In a major blow to plans to generate power from the huge Bristol Channel tides, Greg Barker told MPs he did not have enough information to judge whether a proposed project was viable.
Appearing before the Commons Energy and Climate Change Select Committee, he was asked if he thought it was "realistic" for legislation to enable the project to go ahead to be passed during this parliament.
"Not at all," the minister responded.
The coalition Government backed away from getting involved with all the Severn energy projects, citing the huge costs to the public purse, in 2010. But a consortium led by Hafren Power is now proposing a barrage between Cardiff and Weston-super-Mare.
The Government would still need to give the scheme – which could generate 5% of the UK's electricity and sustain 10,000 construction jobs – its consent.
Mr Barker continued: "To talk of there being a Bill before 2015 really would require some transformational level of information in order for us to give up Government legislative time which will be very squeezed, as well as the political time that would need to go into pursuing what is a very, very substantial project."
Opponents of development fear the impact on wildlife, habitats, the shipping industry and leisure, and Mr Barker stressed that major questions remained unanswered.
He said: "[One] thing's absolutely clear, before you go down that road much further, considering these other environmental and social impacts, any decision on a Severn power scheme or schemes would need to be based on credible and compelling evidence of the full set of costs and benefits.
"In terms of the specific proposal we wish to discuss today we have received an outline proposal from Hafren Power and there have been some discussions between my department and the company.
"However, the information the department has seen so far certainly doesn't allow us to assess if the proposal is credible nor if it could actually stand a chance of achieving the benefits Hafren Power claimed the scheme would achieve."
He added: "[To] date the Hafren Power proposal doesn't go far enough at this stage to justify a Government endorsement of the project."
Labour MP and former Welsh Secretary Peter Hain, who is championing the project, blamed "confusion and division" in Government for delaying the scheme.
He said: "If we're now unlikely to see the hybrid bill required for the Severn barrage in this parliament that will mean two more years' delay for a gigantic £25 billion investment creating 50,000 desperately needed jobs.
"Sadly confusion and division in government now means we're working to a longer timescale."
A Hafren Power spokesman said: "We are pleased to see the Department of Energy is keeping an open mind on the project, but disappointed at the criticism of lack of detail."
