The pair of next-generation mono-bucket foundations being deployed at Northland Power’s Deutsche Bucht wind farm off Germany are en route from steel fabricator Bladt Industries’ yard in Lindø, Denmark.
Being installed by Seajack’s Scylla vessel, the Universal Foundation-developed units – in their first commercial outing – will be mated to 8.4MW MHI Vestas V164 turbines, which are also being used on the wider 269MW wind farm, which is located in 40 metres in the North Sea off the island of Borkum.
UF’s branded Mono Bucket concept, which has hollow, cylindrical steel base that embeds into the seafloor using a combination of suction pressure, gravity and ‘smart’ installation techniques, has been in development since 2001 via prototypes, including a 3MW turbine-topped unit in Frederikshavn, Denmark, and met-mast installations for projects including the UK’s multi-gigawatt Dogger Bank development.
Danish developer Orsted installed a three-legged suction-bucket foundation at the Borkum Riffgrund 1 wind farm in the German North Sea in 2014 and Vattenfall used the technology at Aberdeen Bay in the UK .
The Deutsche Bucht mono-buckets, each weighing 1,100 tonnes, will have a base diameter of 18.5 metres, with skirts that penetrate 16.5-18.5 metres into the project site’s predominantly sandy seabed.
The last of 31 monopile-based MHI Vestas V164s were installed by Van Oord’s Aeolus construction vessel in August.
Deutsche Bucht, Northland’s third offshore wind project, began flowing power to the grid in July and, by the end of 2019, will be producing 1.1 million MWh of power annually, meeting the demand of some 328,000 households.