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23 responses to “Dam Fuel Poverty – Part Two”

    • Jonny Holt

      Hello Dale,

      You are right that the Severn estuary should be harnessed – and the imperatives of coupling an end to fuel poverty with sustainable generation on such a scale are unarguable. It is just that the whole idea of One Big Barrage smacks of a Soviet style corporatist response to a problem. This would be a top down project as out of scale as if the government were to say “lets build one really big turbine – 2Gigawatts or something – it’ll be really impressive and 3,000 feet tall!” I am sure just about all of us would object to that one (leaving aside the considerable technical difficulties).

      The whole point is the design must not only be in sympathy with commercial requirements, but also to other competing interests – and thereby have a scale and diversity with which people can empathise. A system of smaller installations positioned within the tideway could allow the ebb and flow to continue without any significant environmental damage.

      Given that the barrage as proposed will capture only the power available from the head of water upstream, it might be that, say, several dozen smaller installations (extending further downstream) might actually be capable of generating more power.

      If these can be accompanied by a system using wind turbines to provide additional pumped-storage capacity with off-peak wind, so much the better.

    • Neil Law


      You restore my faith in humanity with that kind of response.

      Since I became aware of the issue a couple of years ago, I have always tried to make it clear with others that I want a discussion. I have never seen the point in just scoring points in arguments, or in spoonfeeding people with my evidence.

      I believe my evidence because I found it myself, and then found people who could give me different takes on what it meant. And that is a process that I would advicate for anyone else…be bothered enough to look into it, follow through on what you find…let the evidence lead your opinion.

      Thanks very much, you’ve made my day.


    • Jonny Holt

      Hello again dale,

      Of course my earlier post, in which I said that a barrage would only capture power from the head of water upstream, is not strictly correct. It will operate either upstream or downstream depending on tides – but crucially – not both at the same time.

      What I was getting at is the potential benefit of a system of installations, occupying a much longer and wider stretch of the Severn estuary and into Bristol Channel. The scope for a more dispersed system of structures would allow considerable flexibility, in terms of start-up investment, lead times, staged completion of the project as a whole, eventual load balancing and a lessened environmental impact.

      All in all it has got to be done.



    • Bandidoz

      Whilst I like the idea of Marine Current Turbines, they only produce power in the region of a few MW. The Severn Barrage promises to provide “pulses” of a few GW. For this amount of energy, I don’t believe the MCTs are appropriate.

    • Justin Noe


      I believe your comparing one Marine Current Turbine vs the entire Severn river barrage. A little unfair if I may say so. The great thing about the MCTs is you could just keep adding more and spread the cost over time. They would certainly have less impact on the area.

    • Neil Law

      There are some very recent, and very impressive developments with MCTs… keep watching the media. If the new ones are all cracked up to be, an array of them in the estuary will not only generate far more power than any proposed barrage, but do far less damage (if any) as well.

      In fact, if they are all they’re cracked up to be, putting a barrage alongside would be like comparing an abacus to a modern pc.

      I’m not going to jump up in excitement until I’ve had more info, but so far what I’ve heard is somewhat beyond “interesting”.

      Fingers crossed.

    • Jonny Holt

      If pensioned-off oil tankers could be refurbished as static lagoons and beached in the (relative) shallows lining the estuary, seawater could be used to displace air, which could be expelled through turbines mounted in ducts positoned on deck. In this sense they would operate in a similar fashion to the Wavegen LIMPET (Land Installed Marine Powered Energy Transformer). I suggest they could be dubbed STRUMPET (Super-Tanker Re-Used Marine …).

      Three benefits of giving old tankers a new life are that, the costs will be much lower than building from scratch, the recycling philosophy is very publicly proclaimed and the vessels can be moved if need be.

      Additionally, if wind turbines could be mounted on deck, the water displacement could be exacerbated by wind-powered pumping in periods of off-peak demand. This would, in effect, allow the wind power to be stored so that it can provide instant power to cover the archetypal demand spike at the end of Coronation Street.

      I don’t know if you are into boating, Dale, but given what Reuters report about your (thoroughly deserved) wealth isn’t it about time you got yourself a gin palace? Just with a bit of an eco twist!



