The installation of the first monopile at Denmark’s largest offshore wind farm, Thor, has been completed by heavy-lift vessel Les Alizés, operated by Belgian contractor Jan De Nul Group.
The operation marks a major milestone in what is shaping up to be one of Europe’s most significant offshore energy projects in 2025. Located in the North Sea, about 22 kilometers off the coast of Thorsminde, the Thor wind farm is owned by RWE, and when fully operational, it’s expected to supply electricity to over one million Danish households.
The scope of Jan De Nul Group’s work includes the installation of 72 monopile foundations, all outfitted with scour protection to prevent seabed erosion. The project also covers the complete inter-array cabling system—essential for connecting the turbines—and the export cables that will bring the generated power to shore.
The deployment of Les Alizés, a state-of-the-art heavy-lift vessel specifically built for offshore renewables, shows the company’s shift towards clean energy infrastructure. The vessel is equipped with a 5,000-tonne crane and zero-emission capabilities while in port, aligning with growing environmental regulations and expectations across the sector.
Installing monopiles at sea isn’t a straightforward task. Each one weighs hundreds of tonnes and must be precisely lowered and anchored into the seabed—under tight schedules and harsh weather conditions. The technical complexity is matched only by the logistical planning behind moving massive components from manufacturing sites to offshore coordinates. It’s this intersection of engineering and logistics that’s quietly becoming the backbone of the energy transition.
