Former prime minister Tony Blair signed an agreement in March that 20 per cent of all European energy would come from renewable sources by 2020. Targets for each country are being negotiated. The UK currently generates two per cent of its energy from renewables.
Liberal Democrat environment spokesman Chris Huhne said: "Ministers must not be allowed to wriggle out of firm commitments."
A Department for Business, Enterprise and Regulatory Reform spokesman insisted: "We are committed to the agreement."
But Renewable Energy Association spokeswoman Leoni Green maintained: "The political commitment to renewables is not there, which is a scandal because we have some of the world's best renewable resources."
The EU agreement came under fire in March for its inclusion of nuclear power as a renewable fuel (Planning, 16 March, p5).
Meanwhile Greenpeace is preparing a legal challenge against the government over its second nuclear power consultation, which ended this month.
"We feel strongly that the government has been misleading in the consultation and are taking legal advice," said climate and energy campaigner Nathan Argent.
The government is expected to announce its decision on nuclear power before the end of the year.