Successful Construction Start Deutsche Bucht Offshore Windfarm
Monday, 3 September, the 269MW Deutsche Bucht offshore wind project successfully installed the first of 31 steel foundations (monopile and transition piece). This marks the successful start of construction for the project, located in the German Exclusive Economic Zone, more than 100km from the German mainland. With an investment budget of approximately EUR 1.4 billion, Deutsche Bucht is Northland Power’s third North Sea offshore windfarm.
“We are very pleased to have achieved this important milestone,” notes Mr Jens Poulsen, Project Director of Northland Deutsche Bucht. “Thanks to the committed Deutsche Bucht project team and our experienced general contractor, Van Oord, the offshore building phase of the windfarm started on schedule.” 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 78m in length and weighing 1,100t each, are delivered from Rostock by transport barge and loaded directly onto the installation vessel. The transition pieces are 26m high and weigh more than 300t; they were transported from the production site in Spain and offloaded to interim storage in Cuxhaven until installation. The installation vessel transports three monopiles and transition pieces per trip from the marshalling harbour to the offshore construction site, a distance of approximately 200km. Installation of the steel foundations is scheduled to be completed by the end of 2018.
Construction of the Deutsche Bucht offshore windfarm is subject to strict regulations and laws. This includes protecting sea life from the noise emissions caused by monopile installation. During installation work, the noise level must not exceed 160db within a radius of 750m from the building site. Deutsche Bucht is therefore using a multi-level noise mitigation concept 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. The efficacy of the soundproofing systems is reviewed as part of an efficiency check. In addition to the 31 turbines installed on monopiles, two of the project’s 33 wind turbines will be mounted on innovative Mono Bucket foundations. Mono Buckets comprise a single steel cylinder topped by a shaft and are installed using suction – this enables an installation process with low noise and minimal environmental impact. Deutsche Bucht is the first offshore windfarm to test Mono Buckets as wind turbine foundations in commercial operation.