Danish developer Dong Energy will pioneer a new suction bucket foundation concept at its Borkum Riffgrund 1 wind farm, currently under construction off Germany – as well as boosting its capacity to 312MW by using 4MW Siemens turbines.
The innovative technology – a tripod jacket that uses a vacuum-assisted installation method rather than piles to fix the foundation to the seabed – will occupy a single spot on the outskirts of the development, which otherwise employs conventional monopiles.
The suction-bucket design, being fabricated by Bladt Industries for installation later this year along with the first of the monopile-based turbines, could be moved into serial production by 2017 for UK Round 3 projects.
Borkum Riffgrund 1 was originally down to use Siemens 3.6MW machines.
capacity of our wind farm will be another important step to secure the supply
from renewable energy sources and therefore for the success of the German
energy turnaround,” says Trine Borum Bojsen, managing director of Dong’s German offshore wind
Dong sees the suction bucket tripod – which
marries a welded tubular space frame with a suction caisson concept commonly
used to fix North Sea oil platforms to the seabed – as a key technology in
meeting its target of cutting the cost of energy from offshore wind power
projects by 40% by 2020.
“Having more developers utilising the suction
bucket jacket will benefit optimisation of design, fabrication process and
installation logistics and thereby help to drive down the cost,” says Dong
Energy vice president Tove Feld.
Borkum Riffgrund 1 was chosen for prototype trials
due to its sandy soil conditions, seen as a“highly suitable” test for the new
foundation concept. The flagship suction bucket jacket will be fitted with a
state-of-the-art measurement system to feed-back data for performance
E.ON, Mainstream Renewable Power, ScottishPower
Renewables, Statkraft and Statoil – which all partnered early development of
the design through the Carbon Trust’s cost-cutting Offshore Wind Accelerator
scheme – will be given open access to the collected data and “full visibility”
of the fabrication and installation of the new foundation design to help in
evaluation of the technology for use off Europe.
Suction bucket foundation designs, which are
targeting the coming market for 6MW-plus wind turbines on projects in water
depths of 30-60 metres, are under development at a number of companies,
including Fred Olsen-backed Universal Foundation, which has had its
flask-shaped concept piloted as a foundation for two met-masts at consortium
Forewind’s Dogger Bank development.
1 is owned by Dong Energy (50%) and Lego-owner KIRKBI Invest A/S and William
Demant Holding A/S (together 50%).