RWE reports that it has installed all 49 foundations for the Nordsee Ost offshore wind farm. The German firm says that installation of the jacket foundations 35 km north of the island of Heligoland in waters up to 25 m deep represents an important milestone in the project.
Forty-eight of the foundations are for the wind turbines and one is for the substation. Turbine installation will start in May.
Completion of the foundation installation demonstrates that RWE’s "logistics chain has been working exceptionally well", said Marcel Sunier, RWE’s project director for the Nordsee Ost wind farm. Each foundation is 50 m high, weighs around 550 tons and will support the 700 ton weight of the project’s 6 MW-class wind turbines.
The foundations were installed by the heavy-duty crane of RWE’s own installation vessel, Victoria Mathias. The foundations are anchored to the sea bed with foundation piles.
The jacket foundations were manufactured by Kvaerner in Verdal, Norway, and transported by pontoons to the Nordsee Ost base port at Bremerhaven. Once there, two foundation structures at a time were loaded with the associated eight foundation piles onto the installation vessel and taken to the construction site at sea.
The Victoria Mathias installation vessel is currently being converted in the Mützelfeldt shipyard at Cuxhaven so that it can accommodate the wind turbines’ huge components, including 60 m-long rotor blades, steel turbine towers and nacelles that are the size of a small house. To this end, the transportation frames for the foundations are being removed from the ship’s deck and replaced by appropriate transport restraint systems for the wind turbine.
The Victoria Mathias is due to leave the port for the first time with tower segments and nacelles on board in May. Its sister vessel, Friedrich Ernestine, which is currently erecting the Gwynt y Môr offshore wind farm off the Welsh coast, will assist with turbine installation in the summer.
Sian Crampsie
Photo: Installation of foundations at Nordsee Ost offshore wind farm (Courtesy RWE)