Seafox and their main subcontractor Ardent are pleased to announce the successful decommissioning of the two Forewind Ltd (joint venture of SSE, Statoil and previously Innogy and Statkraft) Dogger Bank Meteorological Masts.
The two Mono Bucket foundations and lattice tower structures were installed four years ago to gather climate data to assess the feasibility of one of the UK’s largest potential offshore wind farm developments. In light of minimising the environmental impact of the now decommissioned offshore structures, Forewind Ltd. opted for the efficient installation and removal operation due to the suction bucket concept.
In preparation of the removal operations, that were successfully executed at the end of September 2017, Seafox and Ardent performed a pre-removal survey to reduce any uncertainties and to confirm the proposed removal procedure of the weather data measuring equipment, lattice towers, platforms and Mono Bucket foundations.
Project preparation and assurance was carried out by the project team, including Seafox, Ardent, SSE, Global Maritime, Universal Foundation and Searoc, ensuring that the removal of the structures were as successful as possible. All project engineering, fabrication and execution were carried out by Seafox and Ardent. As the foundations, platforms and lattice towers lend themselves for re-use, options for re-using are being explored although nothing has been confirmed at this stage. The offshore operations were executed more quickly than originally planned, which given the weather of the North Sea was of huge benefit to the project.
The engineering, fabrication, testing and deploying together with SPT Offshore of a project specific interface frame to control the original suction bucket pump system contributed to the successful removal. The heaviest lift, of the Mono Bucket, with potentially clay-sticking, was calculated at 768t. The meteorological masts are composed of an 80-meter lattice tower on a 16 m2 platform, which was mounted on a single pile, secured by a 15-meter diameter wide and 7-meter tall suction bucket. The successful operation is a testimony to both parties experience and hands on mentality whilst performing safe and efficient offshore projects.
Kristian Ascanius Jacobsen, Head of Business Development said: “This project once again proves the strengths of our Mono Bucket technology, and suction technology in general. Both foundations have been 100% decommissioned, leaving nothing behind and hence restoring the site to the original conditions, which is a significant environmental benefit of the technology.”