south, where much of the country’s industrial demand sits. The congestion that builds up between the two is explained in the grid congestion guide.
The decision to bury it shaped everything that followed. In 2015 the federal government gave underground cables priority over overhead lines for new DC links, despite the much higher cost. The planning, already well advanced for pylons, had to be redone. A Bundestag research paper records that TenneT and TransnetBW put the cost of the whole project at about €10 billion. The converters are voltage-source designs: Siemens Energy supplies the Brunsbüttel–Großgartach link and Hitachi Energy the Wilster–Bergrheinfeld link.
Early construction approvals were granted from December 2022, and construction officially began on 11 September 2023, according to TenneT. On 10 October 2025 the Bundesnetzagentur approved the last section, about 76 km from the Hesse–Thuringia boundary to Henneberg on the Thuringia–Bavaria border, through the Werra valley. With that, the whole route was permitted.
The final planning approval was published on 8 November 2025. Grid connection is due in 2028, thirteen years after the switch to underground cable.
Against the other links
- 7th longest of the 54 links with a published length; the longest is Tyrrhenian Link at 970 km.
- 1st largest by capacity of 60.
- Other links from the same countries: Baltic Cable, Bornholm Energy Island, Hansa PowerBridge, Kontek, Kriegers Flak Combined Grid Solution, NordLink.
SuedLink in brief
How long is SuedLink?
700 km, which makes it the 7th longest of the 54 links in this directory with a published length.
How much power can SuedLink carry?
4,000 MW at 525 kV, 1st of 60 by capacity here.
When will SuedLink be finished?
The published target is 2028.
Which countries will SuedLink connect?
It will run within Germany, from Brunsbüttel / Wilster, Schleswig-Holstein to Großgartach (Leingarten), Baden-Württemberg.
Who is behind SuedLink?
TenneT and TransnetBW.
Who built SuedLink?
Siemens Energy (Brunsbüttel–Großgartach converters); Hitachi Energy (Wilster–Bergrheinfeld converters).