Energy and Climate Change CommitteeWritten evidence submitted by the Gloucester Harbour Trustees (SEV45)
Set out below are comments from Gloucester Harbour Trustees in response to the questions posed by the Commons Select Committee regarding a proposed Severn barrage between Cardiff and Weston.
Given that Hafren Power has neither published details of its scheme, nor approached the relevant authorities for any information, it is very difficult to respond to this consultation. However we feel that it is important to respond as best we can on the basis of the previous STPG work that considered a Cardiff—Weston Barrage and recent anecdotal evidence from reports suggesting that Hafren Power will use low-head turbines and generate power on both the flood and ebb tides. There are unsubstantiated claims of intertidal habitat loss in the order of 5,000 ha.
What contribution could the Cardiff-Weston Barrage make to UK energy security and climate change objectives?
Whilst it has been stated that the barrage may have the potential to generate approximately 5% of the UK’s current electricity requirement, we would suggest that the contribution to UK energy security is very limited. The scheme would only produce power on the ebb and flood, hence there will be interruptions (albeit predictable) in the flow of energy. The scale of such interruptions has neither been acknowledged nor quantified by the promoters of the “new” scheme, nor have any energy “storage” schemes been examined which might deal with overproduction of energy during tidal cycles which do not correspond with periods of high demand.
What risks and opportunities could it pose with regard to flooding in the Severn estuary, and how might any risks be mitigated?
The issue of tidal locking needs further examination to address the impact upon fluvial and pluvial flooding and drainage issues.
What risks and opportunities could it pose to wildlife and habitat in the Severn Estuary, and how might any risks be mitigated?
No comments.
What lessons can be learned from successful development of La Rance tidal barrage in France and other tidal power projects?
The La Rance scheme is several orders of magnitude smaller than a Severn Barrage and operates in an entirely different environment. We feel that it would be inappropriate to draw comparisons.
What risks and opportunities could it pose to local employment and community, and how might any risks be mitigated? In particular, what are the consequences for current ports, fishing and aggregate extraction industries in the estuary?
Only a very limited amount of information is currently available from the promoters of the scheme presently under consideration. However, papers which we have seen indicate a significant lowering of impounded basin levels that would, in all likelihood, render the port of Sharpness completely inaccessible to the majority of the ships which presently trade via the port of Sharpness.
The ports of Avonmouth and Portbury would be similarly affected, and plans for a deep water container terminal to serve the West Country and Midlands (and beyond) would fail to come to fruition.
The aggregate extraction industry in the Severn Estuary is, we understand, sustainable at present due to the net input of sediment from the Bristol Channel and beyond. A barrage of the type proposed seems likely to reduce the opportunity for sediments to be replenished, and the marine-dredged aggregate industry would die.
The promoters of the current barrage cite economic growth in South Wales (and particularly Port Talbot) as one of their key drivers and fail to address the adverse impacts on existing and potential employment within the Estuary and South West. The Select Committee should fully understand these social and economic impacts.
Would the project require support under the proposed new Contracts for Difference mechanism?
No comments.
How does the company plan to engage and consult the community in the development of the project?
No comments.
Are any other proposals for tidal power projects in the Severn Estuary currently under consideration?
None known.
What could be the wider implications of the scheme for UK engineering and UK low-carbon industry?
No comments.
In our view the proposals for a Severn Barrage lack credibility. There are alternative ways of generating renewable tidal energy from the Severn Estuary without such devastating impacts on the existing environment and economy.
November 2012