The comprehensive preliminary work prior to the installation works in Anholt Offshore Wind farm is almost completed.
The stone fisher vessels have almost relocated the approximately 5,000 stones, which were blocking the 111 wind turbine positions and the cable routes.
The relocation of the stones has resulted in the establishment of 30 new, artificial reefs – all located inside the wind farm area. Furthermore, the laying of stone pillows at a total of 42 wind turbine positions is expected to be completed at the beginning of March 2012. The stone pillow prevents erosion around the foundation pile and must be laid before driving the monopile into the seabed.
There are still approximately 50 stones at the seabed which cannot be relocated due to their weight. Some of the stones weigh more than 15 tonnes. The largest of the remaining stones is estimated to weigh approximately 300 tonnes.
Therefore, it will be assessed if it is possible to install the wind turbines and perform cable laying despite the stones. It this is not possible, the only alternative is to remove the stones by blasting.
[mappress] Subsea World News Staff , March 05, 2012; Image: DONG Energy