The promoters want to follow up an initial £850m project for Swansea Bay with four even larger lagoons with a capacity of 7,300MW — enough to meet 10 per cent of Britain’s electricity needs.

The first stage of a £12-billion scheme to build a series of tidal energy plants in Britain started on Saturday as a planning application is submitted for the world’s largest power-generating lagoon in south Wales.

The promoters want to follow up an initial £850m project for Swansea Bay with four even larger lagoons with a capacity of 7,300MW — enough to meet 10 per cent of Britain’s electricity needs.

Tidal Lagoon Power has put in a development consent order under the Planning Act 2008, but must persuade the government to provide subsidies of £156 per MW/h — even more than that going to offshore wind farms.

The project must also overcome scepticism about tidal power following the collapse of the much larger Severn Barrage power generator in the same region.

“Our intention is to supply 10 per cent of the U.K.’s domestic electricity by building at least five full-scale tidal lagoons in U.K. waters by 2023, before the U.K. sees any generation from new nuclear,” said Mark Shorrock, chief executive of Tidal Lagoon Power, who has launched successful wind and solar schemes.

The project, which envisages an area of 4.5 sq.miles cordoned off by a breakwater, would have an installed capacity of 320MW with an annual output of 420GW/h and a design life of 120 years. A six-mile sea wall up to 20m high would need to be built, but Mr. Shorrock says only a little over half of this wall would be visible from the land at low tide, and barely a few metres showing at high tide.

The power will be generated as incoming and outgoing tides — the daily equivalent of 100,000 Olympic swimming pools worth of water — pass through turbines. Mr. Shorrock said it was essential to build more than one tidal lagoon: “Economies of scale bring immediate advantage. A second lagoon will require a lower level of support than offshore wind, for a renewable power supply that is both long-lived and certain. A third lagoon will be competitive with the support received by new nuclear, but comes without the decommissioning costs and safety concerns.” The second project would cost £2.3bn and be based in Colwyn Bay, with a third costing £4bn located in the upper Severn estuary. Two more at a cost of £4.5bn would follow, on as yet unspecified sites.

Mr. Shorrock, who has already constructed 280MW of wind and solar plants, said he had potential financial backing from the Macquarie Group’s infrastructure funds and would like to bring in U.K. pension funds as investors. He said the projects would be far cheaper and more productive than the £30bn Severn Barrage scheme, which was first turned down by the government in 2010 amid huge opposition from many environmentalists.

He said he had support from the local community and leading green activists for the Swansea Bay tidal lagoon, which as well as providing light and warmth for 120,000 local homes could also become a centre for sailing and other recreation.

Sean Christian, special sites spokesman for the wildlife lobby group RSPB, said he welcomed the fact that projects in the Severn estuary were now focused on tidal power lagoons rather than shore-to-shore barrages. “This technology will have less impact on fish and other wildlife than the barrage proposals, which conservationists have spent several years fighting in the estuary, and which the government has repeatedly rejected.

“However, it could still have major impacts on the estuary and its wildlife, and we will need to look at the details of each lagoon proposal closely.” Tidal Lagoon Power has built a potential team of British-based suppliers who would help with the scheme, including Alstom, Sheffield Forgemasters and Atkins. The equivalent of 1,850 fulltime jobs are promised during construction.

David Tonkin, chief executive for the U.K. and Europe at the engineering company Atkins, said: “The tidal lagoon concept ... is a great example of how innovative engineering could be used to harness our natural resources and provide clean, sustainable and predictable power for thousands of homes.” If given the go-ahead for planning and the subsidies, construction is due to begin in the first half of next year, with the first power being generated in 2018.

It would be a boost to local employment opportunities, especially while it is being constructed. Ian Isaac, who runs NSA Afan, a community-based regeneration organisation, said: “Swansea Bay tidal lagoon will be the first of its kind in the world. Importantly, it will be an innovative approach to tackling high levels of unemployment in the area.”

© Guardian Newspapers Limited, 2014

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