Barrage of concerns over the Severn

Published in Tribune, 13 March 2009

PLANS for Britain’s biggest-ever civil engineering project are starting to take shape, amid muted disquiet from environmentalists. The Government has recently published plans to build a massive hydro-electric scheme to harness the tides in the Severn Estuary and is seeking responses from the public to the proposals it has shortlisted.

The Severn Estuary has the highest tides in Europe at around 15 metres (49 feet), and the long, narrow estuary has long been recognised as a possible site for energy production. The last serious proposals to develop the estuary were in the 1980s, although these were dropped for economic reasons. Now climate change and concerns about dwindling oil reserves have revived Government enthusiasm for a massive renewable energy scheme.

Proposed tidal power schemes have usually involved one of two possible mechanisms for generating power. Either a dam can be built across all or part of the estuary, allowing the water to flow in at high tide, then holding it back and running it through turbines once the tide drops. Another more experimental approach is to build a reef or fence of turbines across the estuary, harnessing the ebb and flow of the tides without dramatically changing water levels in the Severn and flooding the estuary’s scientifically important mud flats.

All the proposals retained by the Government on its shortlist involve dams holding back water, which worries environmental groups – although the Department of Energy and Climate Change’s Philippa Heap stresses that the consultation process is still open to hearing responses about other proposals not shortlisted.

But, there is still some disquiet about how and why the shortlist has been drawn up. Five proposals are under active consideration, and all have caused some concern to environmental groups.

The first, biggest and most controversial is a proposed five-mile barrage running from Lavernock Point, near Cardiff, to Weston-super-Mare in Somerset. This could produce around 17 terawatt-hours per year of power – more than any nuclear power station in Britain today, although less than Drax, the country’s biggest coal-fired power plant.

Other proposals include a barrage further upstream near the Severn Bridge, another upstream of the River Wye and two tidal lagoons – large bodies of water along the Welsh or English coast that would be held back as the tide rises, but which would not completely block the flow of the river.

The inclusion of the Cardiff-Weston barrage in the Government’s proposals has caused serious concern in groups as diverse as the Royal Society for the Protection of Birds, the Campaign for the Protection of Rural England and Plaid Cymru – which as a coalition partner in the Welsh Assembly government is a key stakeholder in the development of the tidal schemes.

The RSPB, in particular, is concerned that all the schemes which have been retained on the shortlist feature barrages that would permanently submerge mud flats where birds feed, some of which are recognised as sites of scientific interest. A 2007 report for the RSPB determined that the Cardiff-Weston barrage would essentially destroy the Severn Estuary as we know it. Martin Harper, the charity’s head of sustainable development says he is “extremely concerned” at the prospect.

Harper argues that the other schemes proposed also pose serious threats to wildlife. The two proposals for lagoons would still drown the mud flats, while a barrage, even if it was built much further upstream, would still block the flow of the river and prevent migrating fish such as salmon from swimming upstream. The River Severn, he says, is home to a quarter of the salmon stocks in Britain and their migration routes would be completely blocked by either of the barrage schemes.

The problem with the shortlist, Harper argues, is that it is “skewed heavily towards technical feasibility and cost, and it hasn’t ruled out projects which cause environmental harm”.

The RSPB is concerned that other proposals which could produce as much or even more energy, but which still need further technical development, have been ruled out. In particular, schemes involving a tidal reef and a series of smaller projects along the Severn, he says, could actually produce more power while causing far less damage to fragile habitats. Referring to a recent study by engineering consultancy Atkins, Harper says that the report “found that the principle of generating energy from a smaller size of impounded water is correct”.

Other groups are less strident in their criticisms, but still show some concern. The CPRE is currently preparing its response to the Government consultation and so has not fully determined its position. “It’s a bit early yet”, says Richard Lloyd of the Gloucestershire CPRE. Nevertheless, he already identifies clear problems with the Cardiff-Weston scheme, although he insists that the organisation is going to look at all the proposals seriously and ask: “Could these go to the next stage, are there ones to reject at this stage?”

Encouragingly, the consultation process for the tidal schemes seems to be progressing far more smoothly than the widely panned nuclear power consultation in 2007, and pressure groups remain engaged with the process. The DECC has made serious efforts to reach out to stakeholder groups and provide a forum in which real responses are encouraged – a clear contrast with the skewed consultation over nuclear power which was boycotted by groups including Greenpeace.

“The DECC team have engaged very well with stakeholders”, says Martin Harper. “Officials have done a really good job of engaging with people.” The DECC’s consultation website has attracted wide interest. And the department’s Philippa Heap says it has made strenuous efforts to contact relevant stakeholders and interest groups, and has organised web-chats with ministers in order to invite further responses.

The real concern that stakeholder groups have with the consultation isn’t the process, which appears to have been running smoothly, but with the shortlist itself. “The reef should be on”, Harper says, “the barrage should be off.”

Once the consultation closes in late April, the DECC will collate the responses and publish them, leading to a final preferred option being presented in 2010. Depending on which scheme is chosen, a tidal power station could be operating in 2018 at the earliest, or 2022 if the massive Cardiff-Weston barrage is chosen.

If it is, we can expect today’s quiet concern to erupt into serious opposition in the future.