Hypothetical Severn Barrage rail access

[HSTEd]

Well, it appears that new calculations have demonstrated that the optimum point for a Severn barrage is far further down stream than previously projected.
It appears the location would be somewhere in the vicinity of Port Eynon-Ilfracombe.

Assuming that such a barrage is built, many concepts have called for the construction of coupled electrochemical works to absorb the energy generated by the project - as it is too brief to be of much use for grid electricity without an enormously expensive 'buffering' infrastructure.
The logical location for these facilities would be on the barrage itself - which will likely have a broad crest for construction reasons and will have the shortest possible connections between the works and the turbines that generate the electricity. (Such a facility would have power spikes in the range of 36GWe according to primitive projections I made based on its average power of ~9GWe) Putting the equipment out in the middle of the barrage would also reduce the complaints that 'pristine' terrain had been 'spoiled.

Although the material for barrage construction would likely be delivered by sea, the electrochemical facilities constructed on such a hypothetical barrage would almost certainly require rail access for the delivery of raw materials such as limestone and coke or the export of materials such as ammonia, ammonium nitrate, urea and similar.

So, what would be the best-value way to connect a Gower-Ilfracombe barrage to the rail network for industrial traffic?
I assume through rail journeys would be insignificant in a barrage so far west and what traffic there is would likely be better supported by a relatively minor road across the barrage.

So only a single ended connection is required - and to make it more interesting I will allow a credit for the local services a route can support (for instance a services to Ilfracombe on the southern shore).

So have at it.

 

[jopsuk]

I think I'd agree that a barrage that far west would be near useless for strategic infrastructure- the optimum for transport would surely be Portishead-Newport.

Presumably that far west it would need large ship locks?

Regardless, there's a railway at Barnstaple that could be connected to Ilfracombe- on the welsh side a line to Port Eynon would involve far more new build

 

[HSTEd]

Fairly large locks, probably, yes.
Although a barrage across the Severn might provide an opportunity for a deepwater port to rival Felixstowe or even Rotterdam.

Whilst it would be unlikely to be a 'crucial' strategic connection it would probably be a bad idea to not provide a through public road, especially considering even a 60mph road would likely put Ilfracombe closer to Swansea than Exeter in travel time terms.
That might have some interesting secondary effects in the long term.

As I understand it the route through to Ilfracombe from Barnstaple that once existed has been largely obliterated by construction in Braunton et. al, which means you would need extensive new construction along new alignments on both sides.

I assume no railway ever operated on the Gower penisula?

 

[HowardGWR]

I always think that a good idea is that when one gets a good idea, just go and lie down for 5 minutes and it will go away.

 

[starrymarkb]

I can't see it being built. Crossing it during a storm would also be "interesting"

 

[broadgage]

I doubt that this will be built due to the NIMBY factor and the decades long planning inquiries, stakeholders consultations, and impact assessments.

If however it is built, then yes I agree that the bulk of the construction materials should be delivered by rail, with additional or improved rail links being built if needed.

The completed structure should also carry a rail route.

I doubt that any large electricity consuming facilities will be built in or near the proposed barrage.
Bulk transmission of power is a mature technology and it would probably make more sense to transmit the power via new or existing national grid infrastructure to where needed.

The electrical output of a large tidal power scheme though variable, can be calculated years in advance and is fairly easily accomadated by the national grid.
We are gradually moving towards a european grid, and surplus power can be exported, with imports at times of low production.
Norway in particular has very considerable hydroelectric power, they could import tidal power from us at times of surplus thereby keeping more water in stock behind the dams for later use.

 

[Greenback]

I assume no railway ever operated on the Gower penisula?

There was a short branch from Gowerton (South) to Penclawdd and Llanmorlais at one time.

These days, there would be a great deal of opposition to any railway in the AONB, despite the problems with traffic that the peninsula suffers from every Summer.

On topic, the idea of a barrage between Port Eynon and Ilfracombe is a bit pie in the sky really. Assuming it ever did happen, perhaps Swansea docks would be a good place to bring in materials needed for the construction?

Moving to fantasy island territory, assuming the barrage was ever built and with a railway line operating over it, then it would certainly bring north Devon into the Swansea Bay hinterland economically.

None of this should be taken as a belief that this will ever get off the ground!

 

[HSTEd]

If however it is built, then yes I agree that the bulk of the construction materials should be delivered by rail, with additional or improved rail links being built if needed.

The bulk of construction materials would likely be shipped direct from the probably Scottish superquarry to the 'drop site' offshore by coastal freighter in one move. Rail cannot hope to compete.

The completed structure should also carry a rail route.

There is no demand for a severn crossing railway so far West, noone wants to travel Cornwall-West wales.

I doubt that any large electricity consuming facilities will be built in or near the proposed barrage.
Bulk transmission of power is a mature technology and it would probably make more sense to transmit the power via new or existing national grid infrastructure to where needed.

