ElbX

Technical data

Project description

The ElbX crossing structure is part of the SuedLink grid expansion project, an approx. 700 km long 525 kV direct current line from Brunsbüttel in Schleswig-Holstein to Großgartach in Baden-Württemberg.

It consists of a tunnel structure below the Elbe as well as underground access and joint structures on both sides of the Elbe and the associated above-ground operating buildings
A total of six high-voltage cables are to be routed under the Elbe

Construction method

The two access structures and the two sleeve structures are to be constructed in diaphragm wall construction pits up to approx. 25 metres deep
The TBM tunnel with an internal diameter of 4.0 m is to be excavated using the TBM hydro-shield method with a single-shell segmental lining, lining thickness 30 cm
In addition, short sections are to be constructed using the cut-and-cover method

Geology

artificial fillings
Holocene deposits of the Elbe marsh (organic soft layers, tidal sand, alternating layers of clay/sand)
Deposits of the Elbe glacial valley (sands with gravel intercalations or gravel with stone intercalations)
Boulder clay, Lauenburg layers (silt/clay with fine sand)
Silty fine sands with boulder clay and mica clay

General data

Project

ElbX crossing structure, tunnel section

Client

Porr GmbH & Co. KGaA (as contractor of TenneT TSO GmbH)

Contractor

Wayss & Freytag Ingenieurbau in consortium with Porr GmbH & Co. KGaA (Tunnel ElbX consortium)

Construction period

2023 to 2027

Utilisation
Network expansion
Type
Cable tunnel
Length
approx. 5,200 m
Type of construction
TBM with hydro shield

Wind energy from north to south

The SuedLink grid expansion project of the two transmission system operators TenneT Germany and TransnetBW is one of the key infrastructure projects of the German energy transition.

Once completed, the power line will transport renewable energy over a distance of around 700 kilometres from Brunsbüttel in Schleswig-Holstein to Großgartach in Baden-Württemberg. A special section of this major project is the undercrossing of the Elbe with the ElbX crossing structure.

A modern tunnel with a length of around 5.2 kilometres is being built here, through which six high-voltage cables will be routed under the river. The aim is to efficiently and reliably transport wind energy from the north to the south of Germany and thus make a decisive contribution to a sustainable power supply and the realisation of the energy transition.