Germany facing blackouts...

[UndercoverElephant]

It would be an understatement to say that is an understatement. A barrage like that would be an marine ecological catastrophe of indescribable propotions, for numerous reasons. Absolute non-starter.

UE would you care to give some examples of the "numerous reasons" referred to making this an absolute non starter?

(1) It would change the patterns of the tidal inflows and outflows around the entire coastline and up every river estuary in the UK. This would be disastrous both for the flora and fauna of the inter-tidal zones and coastal wetlands as well as any species which times its feeding or reproduction according to tidal cycles.

The area inside the barrage on that map contains over 50% of the shingle beaches left in the world and one if the highest concentrations of river estuaries and tidal wetlands anywhere in the world. We are located where warm and cold water meet and where three different climate/weather systems interact. Given that there is also so much of it, the coasts of the British Isles end up being of global significance for biodiversity, especially wrt marine and wetland birds. The barrage would compromise all of this.

(2) It would pose an enormous barrier to the free movement of species between inside the barrage and outside, hindering seasonal migrations and species which follow their food sources. Take just one example - the leatherback turtle. This is the largest and rarest turtle on the planet, and for me it is the absolute number one MUST NOT LOSE marine species. They regularly turn up along the west coast of Ireland and in the Irish sea, where they come following the latest bloom of their favourite food - jellyfish. What happens when we build what is effectively an enormous dam around the UK? How do the jellyfish get in? And if they do manage to get in (as youngsters, or because they have been breeding around our coasts), how do the turtles get in? And how do they get out again when the jellyfish have gone elsewhere?

We can't just put up an enormous barrier in the middle of the ocean and expect it not to F--k everything up. Not unless we have learned NOTHING from all of the meddling with nature the human race has previously engaged in - meddling which nearly always has consequence, foreseen and unforeseen, which are proportionate to the size of the meddling.



Adult leatherbacks have no natural predators. They are heading towards extinction entirely because of the activities of the human beings who hunt them as trophies, trample on their breeding beaches and discard plastic bags into the sea which the turtles eat by mistake because they look like jellyfish. Are we now going to build a massive wall under the sea to stop their wandering of the oceans?

[adam2]

The London Hydraulic Power company supplied water at high pressure as a means of transmitting energy to customers who used it to operate machinery.
Prior to the electric age, power if beyond human or animal power, normally meant a steam engine with all the attendant costs.
The LHP mains provided a very useful source of power for intermitant demands, lifts being especialy popular.
The ultimate source of the energy was large steam engines operating high pressure water pumps.
The system was largely superceded by electric power, though parts of the LHP system were used until fairly recently.

Hydraulic accumalators stored power for peak demands, but it must be remembered that these were MOMENTARY or very short term peaks in the operation of machines such presses or heavy lifting equipment. NOT peaks of hours for supplying a housing estate or factory.

Batteries are fine for up to a few KWH and are worth considering up to several hundred KWH.
Traditional lead acid batteries last 25 years or more, and the materials are easily recycled.
Manufacture of such bateries was routine long before the oil age.

A hydraulic store might hold less than one KWH, but can release this very quickly indeed, unlike a battery.

[JavaScriptDonkey]

[SNIP]

The area inside the barrage

[SNIP]

I agree about the marine environment but there is NO BARRAGE. It's all bolted to the sea bed.

[UndercoverElephant]

[SNIP]

The area inside the barrage

[SNIP]

I agree about the marine environment but there is NO BARRAGE. It's all bolted to the sea bed.

OK. So rather than being a tidal barrage (which screws up all of the tides) it is just going to be a wall with a load of water turbines. The water will presumably be forced through the turbines. How does the leatherback turtle get in and out of British waters? Does it swim through the turbine?

[JavaScriptDonkey]

Hydraulic accumulators stored power for peak demands, but it must be remembered that these were MOMENTARY or very short term peaks in the operation of machines such presses or heavy lifting equipment. NOT peaks of hours for supplying a housing estate or factory.

Momentary like Dinorwirg?

Whether the machine is a lift or press or generating turbine is immaterial. It's all a question of scale.

[JavaScriptDonkey]

OK. So rather than being a tidal barrage (which screws up all of the tides) it is just going to be a wall with a load of water turbines. The water will presumably be forced through the turbines. How does the leatherback turtle get in and out of British waters? Does it swim through the turbine?

When the tide runs it isn't just the surface water that moves, the whole sea moves. There is no need for a wall as the tidal stream will flow through the turbine anyway.

The turtles can simply do what they do with everything else that litters the sea floor - swim over it.

[adam2]

Hydraulic accumulators stored power for peak demands, but it must be remembered that these were MOMENTARY or very short term peaks in the operation of machines such presses or heavy lifting equipment. NOT peaks of hours for supplying a housing estate or factory.

Momentary like Dinorwirg?

Whether the machine is a lift or press or generating turbine is immaterial. It's all a question of scale.

The two technologies are not comparable.
The pumped storage system in Wales stores many hundreds of MWH, and is very usefull for meeting unexpected peaks in demand or shortfalls in generation.
A vast amount of water is needed, with a large head, in order to store so much water.
A man-made dam to confine the water at a height is needed, but an entirely man made structure such as a water tower or pressure vessel would be utterly impracticable.
How much does the water at Dinorwic weigh? and at what height is it stored ? Consider what it would cost to build an artificial structure to do that.
Pumped storage is therefore limited to places with a large natural or man made lake at a significant height.

An hydraulic accumalator by contrast is a man made pressure vessel in which water or oil is stored under great pressure, against the force of a spring or weight.
The amount of energy is fairly small, normally less than one KWH, but usefull for large and very brief energy demands in some types of machine.
Not much used these days on account of the risks of pressure vessels failing.

