Jan De Nul Group completed the first part of the cable installation works to connect the Hollandse Kust (north) and (west Alpha) wind farms to the Dutch mainland. The 220 kV high-voltage tests of both the sea and land cables for Hollandse Kust (noord) were also successfully completed, all the way from the onshore transformer station to the platform at sea, 18 km off the coast.
A week later, on November 24, Jan De Nul Group signed a contract with Global Marine Systems Ltd. for the purchase of the offshore support vessel Global Symphony. With this purchase, the Luxembourg marine contractor is investing further in its offshore installation capacity.
Wouter Vermeersch, Manager Offshore Cables at Jan De Nul Group : “The Hollandse Kust (north) and (west Alpha) project demonstrates our expertise in cable installation works. Jan De Nul has a very modern installation fleet, with three large cable laying vessels, supporting cable excavators and amphibious cranes. Our investment in an additional offshore auxiliary vessel, which we will be renaming Symphony out of respect for its previous successes, underlines Jan De Nul's vision to provide the world with a solution for the much-needed energy transition. With the success in the Netherlands and the investment in our offshore installation fleet, we validate our expertise and resolute commitment to this energy transition.”
Cable installation vessel Isaac Newton installed the cables on the seabed. In addition, Jan De Nul used several remote-controlled underwater cable excavators and amphibious cranes in the surf to bury the cable protected in the seabed. The Moonfish (photo) is one of those underwater cable excavators, a design by Jan De Nul tailored to this project.
In the spring, the cable-laying vessel Isaac Newton collected a first lot of 90 kilometers of sea cable from consortium partner LS Cable & System in South Korea. After arriving in the Netherlands, the Isaac Newton installed four different sea cables from the beach.
- Two cables were laid in one length on the seabed, all the way to the Hollandse Kust (north) transformer station.
- For the connection to the Hollandse Kust (west Alpha) transformer substation, the Isaac Newton installed the first 8 kilometers of the two sea cables.
Subsequently, the Moonfish cable excavator set to work to bury the sea cables in the seabed in a shielded way.
- In a first phase, the Moonfish buried the first section of the two Hollandse Kust (north) sea cables, from the beach to 3 kilometers seaward, at a depth of about 6 to 8 meters in the seabed. At 3 kilometers from the coast, the submarine vehicle UTV1200 took over to the transformer station. This 'socket at sea' is located 18 kilometers off the Dutch coast.
- After the summer high season, in October, Jan De Nul completed this first installation campaign by burying the two cable sections off Hollandse Kust (west Alpha) from the beach up to 3 kilometers seaward.