    • Adi


      The Marine Turbines could happen as well as the barriage, but not really instead. They are essentially inflow devices whilst Tidal works on the head difference between high and low tide. There is a large difference between the power potential between the 2 systems – which is why the Barriage is worth pursuing still. The concerns of siltation have been raised but I think if we can send people to the Moon – we can find a solution to this.

      An obvious solution is a flushing period. Take for instance an air to water ground source heat pump, this device has to self cleanse itself frequently otherwise it wont work! With the barriage and the extra head of water stored upstream, the self cleansing potential is indeed much greater than if there were no barriage at all! This could be a solution which marries the engineering and the water management (flood gate control etc) as a way to overcome the problem.

      Certainly elver migration, marine life etc needs to be factored in – and all this leads to a barriage which would not actually deliver the maximum potential of the Severn as a power resource – but, even one which achieves 50% of potential energy is worth it given how much we need this power and the cost (<60% of all life diversity ) of not replacing out existing power supplies adequately. The clock is ticking, its time to break some eggshells. Any news from Jonathan Porritt yet?


    • Neil Law

      Adi, what you say about tst is factually incorrect. They can operate in both directions, in and out.

      Now if you follow the reasoning within turning the tide, barrage turbines cannot generate on the incoming tide with any great efficiency.

      The “flushing “solution also seems somewhat wide of the mark. Storing a head of water further upstream is an even bigger problem , because the further up you go, the greater the silt load. If it is stored, that settles out. If the rush of water released to flush is slow, it will dissipate with insufficient force to resuspend the sediment. If the energy is sufficient to do that job, it seems to me that it is most likely to scour out a very direct path out to sea, leaving any sediment in other areas of the embayment intact.

      We definitely need to act, but we definitely don’t need to be clutching at straws and creating even greater problems.

      I do like the idea of power being generated by strumpets though.

    • Adi

      Dear Neil,

      I didn’t say they couldn’t work both ways, just electrical output is more regulated on the downflow which has its benefits. Also, flushing can be directed by the way.

      On skim reading your comments, pretty much all your comments have an undertone of negativity – you claim to be no expert and then when Dale intends to ask Porritt you claim you have no faith in the experts! Then you have your faith returned because Dale is considerate to your points. Faith could be an issue for you and I am sorry if it is.

      Perhaps you could help instead by sharing the view of WS Atkins (or other engineering companies) on their view on the siltation problem WS Atkins were very involved with a proposed barriage project years ago (before the flood alleviation issue added more weight to build a barrier). Please look into this and let us know what their solution is to the silting. I still haven’t got round to asking Professor Twidell about his known solutions, Im sorry.

      You may likely throw more accusations of irresponsibilty because I have not had the time to look into it further.. I think that is unfair..and I will not be silenced by the fact that I have less time to put to this research than you. So -a s you appear to have the time resources, please see what theoretical solutions exist out there. You maybe right that there is no solution (unlikely) but lets explore both sides constructively first. The barriage if built responsibly may well be better than a bunch of Nuclear power stations and far better than doing nothing and losing 60% of species diversity. There are not that many ways we can achieve a replacement of fossilfuel burning in the UK before its too late. Tidal has to be part of the number of ways and part of the package of solutions and the barriage may be the most effective.


    • Neil Law

      Adi, please.. I DON’T want you or anybody silenced at all. I want you to keep exploring it, arguing your point, and standing up for what you think is right. That’s good for you, good for me, and good for everybody who gives a monkeys about this. I don’t for one second doubt your sincerity.

      Wether I’m seen as positive or negative depends on your standpoint. I’ve seen concrete evidence in the form of damage done by ill-conceived barrages, and nobody here is talking about it.

      I believe that I have put forward alternatives, by the way. I have consistently stated that tidal stream turbines are the way forward, and I continue to do so. In the course of my looking into this I have established a range of contacts, one of whom has a forthcoming press release.. next day or so, which is relevant to this point. Set up a google alert for a few keywords around the issues involved. That will make things much easier to follow if you’re not doing it already.

      The “experts” I don’t trust are those with vested interests, and who to my knowledge haven’t actually built a tidal power barrage before who talk about “proven technologies” where none exist.

