The UK currently generates 2% of its energy from wind power
Half a million people could be pushed into fuel poverty by the UK's drive for wind power, the government's former chief scientific adviser has said.
Sir David King said: "If we overdo wind we are going to put up the price of electricity and that means more people will fall into the fuel poverty trap."
The UK has signed up to an EU agreement for 20% of power to come from renewable sources by 2020.
Professor King told the BBC EU leaders did not understand their own targets.
One of Tony Blair's last acts as Prime Minister was to sign up to an EU target to have 20% of Europe's energy from renewable sources by 2020.
The UK currently generates around 2% of its electricity from wind power but to meet the EU's target the government estimates this will have to increase to around 35% by the end of the next decade.
It will also lead to price rises, the government thinks around 10% for electricity and closer to 20% for gas.
Professor King who who served as chief scientific adviser from 2000 to 2007, told BBC Radio 4's The Investigation that the government is placing too much emphasis on wind power to reach the target and this would mean more people suffering from fuel poverty.
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Listen to The Investigation, Radio 4 Thursday 4 September 2008 at 2000 BST.
"These are difficult numbers to estimate but numbers around half a million are not at all unrealistic," he said.
Professor King said he thought that Mr Blair and the other EU leaders did not understand what they were committing themselves to.
"I think there was some degree of confusion at the heads of states meeting dealing with this.
"If they had said 20% renewables on the electricity grids across the European Union by 2020, we would have had a realistic target but by saying 20% of all energy, I actually wonder whether that wasn't a mistake."
Professor King, who was chief scientific adviser at the time of the decision, added: "I was rather surprised when I heard what the decision was."
The EU needed to renegotiate a more achievable and less expensive target, and he added: "This is an issue which needs to be revisited and I say this as somebody who feels that we really have to reduce our greenhouse gas emissions very substantially but in my view it is an expensive, and not a very clever route to go for 35 to 40% on wind turbines."
However Maria McCaffery, Chief Executive of British Wind Energy Association countered: "We don't have to pay for wind power it just comes to us naturally and is totally sustainable.
"The expectation is that it will in time drive down the basic cost of energy and actually help the fuel poverty situation, that certainly is our expectation"
A government spokesman said it believes the target is ambitious but is fully committed to meeting it and that the impact on energy bills in the short term will be small.