HR Wallingford and Ørsted have worked together to test and refine the design of the suction bucket foundations for the Borkum Riffgrund 2 offshore wind farm in the German North Sea.
The testing was conducted as a part of the research project investigating scour effects, and the most suitable scour protection for the novel foundation structures.
The ten-month study included physical modelling and complex analysis, looking into the types and extents of scour protection that would be required for the suction bucket foundation to be deployed in the North Sea. Testing was also undertaken to assess the likely impacts of scour protection around the cables required to transport power from offshore wind turbines to onshore transformer stations.
The construction of the Borkum Riffgrund 2 offshore wind farm, which will include 20 next-generation suction bucket foundations, has already started.
Prof. Richard Whitehouse, chief technical director, Sediment Dynamics, at HR Wallingford, said: “For complex foundations, we currently use a combination of approaches to estimate likely scour, and this introduces a level of uncertainty in the design process. The research with Ørsted has enabled us to develop greater certainty in the prediction of seabed response, and design more efficient foundation solutions. Ultimately this will help to make offshore wind developments more cost-effective, and developments in exposed locations and deeper waters more economically viable.”
Andreas Roulund, scour engineer at Ørsted, said: “The testing has improved our knowledge of the scour and scour processes that occur at large, complex foundations. We are moving to the construction phase of Borkum Riffgrund 2 with rigorously tested scour protection designs, which increases our confidence in the performance of the scour protection.”
Harland and Wolff are manufacturing the suction buckets for the foundations, while GeoSea vessel ‘Innovation’ is handling their installation, HR Wallingford noted.
The 450MW wind farm, located some 40 km northwest of the island of Borkum, and co-owned by Ørsted and Global Infrastructure Partners, is expected to be fully commissioned during 2019.