(CNN) – The world’s longest submerged tunnel, reaching 40 meters under the Baltic Sea, will connect Denmark and Germany, cutting travel times between the two countries when it opens in 2029.
After more than a decade of planning, construction on the Fehmarnbilt Tunnel began in 2020 and in the months since a temporary port was completed on the Danish side. The soon-to-be-built factory will host 89 massive concrete sections that will form the tunnel.
“The first production line is expected to be ready at the end of the year or early next year,” said Henrik Vincentsen, CEO of Femern A/S, the Danish state-owned company in charge of the project. “By the start of 2024, we should be ready to submerge the first tunnel component.”
The tunnel, which will be 18 kilometers (11.1 miles) long, is one of the largest infrastructure projects in Europe, with a construction budget of more than 7 billion euros ($7.1 billion).
By comparison, the 50-kilometre (31-mile) canal 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 canal tunnel was constructed using a drilling machine, rather than submerging the previously built tunnel sections.
It will be built across the Fehmarn Belt, a strait between the German island of Fehmarn and the Danish island of Loland, and is designed as an alternative to the existing ferry service from Rødby and Puttgarden, which carries millions of passengers each year. The crossing now takes 45 minutes by ferry, and will only take seven minutes by train and 10 minutes by car.
The roof of the first production hall where the tunnel sections will be built in Denmark is completed on 8 June 2022.
The tunnel, whose official name is Fehmarnbelt Fixed Link, will also be the longest combined road and rail tunnel anywhere in the world. It will consist of two two-lane highways – separated by a service lane – and electrified railway tracks.
says Jens Ole Kaslund, Technical Director at Femern A/S, the Danish state-owned company responsible for the project. “When the tunnel is complete, the journey itself takes two and a half hours.
“Today a lot of people fly between the two cities, but in the future it will be better to just take the train,” he adds. The same car trip would be about an hour faster than the day, given the time saved by not lining up for the ferry.
Besides the benefits to commuter trains and cars, the tunnel will have a positive impact on freight trucks and trains, says Caslund, because it will create an overland route between Sweden and Central Europe that will be 160 kilometers shorter than it is today.
Currently, traffic between the Scandinavian Peninsula and Germany via Denmark can either take the ferry via the Fehmarnbelt or a longer route through the bridges between the islands of New Zealand, Funen and the Jutland peninsula.
The history of the project dates back to 2008, when Germany and Denmark signed a treaty to build the tunnel. Then, it took more than a decade for the necessary legislation to be passed by both countries and for geotechnical and environmental impact studies to be carried out.
While the process completed smoothly on the Danish side, in Germany, a number of organizations – including ferry companies, environmental groups and local municipalities – challenged approval of the project due to allegations of unfair competition or environmental and noise concerns.
Dredging work began off the German coast in the fall of 2021.
Now the temporary harbor at the Danish site has been completed, and several other phases of the project are underway, including the excavation of the actual trench that will host the tunnel, as well as the construction of the factory that will build the tunnel sections. Each section will be 217 meters long (nearly half the length of the largest container ship in the world), 42 meters wide and 9 meters high. Weighing in at 73,000 metric tons each, they would be as heavy as more than 13,000 elephants.
“We will have six production lines and the plant will consist of three halls, with the first line 95% complete,” Vincentsen says. The sections will be placed just below the sea floor, about 40 meters below sea level at its deepest point, and will be moved into place by barges and cranes. It will take approximately three years to lay the partitions.
Up to 2,500 people will work directly on the construction project, which has been affected by global supply chain problems.
“The supply chain is a challenge right now, because the price of steel and other raw materials has gone up. We are getting the materials we need, but it’s tough and our contractors have had to increase the number of suppliers to make sure they can get what they need. That’s one of the things we’re really watching. Now, because a continuous supply of raw materials is critical,” says Vincentsen.
Michael Svane of the Confederation of Danish Industry, one of Denmark’s largest business organisations, believes the tunnel will be beneficial for companies outside Denmark itself.
This comprehensive tunnel element demo template was built in July 2022.
“The Fehmarnbelt Tunnel will create a strategic corridor between Scandinavia and Central Europe. Modernized rail transport means more freight from road to rail, supporting climate-friendly transportation. We view cross-border connections as a tool for creating growth and jobs not only locally, but also nationally “.
While some environmental groups have expressed concerns about the impact of the tunnel on porpoises in the Fehmarn Belt, Michael Lovendal Cros of the Danish Society for the Conservation of Nature believes the project will have environmental benefits.
“As part of the Fehmarnbilt Tunnel, new natural areas and stone reefs will be created on the Danish and German sides,” he says. “Nature needs space and there will be more space for nature as a result.”
“But the biggest advantage will be the benefits to the climate. Faster belt passage will make trains a strong competitor for air traffic, and freight in electric trains is by far the best solution for the environment.”