Germany's Wind Parks in the Sea Proven to be Challenging.

Having problems with windmills in the sea and no longer favor nuclear.

This report from Der Spiegel Online
By Frank Dohmen and Alexander Jung

An excerpt of the problems of sea operations.

When building wind farms in the North Sea and Baltic Sea, the operators must overcome substantial obstacles. To protect coastlines and tidal flats, German authorities have required that wind turbines be located up to 40 kilometers from the coast. While neighboring countries like Denmark need just a few months to build wind farms in shallow waters within view of the mainland, German engineers must cope with water depths of up to 50 meters (164 feet).

So build on the land, you get the not in my back yard. They are noisy and environmentalists can stall many projects.