Image credit: RWE

German energy company RWE has signed a contract with DEME Offshore for the transport and installation of a new foundation technology at the 342MW Kaskasi offshore wind farm.

For the first time ever in the renewables industry, special collars will be installed around the monopile foundation at seabed level.

The collars were developed by German civil engineering firm JBO and manufactured by Bladt Industries.

The ‘collared monopile’ is designed based on an 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 – especially in difficult ground.

The steel collars will be installed around three of the 38 monopile foundations for which DEME will deploy the versatile jack-up vessel NEPTUNE. The collar will be installed at seabed level in water depths of up to 25 meters.

The Kaskasi offshore wind farm is located in the German North Sea, 35 kilometres north of the island of Heligoland.

Construction is expected to start in the third quarter of 2021 for commercial operation of the plant to start in 2022.

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The wind farm will consist of a total of 38 wind turbines. Each turbine will have a capacity of up to 9MW.

The project,  RWE’s sixth wind farm off the German coast, will generate enough energy to power 400,000 homes.

To install the wind turbines, RWE will use the “vibro pile driving” installation method, which is an efficient alternative to the conventional method of hammering monopiles into the seabed. This improved installation method could reduce installation time and noise emissions during construction.

Sven Utermöhlen, chief operating officer Wind Offshore Global at RWE Renewables, says:  “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…”