Mammoth German SuedLink underground line starts construction

After an extensive planning and approval phase, construction work has started on SuedLink, an underground cable connection to transport wind power from north Germany to Bavaria and Baden-Württemberg in the south.

The SuedLink cables will cross the Elbe river via a five-kilometre tunnel structure (pic credit: thethomsn/Moment via Getty Images)

At an investment of €10 billion, SuedLink is a central infrastructure project for Germany’s energy transition. The country is aiming for 160GW of onshore wind by 2035.

With a length of around 700 kilometres – making it one of the longest underground power lines in the world – SuedLink will provide 4GW of transmission capacity.

The project was first proposed in 2013. Tennet is responsible for the northern section of the line and the converters in Schleswig-Holstein and Bavaria., while TransnetBW is responsible for the southern section of the line and the converter in Baden-Württemberg.

“With the start of the Elbe crossing’s construction, SuedLink is becoming a reality,” said Tennet chief operating officer Tim Meyerjürgens. He hailed construction starting shortly after the final permit was received in mid-August. “Now we will need to keep this pace up… to enter into operation in 2028,” he added.

Schleswig-Holstein state secretary for energy, Joschka Knuth, said the transmission line would be “a game-changer for our energy supply”. She said that climate-protection efforts and electricity customers would benefit in equal measure, as the project will transport large amounts of green electricity while reducing curtailments in the north.

Lower Saxony energy minister, Christian Meyer, said that an ‘energy transition task force’ had been set up “to turbocharge the construction and permitting efforts”.

The start of construction of the Elbe crossing marks the beginning of an estimated four and a half years of construction work for SuedLink’s largest special structure. The SuedLink cables will cross the Elbe in the stretch between Wewelsfleth in Schleswig-Holstein and Wischhafen in Lower Saxony via a five-kilometre tunnel structure. 

In a subsequent stage, six 525kV power cables will be pulled through the tunnel and connected to the SuedLink underground cables on both sides of the Elbe.