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 “..an 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?
Sources
3 -http://www.wyeuskfoundation.org/Severnbarrage/downloads/ABP%20mer%20Sever
Photo
Dave Hamster Flickr Creative Commons
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