The completion of the special vessel has been delayed to such an extent that Femern A/S, the Danish state-owned company tasked with planning, building and operating the fixed link between Denmark and Germany, says it will be difficult to meet the tunnel’s target opening date of 2029.
The vessel, known as IVY, has been specially designed to install the tunnel elements for the 18km-long tunnel. Each element is 217m long and weighs 73,500 tonnes – substantially heavier and larger than those used in the construction of the Øresund tunnel between Denmark and Sweden, which Femern said was an important model for the construction of the Fehmarnbelt tunnel.
“However, the significantly larger scale and increased complexity of the Fehmarnbelt project introduce unique challenges. For example, the work is taking place at an average water depth of 30m in the Fehmarnbelt, which is twice the depth of the Øresund, necessitating the use of a highly advanced and unique vessel equipped with complex mechanical and electronic systems,” Femern said in a statement.
The vessel has yet to undergo full testing and receive approval from the relevant authorities, resulting in a delay of 18 months in its preparation. Given the current setback with IVY, completing the tunnel within the original timeline is now deemed challenging, the company said.
“The Fehmarnbelt tunnel is the world’s longest immersed tunnel. 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,” said Mikkel Hemmingsen, CEO of Sund & Bælt, the client for the project.
It remains uncertain how much of the lost time can be recovered.
In addition, Sund & Bælt is in ongoing dialogue with the German authorities to find solutions to meet the requirements related to underwater noise and sediment spill in German waters. Also, supplementary geotechnical surveys have shown some parts of the tunnel trench are around 30cm deeper than planned so these need to be levelled with gravel.
When the construction contracts were signed in 2016, the German plan approval for the project had not yet been granted. 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.
“The contracts are nearly 10 years old and were signed before both Covid-19 and the war in Ukraine occurred, and before we knew the scope of the German authorities’ conditions,” said Hemmingsen.
The second part of the project, the Danish railway facilities for the Fehmarnbelt tunnel, consisting of around 110km of new double-track railway from Ringsted to Rødby, is on schedule.
