About 20 kilometres off the coastal town of Sheringham in the eastern part of the UK, the 320 MW Sheringham Shoal Wind Farm forms an impressive sight in the brisk and wind-swept waters. When the wind farm is fully installed in early 2012, the 88 wind turbines will produce clean energy to approximately 220,000 households and contribute to a reduction of 500,000 tonnes of CO2 every year. The foundations for the wind turbines, placed at water depths of 15-22 meters, and the two monopile substation foundations are designed by Ramboll. The project is jointly owned by Statoil and Statkraft through the joint-venture company Scira Offshore Energy Ltd.
Challenging site with extreme waves
The purpose of the substations is to collect the electricity generated by the 320 MW offshore wind farm via cables and transform the electricity for transmission to shore via sea cables. Ramboll has designed two substation monopile foundations and a cable pulling deck. The topside weight is approximately 875 tonnes. The foundations are located at a water depth of approximately 18 meters on a challenging site with extreme waves of more than 14 meters in height. The soil conditions on the site consist of mixed layers of sand, clay, silt, gravel and chalk, which altogether make soil modelling a challenging task.