The prospect of huge wind farms off the British coast have been welcomed by environmentalists.
Hundreds of turbines could be built about five miles off the coast
New turbines, to be sited at three sites off the North West coast, the Wash and Thames Estuary, will generate as much energy as about six nuclear power stations, and create 20,000 jobs.
The government announced on Monday that licences would be issued for hundreds of turbines in a move to meet its own target for renewable energy.
Environmental groups have been enthusiastic about the plan, seen as the biggest single step to increase the amount of electricity produced without polluting the atmosphere.
Global warning threat
Friends of the Earth said it was delighted.
"Hopefully this marks the start of a massive programme to harness the considerable opportunities offered by wind, tides and waves," said energy campaigner Bryony Worthington.
"Renewable energy has the potential to provide all our energy needs and is a clean, safe and affordable alternative to nuclear energy and inefficient coal-fired power stations."
Greenpeace spokesman Rob Gueterbock said the environmental lobby group had no hesitation in applauding the government.
"For 30 years Greenpeace has opposed the pollution of our oceans but can today fully support this massive commitment to harness wind power at sea," he said.
"Global warming poses a unique threat to our planet, but the government is now demonstrating the ambition needed to defeat it."
Announcing the new wind farms, Trade and Industry Secretary Patricia Hewitt said the move was widely supported by the public who agreed with the government that cleaner sources of energy were needed.
"We have got the best wind resources in the whole of Europe and it is crazy that we are lagging behind countries like Germany and Spain and Denmark, when we have the great expertise in offshore developments that we built up with North Sea oil," she told the BBC.
The British Wind Energy Association said it was "fantastic news".
Chief executive Marcus Rand said: "We have the best offshore wind resource in Europe and today's announcement signals that we are now on track to seriously develop it.
Leasing of sea beds on North West coast, the Wash and Thames Estuary
Cost of £6bn
Create 20,000 jobs in manufacturing, installation and maintenance
Will produce 10 times more than existing wind farms
Will generate 5% of total UK power needs
Firms will have three months to submit tenders
"Successful projects from this announcement could account for over half of the government's 10% target and could be supplying clean electricity to four million households by 2010."
National Wind Power, which is currently building the country's first large scale offshore wind farm off the Welsh coast, described the move as "a serious commitment".
"This is the first step of the launch of what is going to be the biggest step in renewable energy in this country," managing director Alan Moore the BBC Radio 4 Today programme.