Offshore wind foundations of the future face many challenges. Projects will be built further from shore, in deeper water, with the ability to be installed without exceeding strict regulatory requirements on underwater noise. The innovative design of the suction bucket jacket, developed by DONG Energy, has been tailor-made specifically to tackle these challenges.
The suction bucket jacket design consists of three legs welded together in a jacket structure, standing on top of three giant suction buckets anchoring the foundation to the seabed. It is a lightweight structure that only requires a single operation when the foundation is installed offshore, reducing the time of the installation and hence contributing to lowering the costs of electricity from offshore wind.
The new foundation concept has been developed by DONG Energy in cooperation with Carbon Trust Offshore Wind Accelerator (OWA) in the UK and marks the beginning of a new technological plateau in the construction of turbines offshore.
The German offshore wind project Borkum Riffgrund 1 in Germany has been selected for testing this foundation due to its sandy seabed, which makes the installation of this concept a challenge. Challenging test conditions provide a more solid case for the evaluation of the concept.
Tove Feld, Vice President in DONG Energy, said: “It’s a great day for us. We’ve now installed the very first suction bucket jacket in the offshore wind industry. The reduction in cost of electricity and our ability to utilise some of the more challenging sites further from shore and in deeper water show some of the potential that this concept has.
“I’m very excited to see that the cooperation between the partners in this project, not least with Carbon Trust in the UK, is paying off with specific results.”
Tom Delay, Chief Executive, the Carbon Trust commented: “We believe innovative foundation designs, such as the suction jacket technology play an important role in our efforts to cut the cost of energy from offshore wind. This foundation has been designed for serial fabrication and will save costs across design, fabrication, installation through to operation. Full scale demonstrations are the last critical step before a new innovative design can be considered for commercial projects. We are very enthusiastic about this design and the impact it will have on the industry and we have been very pleased to collaborate with DONG Energy and the other OWA partners to realise this demonstration.”
The suction bucket jacket is equipped with a comprehensive monitoring system providing data. The OWA project partners, E.ON, Mainstream Renewable Power, Iberdrola/ScottishPower Renewables, Statkraft and Statoil, will get full insight into these data and also have full access to the fabrication and installation of the new foundation design. This will allow them to evaluate whether it should be used in the UK. The data will also be analysed in a separate joint research project between the Leibniz University of Hannover, the German BAM Institute (Federal Institute for Materials Research and Testing) and DONG Energy.
In October this year, a 3.6MW turbine from Siemens Wind Power will be installed on top of the foundation.
Press Release, August 28, 2014; Image: DONG Energy