Based on the extensive seabed surveys carried out in 2010 at Anholt Offshore Wind Farm, 42 turbine positions have been identified as being at risk of extreme scour formation around the turbine foundation and it has therefore been decided to place a pile of rocks at the positions before the monopole is driven into the seabed.
The rocks are placed by special-purpose vessels that lay the rocks in one layer with a thickness of approx one metre and a diameter of 20-23 metres around the turbine position. Of the 42 positions, rock piles have now been installed at 28 positions.
Anholt Offshore Wind Farm
The project site is located in the Kattegat in the waters between Djursland and the island of Anholt in an area with fairly consistent water depths of about 15 to 19 metres.
The project site comprises an area of 144km2. According to the licence conditions, the actual offshore wind farm must not take up an area of more than 88km2 within the project site. The actual offshore wind farm area includes the wind turbines and array cables.
The project site is approx 20km long and between 4 and 12km wide. The shortest distance to Djursland is approx 15km, while there are 20km to the island of Anholt.
[mappress] Subsea World News Staff , February 07, 2012; Image: DONG Energy