The 400MW wind farm is located is located 100km to the north-west of the island of Borkum in waters up to 40m deep.
Bard Engineering, developer of Bard Offshore 1, said that the project consists of 80 5MW turbines.
The first turbines at Bard Offshore 1 were linked to the grid in December 2010 and presently supplies 80% of the offshore electricity produced in Germany
Rösler said "BARD Offshore 1 is the impressive pioneering project of a young industry which has the potential to play a key role in our energy mix in the long term.
"The successful completion of the offshore wind farm represents a technological and logistical feat.
"I would like to express my congratulations and respect to all those who have been involved."
Bard Group chief executive Michael Baur said, "The inauguration today of this pioneering project sends an important signal in terms of the energy turnaround and the future of the offshore wind industry in Germany.
"The team overcame the highly critical initial phase of the project. It took an unparalleled degree of commitment and an extremely sharp learning curve but ultimately we demonstrated that projects of this size and complexity can be successfully implemented."
