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Customer Success Story

Ensuring clean energy reaches thousands of UK households

Transformers vital for world’s largest capacity offshore wind farm

Hitachi Energy continues to help develop offshore wind power in the promising region of the Irish Sea, off the west coast of Northern England.

Following a first order in 2014 for 32 specialty transformers to equip powerful V164 turbines for the Burbo Bank Extension Offshore Wind Farm, Hitachi Energy received another order in 2015 from MHI Vestas Offshore Wind to deploy 40 transformers in similar turbines for the Walney Extension Offshore Wind Farm.

Located around 19 kilometers west of Walney Island off the coast of Cumbria, England, the offshore wind farm is owned by the Danish utility, DONG Energy A/S. The Walney Extension will provide 660 megawatts (MW) of generation potential in addition to the existing offshore wind farm’s 367 MW. Hitachi Energy is supplying transformers for the western part of the extension, which will account for half of the new capacity (330 MW).  

Hitachi Energy’s 10.8-megavolt ampere (MVA), 34-kilovolt (kV) transformers will be installed in the turbine tower with accompanying low-voltage products. These specialty transformers meet the most stringent electrical and mechanical requirements, which are prerequisites for offshore environments where quality and reliability are critical.

They are custom-designed using state-of-the-art raw materials and components to be vibration and short-circuit resistant and weigh 30-percent less than a similar standard transformer, with a compact footprint that can accommodate the turbine door frame. Hitachi Energy will also supply a high-voltage cable system to transmit power from the Walney Extension to the mainland power grid.

Upon completion, the combined Walney offshore wind farms are expected to comprise the world’s largest installed offshore generating capacity, capable of providing clean electricity to more than 800,000 households. This will make a significant contribution to the UK target of achieving 15 percent of total energy production from renewable sources by 2020, and reducing carbon dioxide emissions.

Main data
Customer MHI Vestas Offshore Wind (MVOW)
Product Special transformers
Application Offshore wind farm
Power rating 10.8 MVA, 34 kV
Location West of Walney Island off the coast of Cumbria, UK
Delivery date
Commissioning date 2019