Offshore installation contractor Jan De Nul has completed the installation of 72 wind turbines at Vattenfall's Kriegers Flak offshore wind farm in Denmark.
The Siemens Gamesa turbines, at 8.4MW each, will produce enough green electricity for the annual needs of approximately 600,000 Danish households.
Jan De Nul used the "Vole au vent" offshore installation vessel for the project to install the 72 wind turbines, each 187 meters high. The wind farm covers an offshore area of 132 km² at 15 to 40 kilometers off the Danish East coast.
The Kriegers Flak offshore wind farm is the largest in Denmark and increases Denmark's wind production by no less than 16 percent, Jan De Nul said Monday.
According to the company, the offshore wind farm site has extremely heterogeneous soil conditions with large lateral variability and boulders on the surface and below.
"Despite that, Jan De Nul managed to successfully deploy a Jack-Up Installation Vessel for the installation works," the company said.
Bert Reynvoet, Project Manager of Jan De Nul Group said: “Thanks to elaborate preliminary geophysical and geotechnical studies and with the help of an in-house calibrated leg penetration model, we managed to engineer an efficient jacking procedure. This allowed us to execute the project ahead of schedule.”
In 2017 and 2018, Jan De Nul Group designed, built and installed two large Gravity Based Foundations for the offshore high-voltage substations of this new offshore wind farm. Jan De Nul built both concrete structures of 8,000 and 10,000 tonnes on a floating pontoon in the port of Ostend (Belgium) and then towed them to Denmark. In the Baltic Sea, the crane vessel Rambiz installed both foundations on the seabed.
The wind farm is expected to be fully operational by the end of 2021. About 170 kilometers of subsea cables connect the offshore wind farm to the Danish grid.
