Plans have been submitted to develop the world's first tidal lagoon energy project in the UK.
The developers of the £750 to 850m project in Swansea Bay say their application, if it gets the go-ahead, is the first step to developing lagoon technology that could meet 10 per cent of the UK's electricity needs from the tides by 2023 as it is the first of five planned developments.
The 240MW scheme would involve a six-mile wall built around Swansea Bay, creating a lagoon in the Severn Estuary with an array of low-head bulb turbines at the entrance harnessing the incoming and outgoing tides to generate power 14 hours a day.
Tidal Lagoon Power, the company behind the project, said it was hoping that 65 per cent of expenditure would be in the UK, boosting a homegrown supply chain and a possible future export market.
Sweeteners in the deal include creating a 6.2 mile sea reef, the reintroduction of the native oyster to Swansea Bay, an offshore visitor centre and national triathlon and water sports facilities.
According to the developers, research as part of the project's initial stages found that 86 per cent of local residents were in favour of the scheme.
The Swansea Bay project would save 236,000 tonnes of carbon a year and create 1,850 construction jobs, the company said, with some 150 long term jobs in operation and a boost to jobs in the wider supply chain.
Chief executive Mark Shorrock said: "Until now, tidal energy has been heavily promoted by governments and environmentalists as an intuitive source of clean and reliable energy for our island nation, but the business response has focused on relatively small-scale tidal stream devices.
"The UK has the second highest tidal range in the world and today we are submitting an application for a development that will prove that this resource can be harnessed in a way that makes economic, environmental and social sense.
"Tidal lagoons offer renewable energy at nuclear scale and thus the investment of hundreds of millions of pounds in UK industries and coastal communities."
The project would expect to benefit from subsidies levied on energy bills for clean power, but Shorrock said a second lagoon would require a lower level of support than offshore wind and building more, larger lagoons would bring economies of scale.
A third lagoon, he suggested, would be competitive with the support received by new nuclear plants but without the decommissioning costs and safety concerns and other sites under consideration, such as the Somerset coast, could have added benefits such as flood defences.
He added: "Our intention is to supply 10 per cent of the UK's domestic electricity by building at least five full-scale tidal lagoons in UK waters by 2023, before the UK sees any generation from new nuclear."
The developers have submitted an application which will now be considered by the Planning Inspectorate.
If the application is accepted it will then be assessed with a final decision expected from the Energy Secretary and Natural Resources Wales in early 2015. If the go-ahead is given, construction could start next year, with the first power generated by 2018, the company said.
The project is the latest plan to harness the huge tidal power of the Severn Estuary, after a separate scheme for a barrage across the estuary failed to win political support amid concerns the economic and environment case for it did not stack up.