The Severn Estuary and its wildlife is under threat from a proposal to build an enormous barrage to generate electricity from the Severn's huge tides
The Severn Estuary is one of the largest in Europe and is one of its most important wildlife habitats.
The estuary and the rivers which feed into it contain and support a wealth of wildlife so rich it is considered to be of international importance and is protected by international law. Its saltmarshes and mudflats are used by an average 74,000 birds each winter, its waters support more than 100 fish species and vast numbers of invertebrates. The estuary is a vital migration route for migratory fish, including Atlantic salmon, sea trout and eels.
But the future of the estuary and its wildlife is at risk because of a proposal to build an enormous barrage to generate electricity from the Severn's huge tides. Proposals for a barrage across the Severn have been around for more than 100 years but the urgency of climate change has now brought them back to the fore.
Severn tidal power background
The huge tidal range and high level of surrounding industry and population have long made the Severn Estuary and Bristol Channel a focus for tidal energy schemes. Plans for a Severn Barrage – running 16 km from Lavernock Point near Cardiff to Brean Down near Weston-super-Mare have been discussed for several decades. The UK Government shelved plans for a Severn Barrage in the late 1980s due to cost and environmental concerns. Again, in 2003, a Severn barrage was rejected by the 2003 Energy Review due to 'strong environmental concerns'.
In April 2006, the Welsh Assembly approved the idea of utilising the tidal power of the Severn.
In October 2007, the UK's Sustainable Development Commission (SDC) published a report looking at the potential of tidal power in the UK, including proposals for a Severn barrage. The SDC gave its cautious support to the concept of a Severn barrage, providing a number of strict conditions were met. These included:
- It should be a publicly-led project, and a publicly-owned asset, to avoid short-term decisions and ensure long-term public interest
- Full compliance with the EU Habitats and Birds Directives is vital, as is a long-term commitment to creating compensatory habitats on an unprecedented scale
- Development of a barrage must not divert government attention away from much wider action on climate change
Severn Tidal Power Feasibility Study (STPFS)
In late 2007, the UK Government announced a two-year 'Feasibility Study' into the possibility of using a variety of tidal range technologies to generate clean, renewable electricity from the Severn's tides. An initial 'long list' of 10 possible options was assessed and reduced to a shortlist of five announced by Ed Milliband, Secretary of State for Energy and Climate Change, in early 2009.
The five shortlisted options included two tidal lagoon schemes (Fleming Lagoon and Bridgwater Bay Lagoon) and three barrage schemes (Cardiff-Weston Barrage, Beechley Barrage and Shoots Barrage). By far the largest of the five schemes was the original 'Severn Barrage' - the Cardiff to Weston Barrage - which it is claimed would generate 8.6 gigawatts of zero-carbon electricity from the Severn – the equivalent of several large coal-fired power stations. It is claimed that it could supply 5 per cent of the UK's current electricity needs.
DECC published a summary report of the Feasibility Study and its conclusions in October 2010. The key conclusions included:
- a tidal power scheme in the Severn Estuary could cost as much as £34billion and is high-cost and high-risk in comparison to other ways of generating low-carbon electricity
- a scheme is unlikely to attract the necessary private investment in current circumstances, and would require the public sector to own much of the cost and risk
- the scale and impact of a scheme would be unprecedented in an environmentally designated area - there is significant uncertainty on how the regulatory framework would apply to it
- some habitats including saltmarsh and mudflat would be reduced in area, potentially reducing bird populations of up to 30 species
- fish are likely to be severely affected with local extinctions and population collapses predicted for designated fish, including Atlantic salmon and twaite shad
- water levels would also be affected and in order to maintain current flood protection levels in the Severn Estuary additional flood defences would be required
Severn Embryonic Technologies Scheme (SETS)
As part of the Feasibility Study, DECC also ran a programme called the 'Severn Embryonic Technologies Scheme'. This funded the investigation of three further proposals for the Severn, using innovative and immature technologies, including a low-head barrage and two tidal fences.
These proposals showed promise for future deployment within the Severn Estuary - with potentially lower costs and environmental impacts than either lagoons or barrages. However the technologies were a long way from technical maturity and therefore more work would be required to develop them to the point where their yields, costs and environmental impacts could be properly assessed.
The Corlan Hafren/Hafren Power Tidal Barrage
In 2012, a consortium called Corlan Hafren resurrected the idea of a barrage on the Cardiff-Weston alignment but claimed their proposal had two significant differences:
- Construction could be paid for through private investment, as long as the right level of subsidy from Government could be agreed for the energy produced;
- Low-head rather than a high-head design and would operate on both the flood and ebb tides (rather than just the ebb tide). They claim that as a result of these differences the environmental impacts of their proposal would be much less than those of the Cardiff to Weston barrage examined by the STPFS.
- However, to date, there is no detail on the proposed design or its impacts, and no evidence has been made available to support Hafren Power's claims.
The UK Department for Energy and Climate Change (DECC) said it had received the first draft of a business case for the scheme, and that it was an "interesting proposition".
A high profile media-driven campaign, led by former Labour Welsh Secretary Peter Hain MP, followed during 2012-13, as did a change of company name, to Hafren Power. However, the Hafren Power plan collapsed after it was rejected by three independent committees of MPs and by the UK Government.
The House of Commons' Energy and Climate Change Committee concluded that the case for a barrage was "unproven" and stated that Hafren Power "has yet to provide robust and independently verified evidence of the economic, environmental and technological viability of the project". In September 2013 Hain said that the plan was "dead in the water" in the current parliament.
By January 2014, four key figures had resigned from the Hafren Power, including chief executive, non-executive director and economic coordinator and very little has been heard of the company since.
Tidal Lagoon Power
In 2007, the Severn Tidal Power Feasibility Study several tidal lagoon proposals were assessed alongside of the barrage proposals. Over subsequent years, Tidal Lagoon Power have championed plans for a Tidal Lagoon in Swansea Bay (within the Greater Severn Estuary). This proposal has now gone through the planning process and a consenting decision is awaited from Energy secretary, Ed Davey.
TLP have also made clear their intention to explore the possibility of further, much larger, tidal lagoons at much more sensitive sites within the Severn Estuary including at Cardiff, Newport and Bridgwater Bay. Each of these locations would be within the area designated as a Special Area of Conservation (SAC), a Special Protection Area (SAC) and a Ramsar site.