World’s Longest Immersed Tunnel Will Support Europe’s Transition to Green Mobility

Regular commuting between Rodbyhavn in Denmark and Puttgarden in Germany is done via ferries. But things will change drastically in only a few years. After a decade of planning, an innovative, sustainable tunnel will connect the two countries directly for both car and train transportation.

A four-lane highway and two railway tracks will make commuting not only much faster but also less harmful to the environment. Instead of a one-hour trip on board a ferry, people from Denmark will be able to travel to Puttgraden in just seven minutes, by train, or ten minutes, by car. As a result, the levels of CO2 emissions will also drop significantly.

Travel Awaits reports that the project has hit a milestone, having completed half of the trench dredging for the future tunnel. The dredging process was kicked off last summer and will take two more years to complete. The impressive quantity of soil that needs to be dredged won’t be wasted but will be used later to create new natural and recreational areas.

Unlike conventional tunnel construction that uses a boring machine, an immersed tunnel is built using pre-made sections, which are then placed one by one into the seabed by cranes. A total of 79 standard sections and 10 special ones will be used for the Fehmarnbelt tunnel.

Each one is longer than 700 feet (217 meters) and weighs over 80,000 tons. The highway lanes and railroad tracks will be laid once all the sections are connected. You can find out more about this unique construction process in the video below.

In addition to reducing CO2 levels, the project will also add rail connections for high-speed electric trains to the tunnel. The vision for the Fehmarnbelt is that it will become an important hub for sustainable transportation in Europe.

There’s still a long way to go, with the tunnel expected to become operational by mid-2029. But when it does, it will officially become the world’s longest immersed tunnel.