At the end of July all foundations were in place at the 312MW Borkum Riffgrund 1, located 54km off the German coast and around 37km from the island Borkum and at the end of September, the innovative Suction Bucket Jacket test foundation was also installed.
The 850t weighing foundation, consisting of a 3-legged jacket structure on top of 3 large suction buckets which anchor the foundation to the seabed, was developed by DONG Energy in cooperation with the Carbon Trust Offshore Wind Accelerator (OWA). This type of foundation is already used in the oil S gas sector and will now be tested on its suitability for wind farms located far offshore. As the foundation needs only a single installation operation it could lead to a reduction in installation time and, as a consequence, a reduction in the costs. The foundation is now being tested to see whether it can be deployed in wind farms in the UK.
The sandy seabed of the Borkum Riffgrund I wind farm form challenging conditions for installing this type of foundation making it the perfect setting for testing. The foundation is equipped with a monitoring system to which the OWA project partners, E.ON, Mainstream Renewable Power, Iberdrola/ScottishPower Renewables, Statkraft and Statoil will get full insight in the performance. The partners will also have access to the fabrication and installation. The data will also be analysed in a separate joint research project between the Leibniz University of Hannover, the German BAM Institute and DONG Energy.
In total 78 Siemens SWT-4.0-130 turbines will be installed however the start of the installation has been delayed due to delays in the production at the Siemens factory in Esbjerg. Borkum Riffgrund 1 is expected to be fully operational in 2015, providing electricity for around 320,000 households. It is a project by DONG Energy (50%), KIRKBI Invest A/S and William Demant Holding A/S (together 50%).