Fehmarnbelt tunnel advances with first element ready for immersion

The Fehmarnbelt Fixed Link has reached an important milestone with the completion of ballast filling in its first tunnel element. This is the first of 89 elements that will form the immersed tunnel linking Lolland in Denmark with the German island of Fehmarn.

The element, initially weighing around 73,500 tonnes, has been filled with approximately 4,500 tonnes of ballast concrete. This process is essential, as it enables controlled submersion during the upcoming immersion phase. The work was carried out using a temporary internal access system consisting of five shafts connected to watertight steel bulkheads, supporting material transport, ventilation, and safe personnel access throughout the operation.

Once the ballast installation was completed, most internal equipment was removed and the bulkheads sealed. This prepares the element for tow-out from the production facility at Rødbyhavn to the installation site in the Baltic Sea.

At the same time, offshore preparations are progressing. The trench that will receive the tunnel elements is being carefully shaped and lined with a gravel bed to ensure uniform support. The immersion operation will be carried out using the specialised vessel IVY, which is approaching operational readiness following earlier approval delays.

Supporting this operation is the heavy-lift vessel “Hebo Lift 9”, which will place eight anchors of 500 tonnes each on the seabed. These anchors are required to stabilise the immersion system during installation. After each element is placed, the anchors will be recovered and reused for subsequent sections.

So far, 15 tunnel elements have been cast, representing approximately 2.7 kilometres of the final tunnel length. The first immersion is expected in spring 2026.

Despite steady technical progress, the project timeline has shifted. Completion by 2029 is no longer considered realistic. A revised schedule is expected after the first immersion operations, with implications for both cost and delivery timelines.

Even with these adjustments, the project remains structured as a user-funded infrastructure link, with repayment expected through future traffic revenue.