DONG Energy’s detailed seabed investigations have documented that there are about 5,000 stones at positions, which may cause problems for the wind turbine and cable installation. The stones will be removed and placed in a number of artificial reefs within the 88km2 large wind farm area.
Stone fishing and construction of the artificial reefs commenced in August, and at present, approximately 5-600 stones have been removed, and three artificial reefs have been constructed.
Stones from 0.5 to 30 tonnes
The stones weigh from 0.5 to 30 tonnes; however, the stone fishing vessels cannot carry stones weighing more than 15-20 tonnes.
The few critical stones, which the vessels cannot handle and which are placed where there should be absolutely no obstructions in relation to the construction of the wind farm, will be blasted away.
At present, two vessels are relocating the stones; at the end of October, yet another stone fishing vessel will be sent to the site. The process of relocating the stones will continue as long as the weather allows, and should the work be stopped by adverse weather conditions, it will be resumed in spring 2012.
The vessels locate the stones by means of their advanced positioning equipment based on data prepared by DONG Energy. The expected measure and weight of the stones, which are based on theoretical data analyses, have agreed with the actual finds.
[mappress] Source: DONG Energy, October 05 , 2011