Laying the foundations
The first wind turbine foundation was installed in March 2011. After careful consideration, we chose to use monopile foundations. Also called ‘piles’, these are long cylindrical steel tubes that are hammered into the sea bed. When the monopoles were installed we used a crane to mount the transition piece on top of the pile. These have ladders and platforms for maintenance access and are painted yellow so ships and aircraft can see them.
For Phase One, we needed 177 piles – one for each of the 175 wind turbines and two more for the offshore substations. We used a purpose-built vessel, the ‘MPI Adventure’, to install the foundations in deep water. In shallower areas, the ‘Sea Worker’ was used. These vessels have four extendable legs that lift the deck out of the water to create a stable platform from which we hammered in the piles. HLV Svanen was also used to install a small number of foundations in complex locations at London Array.
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