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SuedLink's Elbe tunnel is done; 700-km power corridor nears 2028 commissioning

SuedLink's Elbe tunnel is done; 700-km power corridor nears 2028 commissioning

Built World

Tunnel boring under the Elbe finishes the hardest single section of Germany's 4-gigawatt north-south high-voltage line

August 24th, 2026: Elbe tunnel completion announced

Overview

Updated Aug 25

A tunnel boring machine named Elsa broke through under the Elbe River in June 2026, completing the single most difficult section of Germany's flagship north-south power line. Operators confirmed the 5.2-kilometer crossing between Wewelsfleth in Schleswig-Holstein and Wischhafen in Lower Saxony in August, clearing the way for high-voltage direct-current cables that will carry wind power south.

SuedLink is a roughly 700-kilometer corridor split between two operators: TenneT builds the northern half, TransnetBW the southern. Together they move 4 gigawatts of wind energy from the gusty north to industrial demand in Bavaria and Baden-Württemberg. Full operation is targeted for the end of 2028 — six years later than originally planned, after a 2015 political decision forced a redesign from overhead lines to buried cables.

Why it matters

SuedLink carries 4 gigawatts of wind power south when it opens in 2028, letting Germany's northern turbines run instead of being paid to shut down.

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Key Indicators

5.2 km
Elbe tunnel length
The tunnel boring machine Elsa drove from Wewelsfleth to Wischhafen at depths up to 40 meters.
4 GW
SuedLink transmission capacity
Total capacity of the direct-current line, enough for an estimated 10 million households.
700 km
Total line length
From Schleswig-Holstein through Lower Saxony and Thuringia to Bavaria and Baden-Württemberg.
10M
Estimated households served
Projection from grid operators once the full line enters commercial operation.
6
Cables for the tunnel
Two cables per SuedLink system plus one spare each, to ease maintenance and boost reliability.

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People Involved

Organizations Involved

Timeline

November 2015 December 2028

7 events Latest: August 24th, 2026 · 3 weeks ago
Tap a bar to jump to that date
  1. Full commissioning targeted

    Upcoming Projection

    SuedLink expected in commercial operation six years behind the original 2022 schedule.

  2. Cable pulling into the tunnel to begin

    Upcoming Construction

    Six cables planned: two for each SuedLink system plus one spare each, pulled through the four-meter bore.

  3. Elbe tunnel completion announced

    Latest Milestone

    Operators confirm the crossing is complete; interior fit-out begins ahead of the late-2027 cable pull.

  4. Elbe tunnel breakthrough at Wischhafen

    Milestone

    Elsa reaches the target shaft after 16 months and 5,224 meters of boring, completing the hardest section.

  5. Tunnel boring machine Elsa starts under the Elbe

    Construction

    Herrenknecht TBM launches from Wewelsfleth, Schleswig-Holstein, boring toward Wischhafen through water-bearing geology.

  6. Construction begins on SuedLink

    Construction

    TenneT starts building the northern section after years of planning delays, route protests, and redesign.

  7. Coalition mandates underground HVDC cables

    Policy

    CDU/CSU-SPD coalition, pushed by Bavaria's Horst Seehofer, requires buried cables for major direct-current lines, forcing SuedLink redesign.

Scenarios

1

SuedLink enters full commercial operation by end of 2028

Likely Resolves by End of 2028

Discussed by: TenneT and TransnetBW, with the Federal Network Agency (Bundesnetzagentur) tracking progress

Cable pulling through the Elbe tunnel starts late 2027 as planned, all six cables thread through, and the remaining above-ground sections finish without major delays. The line energizes at full 4-gigawatt capacity before December 31, 2028. This is the operators' stated baseline and matches their current schedule updates.

2

Cable pull complications push SuedLink commissioning into 2029

Possible Resolves by End of 2028

Discussed by: Citizen initiative groups that challenged the project's cost and route economics

Technical problems installing six cables through the 5.2-kilometer tunnel, or delays in the southern sections, force the operators to revise the commissioning date past the end of 2028. The project has already slipped six years from its original 2022 target, and critics argue the buried-cable mandate made it more expensive and slower.

3

SuedLink comes online in stages before full commissioning

Possible Resolves by End of 2028

Discussed by: Grid analysts watching north-south bottlenecks and wind curtailment volumes

Because TenneT and TransnetBW each build separate stretches, the first sections could energize before the whole line is finished. Partial operation would ease northern curtailment earlier than the full line, with complete commissioning still targeted for the end of 2028. The Elbe tunnel itself completes on schedule even as other sections finish later.

Historical Context

3 moments from history that rhyme with this story — and how they unfolded.

December 1987 – May 1994

Channel Tunnel (1987-1994)

Britain and France built a 50-kilometer rail tunnel under the English Channel, one of the largest private infrastructure projects ever attempted. Political delays, geological surprises, and financing problems pushed it years past schedule and billions over budget.

Then

The tunnel opened in 1994 several years late and nearly bankrupted its operators.

Now

It became a durable cross-border link now carrying high-speed rail and freight, and a standing cautionary tale about mega-project cost control.

Why this matters now

SuedLink shares the profile: an oversized, politically contested crossing that took years longer and cost more than planned, yet delivers lasting value once complete.

1993 – December 1994

Baltic Cable (1993-1994)

Germany and Sweden linked with a 250-kilometer HVDC undersea cable between Lübeck and the Swedish coast, among Europe's first commercial high-voltage direct-current connections. It proved that long-distance HVDC could trade power reliably across borders.

Then

The cable entered service in late 1994 as a working commercial link.

Now

It remains in operation and helped establish HVDC as the standard for long-distance European power transfers.

Why this matters now

SuedLink applies the same HVDC technology at continental scale, roughly three times Baltic Cable's length and sixteen times its capacity.

2014 – May 2021

NordLink HVDC cable (2014-2021)

Germany and Norway built a 623-kilometer high-voltage direct-current subsea cable to exchange wind power with Norwegian hydro storage. Permitting delays and cable manufacturing problems pushed commissioning back repeatedly.

Then

NordLink entered service in May 2021, enabling two-way power flows between the two grids.

Now

It proved the long-distance HVDC strategy Germany is repeating with SuedLink and the companion SuedOstLink and A-Nord corridors.

Why this matters now

The same technology and similar operator structure now apply to SuedLink; NordLink showed both the difficulty of such projects and their payoff once commissioned.

Sources

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