Offshore Project Installs First Monopile Foundation & Begins North Sea Construction

Offshore installation works for the OranjeWind wind farm have officially commenced in the Dutch North Sea following the successful placement of the project’s first turbine foundation.

Located 53 kilometers off the coast of IJmuiden, the joint venture project between RWE and TotalEnergies will feature 53 monopile foundations, with complete installation anticipated by early 2027. The project utilizes a transition piece-less design where wind turbines bolt directly onto the top flange of the monopile foundation. Eliminating the transition piece significantly reduces overall steel consumption. Each foundation measures approximately 90 meters in length and 8 meters in diameter, with secondary steel elements—such as main access platforms, internal cassettes, and boat berths—mounted directly onto the structure during a subsequent installation phase.

The initial monopile was loaded out from Sif’s terminal at Maasvlakte near Rotterdam and transported to the offshore site by Jan De Nul’s installation vessel Les Alizés, which operates under a long-term charter agreement with RWE. The heavy-lift floating vessel utilizes dynamic positioning for precise maneuvering and features a 5,000-ton crane capable of a 160-meter lifting height. Monopiles are lowered into position and driven into the seabed using a hydraulic hammer. Designated as an Ultra-Low Emissions Vessel, Les Alizés goes beyond MARPOL air emission standards by incorporating advanced onboard technology that significantly cuts nitrogen oxides and particulate matter emissions.

Environmental mitigation measures are deployed during driving operations to mitigate underwater sound pressure on marine life. Compressed air is pumped through a submerged hose around the piling zone to generate a bubble curtain that absorbs and reflects acoustic waves, while noise monitoring is conducted outside the perimeter to verify adherence to regulatory limits.

Sven Utermöhlen, CEO RWE Offshore Wind, said, “RWE and TotalEnergies are realizing one of the largest wind farms in the Dutch North Sea. After years of planning, the project has become a reality with the installation of the first monopile. This is a huge success for the team and the partners in the supply chain. We are now taking the first steps to supply the Netherlands with renewable energy with OranjeWind.”

Olivier Jouny, Senior Vice President Renewables TotalEnergies, commented, “The successful installation of the first monopile is an important milestone for OranjeWind and for TotalEnergies’ ambition to build an integrated energy company in Europe. Together with RWE, we are developing a major offshore wind project that will contribute to the supply of renewable electricity in the Netherlands while simultaneously supporting our own roadmap for emission reduction through the production of green hydrogen for our refineries in Northern Europe. OranjeWind is a concrete example of how TotalEnergies combines scale, innovation, and partnerships to realize the energy transition.”