The world’s largest offshore wind farm located in the UK


In September 2018, the world’s largest operational offshore wind farm, Walney Extension, opened in The Irish Sea. Walney Extension, which is owned by Ørsted and its partners PFA and PKA, is the first project to use wind turbines from two different manufacturers.

The size of the wind farm is equal to 20,000 football pitches

In 2018, The Irish Sea became home to the world’s largest offshore wind farm – Walney Extension. The offshore wind farm has 87 wind turbines generating enough green energy to power almost 600,000 UK homes. Walney Extension covers an area of 145km2 in The Irish Sea which is equal to 20,000 football pitches. The project becomes Ørsted’s 11th operational offshore wind farm in the UK.

The 659MW project, owned by Ørsted (50%) and its partners, the Danish pension funds PKA (25%) and PFA (25%), leapfrogs London Array to become the world’s largest operational wind farm.

Utilising the latest technology from two of the world’s leading turbine manufacturers, Walney Extension features 47 MHI Vestas 8MW wind turbines and a further 40 Siemens Gamesa 7MW wind turbines.

Construction of Walney Extension was co-ordinated from Ørsted’s West Coast Hub, at the Port of Barrow, which will now become home to the project’s operations and maintenance team. The West Coast Hub also services three further Ørsted offshore wind farms, i.e. Barrow, Walney and West of Duddon Sands.

The completion of Walney Extension brings Ørsted’s total capacity operating out of Barrow up to 1.5GW. Ørsted’s ongoing operations and maintenance activities will support more than 250 direct jobs in the region.

About Walney Extension Offshore Wind Farm

  • Owned by Ørsted (50%), PKA (25%) and PFA (25%)
  • Located in the Irish Sea – approximately 19km from the Walney Island coast in Cumbria
  • Covers an area of 145km2 equal to around 20,000 football pitches
  • Total capacity of 659MW – capable of powering almost 600,000 UK homes
  • First project to use turbine technology from two different manufacturers
  • More than 200km of cables used to connect the turbines offshore to the National Grid onshore
  • Features two offshore substations, each weighing 4,000 tonnes. The jacket foundation height is 50m, and topside height is 18.5m.

About the offshore wind turbines at Walney Extension

Siemens Gamesa

  • 40 x 7MW
  • Rotor diameter: 154m
  • Height (from sea level to blade tip): 188m
  • Each blade weighs 28 tonnes

MHI Vestas

  • 47 x 8MW
  • Rotor diameter: 164m
  • Height (from sea level to blade tip): 195m
  • Each blade weighs 34 tonnes

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