Five-kilometre tunnel under the Elbe: SuedLink reaches another key milestone

The SuedLink backbone transmission project in Germany has reached another construction milestone with the completion of a more than five-kilometre tunnel beneath the Elbe. The ElbX river crossing project, which connected sections of the route between Schleswig-Holstein and Lower Saxony, is among the technically most complex parts of the 700-kilometre high-voltage direct-current link. From the end of 2028, it is set to strengthen electricity transmission capacity from northern to southern Germany.

TenneT, which operates part of the German transmission system, together with representatives of both federal states, symbolically marked the completion of tunnelling for the ElbX tunnel, which connects Wewelsfleth in Schleswig-Holstein with Wischhafen in Lower Saxony. The tunnel, approximately 5.2 kilometres long, now structurally connects the northern sections of the SuedLink route on both banks of the Elbe.

The tunnel-boring machine reached the receiving shaft in Wischhafen as early as June, meaning the breakthrough has now completed the underground construction phase of this section. The machine was launched from Wewelsfleth on 1 February 2025 and passed through variable sandy and clay sediment layers during excavation.