/ Severn Barrage
It's not 5% of the UK's energy - it's 5% of the UK's electricity. There's a big difference.
And is it the best way to spend £25bn on electricity? What could be done by spending that much money on more efficient use of the generation we have. Might we be better off with £25bn spend on CHP, or micro-generation, or lots of alternatives?
I don't know the answers, but the bald statement that the barrage could produce 5% for £25bn doesn't really cover a very wide range of complex issues.
Only produces it at certain times of the day too (outgoing tide). Without other barrages which can provide supply at different tide phases, Solway Firth or the Mersey for instance, the Severn Barrage would still need to be backed up by conventional supply during the incoming tide. That said, the advantage for tidal power over wind or wave generated electricity is that it is predictable.
Agree with you re efficiency measures and reducing consumption, although that would have to be done in such a way as to prevent a possible rebound effect.
> Only produces it at certain times of the day too (outgoing tide).
Are you sure about that? Why wouldn't it work on the incoming tide as well? According to the company website, it can deliver a bit over 15 hours per day although that 15 hours does vary with the tides, so there would be times when it's generating when demand is low.
Even then, there would be 4 peaks per day, with very little power generation in the hours around high and low water. There would also be variation due to the spring/neap cycle. Perhaps this variation is not important if there is suitable long distance distribution?
Not many Tory votes in S Wales though, are there? And it's a bit out in the sticks.
You're right, many of these renewables work best in combination with other technologies, it's one of the things that makes them an easy target for critics. Conveniently the uk has a coastline that could be used to provide '3 phase' tidal power smoothing out the tidal supply ripple almost completely but it's obviously a *much* bigger project.
The variation's not important from a technical perspective if it's predictable and a relatively small fraction of the total supply which it is and it is. Dealing with the economics of it all looks a bit more challenging.
You don't get as much generation overall with a 2 way system as the barrage limits the water inflow to the estuary so high tide doesn't get as high as it would without the barrage.
It's not a new idea, tidal generation using a Severn Barrage was studied in quite some depth in the '80s and it isn't without considerable environmental penalties.
Would it not be (proportionally) far more expensive to build similar generating capacity at other points around the UK? As I understood it, the tidal range and area of the Severn estuary makes it something of a special case (in the UK at least).
> Would it not be (proportionally) far more expensive to build similar generating capacity at other points around the UK? As I understood it, the tidal range and area of the Severn estuary makes it something of a special case (in the UK at least).
The Severn estuary is the main one as it gets the full tidal surge off the Atlantic and the biggest height differences between high and low tides. As I said above, Solway Firth in Scotland and the Mersey estuary on the west coast are also viable sites, as is The Wash on the East coast. Those other sites have less technical potential and far less economic potential than the Severn though.
In a word, yes.
The Severn estuary is well suited to a barrage as are a few smaller locations around the coast but it may be better to look at tidal flow devices in pinch-points elsewhere. I suspect in the medium term they (and the barrage) will meet with insurmountable opposition from a broad range of pressure groups.
It's the environmental impact that worries me, that is to say that I don't really know what impact it will have as nobody entirely impartial has put anything into wide circulation.
Anyone on here able to shed some light on this?
The opponents of the previous Severn Barrage proposal brought two hydro-engineers over from the Dutch State Hydro Board to categorically state that barrages are a bad thing. The construction of the Markerwaarddijk in 1975 across the IJsselmeer has led to the accumulation of massive amounts of pollutants in the sediments of the Markermeer and it is costing the Dutch Govt billions to clear the mess up.
The Severn may be a very dynamic river and estuary but its hydrography and current patterns are poorly understood. It is also fringed by massive industrial developments such as Avonmouth cheek-by-jowl with wetlands of world importance such as Slimbridge and Goldcliffe.
Instead to consuming more energy and emitting more carbon in pursuit of more "green" power, why don't we just save energy or is that too obvious?
In practice we are doing, e.g. by using energy saving light bulbs rather than tungsten etc, and by modern devices being more energy efficient.
But some nuclear power stations are being decommissioned, and something has to replace them. Personally I think that should be more nuclear power stations, but I suspect I'm in the minority.
I agree with your sentiment but this is hardly a new idea and I would imagine that its dismissal is more political than practical. The coalition is currently pretty weak, especially with the current lobbyist scandal starting to build momentum. The Severn Barrage project has the potential to stir deep seated emotions on both sides of the debate and would certainly bog down any government that proposed the idea as viable.
The tidal flow systems that JK mentioned above seem to be a far better option for the Severn Estuary environmentally.
There will always be a substantial political component to such a decision, but as outlined above in the wikipedia description of previous studies, apart from informed comments by people like Ring-Ouzel, there are very substantial practical problems. It may just not be as good a scheme as it first sounds like.
There opponents are even weaker however, while lobbying seems like standard Westminster village froth.
Similar to HS2, most people are in favour and it sounds like a magic bullet, until the costs and details become more apparent. But any major infrastructure project in a country as crowded as the UK is going to arouse masses of passionate objection, that does not mean we can forever put them off.
> There opponents are even weaker however, while lobbying seems like standard Westminster village froth.
True, but they are very vocal and more than likely to use unorthodox methods to get their point across. I guarantee that this debate will rumble on forever whilst never being built.
I am firmly behind thorium nuclear as the best of a bad bunch.
Some interesting reading here -- http://www.foe.co.uk/resource/briefings/severn_barrage_lagoons.pdf
As an engineer I find it an interesting concept, that seems to address a lot of the environmental concerns over silting caused by a tidal barrage on a river estuary or the likes of Morecambe Bay or the Solway.
> The Severn estuary is the main one as it gets the full tidal surge off the Atlantic and the biggest height differences between high and low tides. As I said above, Solway Firth in Scotland and the Mersey estuary on the west coast are also viable sites, as is The Wash on the East coast. Those other sites have less technical potential and far less economic potential than the Severn though.
What about the Thames? And IIRC the Solent which has 4 tides a day?
The Solent doesn't have 4 tides a day, it has a double high tide (which is slightly different).
One of the reasons that the Severn has such a large tidal range is that it is a long way from the north Atlantic amphidrome. The same is not true in on the east coast, as there are a number of amphidromic systems in the north sea.
Indeed - but that would mess with Cowes week so that is dead in the water before it even starts! :-)
Wrong answer. Dinrowic can buffer something like 30sec of power.
There aren't enough sites in the UK to make it workable, and if there were, converting them to pumped storage would be an environmental disaster eclipsed only by the Severn Barrage.
Draining Dinorwic in 30 seconds would be pretty exciting*. From full, running at peak output of 1.8GW it has around 5hrs of energy stored. Whether they can keep it cool for 5hrs flat out...
*read utterly devastating and thankfully impossible
There are 100s of sites in the uk that are physically suitable for pumped storage. You're right, there's an environmental cost associated with their development but then that's true of doing nothing as well.
> Wrong answer. Dinrowic can buffer something like 30sec of power.
Are you sure about that?
Curious about this. Don't you end up with Radon as a by-product? Although non-fertile is better, a gas is inconvenient...
Agree about the requirement for nuclear though.
> Are you sure about that?
Apparently not. It was the figure I had in my head, it seems 30sec is more like the startup time from cold. Perhaps also it's the duration of the kettle induced spikes it often smoothed out and the end of corrie/Eastenders.
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