Denmark and Germany now building the world's longest immersed tunnel
After more than a decade of planning, construction started on the Fehmarnbelt Tunnel in 2020 and in the months since a temporary harbor has been completed on the Danish side. It will host the factory that will soon build the 89 massive concrete sections that will make up the tunnel.
"The expectation is that the first production line will be ready around the end of the year, or beginning of next year," said Henrik Vincentsen, CEO of Femern A/S, the state-owned Danish company in charge of the project. "By the beginning of 2024 we have to be ready to immerse the first tunnel element."
By way of comparison, the 50-kilometer (31-mile) Channel Tunnel linking England and France, completed in 1993, cost the equivalent of £12 billion ($13.6 billion) in today's money. Although longer than the Fehmarnbelt Tunnel, the Channel Tunnel was made using a boring machine, rather than by immersing 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. Where the crossing now takes 45 minutes by ferry, it will take just seven minutes by train and 10 minutes by car.