More than a month after the first tunnel element was lowered into the Fehmarnbelt, only one element remains in place on the seabed off Rødbyhavn.
The next element has been prepared for installation but has not yet been lowered. According to the Fehmarnbelt project, currents and poor weather have made it necessary to wait for a new weather window.
That has put renewed focus on the pace of the tunnel’s most critical construction phase. The Fehmarnbelt tunnel consists of 89 elements that must be lowered one by one into the 18-kilometre trench between Lolland and the German island of Fehmarn. Each element must be towed out from the production area near Rødbyhavn, positioned in the trench and connected underwater to the previous section.
FemernBusiness revealed in August 2025 that the timetable for opening the link in 2029 could no longer be met. That makes the pace of the immersion work crucial. The first element is now in place, while the second has been prepared but is still waiting to be lowered on to the seabed.
2.5 elements a month
The original master schedule allowed 36 months for the immersion of the tunnel elements. That equates to an average of about 2.5 elements a month over the full construction period. If each element takes more than a month to lower, the immersion work alone would take 89 months, or more than seven years.
A longer pause after the first installation does not in itself derail the overall plan. But it illustrates how sensitive the rhythm is in the phase on which the project’s next timetable will depend.
The operation requires several conditions to align. The element must be towed out, kept stable, lowered in a controlled manner and connected with a high degree of precision. Currents and weather are therefore real constraints, even at the coastal start of the tunnel trench off Lolland, where the work should be among the more manageable parts of the process.
The delay follows a prolonged period in which the immersion phase has been at the centre of the project’s difficulties. Ivy, the specialised vessel used to handle the elements, was delayed by two years before final approval was granted. At the same time, the tunnel trench has been one of the main points of dispute between the client and the main contractor. Sund & Bælt has paid FLC additional compensation to complete the first part of the trench.
The Fehmarnbelt project has said it will present a revised schedule once five standard elements and one special element have been lowered.
Disputes and claims
The remaining part of the 18-kilometre tunnel trench is still part of the broader dispute on the project. In addition, the main contractor, Femern Link Contractors, has lodged a DKr14.5bn claim against Femern A/S, which is owned by Sund & Bælt. An international arbitration case over Covid-related delays is also under way.
Further out in the Fehmarnbelt, the project will also be subject to German environmental conditions. The working area in the Natura 2000 zone has been expanded to 1,100 metres, but requirements on underwater noise remain in force. On the Puttgarden side, there are also special restrictions on sediment release during the summer months. The project will therefore have to maintain its pace within a series of environmental constraints later in the process as well.
