Iemants and Jan De Nul Group to construct, install, ballast and protect GBFs for the EPCI Kriegers Flak OSS Project in Denmark

In the framework of the Kriegers Flak Offshore Wind Farm, a 600 MW offshore wind farm in the Danish Baltic Sea, together with the Combined Grid Solution interconnector project, and 50Hertz Transmission GmbH awarded the Joint Venture Iemants – Jan De Nul Group the EPCI contract for 2 Gravity Based Foundations (GBF).

Iemants joins with Jan De Nul Group for the engineering, construction and installation of 2 Gravity Based Foundations (GBFs) for 2 offshore substations, serving both for the future Krieger Flaks offshore wind farm as well as an interconnector between the Danish and German power net. The interconnector project is funded by the European Energy Programme for Recovery.

The wind farm consists of 2 sections, each with its own substation. Kriegers Flak A, the west section, will have a total capacity of 200 MW. The east section, Kriegers Flak B, will have a total capacity of 400 MW.

Jan De Nul Group is in charge of the design, construction, transport and installation of the GBFs, whereas Iemants will take care of the detailed design, fabrication and transportation of the steel shafts and decks which will be placed on top of the GBFs. The steel structures will be (pre)fabricated at the Iemants’ facilities in Belgium.

The GBFs will be constructed on a barge based along the REBO quay in the port of Ostend (Belgium) and towed to the Baltic Sea. In Denmark, Jan De Nul’s backhoe dredger Gian Lorenzo Bernini and the fallpipe vessel Adhémar de Saint-Venant will take care of the excavation of the foundation pit and installation of the gravel bed. Once the barge with GBFs arrives in Denmark, it will be immersed to offload the structures upon which the foundations will be installed onto the gravel bed. Finally, the GBFs will be ballasted and protected through scour installation by means of the Adhémar de Saint-Venant.

The Gravity Based Foundations shall be installed offshore by the end of 2017. By 2022, Denmark's to date largest offshore wind farm will start generating CO2-free electricity for approx. 600,000 households.


About is an independent public enterprise owned by the Danish state as represented by the Ministry of Energy, Utilities and Climate. owns the Danish electricity and gas transmission system and is the co-owner of the electrical interconnections to Norway, Sweden and Germany. The main task is to maintain the overall short-term and long-term security of electricity and gas supply.'s vision is balance in a sustainable energy system concurrently with covering an increasingly larger part of Denmark's energy consumption from renewable energy.

About 50Hertz Transmission GmbH

With over 950 employees, 50Hertz handles the operation and the extension of the electricity transmission system. Furthermore, the company is responsible for the management of the overall electrical system throughout the German federal states of Berlin, Brandenburg, Hamburg, Mecklenburg-Western Pomerania, Saxony, Saxony-Anhalt and Thuringia. As transmission system operator active in the Central European market, 50Hertz is responsible for the secure integration of renewable energy, the development of the European electricity market and for maintaining a high level of security of supply. Since 2010, Belgian grid operator Elia and Australian infrastructure fund IFM Investors are shareholders of 50Hertz, holding stakes of 60 % and 40 % respectively. As a European transmission system operator, 50Hertz is part of the Elia Group and a member of ENTSO-E, the European Network of Transmission System Operators for Electricity.

About Iemants 

Iemants is an international steel construction company with a proven track record in the engineering, production, delivery and assembly of mainly heavy, technically complex steel constructions. Iemants ranks among the world's top steel construction companies. With regards to substations and their foundations, Iemants offers a full range of services from fabrication to complete EPCI projects. Iemants and its sister companies belong to Eiffage, one of European leaders in construction and concessions.

About Jan De Nul Group

Design. Build. Connect. Jan De Nul Group offers specialized services for the installation of subsea structures for oil, gas and renewable energy industries. They comprise seabed preparation, trenching, stabilization and ballasting and can be related to subsea pipelines, cables, umbilicals, foundations or entire offshore wind farms. In addition, Jan De Nul Group also installs cables and umbilicals for these three offshore industries. These types of services can be offered on an EPC basis tailor-made to the client’s specific wishes.