Last week, all 77 monopile foundations were successfully installed at the offshore wind farm Borkum Riffgrund 1 in the German North Sea.
Installation was carried out using a noise mitigation system to lower the impact on adjacent marine life. It is the first time ever that this system has been used this way.
The 77 units consisted of monopiles, weighing between 495 tonnes and 684 tonnes and measuring a diameter of 5.9 metres and a length of up to 66m, and transition pieces of weighing around 330 tonnes.
https://www.youtube.com/watch?v=lhZgmiDiKaU
Press Release, August 07, 2014