The expansion of renewable energies requires that large national transmission grids need to transport the electricity generated by offshore wind parks to centres of high consumption. The operators TenneT and TransnetBW are building the SuedLink, an underground extra-high voltage direct current link between Schleswig-Holstein in the north and Baden-Württemberg and Bavaria in the south of Germany.

The sub-project to be planned includes the ElbX crossing structure required for passing the cable under the Elbe River. As part of the preliminary design, three alternative Elbe crossing corridors were evaluated and a preferred route was identified. An accessible tunnel of approximately 5.3 km in length is planned. The tunnel will have an internal diameter of approximately 4 m connecting at each end to a watertight concrete start and target shaft. The approximately 25 m deep excavation pits required for the shaft structures will be constructed using the diaphragm wall method and will be watertight as the groundwater rises to the surface.

Consideration of the comprehensive environmental and hydrogeological characteristics of the North German marshes is part of the integral planning for the planning approval process.

The project is being designed using the BIM method. For this purpose, a 3D information model of the entire Elbe crossing structures, a 4D simulation for model-based construction sequence planning and a 5D model for model-based quantity determination and contract specifications have been created. Planning meetings are held using the models, and visualisations and animations have been developed for plan approval and public relations purposes.