Bristol Channel Tidal Barrage

Although it will add a little aggravation to me, I am in favour of the barrage and pretty much always have done. I can't fully understand the argument about changes to habitats. Delaying the outgoing tide may allow a little more settlement of the silt.
When this came up in the 80s, one quite good argument against it was that they would have to move the Mendip hills into the channel to build it.
Allan
 
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This is a likely site for such a barrage.

From Brean Down in the SE, to Steep Holm, then across the deep water channel to Flat Holm, then landfall at Lavernock Point to the south of Penarth.

Motorway links to the M5 in Somerset, and to the M4 west of Cardiff, would bring even more employment to each needy area.
 
oldbilbo said:
It would appear this revamped scheme is being 'dusted down' again.

As we've seen many times in the past, any displaced birdlife will simply find other feeding/roosting space - especially if the plan creates some protected reserves.

I'm in favour. :)
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I really, really hope this comes off, I am not sure though if it's as well as the wind turbine plan or instead of? I very much hope it's the latter. I don't mind wind turbines, but that site off Lundy is an appalling idea (imho).
 
Allan said:
When this came up in the 80s, one quite good argument against it was that they would have to move the Mendip hills into the channel to build it.
Allan
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I doubt that much land-won material will be used. Much cheaper to bring large quantities in by sea. I expect the bulk would be sand and gravel dredged offshore with rock armour delivered direct from Norwegian quarries.
 
Hmmm.

It'll put an end to the Severn bore and how long before the mud normally carried away into the Bristol Channel clogs the whole thing up?

Similar schemes in the Netherlands have had a dramatic impact on the environment, reducing salinity, and causing changes to the ecology of the region.

I am convinced that it is a better way of generating power than wind generation, but I'm not sure of the impact.
 
I don't sail in the Bristol Channel so I'm a NIMBY, but I am a firm believer the predictable power and torque of water power makes tidal systems ( 'barrage' sounds rather negative ! ) a far better bet than idiotic windmills, also it's not an eyesore or hazardous to navigation; so how about diverting some of the huge subsidies wind farms enjoy to something that actually works ?! :rolleyes:
 
I may be entirely wrong, but my understanding was that it wouldn't be a dam entirely blocking the Severn Estuary, but rather a series of works to channel flow into turbines, rather like the turbines being installed in the Sound of Islay. This is a tidal project, so net flow across the engineering has to remain much the same as it is now; it won't work otherwise.
 
Barrage - but where ?

There is a lot of support for tidal energy in this area - but I just wish there were a bit more "joined-up" thinking about it. The most likely site is North of the "Somerset levels" ( see chart above ) although this is the area of UK designated as the second most likely for serious flooding in the near future.
This could be protected if the barrier were to be moved West, downstream and it would be running from cliff edge to cliff edge across the channel.
Unfortunately it seems that these are two conflicting interests and are not addressed together. Sadly.
Ken
 
AntarcticPilot said:
I may be entirely wrong, but my understanding was that it wouldn't be a dam entirely blocking the Severn Estuary, but rather a series of works to channel flow into turbines, rather like the turbines being installed in the Sound of Islay. This is a tidal project, so net flow across the engineering has to remain much the same as it is now; it won't work otherwise.
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If the scheme is like that, I'm more open to it. However, these things have a habit of growing, and other variants - such as in effect a "dam", with a new toll road across it, and then the inevitable "new towns" at either end, etc etc would rear their ugly heads again.

It may be more efficient that wind turbine farms, but a full barrage would have such vast environmental disbenefit, when you added in every single cost of consutruction (including fuel to transport materials, damage to sites providing the materials, etc) that it becomes totally unacceptable.

I'm also very interested to see exactly the effect on drainage from the Severn flood plains.

If you look at the amount of electricity such a scheme might generate, it's tempting. But not as tempting as investing the same money in energy conservation.

I suppose at least it might be a good thing to use the cash earmarked for the ridiculous HS2 for to slightly more public good.
 
AntarcticPilot said:
I may be entirely wrong, but my understanding was that it wouldn't be a dam entirely blocking the Severn Estuary, but rather a series of works to channel flow into turbines, rather like the turbines being installed in the Sound of Islay. This is a tidal project, so net flow across the engineering has to remain much the same as it is now; it won't work otherwise.
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There will be a reduced tidal range inside the barrage due to the restrictions on flow caused by the turbines. But in the French scheme on the Rance in North Brittany they open sluice gates close to high and low water when there isn't enough difference in level to work the turbines. This fills or empties the lagoon to increase the difference in level after the tide turns. The use of sluices results in a tidal range in the lagoon closer to that which existed before the barrage was built. It also keeps the flows high to help reduce siltation.
 
kds said:
There is a lot of support for tidal energy in this area - but I just wish there were a bit more "joined-up" thinking about it. The most likely site is North of the "Somerset levels" ( see chart above ) although this is the area of UK designated as the second most likely for serious flooding in the near future.
This could be protected if the barrier were to be moved West, downstream and it would be running from cliff edge to cliff edge across the channel.
Unfortunately it seems that these are two conflicting interests and are not addressed together. Sadly.
Ken
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I agree. If the barrage is to be built then it should be much further west. In addition, I remember a scheme that was doing the rounds in the 60s. This called for 2 basins to be built which, due to difference in levels between basins and sea level, would allow turbines to operate 24/7.

Having been raised in Watchet, I'm very familiar with the problems of silt :(. There must be millions of tons of silt held in suspension in the Channel - I would like to see a lot of research on what would happen when this silt falls out of suspension.
 
paul.norton said:
I agree. If the barrage is to be built then it should be much further west. In addition, I remember a scheme that was doing the rounds in the 60s. This called for 2 basins to be built which, due to difference in levels between basins and sea level, would allow turbines to operate 24/7.

Having been raised in Watchet, I'm very familiar with the problems of silt :(. There must be millions of tons of silt held in suspension in the Channel - I would like to see a lot of research on what would happen when this silt falls out of suspension.
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I suppose someone much cleverer than me could find a way of harnessing the power of so much silt / mass, rather than simply trying to filter it out...

A chum's father ran a power station in Wales where water was pumped up to the top at low peak times, then let loose to drive turbines at peak; I'd love to know how that's really efficient mechanically, seems rather like a 'perputual drive 100% job' ?!
 
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Seajet said:
A chum's father ran a power station in Wales where water was pumped up to the top at low peak times, then let loose to drive turbines at peak; I'd love to know how that's really efficient mechanically, seems rather like a 'perputual drive 100% job' ?!
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I take it that is the Dinorwig Power Station. Perhaps efficiency in its normal sense is not so important, however, the ability to produce its fully output in just 16 second is said to save the national grid having at least one hot-spinning power station on standby.
 
Seajet said:
A chum's father ran a power station in Wales where water was pumped up to the top at low peak times, then let loose to drive turbines at peak; I'd love to know how that's really efficient mechanically, seems rather like a 'perputual drive 100% job' ?!
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It's not meant to be particularly efficient, its main purpose is to satisfy the huge upsurge in demand when ten million 2kW kettles get turned on during the adverts in Coronation Street!

http://en.wikipedia.org/wiki/Dinorwig_Power_Station
 
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