Jan De Nul Group provides services related to the installation of offshore wind farms, including installation of export and inter array cables, fabrication and installation of gravity based foundations, transport and installation of jacket or monopile foundations and high voltage stations, installation of scour protection around the foundations, and installation of the entire wind turbines itself.


Through a constant pursuit of quality and technical innovation, Jan De Nul Group has a very modern and well-balanced marine fleet for all stages involved in the seabed preparation, wind farm installation and ballasting of the structure, as well as in cable and umbilical installation.

The company owns three Offshore Jack-Up Installation Vessels and one Heavy Lift Vessel for floating installation. Two of them are still under construction. These offshore installation vessels Voltaire, Vole au vent, Taillevent and Les Alizés are especially built to install offshore wind farms. Their large cargo deck space and payload, and the lifting capacity of their on-board cranes enable swift and safe installation of the heaviest foundations and other components of offshore wind parks.

With an unrivalled crane capacity of over 3,000 tonnes, the Voltaire, under construction and set to be delivered in 2022, is specifically designed to transport, lift and install offshore wind turbines, transition pieces and foundations. Compared to Jan De Nul’s two other jack-up vessels, the Vole au vent and the Taillevent, this new vessel has almost double the deck space. Not only is this vessel capable of loading the next generation of wind turbines and foundations, the larger deck space will also enable Jan De Nul to optimise installations at sea and to lower the fuel consumption and emissions.

The Vole au vent and the Taillevent are both 140m long. The Vole au vent is equipped with a 1,500t crane and four spuds to lift itself above the sea level for stable working conditions. She can install all kinds of foundations, as well as the latest generation of wind turbines, in water depths up to 50m. The Taillevent has a 1,000t crane, six spuds and a maximum working depth up to 40m.

Les Alizés, under construction and set to be delivered in 2022, is equipped with a crane having a lifting capacity of 5,000t and equally impressive lifting heights. Thanks to her dimensions and impressive lifting and loading capacities, Les Alizés will be able to load out, transport and install multiple units of the largest and heaviest wind turbine foundations. In addition, as a crane vessel that floats, it will be able to install heavier and larger foundations into deeper waters and in more challenging seabed conditions.

The Group also disposes of versatile and most efficient multipurpose vessels and in-house designed trenching tools to overcome unnavigable tidal areas. Thanks to their versatility, these vessels can be deployed on a variety of projects: installing subsea cables, trench dredging and subsea rock installation, which definitely makes those vessels unique. This allows Jan De Nul Group to better meet the clients’ requests to have a project executed by one contractor of one vessel and to reduce the mobilisation costs for its clients.


Clients are increasingly seeking a complete, one-stop-shop solution for their projects – with an integrated approach from first designs to final installation. Jan De Nul Group’s deep expertise in marine design, procurement and construction engineering enables the Group to respond with a total package on an EPC basis, eliminating the risks for the client. Jan De Nul Group has an in-house engineering department that designs new equipment, or modifies existing equipment, as needed. Each offshore job brings new challenges. Vessels and equipment are constantly adapted to find the ideal solution to specific customer needs, even if it’s only for one particular project.

Track record

Jan De Nul Group executes and has executed several offshore wind projects in Belgium, the UK, Sweden, Denmark, Finland, Germany and Taiwan. In 2018, Jan De Nul secured its first offshore wind projects outside Europe: the design and installation of the offshore wind parks Changhua and Formosa 1 Phase 2, the very first offshore wind farms in Taiwan. In 2019, Jan De Nul secured a hat trick in Taiwan by winning the Formosa 2 project, neighbouring the Formosa 1 Phase 2 wind farm.

More specifically in Belgium, Jan De Nul installed the Nobelwind farm with 50 turbines of 3.3MW each in 2016. In the summer of 2019, the Group kicked off the installation of the Northwester 2 wind farm with 23 turbines of 9.5MW each, the largest offshore wind turbines in the world.


Onsite health and safety are given absolute priority, supported by thorough training and maintaining constant safety awareness, using the Group’s internal awareness programme ‘Imagine. Think. Act.’ ITA makes Jan De Nul employees imagine what is possible and put those ideas into action in ways that demonstrate care for our co-workers and the environment. ITA is the Group’s guarantee for sustainable, safe, creative and successful solutions that are tailored to the Client’s specific project. Thanks to these ongoing efforts, the company has received several safety certificates, including the “A rating” in Australia.