The BBC has just reported that George Osborne, the Chancellor, has told Chris Huhne, energy and climate change Secretary, to axe the Severn barrage.
This is a blow to the country's efforts to move towards a much lower carbon economy. Huhne is instead likely to sanction the building of new nuclear power stations.
The other options were intended to appease environmental campaigners worried about the loss of precious wildlife habitats in the estuary.
The technology could have generated up to 5% of Britain's electricity requirements, and created hundreds of jobs and develop technology that could have been exported around the world.
Instead eight sites have been approved for new nuclear power stations by 2025, which, if they go ahead, are likely to be financed and owned by foreign companies and produce fewer jobs. These are:
• Bradwell, Essex
• Hartlepool, Borough of Hartlepool
• Heysham, Lancashire
• Hinkley Point, Somerset
• Oldbury, South Glos.
• Sellafield, Cumbria
• Sizewell, Suffolk
• Wylfa, Isle of Anglesey.
They would add to the growing and expensive stockpile of nuclear waste, providing danger for thousands of years to come. In the Spending Review, more money was allocated to the task of safeguarding the existing stockpile.
Tidal power, on the other hand, is renewable and free, but the uranium for nuclear power stations is dangerous to mine and is likely to run out within 60 years.
A tidal scheme could last around 120 years, significantly longer than nuclear, thermal, wind, and other energy infrastructure, but in common with other hydropower generation projects.
This makes its overall levelised costs – lifetime costs – comparable to or better than other forms of generation, but the initial high capital cost is prohibitive in the current economic climate, the report says.
Supporters of the tidal project, which would link Lavernock Point near Cardiff, to Brean Down near Weston-Super-Mare, claimed it could generate 5% of Britain's electricity.
Dr Rob Kirby, an independent expert on the Severn Estuary, has worked on the project for the last 40 years, said: "The government's view is that it's too big a project to approach in financial terms.
"It's quite unambiguous - the Cardiff to Weston (barrage) can only benefit the environment and those who say otherwise are not telling the truth."
Shadow Welsh Secretary Peter Hain said scrapping the barrage would be "equally disastrous" for the economy and the environment.
"Not only is Chris Huhne turning his back on the proposed barrage scheme that would have created hundreds of good quality green jobs for Welsh people, it appears that he decided to abandon in its entirety the idea of using the Severn estuary as a generator of electricity," he said.
The feasibility study into a tidal energy project in the Severn estuary concludes that its total cost – over £30 billion – makes it unaffordable at the present time because a significant proportion of the funding would have to be borne by the taxpayer, and it would be difficult to attract sufficient private investment.
The report does not rule out a project in the estuary in the longer term if it could be shown that it did not fundamentally change the estuary's natural environment.
It also highlights the fact that even the scale and impact of smaller schemes like a tidal lagoon would be unprecedented in an environmentally sensitive area. Providing compensation for any possible damage is considered to be challenging.
The report argues that other low carbon energy sources represent a better deal in the short term for taxpayers, industry and consumers.
Dr Neil Bentley, CBI Director of Business Environment, commented: “Tidal power has the potential to play a significant role in the UK’s energy future. Given the state of the public finances, it is understandable that Government investment in the main Severn Barrage scheme has been ruled out at this time. But the Government should continue to encourage innovation in tidal power to reduce the cost of this technology.”
Welsh Environment Minister Jane Davidson added, “Two of the three schemes assessed under SETS showed a good deal of potential for extracting renewable energy from the area.
“However further work is needed to develop these technologies to the point where they may be considered as part of any future Tidal Power scheme.
“I would urge the UK Government and others to continue working with us and key business partners such as Veredeg and Rolls Royce on the development of these emerging technologies, not just for applications in the Severn but also in other locations around our resource rich coast line.
"These technologies have real potential to provide a vital source of renewable energy for the whole of the UK, which would enable us to increase our energy security and help in the global fight against climate change”