Work has finally begun on the world’s longest immersed tunnel. The Fehmarnbelt Tunnel is set to open in 2029 and it will connect the German island of Fehmarn and the Danish island of Lolland across the Fehmarn Belt.
Today, if you were to take a train trip from Copenhagen to Hamburg, it would take you around four and a half hours. When the tunnel will be completed, the same journey will take two and a half hours.
Jens Ole Kaslund, technical director at Femern, told CNN
Construction of the Fehmarnbelt Tunnel from Femern A/S on Vimeo.
Normally, taking a ferry across the trait takes about 45 minutes but, once the tunnel is complete, the journey will only take 7 minutes by train (travelling at an average speed of 200km/h), or about 10 minutes by car (travelling at an average speed of 110 km/h).
Furthermore, despite concern over the construction site’s impact on the environment, assurances come on the benefit of the tunnel. “The upgraded railway transfer means more freight moving from road to rail, supporting a climate-friendly means of transport”, Michael Svane, from the Confederation of Danish Industry, told CNN. “As part of the Fehmarnbelt Tunnel, new natural areas and stone reefs on the Danish and German sides will be created. Nature needs space and there will be more space for nature as a result”, Michael Løvendal Kruse, from the Danish Society for Nature Conservation, added. Last, but not least, with the improved travel time, it will be easier and faster for people to take the train rather than the plane to travel between the two countries.
But the biggest advantage will be the benefit for the climate. Faster passage of the Belt will make trains a strong challenger for air traffic, and cargo on electric trains is by far the best solution for the environment.
Michael Løvendal Kruse, the Danish Society for Nature Conservation, told CNN
The 18 km long tunnel, build 40m under the Baltic Sea, is one of the largest infrastructure projects in Europe, with a construction budget of over €7 billion and, once complete, will be the longest immersed tunnel in the world, as well as the longest combined road and rail tunnel in the world. The Channel Tunnel, between France and the United Kingdom cost the equivalent of about €14 billion in today’s money (compared to 1993, the year the tunnel was completed) and although it is 50km long, it was made using a boring machine, not by immersing pre-built tunnel sections.

Femern, the state-owned Danish company in charge of the project, estimates it will take approximately 3,000 people to build the tunnel over 8-9 years and will require an amount of steel that the CNN equivalates to about 50 Eiffel Towers.
The first stage of the construction has already started and consists of building a new harbour in Lolland and a factory on the island. Construction on the tunnel itself is estimated to begin in 2023.