The project got a qualified welcome from environmental campaigners. The site, a forest of giant turbines in the North Sea off the southeastern English coast, has 100 turbines so far.
Swedish energy company Vattenfall, which built the farm, says it has the potential to power 200,000 homes. The farm will increase Britain's capacity to generate wind power by more than 30 per cent.
Situated around 12 kilometres out to sea, the 380-foot 115-metre high turbines are spread over more than 35 square kilometres and are visible from the shore.
Up to 341 turbines will be installed at the site. The farm is expected to produce 300 megawatts of energy at full capacity, which would see Britain's renewable energy capacity rise to five gigawatts.
Energy and Climate Change Secretary Chris Huhne welcomed Britain's progress on wind power. "We are in a unique position to become a world leader in this industry," he said. "We are an island nation and I firmly believe we should be harnessing our wind, wave and tidal resources to the maximum.
Craig Bennett, the campaigns and policy director for Friends of the Earth, said the wind farm was an "important stride forward" but warned that Britain's record on renewable energy was "dismal". Critics point out that the turbines only produce energy when the wind is blowing and that as yet no cost-effective fuel cell has been developed for storing the power once it has been produced.
Professor Ian Fells, an energy expert, said: "What worries me is the government seems to be obsessed with the option of wind farms and neglects other sources of renewable energy, which in may ways could be more important
