Looking beyond energy demands

Planning, 20 June 2008

With increasing pressure to use renewable energy resources, the Severn Estuary is recognised as offering enormous generating potential because it has the largest tidal range in the world.

The debate at a recent conference about how or even whether the estuary should be used focused on key questions about the most suitable technology given the estuary's ecological and maritime significance. Speakers from a diverse range of backgrounds contributed to the debate, which was opened by Welsh Assembly Government environment minister Jane Davidson.

Although tidal stream turbines, offshore tidal impoundments and wave energy-harnessing Manchester bobbers could all be used, the conference focused unequivocally on the Severn barrage prospect. The potential benefits of a barrage are wide. It would offer a long-term source of renewable energy as well as flood mitigation inland of the barrage. It would provide an additional transport link across the estuary and bring financial benefits such as investment and tourism.

However, as Sustainable Development Commission Wales head Peter Davies emphasised, the barrage is not an end in itself. Reducing energy demand and microgeneration also need to be considered.

Beyond the huge financial implications, the greatest costs of the barrage would be to the unique estuary environment. Countryside Council for Wales head of marine Maggie Hill pointed out that its ecological importance has long been recognised through national, European and global wildlife and habitat designations.

If built, the barrage would inevitably affect protected habitats and native wildlife and there are unanswered questions on whether the adverse environmental impacts of such a major infrastructure project could be adequately mitigated. This calls for further research. One mechanism is the forthcoming strategic environmental assessment that is part of the Severn barrage feasibility study, due to be carried out later this year.

Rather than looking for solutions from a spatial planning perspective, the conference focused on engineering. However, engaged at an early stage, the objective skills of planners would ensure that the designs reflect the entire spectrum of sustainability concerns. These would include taking into account the social and economic implications on both sides of the estuary.

Any proposals for energy generation in the Severn Estuary also need to be firmly rooted in a wider national energy strategy. Planners need to ensure that energy generation in the estuary does not result in an irretrievably "wrong" solution in the long term.

Sarah Minett is an assistant sustainability consultant at Atkins in Cardiff. Julia Krause is a graduate planner at Drivers Jonas in London.