The Severn Barrage
History
The idea of a Severn Barrage is nothing new. Early proposals in the mid 1800's were mainly driven by harbour creation, flood defence and transport links across the estuary. From the 1920's onwards, however, initiatives were more born out of aspirations to harness the energy from the Severn's 14 metre (45 foot) tidal range, the second largest in the world.
The Severn estuary is a habitat that is unique for its massive intertidal zones and huge volumetric flows of water. It is a vast overwintering site for a whole range of migrating birds but of particular relevance for the Foundation, it is the conduit for several extremely rare migratory fish species: Allis and Twaite shad; Sea and River lamprey; Atlantic salmon and Sea trout and European eel.
Against the background of climate change, the need to drastically reduce the use of fossil fuels that release stored carbon and a timely opportunity to renew or upgrade our outdated and under invested power generation systems, the government is investigating all potential "renewable" sources of electricity generation. For full details please see http://www.berr.gov.uk/whatwedo/energy/whitepaper/page39534.html
An inspection of the Severn estuary and its huge tidal range would suggest that there should be potential for harnessing the massive forces of water movement to generate renewable electricity, thus reducing our dependency on fossil fuels.
Drivers for the Barrage
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30% of UK's electricity generation will be lost by 2020.
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40% of our electricity needs to be from renewables (currently < 1% but targeted at 10% by 2020).
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Populist and big business pressure.
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Tidal power is a genuine renewable source.
In October 2007, the Sustainable Development Commission looked into the UK's tidal energy possibilities, including the Severn estuary. Some of their conclusions were:
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A Severn Barrage should be part of a wider action on climate change.
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It must comply with existing environmental legislation i.e. Habitats Directive.
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Provision of compensatory habitat is an integral part of any proposal.
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Early work on scientific and legal feasibility of compliance and cost should be a priority.
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The Severn tidal range could generate 5% of UK electricity.
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The Severn tidal stream resource is not one of UK top ten sites.
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The project should be government owned and run.
See www.sd-commission.org.uk/publications.php?id=607 for the full report.
2009 Where are we now?
A government feasibility study, started in 2007, concluded its first phase when a public consultation was launched on 26th January 2009. This public consultation was finished on 23rd April and covered, amongst other things, the proposed scope of the Strategic Environmental Assessment (SEA) for up to 11 possible barrage schemes. This was shortlisted to 5.
A consortium led by the engineering consultants, Parsons Brinckerhoff (PB), has been appointed to manage this part of the project. The study will culminate in a full public consultation in 2010.
| Proposal | Location | Installed Capacity | Construction Cost | CO2 Savings/year |
| Shoots Barrage | By Severn road crossings | 1.05 GW | £3.2bn | 1.2 Mt |
| Beachley Barrage | Just upstream of the Wye confluence | 0.625 GW | £2.3bn | 0.7 Mt |
| Fleming Lagoon | Between Newport & Severn Road crossings | 1.36 GW | £4.0bn | 1.0 Mt |
| Bridgwater Bay Lagoon | English shore between Hinkly Pt & Weston Super-Mare | 1.36 GW | £3.8bn | 1.1 Mt |
| Cardiff-Weston Barrage | (Lavernock Pt - Brean Down, known as Severn Barrage) | 8.64 GW | £20.9bn | 7.2 Mt |
So what are the Issues for us?
One would expect an environmental organisation set up to restore and protect fish and fisheries to be against any scheme that could severely reduce or extinguish runs of migratory fish. Salmon, shad and lamprey currently enjoy the protection of the EU Habitats Directive. The schemes shortlisted will present massive problems for planners attempting to reconcile these important environmental considerations. We believe that this crucial aspect should have been reflected in the short listing as the issue of providing compensatory habitat is such a "Significant Challenge" that the process may be set back very substantially while resolution is investigated. Equally, the barrage presents huge challenges to one of the most important RAMSAR sites, where birds both live and over-winter in the unique habitat. Colleagues in the RSPB, WWF, Wildfowl and Wetlands Trust (Slimbridge) and other wildlife trusts therefore have parallel concerns and together we are creating a united front. The size and strength, experience and ability of these organisations make for welcome allies.
There are, however, plenty of other reasons for opposing the barrage, amongst which are ...
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It's disproportionately expensive (see table below).
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Tidal Power is Intermittent: power produced at night and in short, heavy bursts requiring grid restructuring
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It won't solve the problem of either Climate Change or Power Generation as effectively as some other schemes.
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There are as yet unresolved technical issues.
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There is a lot of money involved.
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It's a risky "all eggs in one basket" scheme.
Are there better alternatives to the Barrage?
The table above would suggest so. The list of potential alternative sources of energy includes ...
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Tidal stream – elsewhere in UK.
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Wind power (sea and land).
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Nuclear.
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Micro generation – new technologies being developed.
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Energy conservation (turn off the lights!).
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Tidal reef.
Tidal Reef
One of the 11 original schemes was a proposal by Evans Engineering for a 12-mile tidal reef stretching from Minehead to Aberthaw. The reef gives the prospect at least of being environmentally benign, ie allowing fish to pass and only slightly reducing the intertidal zone, so important for birds. It would permit shipping to pass and generate at least as much electricity as any other scheme, probably over a longer period. Despite strong support for this scheme from environmental organisations, it did not make it onto the shortlist of 5 with the Government saying that tidal reef technology was not yet developed enough. They added, however, that this and other schemes could be revisited before any final decision was taken and promised some funding for further research.
Advantages of the Tidal Reef:
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Works on low head ... 6'.
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Less demanding structure .
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Many slow turning turbines.
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Situated a long way down the estuary.
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Generates for a longer period - on both tides.
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Less change to intertidal zone.
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Shipping OK.
What has the Wye & Usk Foundation done about the Barrage proposals?
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We sit on the Strategic Environment Assessment Steering Group.
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And Migratory Fish Technical Group.
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We have joined with other NGOs such as the RSPB, WWF, WWT and WTs to form a robust resistance to environmentally unfavourable schemes.
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Submitted papers at call for evidence.
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Two presentations to at WSFOA and UUFA AGMs.
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Presentations to Parliamentary groups.
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Responded on your behalf to the Public Consultation (see pdf below).
What next?
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Continue with lobbying, attending steering group and technical meetings.
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Working with other NGOs to resist any unfriendly scheme and ensure the existing SAC legislation is upheld.
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Press for the best environmental solutions to Climate Change.
Further reading:
