• RWE-patented technology deployed for the first time
  • New monopile foundation collars increase load-bearing capacity
  • DEME Offshore carried out installation of 3 foundation collars - each weighs 170 tons

An innovative foundation technology is celebrating its premiere at RWE’s Kaskasi offshore wind farm: For the first time ever in the renewables industry special collars were installed around the monopile foundation at seabed level. The ‘collared monopile’ is a design based on a RWE patent. The new technology will provide additional support for lateral loading, increase the bearing capacity and improve the structural integrity of the entire foundation. Installation works were carried out by DEME Offshore.

Sven Utermöhlen, CEO Offshore Wind, RWE Renewables: “At our Kaskasi offshore wind farm we use innovative technologies that will set standards throughout the entire offshore industry. It’s a great credit to the project team and our contractors that we developed, manufactured and safely installed the three innovative foundation collars. The collared monopile, a patented solution developed in-house, will help to increase stability in difficult ground. This showcases our technical expertise as the second largest player in offshore wind globally.”

Collared monopiles strengthen behaviour of entire structure

Kaskasi is RWE’s sixth wind farm off the German coast, the 342-megawatt project is currently under construction 35 kilometres north of the island of Heligoland. In total three innovative foundation collars were successfully embedded into the seabed – each 7metres high, weighing 170 tons. The installation in water depths of up to 25 metres was carried out by the jack-up vessel ‘Sea Challenger’ from DEME Offshore. The space between collar and monopile foundation was filled with grout material, creating finally a stable connection. RWE will carry out accompanying tests to verify that the collar improves the structural behaviour in comparison with standard monopiles.

The detailed design of the collars was developed by the German civil engineering company JBO based on the RWE patent, Bladt Industries was selected as manufacturer and DEME Offshore was responsible for the transportation and installation.

Bas Nekeman, Business Unit Director Northern Europe at DEME Offshore, emphasises: “Whilst these monopile foundation collars represent only a relatively small scope of work DEME Offshore is performing at the Kaskasi offshore wind farm, we are extremely happy achieving this important milestone for the project. The installation of these type of structures is a world’s first which required us to develop a tailor-made solution. The completion of the three monopile foundation collars demonstrates our ability to deliver our customers the right technical know-how, operational excellence and team spirit required for the successful delivery of these types of innovative projects.”