Next-gen vessels install tomorrow's wind turbines

Higher, more powerful, more efficient. Offshore wind turbines underwent an enormous increase in scale in recent years. Eventually, we will have to ask ourselves “How big is too big?”, but for now the evolution continues. Today, the largest turbines already measure over 270 metres, with rotating blades covering an area of ten football f ields. Who installs these mastodons? Our vessels Voltaire and Les Alizés.

Double interview with Sven Cras, Project Manager, and Rutger Standaert, Manager Vessel Construction.

Suited for the largest turbines and foundations

How does Jan De Nul Group manage to keep up with the lightning-fast evolution of wind turbines?

Sven Cras: "With a mix of vision, expertise, healthy finances and a portion of courage. For instance, we regularly seek input from our colleagues in commercial roles and closely monitor the market. Based on this input, we determine what the offshore wind farms of 11 tomorrow and the day after tomorrow will look like, and which vessels we will need to install them. Then you must make a reasoned choice, because you are actually investing in vessels for a market that is still under construction.”

Rutger Standaert: “It takes about three years to build an installation vessel. If you do not look ahead, your vessel will already be outdated by the time it is launched. But a well thought-out plan allows you to anticipate market trends. With Voltaire and Les Alizés, for instance, we are now reaping the benefits of design choices made in 2019.”

Sven: “We also gained time on our competitors. When Voltaire and Les Alizés were being built, we were not yet sure about specific projects, these only came later. It is often the other way around: first you win a project, then you start building.”

What is the greatest added value of Voltaire and Les Alizés?

Sven: “Together, they can handle the world’s largest turbines and foundations. This means we can offer customers an overall package, whereas with other players it is often one or the other. And that will remain so for quite a while yet. With both vessels, we are definitely on firm ground until well beyond 2030.

Also, the vessels are very complemen tary. The stable Voltaire is ideal for working upwards, while Les Alizés easily braves deeper waters and difficult subsoils because the vessel operates while floating. In short: this duo offers a solution for every region or project requirement.”

On Gode Wind 3, we installed an offshore substation for the first time, no less than five floors high. And, weighing 1,900 tonnes, it was also the largest lift Jan De Nul Group has ever executed. With Les Alizés, we are determined to push our own limits.


Gode Wind 3

Offshore substation Gode Wind 3

Sought and found: confidence in our own abilities

Meanwhile, the brand-new vessels are up and running. What will you remember from 2023?

Rutger: “We designed and built the Voltaire ourselves. That allowed us to closely involve the operational departments in the design process. Result: the vessel perfectly performs what it is supposed to do, meeting not only customer requirements but also ours. That is when a vessel can be considered ready for use. Now that the vessels are effectively up and running, we have further optimised our human capacity. Confidence is growing within our teams, which have become increasingly attuned to each other.”

Sven: “By making larger vessels available, you also open up new markets and opportuni ties. This has been a successful strategy since the early days of Jan De Nul Group. If you build a stronger cutter suction dredger, for instance, you can handle harder subsoils. The same for installation vessels: thanks to a heavier crane, you can work out new technologies. We spend great time and effort on such innovations.”

When completed, Dogger Bank will be the world's largest offshore wind farm. The size of this project perfectly matches the capabilities of Voltaire, a vessel that is able to operate smoothly in water depths of up to 80 metres with a lifted cargo of 16,000 tonnes.

Dogger Bank A, B and C

Voltaire Dogger Bank