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Tidal power generated from more than 200 turbines in a 10-mile
long barrage across the Severn estuary, could provide nearly
5% of Britain's electricity for 120 years with minimal climate
change emissions and should be investigated urgently, government
advisers have said.
However, what would be Britain's largest power project and
one of the most ambitious civil engineering challenges in
the world, would significantly affect the visual and marine
environment for up to 30 miles around it and have mixed long-term
economic and ecological impacts, said the Sustainable Development
Commission.
It would mean the loss of 11,000 hectares of inter-tidal
and other protected land, could limit the expansion of shipping
in the estuary and would affect miles of beaches as well as
the Severn bore. However, it could also provide a much-needed
river crossing and be a fillip to tourism and the economies
of Wales and south-west England, it said.
Controversially, the advisory body's report insisted that
the £15bn scheme should be paid for by government. "It
is imperative that a project of this national importance should
be publicly-led and publicly-owned - but, we do not rule out
private enterprise partners" - said Jonathon Porritt,
chair of the commission.
"The potential for [it] to reduce carbon emissions and
improve energy security needs to be balanced against the impact
on the estuary's unique habitat, as well as communities and
businesses" - he added.
The SDC emphasised that the lower rate of interest available
to government-led projects would provide the only realistic
way of funding an 'immense' compensatory package for
the environment lost - as well as providing electricity at
a competitive price.
SDC commissioners suggested that the 15,000 hectares of protected
land that would be affected could be compensated for by the
sacrifice to the sea of low-grade farm land in East Anglia,
Wales and elsewhere, which is already proving impractical
and expensive to defend against storms.
The technical principle of the barrage is well-tested and
would be ideal for the Severn, which has one of the highest
tidal ranges in the world, says the report. It works by trapping
water behind it at high tides and releasing it through the
turbines.
The major Severn scheme considered by its engineers would
cross the estuary downstream of Cardiff in the north and Weston-super-Mare
in the south. It would employ 300-odd turbines and generate
8GW of predictable power - as much as 10 or more nuclear power
stations.
The report, which followed a series of workshops and forums,
said that Britain had completely ignored its potential for
tidal energy. Up to 10% of its electricity needs could be
generated in different ways from the tides - it said - and
it recommended a pilot project to consider tidal lagoon technology,
which is backed by groups such as Friends of the Earth.
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