Severn Barrage: Five firms join Hafren Power project
The company hoping to build an energy-generating barrage between south Wales and Somerset says it has been given a significant boost.
Five major companies, including engineering giant Arup, have signed up to work on the £25bn project.
Hafren Power said engineering and project management experts will "add credibility" to the scheme, as it looks to get the go-ahead.
It is still awaiting UK government approval.
The 11 mile (18km) barrage would take nine years to build and would be the largest construction project in Britain since the Channel Tunnel.
The companies which will come on board also include logistics group DHL, Bechtel, consultants Mott MacDonald and URS corporation.
Hafren Power has been criticised for failing to provide ministers with details of the scheme. A committee of MPs has been holding an inquiry into the project and is due to deliver its report shortly.
But chief executive Tony Pryor said: "Government has an open mind on our proposal and we are working hard to provide further details of construction, environmental and business impacts and mitigation.
"These companies have successful track records in delivering large infrastructure projects and are bringing considerable expertise and momentum to the process.
"As part of the energy mix, tidal power is greatly under-utilised. As a sustainable energy source the Severn estuary barrage will help the UK meet its renewable energy requirements.
"The engineering could also become the standard for schemes elsewhere in the world."
Hafren Power claims an energy-generating barrage between Lavernock Point near Penarth and Brean in Somerset, would be capable of meeting 5% of the UK's annual energy needs.
Environmental groups oppose the plan, claiming a barrage would damage wildlife sites.
Friends of the Earth Cymru director Gareth Clubb said: "Regardless of how big the companies involved are the sums just don't add up. You can have the biggest companies in the world working on it but the economics of the project don't work so I don't see it being given the go-ahead."
Questions have also been raised after a BBC Wales investigation revealed that two of the project's founders had previously been declared bankrupt. The founders said past mistakes in unrelated companies should not distract from the importance of the scheme.
Hafren Power hopes to persuade the UK government to allocate parliamentary time to a new law that would pave the way for the barrage to be built.