Sheringham Shoal offshore wind farm, situated off the UK coast, was constructed by Scira Offshore Energy Ltd., owned by Statoil and Statkraft, each with a 50% share in the operation. The nearest turbine is no fewer than 9 nautical miles (17 km) from the shoreline.
The Sheringham Shoal offshore wind farm consists of 88 wind turbines, each with a height of 80 metres. They are spread across a diamond-shaped area of 35 km². The turbines are placed on foundations fixed to the seabed alongside two offshore substations. Together, the turbines produce 1.1 TWh of green energy which is fed into the national grid and is sufficient to supply power to 220,000 homes. The power is exported to the shore via two 22 km, 145 kV XLPE submarine export cables, together with a fibre-optic cable.
VBMS was responsible for handling the work at the landfall site near Weybourne, Norfolk, UK, and also looked after the coordination and cable pull ashore.
The scope of work was as follows:
Complicating factors included the exit points of the horizontal directional drilling and the position of the cable-laying vessel Team Oman.
The remote position of the offshore duct exit points brought about an additional challenge, as the nearest port is Great Yarmouth, 40 nautical miles from the site. The two duct exits are situated offshore at a water depth of approx. 6 metres below Chart Datum and they are located 85 metres from each other. The tidal currents are strong and the surf zone close by. Pull wires were installed and after pull-in, concreted weight mattresses and split flanges were put in position. The water depth at the cable exit points forced the cable laying vessel, Team Oman, to relocate to a position 400 metres further offshore. The section between duct and vessel was conducted by a float-in.
The VBMS-owned 40-ton pulling winch was being used to pull in the two145 kV XLPE submarine export cables together with a fibre-optic cable. Although the schedule was tight, VBMS was able to pull the cables with a minimum of delays to the cable-laying vessel Team Oman.
Thanks to close co-operation between all intercompany parties (VBMS and VolkerInfra) the near-shore cable work was completed to the satisfaction of the client.
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