π Project Overview
Walney Extension was briefly the world's largest offshore wind farm on commissioning in 2018, and remains one of the UK's most productive at nearly 659 MW. Located in the Irish Sea west of Walney Island, it extends the cluster of Walney 1 and 2 wind farms developed earlier. The extension uses two turbine models β MHI Vestas V164-8.25 MW and Siemens SWT-7.0 β the first time two different turbine types were deployed on the same offshore project at commercial scale in the UK.
Site Schematic
Schematic diagram β not to scale. Illustrative layout based on project specifications.
β‘ Key Facts
Was the world's largest offshore wind farm at commissioning in 2018
First UK project to mix two turbine models at commercial scale
87 turbines across 149 kmΒ²
Part of the Walney Island wind cluster in the Irish Sea
~600,000 homes powered by clean energy
π§ Technical Specifications
| Capacity (MW) | 659 MW |
| No. of turbines/units | 87 |
| Turbine / unit model | MHI Vestas V164-8.25 (47) + Siemens SWT-7.0-154 (40) |
| Unit capacity | 7.65 MW each |
| Rotor diameter | 164 m |
| Hub height | 107 m |
| Tip height | 189 m (approx) |
| Foundation type | Monopile |
| Water depth | 19β47 m |
| Distance from shore | 19 km |
| Site area | 149 kmΒ² |
| Annual output | 2,300 GWh/year |
| Homes powered | 600,000 homes |
π Grid Connection & Infrastructure
| Grid connection point | Heysham, Lancashire onshore substation |
| Voltage | 132 kV |
| Export cable | 19 km subsea to onshore substation |
| CfD held | No (merchant / PPA) |
π’ Development & Ownership
| Developer | Γrsted (formerly DONG Energy) |
| Owner / operator | Γrsted (50%), Greencoat UK Wind (25.1%), PFA (12.5%), PKA (12.5%) |
| Year consented | 2014 |
| Construction started | 2016 |
| Commissioned / target | 2018 |
| Capex estimate | ~Β£1.3 billion |
| Location | Irish Sea, west of Barrow-in-Furness, Cumbria β 19 km offshore |
| Region | Irish Sea |
| Coordinates | 53.97Β°N, 3.64Β°W |
π Project Timeline
πΏ Environmental & Planning
Part of the Walney Island cluster. Cumulative environmental studies with Walney 1 & 2 informed consent. Seabird, marine mammal and benthic surveys conducted.