If our government insist on progressing this plan with all the readily available information to say that it just isn’t commercially viable and certainly isn’t green then doesn’t it make you ask the question is this yet another payment from the gravy train for our fat cat politicians. When are they going to start thinking about the planet and fellow human beings instead of lining their own nests.

Comment from moderator: Thanks for your comment Steve, there is a lot of money involved in this and it does blind people to the issues. One major concern is that the consortia that has won the contract to do the feasibility study (said to be worth £100 million) is the same company behind one of the barrage proposals! How on earth can that be carried out in a neutral way - something stinks there.

It certainly does smell very fishy and it sounds like they are breaking every standing order set down by the auditors. How do they get away with it?

I think you may be quoting comments that I made about my ‘Tidal Reef Proposal’ since you laugh at the idea of fish or even a person passing through it, and you refer to flood alleviation. May I make a few comments of my own.

*Dear Rupert, thanks for your comments. The claims that a man can pass through a turbine are coming from the group supporting the barrage proposals. I have heard of the Tidal Reef proposal but I have a some trouble understanding it. I will call you to discuss. (Replies from moderator are marked with an*)

1. This is not a proposal from a large company but a possible way of bringing the different sides together for an environmental benign solution.
*That sounds very promising. Our stand point is that if any proposal causes the estuary to silt up, it is not renewable. The Sustainable Developments report on states that a barrage head pond could loose 50% of it’s capacity in as little as 10 years. The Government define ‘renewable energy’ as being inexhaustible. The resource is not the tide for that is everywhere. The resource is the funnel shaped estuary and any proposal that slows the current and induces the flocculation process it will block the estuary and ‘use up’ this resource. Therefore it will not help towards the 15% renewables target and we should look at solutions that do.
2. I built the first ‘Tidal Stream turbine’ that you refer to, and this proposal is a development from it, because the ‘fence’ idea that I floated over 10 years ago simply won’t work because of the hydraulics.
*Dr Graham Daborn, Acadia University Centre for Estuarine research, Nova Scotia shares you concerns over ‘tidal fence’ proposals. He fears that they could block an estuary quicker than a barrage!
3. This proposal is much further west between Minehead and Aberthaw in Wales, so it will afford some protection to all the low areas upstream, unlike the Carfiff Weston barrage.
*I do not understand your proposal so will I can’t comment on it specifically. But as stated, any proposal that slows the current in the estuary is likely to cause flooding. If siltation is induced on the massive scale experienced in other estuaries then this blockage would cause flooding both above and below the obstruction as seen in The Bay of Fundy.
4. I guarantee that salmon will pass unharmed through the turbines. Why am I so sure? It’s simply that the head difference is so small (less than two metres) that it won’t damage their swim bladders. The turbines rotate slower than the tidal stream turbine and have simply vast clearences and backward facing runner inlets. If anyone can improve on the concept I would be delighted to talk to them.
*This good news. It is important that we realise the impact any obstruction in the Severn would have on aquatic life. It is the entrance and exit to most of the rivers of the Midlands, The South West and Wales. All migratory species that use those rivers pass through the Severn Estuary and would be impacted by any degredation of it. It is also a very important nursery and spawning ground to a multitude of marine fish species. It is not only fish that use the estuary but marine mammals too. Porpoise are regularly seen as far north as Slimbridge and in August a Seal made it all the way to Tewksbury.

5. local disturbance is reduced to a minimum because both sides of the estuary have rail links to bring materials right to the construction site.
*I’m pleased that total build impact is being considered. I see that the barrage proposals don’t include any decomissioning costs. How much would it cost to clear a blocked estuary and dig out a redundant barrage?

6. Above all the operating system won’t damage the intertidal feeding grounds or the salt marshes. This is because I have taken the environmental requirements as the starting point and not the end point.
*I am delighted to hear you have started with the environment and hope you have found a workable proposal.
Having nine national and international awards for renewable energy and the environment, I ask that you support what I am proposing so that it will defeat the monsters that the ‘big boys’ are proposing. I want this proposal to be owned and driven by the environmental interests. I look forward to hearing your comments.

Thank you for your comments about the ‘Reef’. It would only be possible to build if it gets a lot of support from environmental groups (not, I hope, just because it would be the least bad alternative!) With regard to decommissioning, I would obviously hope that it would be a great success and would carry on in operation for hundreds of years BUT and with all complex environmental issuesthere could be a hidden flaw. In this case all the top works of the structure can be floated away (because that is how it is built and maintained). The foundation caissons are gravety structures that are not concreted to the sea-bed, so it it was necessary to remove them as well, it would be prefectly feasible. The number one feature of the ‘Reef’ is that its operation is totally flexible after construction, in other words, the point at which generation starts and stops, the point at which the ‘Reef’ opens to allow water to flow freely, will vairy from tide to tide depending on the need for generation, shipping and wildlife. The issue of siltation is very complex and at this stage I am trying to get the project studied in detail because I (like any other designer…if they are honest!) can’t put their hand on their heart ans say there will be no changes. What I can say is that by building into the project considerable flexibility, there is a very good chance that any localised problems of siltation should be soluable by changing the timing and sequencing of gate openings. Unlike the ‘Big Barrages’ (where the options are set in concrete) I am not proposing to hold the water (allowing sedinentation) for more than a couple of hours. If it turns out after a detailed study that there is no way to dovetail a project together to generate much needed clean energy without causing significant environmental, well at least I have tried!