DONG Energy has installed the first of 77 foundations at the Borkum Riffgrund 1 offshore wind power project in the German North Sea.
The 161m-long installation vessel Pacific Orca has transported the first four foundations and transition pieces to the construction site and the monopiles have a diameter of approximately 6m and a weight of up to 750t.
During installation, the developers have used a double walled noise mitigation system with an internal bubble curtain to keep the noise level at minimal.
Borkum Riffgrund 1 project foundations manager Andreas Elkjaer said, "We had ideal weather conditions during the installation process. Calm sea and a low wind are perfect for the construction work."
The project will feature 77 Siemens wind turbines, each with a capacity of 3.6MW and a rotor diameter of 120m.
In February 2011, Siemens had secured a contract to supply, install and commission the wind turbines at the plant and provide five-year maintenance services and warranty.
The developer had started construction work in 2013 and expects the first power production in 2014, while the full completion is set for 2015.
Once operational, the project will generate enough green power to power approximately 285,000 households and will be operated and maintained from the Lower Saxony harbour Norddeich in Germany.
Earlier in late 2009, DONG Energy had assumed the full ownership of the Borkum Riffgrund 1 and 2 offshore wind turbine projects from PNE Wind for a total up-front payment of approximately DKK100m (€13.4m) and additional payments subject to the parks being built.
Prior to that, DONG Energy had acquired Vattenfall's 49% stake in Borkum Riffgrund 1 Holding, which owns 50% of Borkum Riffgrund 1.
Image: DONG Energy installs first foundation at Borkum Riffgrund 1 in the German North Sea. Photo: courtesy of DONG Energy.