A £3.6 billion offshore windfarm that will surpass the London Array to become the "world's largest" was given the go-ahead on Thursday.

Energy secretary Ed Davey granted planning consent for Triton Knoll, a 1,200MW windfarm off the Lincolnshire and Norfolk coast.

The Department of Energy and Climate Change said Triton Knoll’s 288 turbines would power the equivalent of 820,000 homes. Developer RWE Npower gave a figure of “up to 900,000 UK households”. The exact figure will vary depending on the weather.

Davey will today visit another record-breaking wind development in South Wales. Vattenfall’s £400 million Pen y Cymoedd windfarm, due to start construction in 2014, will at 230MW be the biggest onshore development in England and Wales.

Davey said: “These two projects will attract billions in investment into the UK, support hundreds of skilled green jobs in Lincolnshire, Norfolk and in the county boroughs of Neath Port Talbot and Rhondda Cynon Taf whilst providing homes with clean energy.

“Only last week the Prime Minister opened the London Array, the largest operating wind farm in the world, and today we gave planning permission to build a bigger offshore wind farm and also welcome the go-ahead of the biggest onshore wind farm in England and Wales. Offshore and onshore wind is an important contributor to our energy mix.”

Triton Knoll project manager Jacob Hain said the decision sent “another positive message” to industry about the potential for renewables in the UK.

However, he added: “In order to realise these ambitious offshore projects, the government’s Electricity Market Reform must deliver a regulatory framework which is bankable to attract the required levels of investment.”

Vattenfall, which has invested more than £2 billion in five UK wind schemes since 2008, offered an even stronger endorsement of government policy. Sustainable energy projects director Peter Smink said: “The UK market for investing in onshore wind power is an attractive market because the coalition government has backed its development as a crucial part of its economic growth agenda.”

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