Your browser is no longer supported

For the best possible experience using our website we recommend you upgrade to a newer version or another browser.

Your browser appears to have cookies disabled. For the best experience of this website, please enable cookies in your browser

We'll assume we have your consent to use cookies, for example so you won't need to log in each time you visit our site.
Learn more

Viewpoint: Walk before running

Perhaps the Cardiff-Weston barrage should wait until smaller schemes have matured.

It has been reported that next month’s government spending review will axe the barrage across the Severn estuary between Somerset and south Wales when it rules out public funding for the controversial £20bn plan. An extensive feasibility study concluded that it would be impossible to finance the project through private funding alone and, in the current economic climate, a new public project of this scale is unlikely to win support.

The Renewable Energy Association (REA) welcomed the government’s decision in 2007 to conduct a feasibility study into harnessing tidal power from the Severn estuary, which included consideration of the Cardiff-Weston Tidal Barrage, along with 16 other proposals.

The Cardiff-Weston barrage is the largest scheme proposed and would meet 5% of the UK’s electricity demand.

But this still represents only 1% of gross energy consumption – a small fraction of the 15% the European Union has allocated to the UK as the target for 2020.

The Department of Energy and Climate Change made sensible decisions in shortlisting five of the 17 proposals, choosing three barrage options which involve established technologies.

The Cardiff-Weston Barrage was an obvious choice, since so much work has been done on this project in the past. Indeed, it was used during the feasibility study as a benchmark against which to measure the predicted performance of the other proposals.

The smaller Shoots and Beachley Barrages were probably selected because their environmental impact will be lower than that of the Cardiff-Weston Barrage, with a smaller loss of habitat. Likewise the environmental impact of the two other shortlisted proposals, for tidal lagoons, will be lower than a barrage, since they do not extend right across the estuary.

But their predicted energy generation is lower, at a level that has yet to be proven. However, none of these smaller schemes will harness the full generating potential of the Severn and they would sterilise the estuary for any subsequent Cardiff-Weston Barrage scheme.

The REA’s preferred option would be to build a barrage across a smaller estuary, so that the impacts can be fully monitored and understood, and mitigation procedures developed. With that knowledge, government will be in a better position to move forward (or not) with the Cardiff-Weston scheme.

The REA wants to see renewable energy projects of all scales progressed.  While welcoming the government’s initial enthusiasm for the Severn Barrage, we cannot let it take its eye off the ball. 

The attraction of most renewables projects is that they are modular, can be developed quickly and so can deliver their carbon savings in a short time scale, and on a decentralised basis. 

If the government does not bring down the barriers so these relatively easy projects can be developed, what confidence can we have that a large project like the barrage can be achieved successfully?

  • Stephanie Merry is head of marine at the Renewable Energy Association

Have your say

You must sign in to make a comment

Please remember that the submission of any material is governed by our Terms and Conditions and by submitting material you confirm your agreement to these Terms and Conditions. Please note comments made online may also be published in the print edition of New Civil Engineer. Links may be included in your comments but HTML is not permitted.