      Jonathon Porritt is someone I used to have huge respect for, but without saying any more, I think he’s headed in an unhealthy opinion. There is untruth in some of the things he has said.. not lies, to be clear, but statements which are not true as far as I can see.

      Why build a bloody great wall across an estuary when there is no need? The technologies already exist to do the same thing without causing further environmental damage.

      Bear in mind something I was reminded of only yesterday: obstructions in the flow of the tide have massive effects at great distances from the obstruction. Flood alleviation works on the South East coast of England has been found to have caused higher tides, bringing increased risk of flooding as much as 50 or 60 miles away. I can’t remember wether it was a proposed project or an actual barrage, but there’s something in the material I’ve been reading through recently which details increased flooding and coastal erosion something like 800 miles from a tidal range project. I think that was another one in the Bay of Fundy, but I may be wrong. My point here is that just because it doesn’t burn, or smell, or make buildings fall down in some cataclysm doesn’t mean that it isn’t as dangerous as an out of control nuclear reactor. Of course it has that potential. If it didn’t, we wouldn’t be looking to tap into it.

      The price of inaction is something we both agree on. The price of getting it wrong could potentially be a lot higher.

    • Justin Noe

      It appears Ed Miliband has unveiled a shortlist of five schemes (Monday 26 Jan 2009), which include The Cardiff-Weston barrage, The Shoots barrage, Beachley barrage, The Bridgwater Bay lagoon and the Fleming lagoon. I believe other schemes have been put forward but are not really part of the Government’s plans. A three Month consultation period will begin after which five projects will make the final shortlist and considered in more depth, with a view to making a final decision on how best to harness the energy of the Severn estuary in 2010.
      It seems me that whatever is the right choice for the Estuary is becoming quite academic!
      I hope that Neil’s views can be heard in Whitehall because Ed is making his choices.

    • Neil Law


      I forgot to say.

      I am aware of W S Atkins’ previous involvement.I have read the report which backed up the RSPB’s press coverage about the reef before christmas. That document was limited, but that’s no criticism,as I think it’s production was under an extreme pressure of time, to help get the message across about the reef’s capabilities at a time when all the proposals were in the final weeks of this stage of the assessment.
      I’m currently trying to take in the new DECC document about the public consultation stage. That may be beyond me as it seems to be over 1000 pages long, it’s quite daunting. I’ll follow up on Atkins and see where it leads.

      The turbines I mentioned earlier were Mrev drag-lift turbines, being developed in Exeter.


    • Justin Noe

      This may sound silly but may I be so bold to suggest that Ecotricity partner up with Marine Current Turbines and stick a Wind Turbine on top of SeaGen? I personally think this is a neat solution to help with planning applications and doubling the output of such devices. Just a thought…

    • Bandidoz

      Justin – I’ve already posed that question to Peter Fraenkel, who responded with:

      “We have considered installing a wind turbine on top of the pile for our tidal turbines, and even secured a patent to that effect – it is also regularly suggested to us. In practice it is not as good an idea as might be thought due to the fact that a large windturbine would need to be spaced some 500m or so from its nearest neighbour to avoid wake interference but tidal turbines which use a bi-directional flow may be placed only 50m apart across the flow. So clearly windturbines could not normally be placed on more than the occasional tidal turbine. In addition most tide races tend to be close to hilly shorelines which are usually not good wind sites and then there is hostility to windturbines being located close offshore because of visual impact. The structural issues are also non-trivial.”

    • Bandidoz


      “I believe your comparing one Marine Current Turbine vs the entire Severn river barrage.”

      Not at all – but obviously there would need to be hundreds of them in order to achieve parity. I just think the turbine approach is more suited to fast-flowing tidal races such as those found in the Menai Straits and the choke point for Strangford Lough. There is no such choke point in the Bristol Channel.

      The barrage scheme should also provide a pumped-storage element, something that tidal stream technology won’t be able to do. In order to support large scale penetration of renewables on the grid, a large pumped storage facility will certainly be needed.

    • Neil Law

      Flood pumping is covered in “turning the tide”. It is feasible, but at a reduced efficiency. Storage of the tidal waters goes back to the siltation issues I’ve already covered. Heavily silted waters held still will drop a very large amount of fine particled silt very quickly etc, etc.

