A push for a huge programme of windfarm building in the seas around Britain was launched today as the Government attempts to drive a massive increase in renewable energy.

The Crown Estates, which manages the seabed around Britain, is calling for bids to build wind farms in 11 offshore sites, ringing the country from Devon to the northeast of Scotland. The sites could produce up to 25 gigawatts of power, more than tripling the first two phases of offshore windfarm development, which are developing a total capacity of eight gigawatts.

If the schemes are successful, offshore windpower could provide a quarter of Britain's energy by 2020 - enough to power all the households in the country. This will underpin the Government's commitment to the EU target of getting 20 per cent of Europe's energy needs from renewables by 2020. Bidding and approval for the sites is expected to end by 2015 and construction five years after that.

Rob Hastings, The Crown Estate’s Director of Marine Estates, said that up to GBP80 billion of investment would be needed to build the windfarms. The Crown Estate has promised to fund up to half the cost of getting planning consent for the sites: "The new approach to the deployment of offshore wind that The Crown Estate have set out today requires us take an important facilitating role in which we will share developer’s risk," Mr Hastings said.

"For the first time we will be investing directly in offshore windfarm development. We will be helping to identify suitable sites and working closely with commercial partners who we expect to make considerable capital investments in offshore windfarm assets."

The Energy minister, Malcolm Wicks, said: “We will shortly become the leading country in the world in terms of the number of windfarms operating offshore. The potential for round three will add to that success.

“Government is aware of the costs and supply challenges facing the industry. It’s hoped The Crown Estate’s investment and leasing programme for round three will provide developers with confidence to make investments much earlier on, like signing grid connection agreements or ordering turbines. We are working to reduce other barriers such as radar, shipping, grid access and infrastructure issues.”

The announcement came after the head of the UK arm of E.On, the utility company which is developing several current offshore windfarms and is likely to be in the running for the new sites, said that new power plants are urgently needed to avoid blackouts around the country.

Paul Golby said that said more coal and gas fired plants would be needed to keep up electricity supplies during lulls in windfarm output. He said that new capacity from all sources was needed to replace plants due to close over the next decade - and that the result would be higher energy bills for consumers.

"My fear is that last week’s blackouts, while not in themselves significant, were an indication of the ageing infrastructure in this country and a small indication of what could happen if we don’t get on and fill this gap [in generation capacity],” Golby said. “Unless we do build we are simply going to be unable to meet the country’s energy needs.”

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