The Government's energy policy is "hopelessly unrealistic" and leaves the UK vulnerable to a shortage crisis, a panel of leading academics will say today.
Ministers rely far too heavily on the success of green energy sources and ignore serious concerns about the lack of reliable gas supplies, it warns.
The Royal Academy of Engineering today launches a broad critique of the energy review published by the Cabinet Office's performance and innovation unit.
The academy will tell Brian Wilson, the Energy minister, it is deeply worried about the security of Britain's gas supplies.
It says the Department of Trade and Industry's own figures indicate that by 2020 the UK might need to import up to 90 per cent of its gas requirements.
"We could experience gas shortages as soon as 2004 or 2005 in a severe winter," the academy said.
It urges the Government to address the planning, funding and operational questions involved in expanding the pan-European gas transmission network, so the UK can access imported gas. The energy review set a target of generating 20 per cent of the country's energy from renewable sources by 2020.
It also placed great faith in wind energy and proposed installing 22,000 megawatts of turbine capacity by 2020. Its other attention-grabbing finding was that the nuclear option should be kept open in case we cannot find alternative sources.
However, the report, which was prepared by a high-profile team including Rolls-Royce's engineering director, and six academics including Michael Laughton at University College London, takes issue with the findings.
It says greater reliance on renewable sources is a "laudable" aim, but brands it "over-optimistic" and accuses it of failing to address the problem that renewable energy is intermittent.
"Experience on the Continent has shown that grid stability can be adversely affected when the penetration of intermittent renewables reaches about 15 per cent," the report says.
The academy says that to hit targets for reducing carbon dioxide emissions, Britain must replace nuclear reactors coming to the end of their lives with non-carbon emitting energy sources.
"But it takes so long to build new power stations that we need to commission them in the next few years if they are to be on stream in time to prevent supply shortages," it says.
A DTI spokeswoman said a White Paper would be published "at the turn of the year" and it would not be appropriate now to comment on the report.