New talks on Severn barrage plan from Cardiff to Weston
UK government ministers are in talks with a private consortium over revived plans to build a multi-billion-pound barrage across the Severn Estuary.
Corlan Hafren wants to harness tidal power between south Wales and Weston-super-Mare to create electricity.
The UK government previously rejected plans for a publicly-funded barrage but did not rule out private schemes.
The Department of Energy and Climate Change (DECC) is talking to the group over a plan which may cost up to £34bn.
It said that, along with other departments, it had received a first draft of a business case for a privately financed barrage between Lavernock Point near Cardiff and Brean Down near Weston-super-Mare in Somerset.
It was previously reported that a barrage could generate up to 5% of the UK's electricity needs.
DECC said that a private sector scheme would be eligible for support from the government.
"This is an interesting proposition, particularly if it can contribute to 2020 renewables targets," a spokesman said.
"We are discussing with the consortium the next stages to develop the outline proposal so it can be fully considered by the government to assess whether the benefits of the project in terms of economic growth and renewable energy justify the cost of the subsidy that would be still needed and the environmental consequences for the Severn estuary."
Plans for a 10-mile barrage across the Severn were shelved by the government in 2010 amid concerns about the potential costs involved.
However, a feasibility study did not rule out a privately financed scheme coming forward to build the barrage.
DECC said potential environmental impacts of a barrage would have to be considered.
"In addition to the capital cost and cost of energy, any planned scheme needs to consider environmental impacts, for example on fish, birds and flooding, as well as potential impacts on navigation and other sea users," the spokesman added.
Corlan Hafren is a consortium that includes Halcrow, which provides planning, design and management services for developing infrastructure and engineering company Arup. It said it did not want to comment.
But on its website it says: "The Severn Barrage will act as a catalyst for regeneration in Wales and south-west England, bringing substantial new, permanent jobs to the region and creating an internationally recognised centre of expertise in renewable energy provision and manufacture.
"The company recognises the significant environmental challenges associated with the proposals - the importance of minimising impacts and providing compensatory and mitigation measures is at the heart of the company's objectives."
The Welsh government said all "reasonable options" should be considered in meeting Wales' and the UK's growing power needs.
"We have ambitious goals to reduce carbon dioxide emissions from energy and to secure our energy supply," a spokesman said.
"Increased energy efficiency, renewables, all have a role to play - and we must consider all our reasonable options.
"The huge tidal range in the Severn estuary could be a source of carbon-free electricity over a very long term, providing significant benefits in jobs, practical skills and supply chain.
"We recognise the estuary is important for its special environmental features, and the potential impact on these must be considered in the assessment of different technologies for harnessing the energy of the tidal range."