RWE said it used two installation vessels simultaneously to erect the turbines. It will now work on commissioning each turbine individually with the whole project expected online by spring 2015.
The first power from Nordsee Ost was exported in December. The project is located 35 kilometres off the German coast in the North Sea.
Nordsee Ost was completed just a month after construction activities were finished on RWE's 576MW Gwynt y Mor project in the Irish Sea.