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Wave hello to British sea power

A seawall and 16 turbines in Swansea Bay could generate electricity for 120,000 homes
  • @BawdenTom

Big plans are afoot to transform Swansea Bay into the world’s first tidal lagoon power station.

The £850m, six-mile-long U-shaped seawall by the Swansea docks will not only generate enough electricity to power 120,000 homes for 120 years – it will also create nearly 2,000 construction jobs in the two years it takes to build; and it will leave the city with a tourist attraction drawing in up to 100,000 visitors a year.

That’s what Tidal Lagoon Power, the industry’s eponymous leading player, told a gathering of locals last month as it sought to win them over.

“The UK has the second highest tidal range in the world [after Canada] 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,” Mark Shorrock, the chief executive, said.

The company has an almost messianic attitude to its fledgling technology, arguing that the Swansea Bay project – which has yet to receive planning permission – could be the first of five tidal lagoon power stations, including one in Liverpool Bay and another in Colywn Bay, North Wales, which between them could meet nearly a 10th of the UK’s electricity needs. It hopes to agree subsidy levels with the Government by October and to receive planning permission next spring. Building is scheduled to commence in May, assuming it can raise the necessary finance. The company has raised £10m so far – Macquarie, the Australian infrastructure investor behind Thames Water and the M6 toll road, is understood to be leading the fundraising.

The project will use a new type of technology to harness the “tidal range”: an “impounding” seawall, capable of holding four square miles of water. It would then let it run out through 16 turbines at both high and low tides, generating electricity. At low tide, water would flow from the lagoon into the sea and at high tide, water would flow from the sea into the lagoon – a total of 100,000 Olympic swimming pools’ worth a day.

It is the most ambitious of a handful of tidal energy proposals. As an island, the UK is ideally placed to generate huge amounts of electricity from the water and a recent government report said wave and tidal power had the potential to generate up to a fifth of the country’s needs. Yet the technology – in the UK and elsewhere – has barely made a dent, accounting for just 0.002 per cent of the country’s consumption last year. The technology used to harness the tides is a long way behind wind and solar power, because the engineering is more complex and the conditions volatile.

Essentially, engineers try to tap the tide in two ways: one involves using the ebb and flow of the waters to turn turbines – by building barrages across tidal estuaries or through lagoons just off the shore. The other method involves planting turbines underwater in fast-flowing tidal streams, in coastal waters around Cornwall or Scotland. MeyGen, a subsidiary of Aim-listed Atlantis Resources, has been given planning permission to deploy tidal stream technology in the Pentland Firth; it should generate enough electricity to power about 40,000 Scottish homes by 2020. Bristol City Council is working on a plan for a tidal lagoon project on the Severn estuary; and Devon-based startup LongBay SeaPower is proposing another for the Bristol Channel.

It is not difficult to see why Tidal Lagoon’s Mr Shorrock is so excited about the prospects. Unlike fossil fuels, it is green and the power source is free. And unlike other forms of renewable energy, it is predictable – meaning it’s not beholden to the vagaries of the wind and the sun. Furthermore, the lagoons can help protect against flooding, which is an increasingly important consideration.

A study by the Centre for Economics and Business Research, for Tidal Lagoon, found that the company’s plan to build a total of six projects could generate £27bn for the economy by 2027 just from the construction. Once built, the fleet of lagoons would supply 8 per cent of the UK’s electricity and would contribute £3.1bn a year to the economy over their 120-year lifetimes. Furthermore, the programme would create and sustain thousands of jobs, reduce carbon emissions and put the UK at the forefront of the technology – potentially securing an extra £70bn in exports.

“The report paints a compelling picture for the potential contribution of tidal lagoon infrastructure. We have the resource and we have the industry,” said John Cridland, director general of the CBI.

However, opponents question whether it is a cost-effective way to produce green electricity – and in some cases, how green it really is.

“Many sites that are suitable for lagoon power are in areas of high impact to wildlife. So while we are in favour of tidal power in principle, often we would oppose developments because they might cause problems for wading birds or migrating fish,” said the RSPB’s Grahame Madge.

Apart from the difficulty in obtaining planning permission, there is also the problem of whether the economics stack up – which will dictate whether it will get the funding it needs. This is where opinions differ quite widely.

Tidal Lagoon said, in a report commissioned from the Pöyry consultancy, that the lagoons could potentially produce power for about £100 per megawatt hour. This compares with Government calculations for a deep-sea offshore wind farm of about £131 per MWh, but is more than the cheapest projects – £90 per MWh for onshore wind, solar and gas-fired plants. However, Tidal Lagoon conceded that the £100 price can only be achieved on completion of the third giant project. The first – Swansea – would cost £168 per MWh, the second £130 and the third, £92.

“Swansea is the first of its kind and so will cost more. But economies of scale bring immediate advantages and each project becomes significantly cheaper,” Mr Shorrock said yesterday.

A second lagoon will require a lower level of support than offshore wind, he added. And a third lagoon will be competitive with the support received by new nuclear, but comes without decommissioning costs and safety concerns.

“And it will be a net benefit for the environment. The lagoon walls will create an artificial reef which will attract sea bass, lobster and seagrass; the birds and fish will not be disturbed,” Mr Shorrock added. He founded the Low Carbon Accelerator fund in 2006, which invested in green energy projects.

The scale of the opposition to tidal power was underlined by an attempt by Hafren Power to build an 18-mile sea wall on the Severn. Last summer the cross-party Committee on Climate Change found that the scheme was unsatisfactory for economic and environmental reasons and the proposal was rejected.

But the Swansea project may just be different enough to have legs, according to Tim Yeo, the chairman of the committee. For a start, the Severn plan was for a barrage rather than a lagoon – it would have been built across the banks of an estuary, potentially causing much greater disturbance to the local wildlife.

“The Severn Trent project was so huge that only a couple of other places in the world would have been big enough to replicate it, whereas the smaller Swansea project can be replicated. This looks like a much more viable concept and can be trialled on a smaller basis,” Mr Yeo said.

“It is certainly worth examining and it is right for the Government to be putting money into research,” Mr Yeo said, but added: “But we shouldn’t get too excited about its near-term importance.”

It seems that the prospects for a successful tidal lagoon industry – and for marine energy – are likely to continue to tread water for some time.