      The barrages also involve large arrays of turbines. They typically generate over a shorter period than tst’s. The generation times an ebb-generation barrage are not exactly ideal, given that on the best tides these all seem to be at times when demand for power is dropping off. I know that can be ameliorated to some extent by having a 2-stage barrage, retaining a second embayment full of water for use at a time to offset the main generating period, but even the Black and Veatch report seemed to voice a concern over siltation with that idea.

      As to the generating capabilities of the 3rd generation tsts’s I have heard that if expenditure was similar on them as per the Cardiff-Weston proposal, they would be generating more than twice the power of the barrage, with a very much reduced flat spot in the generating cycle, as they work equally as efficiently on the ebb as they do on the rising tide. They are designed for use in shallow estuarine situations. No need for a tidal race.

      BUT… this is just at the stage of “What I have heard”. Even so, they are not the only designs now capable of working in the estuary shallows. I don’t know about advances in MCT units, but a year ago Peter Fraenkel was very honest in saying that he didn’t think MCT products could help.

      As for the speed and power of the current in the estuary, I don’t have numbers, but I do have an account from a retired pilot who used to work in the Bristol Channel, and now volunteers on the SARA boats (if I recall) on the lower Severn. He said that when the tide is in full flow, a boat needs to be making a few knots of headway just to stand still. In the absence of firm data, and in the knowledge that the Severn has a pretty fierce flood tide, I reckon it’s as strong as many tidal races.


    • Jonny Holt

      Justin, Bandidoz, et al

      It is unarguable, to my mind, that a tidal power system of whatever sort should have a role in providing platforms for wind turbines.

      I do not dismiss Peter Fraenkel’s reservations. He has looked into it and obviously knows a lot more about it than I do. However, I feel that to combine a wind turbine with Seagen would be something of a wasted opportunity. It would be a platform, but no more than that.

      Tidal lagoons, the barrage or my STRUMPET idea (which is not entirely tongue in cheek) can all benefit from the added head of water that a pumped storage scheme can provide. This can quite easily be run so that the tidal range, wind and consumer demand cycles can be balanced to give the optimum degree of stored power. Who knows, perhaps it could kick in when a nuclear plant goes off-line?

      The Achilles heal of wind power – in the eyes of its detractors – is its percieved inability to generate power when the wind stops blowing. Pumped storage is the way to nail that lie and, in so doing, convince the general population that we really can have wind generated electricity even on calm days.



    • alistair leslie

      Have you thought about having windmills like a childs playground roundabout I E horizontal
      so they could generate around a core turbine .?
      Wind can be captured 360 degrees and they could be mounted in layers giving more bang for the buck.

    • Damon Hart-Davis


      I believe that what you’re thinking about is known as a VAWT (Vertical Axis Wind Turbine) and for various reasons they are hard to make as efficient and large and robust as ‘normal’ HAWT (Horizontal Axis Wind Turbine) designs.

      Google for VAWT.



    • Rupert Armstrong Evans

      The ‘Severn Tidal Reef’ concept was born out of a desire to get as much ‘green energy’ with the minimum of environmental impact. Laughed at initially, but later supported by the RSPB and other environmental groups, it was investigated by W.S.Atkins who agreed with me that it could generate as much or even more power than the Cardiff-Weston barrage, but without the environmental impact and possibly cheaper. The Government has however, chosen to support a rival proposal submitted by Atkins and Rolls Royce that appears to be a copy, but they have refused to say what the proposal is or to divulge details to an independent third party. To me this look like the biggest ‘stitch-up’ on record, since Atkins and Rolls undoubtedly have their eyes on the hundreds of millions to be made from the detailed design work.

    • Justin Noe

      I hear that OFGEM’s latest report predicts rises of up to 60% in our energy bills by 2016! This it blames on increasing reliance on gas imports and lack of Nuclear power plants. Is OFGEM ignoring any real increases in renewables or will they (Renewables) not have the capacity to take up the slack by this date.? Price rises of this magnitude are likely to create enormous numbers of people fall into fuel poverty. Where will the average Joe be if this project and any others like it cannot supply us with the energy we need? And at affordable prices? Will we have enough Windmills?