UK govt announces further study on tidal barrage.

Image: Tidal barrage at La Rance, Brittany.

Speaking at the Labour Party’s annual conference in Bournemouth, business and enterprise secretary John Hutton signalled that a multi-million pound feasibility study will go ahead to look at siting a barrage between Wales and England at the Severn estuary. The study will examine the social, economic and environmental aspects of the barrage.

Strathclyde University has a fairly simple web page explaining tidal power concepts such as the barrage and also other options including tidal fences and tidal turbines.

Even though such a renewable energy scheme could provide 5% of the UK’s energy needs, reaction to the idea of the barrage has always been mixed. The Royal Society for the Protection of Birds (RSPB) said the barrage would put thousands of birds, salmon and other fish at risk. The estuary contains mudflats, saltmarshes, rocky islands and food that support some 65,000 birds in winter.

They are proposing that the feasibility study examine tidal lagoon and tidal stream schemes which could do less damage and generate more energy. Tidal lagoons are artificially created offshore pools. Water would flow through turbines in and out of the lagoons as the tide rose and fell. Some analysts say this could generate more power than the barrage with less local environmental disruption.

With the barrage carrying an estimated £14bn price-tag, some believe the lagoon concept would also be cheaper.

Currently the only sizable barrage is located over in France at La Rance, Brittany.

The debate rumbles on but at least moves one step further forward.


The Sustainable Development Commission (SDC) has carried out a comprehensive study of tidal power in the UK, including an evaluation of proposals for a Severn barrage. Their just released report, ‘Tidal Power in the UK’, includes a series of recommendations to Government on how to develop our tidal resource, and emerging tidal technologies, to provide secure, low carbon electricity for the long term.

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5 Responses to UK govt announces further study on tidal barrage.

  1. Pete Smith says:

    Am I alone in thinking that mega-projects like this barrage seem very old-fashioned? I know that the technology and building techniques will in themselves be state of the art, but the philosophy behind it, massive centralised infrastructure dumped on the landscape, seems so last century.
    Seems the UK is the last holdout for this approach to tidal power, everyone else seems to be going for lagoons. Apart from the South Koreans of course, they go their own way as usual.
    A good resource for tidal power information is at
    An excellent personal view of Severn Barrage pros and cons is at

  2. matt says:

    Clive’s blog on Tidal power is good and I particularly like the ‘baconbutty’ part to his blog address!

    The technology options seemed to have moved on and widened, although how many of them have been thoroughly tested remains to be seen. Has anyone bothered to find out if an analysis has been done on the operations of the French barrage?

  3. Pete Smith says:

    The barrage at La Rance was opened in the 60s, any reviews of its performance predate the interweb so are a bit tricky to track down. In terms of payback it’s acknowledged as a great success. I’ve come across a few interesting asides in other tidal documents.
    It was originally designed to do 2-way generation, but the turbines are less efficient in reverse and instead the operators found that pumping extra water in during high tide (when the height difference is small) gives extra volume to drive the turbines when the height difference is large.
    Fish stocks and ecology in the La Rance estuary are flourishing now, despite being wiped out when the estuary was blocked for construction when the salinity was strongly reduced. There have been problems with silting.

    Bear in mind that La Rance is very much smaller than the Severn project. A more appropriate comparison with the Severn would be the Bay of Fundy in Canada, which has the highest tidal range in the world. Interestingly, a barrage has been rejected there on environmental grounds.

  4. matt says:

    Yes, I have wondered about whether silting would be a major problem and if so, would the costs be significant to deal with it and what of the CO2 emissions from the vessals used to do the clearing. No doubt a minor point as far as the intended ‘review’ is concerned.

  5. Pete Smith says:

    Quantifying factors such as silting within a model of something as huge and complex as the Severn estuary would be as inconclusive as climate modelling. Even if the review had numbers for it, the margin for error would make them meaningless.

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