[JavaScriptDonkey]

The two technologies are not comparable.

I don't understand your need for differentiating between storing low density electricity from renewable sources as PE in large or small structures.
Obviously no one is going to build a tower as big as a Dinorwig which is why Dinorwig is built into a mountain.

If you need a local supply of PE for whatever purpose then build a hydraulic store. If you need a larger supply then build another Dinorwig. The point is just that the energy is stored and we can avoid tripping over vast arrays of gassing lead acid batteries.

Also, we can completely discharge a PE store whereas completely discharging a lead acid battery is the quick route to sulphation.

Also, also we can quickly discharge a PE store if we need to whereas quickly discharging a lead acid is a quick route to plate warp.

Also, also, also PE stores, once 'charged' can be left alone, completely diverting the renewable to something else. Lead acid batteries need to be under nearly constant charge.

Also, also, also, also a PE store, once built should last for decades. Lead acid batteries will give about 300 cycles before they are junk.

Also, also, also, also, also a PE store pressure vessel is relatively easy to make safe as is done with countless industrial boilers/heating systems throughout our major cities. Banks and banks of lead acid batteries is an explosive disaster waiting to happen.

I can't see us as a nation ever going down the battery storage route.

[ujoni08]

RalphW, spot on. Ignorance and selfishness are indeed the two big barriers, plus a half-hearted government programme.

[An Inspector Calls]

(1) It would change the patterns of the tidal inflows and outflows around the entire coastline and up every river estuary in the UK.

If you're answering the question of the effect of a barrage then I would think the effects of one tidal barrage on the remainder of the UK's tidal flows would be miniscule. And you're forgetting that the barrge, if it's to work at all, has to have minimal effect on tidal flow.

The area inside the barrage on that map contains over 50% of the shingle beaches left in the world and one if the highest concentrations of river estuaries and tidal wetlands anywhere in the world. We are located where warm and cold water meet and where three different climate/weather systems interact. Given that there is also so much of it, the coasts of the British Isles end up being of global significance for biodiversity, especially wrt marine and wetland birds. The barrage would compromise all of this.

Why should it? The shingle beaches will still be there, they'll still be covered/uncovered with each tide. The rivers will still flow. The wetlands will still be there.

(2) It would pose an enormous barrier to the free movement of species between inside the barrage and outside, hindering seasonal migrations and species which follow their food sources. Take just one example - the leatherback turtle.

Well, given that a man can pass through a turbine of the type that will be used on the Severn barrage (a man has swum through the turbines at La Rance) I would think the leatherbacks would be hardly affected.

[UndercoverElephant]

OK, this discussion appears to be based on nobody understanding the details. When I see a detailed technical explanation of how this is actually supposed to work, then I will continue the discussion.

If it is just things sticking out of the seabed, why was I responding to a diagram of a great barrage? You could stick things out of the seabed all over the place. No lines of them would be required.

[An Inspector Calls]

Since your reply (the one I quoted) includes the word barrage four times, three of which your own use, I assume you know perfectly well what's involved. You also seem to have grasped the fact that a barrage would be close to the shore, close enough for you to claim, erroneously, that it would seriously modify shingle beaches and river flows.

[JavaScriptDonkey]

May I suggest a Google moment?

Pay particular attention to DeltaStream from Tidal Energy Limited who are contracted to make this,



The Dummy's Guide version of Tidal Stream Capture for the North Sea.

The North Sea is shallower than the Atlantic.

The tidal flow, pulled by the moon, goes from West to East.

The Eastern edge of the North Sea is a land mass called Europe.

When the tide flows it flows from the Atlantic into the North Sea where it it can't go any further because of Europe.

When the moon lets go this water sloshes back into the Atlantic.

Seabed turbines are turned by the water as it's pulled into the North Sea by the moon and as it sloshes back into the Atlantic by Earth's own gravity.

This leads to 4 tides a day (2 high and 2 low) which gives an almost constant flow of water.

I'm frankly shocked that anyone could have contemplated being so anti a technology without actually finding out how it worked.

[JavaScriptDonkey]

OK, this discussion appears to be based on nobody understanding the details. When I see a detailed technical explanation of how this is actually supposed to work, then I will continue the discussion.

If it is just things sticking out of the seabed, why was I responding to a diagram of a great barrage? You could stick things out of the seabed all over the place. No lines of them would be required.

There is a question of whether an upstream turbine will reduce the efficiency of downstream devices in the same manner as one sail boat can steal another's wind. That is a function of complex fluid dynamics best left to specialists.

It is assumed that there will be a ideal density of turbines for a given flow and that the deployment would be mostly linear.

That small map with a big red line was just indicating where that linear deployment would have to be to get enough tidal flow to generate the required amount of electricity.

[UndercoverElephant]

May I suggest a Google moment?

Pay particular attention to DeltaStream from Tidal Energy Limited who are contracted to make this,



The Dummy's Guide version of Tidal Stream Capture for the North Sea.

The North Sea is shallower than the Atlantic.

The tidal flow, pulled by the moon, goes from West to East.

The Eastern edge of the North Sea is a land mass called Europe.

When the tide flows it flows from the Atlantic into the North Sea where it it can't go any further because of Europe.

When the moon lets go this water sloshes back into the Atlantic.

Seabed turbines are turned by the water as it's pulled into the North Sea by the moon and as it sloshes back into the Atlantic by Earth's own gravity.

This leads to 4 tides a day (2 high and 2 low) which gives an almost constant flow of water.

I'm frankly shocked that anyone could have contemplated being so anti a technology without actually finding out how it worked.

It was an understandable misunderstanding given the nature of the map I was responding to and the fact that a tidal barrage has already been considered for the Severn estuary. I assumed what was being proposed was a much larger version of the same thing.