THE project to construct the Fehmarn Belt Tunnel and a new cross-border railway between Denmark and Germany is facing delays due to challenges with deploying the specialised marine vessel that will support construction of the 18km immersed tunnel.
Contractor Sund & Bælt has confirmed in a statement that the specially designed immersion vessel, Ivy, has yet to undergo full testing and secure approval from the relevant authorities, resulting an 18-month delay to its deployment.
“Given the current setback with Ivy, completing the tunnel within the original timeline is now deemed challenging,” the company says, adding that it is uncertain how much time can be recovered. The €7.4bn project was originally scheduled for completion in 2029.
The immersed tunnel is being constructed in a 12m deep trench on the sea floor using pre-cast concrete sections. A standard 217m-long element weighs 73,500 tonnes and consists of nine segments, which are preassembled on land before being towed out to sea.
This method was previously used for the 4km Øresund Tunnel between Denmark and Sweden. However, Sund & Bælt points out that the Fehmarn Belt project is of a much larger scale and far more complex. For example, the average depth of 30m in the Fehmarnbelt is two times that in the Øresund, which necessitates the use of a highly advanced and unique vessel equipped with complex mechanical and electronic systems.
“When the construction contracts were signed in 2016, German planning approval for the project had not yet been granted,” Sund & Bælt says. “As a result, specific requirements, such as restrictions on noise emissions from work vessels, could not be incorporated into the contracts. This may make it difficult to accelerate the construction process at a later stage.”
It adds that it is continuing discussions with the German authorities to identify practical solutions to meet the requirements for underwater noise and sediment spill in German waters.
“In addition, parts of the tunnel trench still need to be levelled with gravel as supplementary geotechnical surveys have shown that parts of the tunnel trench are around 30cm deeper than planned.”
Two consortia
On-site work on the tunnel element of the project began in 2021 under a contract with two consortia, Fehmarn Belt Contractors (FBC) and Fehmarn Link Contractors (FLC). Sund & Bælt and the European contractor consortium Femern SICE Cobra (FSC) signed the contract to equip the tunnel in May 2022.
The tunnel is a key component of the project to deliver a new 160km rail corridor between Denmark and Germany, which will reduce Copenhagen - Hamburg journey times from 4h 30min to 2h 30min. While the tunnel is facing delay, construction of a new 110km double-track line from Ringsted to Rødby in Denmark to connect with the tunnel is on schedule.
“The Fehmarn Belt Tunnel is the world's longest immersed tunnel,” says Mikkel Hemmingsen, CEO of Sund & Bælt. “It is a mega-project and with that come inevitable challenges and unpredictable events. Ivy is a prototype that has been specially built for us, and it has taken more time than anticipated.”
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