In what has been described as the world's first, DEME Offshore has installed special collars around the monopile foundations at the seabed level, at RWE's Kaskasi wind farm, offshore Germany. 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," RWE said.
Kaskasi is RWE’s sixth wind farm off the German coast. The 342-megawatt project is currently under construction 35 kilometers north of the island of Heligoland. In total, three innovative foundation collars were successfully embedded into the seabed – each 7 meters high, weighing
170 tons.
The installation in water depths of up to 25 meters was carried out by DEME Offshore's jack-up vessel ‘Sea Challenger’. The space between collar and monopile foundation was filled with grout material, finally creating a stable connection.
RWE said it would carry out accompanying tests to verify that the collar improves the structural behavior 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 the manufacturer and DEME Offshore was responsible for the transportation and installation.
Also, the Kaskasi offshore wind farm in interesting for its unique turbines too. At Kaskasi offshore wind farm Siemens Gamesa and RWE will equip a number of wind turbines with recyclable rotor blades.
"The blades are the first of their kind, thanks to an innovative resin that enables components to be recycled for new applications at the end of their
lifecycle. Installation of the wind turbines is scheduled to start this summer. By the end of 2022 a total of 38 wind turbines are to be fully operational. Then, the Kaskasi offshore wind farm will have the capacity to supply the equivalent of approximately 400,000 households with green
electricity every year," RWE said.