The Barrow Offshore Wind Farm is a 30 turbine 90MW capacity offshore wind farm in the East Irish Sea approximately seven kilometres (four nautical miles) southwest of Walney Island, near Barrow-in-Furness, Cumbria, England.[7] The initial Warwick Energy proposal was for a 30 turbine wind farm 7 km southwest of Walney Island (Cumbria), with a generating capacity of up to 108 MW; electrical power supply to the mainland was to be via a ~25 km long 132 kV cable making groundfall near Heysham, with connection to the mainland electrical grid at an extension to an existing electricity substation south of Heysham nuclear power station.[11][12] IEC 1A class Vestas V90-3.0 MW wind turbines were used, mounted on a 75 m tower connected to 4.75 m (15 ft 7 in) monopiles supplied by a Sif/Smulders joint venture.[1] Since 2008 (to 2012) the farm operated at between 30 and 40% capacity factor, generating between 240 and 320 GWh of electrical energy per year.[17] In 2011 regulatory changes required Ørsted/Centrica to divest the electrical transmission assets of the wind farm, which were sold to TC Barrow OFTO Ltd. for £34 million.