The machines — a pair of Siemens’ 6MW SWT-6.0-120s — are the first designed by the German company specifically for the extreme rigours of operation in the rough seas of northwest Europe.

Standing 148 metres tall and topped by 120-metre-diameter rotors, the giant turbines are at the centre of a pioneering pilot project being run by Denmark’s Dong Energy alongside its three-year-old Gunfleet Sands wind farm, a UK Round 2 development currently flowing enough electricity for 125,000 homes.

Great store is being put by these next-generation Siemens units, which are on…