The world’s longest immersed tunnel, which descends up to 40 meters beneath the Baltic Sea, will connect Denmark and Germany, cutting travel times between the two countries when the tunnel opens in 2029.
The first tunnel element of the Fehmarnbelt Tunnel was inaugurated by King Frederick
On the Danish side, east of Rødbyhavn, the factory that will build the 89 massive concrete sections that will comprise the tunnel was completed last year. Fermern A/S, the Danish state-owned company responsible for the project, says it is the largest and most advanced production facility of its kind.
The tunnel, which will be 18 kilometers long, is one of Europe’s largest infrastructure projects, with a construction budget of more than 7 billion euros.
By comparison, the 50-kilometer Channel Tunnel connecting England and France, completed in 1993, cost the equivalent of £12 billion ($13.6 billion) in today’s terms. Although longer than the Fehmarnbelt Tunnel, the Channel Tunnel was created using a boring machine, rather than by sinking pre-built tunnel sections.
It will be built across the Fehmarn Belt, a strait between the German island of Fehmarn and the Danish island of Lolland, and is designed as an alternative to the current ferry service from Rødby and Puttgarden, which carries millions of passengers every year. While the crossing now takes 45 minutes by ferry, it is only seven minutes by train and ten minutes by car.
Faster journey
The tunnel, officially called Fehmarnbelt Fixed Link, will also be the longest combined road and rail tunnel in the world. It will consist of two double-lane highways – separated by a service corridor – and two electrified railway lines.
“If you were to take a train journey from Copenhagen to Hamburg today, it would take about four and a half hours,” said Jens Ole Kaslund, technical director at Femern A/S, in 2022. “When the tunnel will be completed are completed, the same journey will take two and a half hours.
“Today many people fly between the two cities, but in the future it will be better to just take the train,” he adds. The same journey by car will be about an hour faster than today, taking into account the time saved by not queuing for the ferry.
In addition to the benefits for passenger trains and cars, the tunnel will have a positive impact on trucks and trains, Kaslund said, because it will create a land route between Sweden and Central Europe that will be 160 kilometers shorter than today.
Currently, traffic between the Scandinavian Peninsula and Germany can take the ferry across the Fehmarnbelt via Denmark or a longer route via bridges between the islands of Zealand, Funen and the Jutland Peninsula.
Work is in progress
The project dates back to 2008, when Germany and Denmark signed a treaty to build the tunnel. It then took more than ten years for the necessary legislation to be passed by both countries and for geotechnical and environmental impact studies to be carried out.
While the process went smoothly on the Danish side, in Germany a number of organizations – including ferry companies, environmental groups and local municipalities – appealed the project’s approval over claims of unfair competition or environmental and noise concerns.
In November 2020 a federal court in Germany turned down the complaints. “The ruling brought with it a number of conditions that we kind of expected and were prepared for, about how we monitor the environment while we’re building, about things like noise and sediment spills. I believe that we really need to ensure that the impact on the environment is as small as possible,” said Henrik Vincentsen, CEO of Femern A/S, in 2022.
Several other phases of the project are underway, including digging the actual trench that will house the tunnel. Each section will be 217 meters long (about half the length of the world’s largest container ship), 42 meters wide and 9 meters high. Weighing 73,000 tons each, they will be as heavy as more than 13,000 elephants.
The factory has three halls and six production lines. The sections are placed just below the seabed, at the deepest point about 40 meters below sea level, and moved into place by ships and cranes. Positioning the sections will take approximately three years.
A broader impact
Up to 2,500 people will work directly on the construction project. Michael Svane of the Confederation of Danish Industry, one of Denmark’s largest business organizations, told CNN in 2022 that he believes the tunnel will benefit companies outside Denmark itself.
“The Fehmarnbelt Tunnel will create a strategic corridor between Scandinavia and Central Europe. The improved rail transfer means more freight moves from road to rail, supporting a climate-friendly mode of transport. We see cross-border connections as a tool to create growth and jobs, not only locally, but also nationally,” he said.
While some environmental groups have expressed concerns about the tunnel’s impact on porpoises in the Fehmarn belt, Michael Løvendal Kruse of the Danish Association for Nature Conservation believes the project will bring environmental benefits.
“As part of the Fehmarnbelt Tunnel, new nature reserves and stone reefs will be created on the Danish and German sides. Nature needs space and that creates more space for nature,” he says.
“But the biggest benefit will be the benefit for the climate. The faster passage of the Belt will make trains a major challenger to air traffic, and freight on electric trains is by far the best solution for the environment.”
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