1 Introduction
1. The UK possesses significant wave and tidal resources.
A recent report by the Crown Estate suggested that the theoretical
potential of UK wave and tidal resources was up to 118 GW (Gigawatts)
of generating capacity.[1]
Current UK electricity power plant capacity is approximately 89
GW (based on 2011 figures).[2]
The Crown Estate's theoretical estimate for the generating capacity
of tidal range technologies is 59 GW. Of this, 45 GW could be
provided by tidal barrages while tidal lagoons could account for
14 GW.[3] The Severn estuary
alone could provide up to 5% of the UK's current electricity generation
from an indigenous renewable source, offering decarbonisation
and security of supply benefits in addition to significant potential
for national and local employment.[4]
2. Proposals for harnessing the tidal power of the
Severn estuary, which has the second highest tidal range in the
world, have been extensively studied since the early 19th
century.[5] The most comprehensive
study undertaken to date by Government is DECC's Severn Tidal
Power Feasibility Study (STPFS), which concluded in 2010.[6]
The study carried out a cost-benefit analysis of five short-listed
tidal power schemes for the Severn estuary, examining a variety
of tidal technologies including barrages, lagoons and fences.[7]
Of these schemes, the Cardiff-Weston tidal barrage was identified
as offering best value for money, although it was also found to
be the most environmentally damaging of the schemes put forward.
At the time, the Government did not see a strategic case for public
investment in a Severn tidal power scheme, although it did not
preclude a privately-financed scheme coming forward.[8]
Context of the inquiry
3. In August 2012, press reports stated that David
Cameron had ordered the Secretary of State for Energy and Climate
Change Edward Davey and Minister of Government Policy at the Cabinet
Office Oliver Letwin to look in detail at new proposals from the
consortium Corlan Hafren for a privately financed tidal barrage
scheme in the Severn, which claimed to mitigate impacts on the
estuary's wildlife habitats.[9]
At the time of launching our inquiry there were no details of
the new proposals in the public domain. The Consortium, which
has since dissolved and reformed as Hafren Power Ltd, submitted
written evidence outlining its new proposals in more detail. This
evidence is published on our website.[10]
4. The purpose of our inquiry was, in light of the
attention given to the Hafren Power proposal by the Prime Minister
and the Secretary of State for Energy and Climate Change, to examine
the Hafren Power proposal in the context of current UK energy
policy. The UK needs to ensure the security of its future energy
supply while meeting its decarbonisation targets and keeping energy
prices as low as possible. In recent reports we have identified
challenges in getting new nuclear power stations up and running,
and demonstrated that the scale of recoverable shale gas reserves
is as yet unknown and the benefits of shale gas development may
take some time to realise.[11]
The Hafren Power proposal for a Severn barrage, which could potentially
meet 5% of the UK's energy needs from a renewable source, clearly
warranted investigation.
5. Hafren Power's proposal is for an 18km fixed tidal
barrage between Brean in England and Lavernock Point in Wales.
The barrage would consist of 1,026 Very-Low-Head (VLH) bi-directional
turbines, generating approximately 16.5 TWh/year on both ebb and
flood tides.[12] It is
this ebb-flood nature of the barrage, which allows for a closer
replication of the natural tide, together with a turbine design
which Hafren Power suggested will optimise "fish-friendly"
characteristics, which together constitute the primary differences
to the 2010 Cardiff-Weston proposal and which form the basis for
claims about environmental mitigation.
6. Hafren Power claimed that the £25 billion
required to fund the project would come entirely from private
sources. In practice however, Government support would be required
over a 30-year period through Contracts for Difference (CfD) or
a similar mechanism.[13]
Our inquiry
7. We received 93 submissions of written evidence,
and, in addition, 14 submissions of supplementary written evidence.
We held three public oral evidence sessions and one private oral
evidence hearing. We are grateful to all those who provided written
and oral evidence. In addition, the Parliamentary Office for Science
and Technology (POST) produced a useful note on tidal barrages
we have drawn upon in our assessment of environmental impacts.[14]
- In March 2013, we received, in confidence, a
business case from Hafren Power. On occasion, Committees receive
papers in confidence to assist in deliberations. This recognises
the fact that there may be relevant material that is not appropriate
for publication. We accepted the business case on a confidential
basis and will therefore not publish it. However, we urged the
Consortium to make as much of this information public as possible,
and believed that this could be done without serious breaches
of commercial confidence. Hafren Power has since published a redacted
version of the business case on its website.[15]
1 The Crown Estate, UK Wave and Tidal Key Resource
Areas Project, October 2012 Back
2
DECC, Digest of UK Energy Statistics 2012 Back
3
Tidal range technologies use the change in water height brought
about by tides, using principles similar to a hydroelectric dam.
Tidal barrages are built across an estuary or waterway; tidal
lagoons are impounded areas of water across one part of a coastline. Back
4
DECC, Error! Bookmark not defined., October 2010; See also Ev
69, Ev 107, Ev 153; Back
5
Error! Bookmark not defined. Back
6
DECC, Error! Bookmark not defined., October 2010 Back
7
These structures all make use of tidal range: barrages are built
across an estuary or waterway; tidal lagoons are impounded areas
of water across one part of a coastline, and tidal fences deploy
an array of tidal turbines on a fixed structure using both tidal
stream and tidal range to generate electricity. Back
8
Ev 69 Back
9
The Independent, No 10 asks Ministers: Can we now support £30
bn barrage?, 19 August 2012,www.independent.co.uk/environment Back
10
Ev 153 Back
11
Energy and Climate Change Committee, Sixth Report of Session 2012-13,
Building New Nuclear: the Challenges Ahead, HC 117 and
Seventh Report of Session 2012-13, The Impact of Shale Gas
on Energy Markets, HC 785 Back
12
An ebb-flood barrage generates on both the incoming and outgoing
tides and water is not temporarily held back on the outgoing tide
as in the case of an ebb-only barrage. This is likely to allow
for a closer replication of natural tidal flows. Back
13
Q 197; Qq 139-140 Back
14
Environmental Impact of Tidal Barrages, Draft provisional
POSTnote 435, Parliamentary Office of Science and Technology,
June 2013 Back
15
Hafren Power Severn Barrage business case, Issue B, 10 May 2013,
Error! Bookmark not defined. Back
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