The first of the 31 monopile foundations has been installed on Northland Power’s 269MW Deutsche Bucht offshore wind farm in the German North Sea.
Northland Deutsche Bucht has contracted manufacturing and installation of the monopiles and transition pieces from Van Oord. In Cuxhaven, the components are loaded onto the jack-up installation vessel Scylla, supplied by offshore solutions provider Seajacks.
The monopiles, measuring an average of 78 metres in length and weighing 1,100 tons each, are delivered from Rostock by transport barge and loaded directly onto the installation vessel.
The transition pieces, 26 metres high and weighing more than 300 tons, were transported from the production site in Spain and offloaded to interim storage in Cuxhaven until installation.
The Seajacks Scylla transports three monopiles and transition pieces per trip from the marshalling harbour to the offshore construction site, a distance of approximately 200 kilometres. Installation of the steel foundations is scheduled to be completed by the end of 2018.
“We are very pleased to have achieved this important milestone,” said Jens Poulsen, Project Director of Northland Deutsche Bucht GmbH. “Thanks to the committed Deutsche Bucht project team and our experienced general contractor, Van Oord, the offshore building phase of the wind farm started on schedule.”
Deutsche Bucht is using a multi-level noise mitigation concept during the installation of the foundations, which includes deterrence measures and deployment of both a hydro sound damper (HSD) and a double Big Bubble Curtain. The combined effect dampens underwater sound waves of a wide range of frequencies.
In addition to the 31 MHI Vestas 8.4MW turbines installed on monopiles, two of the project’s 33 wind turbines will be mounted on Mono Bucket foundations. Mono Buckets comprise a single steel cylinder topped by a shaft and are installed using suction – said to enable an installation process with low noise and minimal environmental impact.
The wind farm is located about 95 kilometres to the northwest of the North Sea island of Borkum in Germany’s Exclusive Economic Zone (EEZ). Completion of the commissioning phase is planned for the second half of 2019.