Friday, 21 June 2013

Severn Barrage inquiry finds too much environmental uncertainty

The recently revised Severn Barrage proposals raise questions over its potential environmental impact. Will power generation in the Severn ever be economically and environmentally acceptable?

An inquiry report1 by the UK Energy and Climate Change Committee found that the environmental impacts of the revised Severn Barrage tidal power scheme were currently too unclear. The report1 states that “further research, data and modelling will be needed before environmental impacts can be determined with any certainty”. Raising particular concern over the need for “ unprecedented scale..” of compensatory habitat, “..casting doubt..” on the project being compliant.

Lessons from across the globe point towards a cautious evidence based approach being needed. During the inquiry2, examples from La Rance (France) and Bay of Fundy (Canada) were both referenced. It is the Canadian example which seems to bear the closest similarity to the conditions of the Severn Estuary, with ecological impacts, from Canada being cited as fish mortality and habitat degradation and loss. However both the technology used for power generation and the knowledge available have advanced.

Can lessons be learnt and if so will it be enough to make the Severn proposals compliant and acceptable? One of the original Severn Barrage reports3 reported an intertidal habitat replacement cost of £65,000 per hectare. The latest proposal, from Hafren Power4 estimates less than 5000 hectares of habitat will be directly lost. Looking only at the direct habitat which might be lost, and on a like for like basis (1:1) this direct habitat replacement cost could equal £325 million.

However, if existing habitat could be acceptably modified, perhaps the issue of habitat loss might not be so great. The latest business case4 from Hafren Power, seems to suggest some novel approaches to try an address this issue. Such as proposals to raise any potentially impacted habitats and better control over estuary water movement.

Whether the project ever becomes environmentally viable remains to be seen, but certainly robust data sets and evidence must be used to ensure environmental impacts are accounted for and mitigated. Can the economic and environmental considerations ever be balanced?


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Dave Hamster Flickr Creative Commons