EnBW has installed the first of 71 turbines at the 497MW Hohe See offshore wind farm in the German North Sea.
Fred Olsen Windcarrier jack-up Brave Tern supported by Blue Tern erected the Siemens Gamesa 7MW machine on 5 April.
The vessels will continue to the install first four turbines before returning to Esbjerg for the next load.
Hohe See and sister project, the 112MW Albatros wind farm, are due to be connected to the grid by the end of the year, EnBW said.
EnBW chief technical officer Hans-Josef Zimmer said: “EnBW Hohe See and Albatros are being constructed as one combined project and together represent the largest offshore project currently being realised in Germany.
“We will place both wind farms into operation in 2019.”
The company added that over 600 employees are working at the construction site with about 50 ships involved in the work.
Other investors in the project are Canada Pension Plan Investment Board and Enbridge.