Vattenfall purchased the development license from Sandbank Power. The site has permission for 96 6MW wind turbines and an option to expand this number by 40.
The project is close to the DanTysk offshore project, which Vattenfall co-owns. The company's total investment in offshore between 2011 and 2015 is SEK 26 billion (€2.6 billion).
Sandbank was being developed by German developer Projekt. Last year, the company made a down payment with Vestas for 96 Vestas 3MW turbines.
Vattenfall said construction would start in 2014. Projekt was due to commence construction this year.
Speaking about the deal, Vattenfall head of BU Renewables Anders Dahl said: "With Sandbank 24 Vattenfall is actively supporting the ongoing energy turnaround in Germany.
"We are convinced that offshore wind power will play an important role in Germany in the future and that this young industry will become successfully established in Germany as well."