All 150 turbines produced power simultaneously last week at the 600MW Gemini wind farm in the Dutch North Sea.
The developer said testing and final works are continuing to ensure the project is completed on time in spring 2017.
The shareholders in Gemini are Northland, Van Oord, Siemens and Dutch municipal utility HVC.
It consists of 4MW Siemens machines.
Image: Van Oord
Gemini tests at full power
All 150 turbines produce electricity simultaneously for the first time
By EBS