The Fehmarnbelt Tunnel will be the longest immersed tunnel in the world

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(CNN) — Descending up to 40 meters under the Baltic Sea, the world’s longest submerged tunnel 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 began on the Fehmarnbelt Tunnel in 2020 and in the months since a temporary port on the Danish side was completed. It will host the factory that will soon build 89 large concrete sections that will form the tunnel.

“The expectation is that the first production line will be ready by the end of the year, or the beginning of next year,” said Henrik Vincentsen, CEO of Femern A/S, the state-owned Danish company managing the project. “At the beginning of 2024 we have to be ready to immerse the first element of the tunnel.”

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-kilometer (31-mile) Channel Tunnel linking England and France, completed in 1993, cost the equivalent of £12 billion ($13.6 million) in today’s money. Although longer than the Fehmarnbelt Tunnel, the Channel Tunnel was constructed 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 . Where the crossing now takes 45 minutes by ferry, it will take just 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 was completed on June 8, 2022.

Femern A/S

Travel faster

The tunnel, whose official name is Fehmarnbelt Fixed Link, will be the longest combined road and rail tunnel anywhere in the world. It will consist of two double-lane motorways — separated by a service passageway — and two electrified railways.

“Today, if you take a train from Copenhagen to Hamburg, it will take you about four and a half hours,” said Jens Ole Kaslund, technical director at Femern A/S, the state-owned Danish company in charge of the project. “Once the tunnel is 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 added. The same trip by car would be about an hour faster than it is now, taking into account the time saved by not queuing for the ferry.

Besides the benefits to passenger trains and cars, the tunnel will have a positive effect on trucks and freight trains, Kaslund said, because it creates a land route between Sweden and Central Europe that will be 160 kilometers longer. shorter than now.

Today, traffic between the Scandinavian peninsula and Germany via Denmark can be taken by ferry on the Fehmarnbelt or on a longer route via bridges between the islands of Zealand, Funen and the Jutland peninsula.

The work will begin

The project was built in 2008, when Germany and Denmark signed an agreement to build the tunnel. It took more than a decade to pass the necessary legislation of both countries and to conduct geotechnical and environmental impact studies.

Although the process went well on the Danish side, in Germany several organizations — including ferry companies, environmental groups and local municipalities — appealed against the project’s approval due to claims of unfair competition or environmental and noise concerns.

Dredging off the coast of Germany began in the fall of 2021.

Dredging off the coast of Germany began in the fall of 2021.

Femern A/S

In November 2020, a federal court in Germany dismissed the complaints: “The decision came with a set of conditions, which we quite expected and we prepared for, how we monitor the environment while we are building , on things like noise and sediment. spill. I believe that we really need to make sure that the impact on the environment is as small as possible,” said Vincentsen.

Now that the temporary port at the Danish site is finished, several other phases in the project are underway, including the digging of the actual trench that will host the tunnel, as well as the construction of the factory that will manufacture the tunnel sections. . Each section will be 217 meters long (almost half the length of the world’s largest container ship), 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 factory will consist of three halls, the first of which is 95% complete,” said Vincentsen. The sections will be placed just below the seabed, about 40 meters below sea level at the deepest point, and moved into place by barges and cranes. The positioning of the sections will take approximately three years.

Greater impact

Up to 2,500 people will work directly on the construction project, which has been affected by the global supply chain problem.

“The supply chain is a challenge right now, because the price of steel and other raw materials has increased. We get the materials we need, but it is difficult and our contractors have 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 right now, because a continuous supply of raw materials is so important,” Vincentsen said.

Michael Svane of the Confederation of Danish Industry, one of Denmark’s largest business organizations, believes the tunnel will be beneficial to businesses beyond Denmark itself.

The full-scale test cast of a tunnel element was built in July 2022.

The full-scale test cast of a tunnel element was built in July 2022.

Femern A/S

“The Fehmarnbelt tunnel will create a strategic corridor between Scandinavia and Central Europe. The improved railway transfer means more freight moving from road to rail, supporting a climate-friendly form of transport. We consider cross-border connections a tool for creating growth and jobs not only locally, but also across the country,” he told CNN.

While some environmental groups have expressed concerns about the tunnel’s impact on porpoises in the Fehmarn Belt, Michael Løvendal Kruse of the Danish Society for Nature Conservation thinks the project will have environmental benefits.

“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,” he said.

“But the biggest advantage is the benefit for the climate. The faster passage of the Belt will make trains a strong challenge for air traffic, and freight on electric trains is currently the best solution for the environment.”