RWE Renewables has signed a contract with DEME Offshore for the transport and construction of the latest technology of the RWE 342-MW Kaskasi offshore wind farm situated in the Germany North Sea, 35 kilometers north of the island of Heligoland.
DEME Offshore is pleased to partner with RWE in this project, which highlights the emphasis of both companies on further refining advanced technologies and new ideas in the renewables field.
“At our Kaskasi offshore wind farm we use innovative technologies that will set standards throughout the offshore industry. The collared monopile, a patented solution developed in-house, will help to increase stability in difficult ground. Furthermore, Kaskasi will be the first commercial offshore wind farm in the world to use an improved installation method to drive all monopile foundations to target penetration.
“The vibro pile driving technique will reduce both installation time as well as noise emissions for marine life. This showcases our technical expertise as the second biggest player in offshore wind globally and means that we will continue to be at the forefront of the evolution of technology in this industry.”Sven Utermöhlen, chief operating officer wind offshore global at RWE Renewables.
The Kaskas offshore wind farm will consist of a total of 38 wind turbines. Each turbine has a capacity of up to 9 MW. The wind turbines will be installed on the monopile foundation. Installation of the foundations will begin in the third quarter of 2021.
RWE will use the “vibro pile driving” installation process, which is an effective alternative to the traditional method of hammering monopiles into the seabed. This improved installation method could minimize installation time and noise during construction. Kaskasi will be the first commercial offshore wind farm in the world to use the Vibro Driving Technique to install all the monopile foundations to target penetration. This highlights RWE’s desire to be a pioneer in driving innovation and technology.
When the target penetration is achieved, the foundation collars will be mounted at three wind turbine locations. The detailed design was developed by the German civil engineering company JBO on the basis of the RWE patent.
Bladt Industries has been chosen as the manufacturer.
DEME Offshore will move the three collars from the loading port of the manufacturer in Aalborg, Denmark, to the Kaskasi construction site near Heligoland. The DEME Offshore team will then mount the steel collars around three of the 38 monopile foundations for which DEME will deploy the flexible NEPTUNE jack-up vessel.
The collar shall be mounted at seabed level in water depths of up to 25 meters. The gap between the collar and the monopile base will be filled with grout material to create a secure bond. RWE will carry out corresponding tests to check that the collar enhances structural behavior relative to regular monopiles.
The Kaskasi wind farm is expected to begin commercial operations in the summer of 2022. Once all wind turbines are fully operational, the farm will supply more than 400,000 homes with green electricity. Kaskasi is RWE’s sixth wind farm off the coast of Germany. The company operates the nearby offshore wind farms Nordsee Ost (295 MW) and Amrumbank West (302 MW) as well as Arkona, the largest offshore wind farm in the Baltic Sea, with an installed capacity of 385 MW (RWE 50 percent). In addition, RWE holds shares in Nordsee One and Alpha Ventus, the first offshore wind farm to be built off the German coast.