The world's biggest offshore wind farm, the UK's London Array, is producing power from all 175 of its Siemens turbines.
The project now has its full first-phase capacity of 630MW operational in the Thames Estuary in southern England.
The last of its 3.6MW turbines was installed in December, with the final machine commissioned over the weekend.
The news was welcomed by industry body RenewableUK, which said: “Britain has a real achievement to celebrate here – the largest operational offshore wind farm in the world is generating clean electricity for British homes and businesses. It’s a monumental feat of green engineering."
The London Array is a joint development by E.ON, Dong Energy and Masdar.
Tony Cocker, CEO of E.ON UK, said: “It’s been a tough time for the team working on site. The recent bad weather and north easterly winds have whipped up the waves preventing access to the site so this milestone is true reward for their hard work.”
A London Array second phase, which is currently seeking approval, would take the total project to 870MW.