The Walney 1 Offshore Wind Farm, off the shore of Cumbria, north-west England, has begun generating power for the UK's national grid.
Electricity has been generated from the first of the 51 turbines that the project will consist of once completed.
Walney 2, also with 51 turbines, will begin installation in March 2011 and is expected to be fully operational by the end of 2011.
Once fully operational, the Walney 1 and 2 wind farms worth about £1bn ($1.5bn), will have a capacity of 367.2MW to power around 320,000 homes.
The wind farms are located about 15km from the coastline of Walney Island, covering an area of about 73 million square metres.
The plants are owned by DONG Energy, Scottish & Southern Energy and a consortium of PGGM and Dutch Ampère Equity Fund.