Plans for a £1.3bn tidal lagoon in Swansea Bay have been backed by a government-commissioned review.
Charles Hendry, a former energy minister, said his independent review of tidal power had concluded a small trial lagoon at Swansea Bay was a "no regrets option" that could open the way to at least five other full-scale projects around the UK.
Harnessing tidal power
The company Tidal Lagoon Power, which has proposed the project for Swansea, has already spent £35m on the south-west Wales lagoon. It said that if a subsidy deal could be agreed with the government construction could start next year and provide 2,000 jobs.
The company wants to build a U-shaped breakwater across the city's bay and use the incoming and outgoing tides to turn a bank of 16 hydro turbines in the breakwater to generate enough electricity for 150,000 homes.
The UK government still needs to agree on a deal and a marine licence would also need to be approved.
Mr Hendry said moving ahead with a pathfinder lagoon off the Swansea coast should be seen as a "no regrets" policy.
There are hopes of developing a network of larger lagoons around the UK coast, harnessing power from the ebb and flow of the sea's tides.
But Mr Hendry believed that was "too ambitious a goal" before even one had been built and "could only be considered properly when more progress had been made."
Mr Hendry made 30 conclusions, including:
The technology would "contribute positively" towards the UK's decarbonisation goals
It was "beyond question" that local economic regeneration would follow a tidal lagoon
It offers "significant economic opportunity" for Wales and the UK
The potential impact on consumer bills of large scale tidal lagoons "appears attractive, particularly when compared to nuclear projects" in the long term
A high level of monitoring of environmental impacts would still be needed
A Tidal Power Authority should oversee the new industry
Competitive tendering for future projects "to deliver the most substantial cost reductions" - similar to the nuclear industry
Mr Hendry has been gathering evidence for nearly a year for his independent inquiry, including visits to all the potential sites and discussions with industry.
He said: "If you look at the cost spread out over the entire lifetime - 120 years for the project - it comes out at about 30p per household for the next 30 years. That's less than a pint of milk.
"That's where I think we can start a new industry and we can do it at an affordable cost to consumers."
Looking to the future
The Swansea Bay project would involve 16 turbines along a breakwater but is seen as only the start - a prototype for much larger lagoons.
The "fleet" includes one off the coast of Cardiff - east of where Cardiff Bay is now - Newport, Bridgwater Bay in Somerset, Colwyn Bay and west Cumbria, north of Workington.
Tidal energy plans for Swansea Bay first emerged in 2003 but the current project has been developed over the last four years.
But there are still environmental concerns and Natural Resources Wales (NRW) will be looking at the impact on flooding, fish, birds and marine habitats before it awards the all-important marine licence.
Business and Energy Secretary Greg Clark welcomed the hard work that had gone into the review and said the UK government's energy planning was focused on ensuring affordable, secure, low-carbon energy.
The RYA acknowledges the Government's desire to promote renewable energy; however we are keen to ensure the navigational safety of recreational boating around the coast.
The RYA is regularly monitoring the developments in tidal energy technologies, as well as the seabed areas leased by The Crown Estate, and assessing their potential impact on recreational boating. We meet regularly with the developers involved to discuss recreational navigational safety and respond to national consultations on behalf of recreational boating.
The RYA is a member of the Nautical and Offshore Renewable Energy Liaison (NOREL) group which works to ensure that the commercial and recreational shipping and ports industries successfully co-exist with the offshore renewable energy industries.