Peak power would be 35GWe or more, attempting to move it anywhere would require ridiculously large New transmission infrastructures of comparable scale to the entire national grid.

The electrical output of a large tidal power scheme though variable, can be calculated years in advance and is fairly easily accomadated by the national grid.

This is not really accurate, all that this does is convert baseload into peaking power because you get enormous spikes appearing at any hour of day or night, whether you want it or not.

We are gradually moving towards a european grid, and surplus power can be exported, with imports at times of low production.
Norway in particular has very considerable hydroelectric power, they could import tidal power from us at times of surplus thereby keeping more water in stock behind the dams for later use.

Norway has enough issues propping up Germany and Denmark without the UK joining in that mess. As to a European grid - it has geopolitical issues with so much European power being derived from gas produced in or transiting over Russian territory or the territory of its satellites.

I can't see it being built. Crossing it during a storm would also be "interesting"

As a road would almost certainly be on the 'inner' side of the barrage you would be 100m or more from the sea with those industrial facilities between you and the facing sea wall.

 

[snowball]

Despite power transmission technology, wasn't the Holyhead smelter deliberately put fairly close to the Wylfa nuclear power station?

And wouldn't the case for doing something similar be stronger in the case of a power source with a high ratio of peak to background power level?

 

[Llanigraham]

Fairly large locks, probably, yes.
Although a barrage across the Severn might provide an opportunity for a deepwater port to rival Felixstowe or even Rotterdam.

Err, no. VERY large locks would be required!! Have you seen the size of the colliers that go into Portishead, or the Ore carriers to South Wales, or the car carriers to Portishead?

 

[IKBrunel]

The point which has been missed in the discussions here about supply and demand, is that by in creasing the barrage height a bit you can allow the water to back up or not. and you can stall or bring forward when you run the turbine by an hour each way.

My impression is that the debate is moving away from barrages and towards tidal lagoons and tidal turbines. To aggregate impact on grid there's an argument for a series of smaller tidal projects around the coast. but bcr for individual projects will be lower& cost /kWh higher.

I also think the intermittency of renewables can be overstated. varying supply has the same impact as varying demand. The national grid has always been designed to cope with variations in demand.

There is also a lot more that could be done with dynamic demand management. You can lead/lag switch on/switch off commercial/industrial heating/cooling plant to balance varying power availability with negligible impact on actual temperatures.

The grid will have to cope with greater intermittency of supply in the future. Germany has way more renewable than we do & don't have power cuts as a result, they've learned to predict and prepare. Energy storage is very expensive and will be the last resort after regional interconnects, etc, etc options have been exhausted. To say that we can't achieve what Germany has already, underestimates British electrical engineering.

 

[Holly]

I think I'd agree that a barrage that far west would be near useless for strategic infrastructure- the optimum for transport would surely be Portishead-Newport.

Yes, a Severn Barrage is not going to happen. And even if it did the only possible rail demand would be for a fair weather touristy light rail (which might then find use by maintenance engineers). Putting all-weather heavy rail in place would be hugely expensive, especially the crossing of the locks. And there is next to no demand.

As contrasted with barrages, multiple tidal lagoons make sense for their diversity and scalability. Perhaps one day in the far future we might see tidal lagoons in Wales linked to tidal lagoons in Ireland by a chain of bridges and then a railway would definitely be worthwhile.

 

[HSTEd]

Err, no. VERY large locks would be required!! Have you seen the size of the colliers that go into Portishead, or the Ore carriers to South Wales, or the car carriers to Portishead?

The entrance to the Royal Portishead Dock might be large by British standards but it is not very large by global standards.
And I am not sure the Colliers to Portishead are likely to be around in a scenario where the barrage is built, as this will likely be fairly late into the Coal Phase out process.

Ore Carriers are more problematic but they should be able to fit through a similar lock to the one provided for Portishead.
New Panamax demonstrates just how large locks can be made this day.

The point which has been missed in the discussions here about supply and demand, is that by in creasing the barrage height a bit you can allow the water to back up or not. and you can stall or bring forward when you run the turbine by an hour each way.

Which then raises the high tide mark a metre all around the estuary, which causes all sorts of problems for flood defences all over the place, all of which will have to be reinforced.
Can you imagine what would happen if one failed while the barrage was artificially increasing the water level? the Political fallout would be... extreme.

My impression is that the debate is moving away from barrages and towards tidal lagoons and tidal turbines. To aggregate impact on grid there's an argument for a series of smaller tidal projects around the coast. but bcr for individual projects will be lower& cost /kWh higher.

Indeed, the debate is moving because the subsidies provided for such technologies is enormous.
There is little evidence they will ever be able to deliver competitive amounts of electricity at reasonable cost.

I also think the intermittency of renewables can be overstated. varying supply has the same impact as varying demand. The national grid has always been designed to cope with variations in demand.

Yes, and by increasing those variations you increase grid costs, pushing the cost of electricity still higher. It is technically feasible to do a 100% grid if you are willing to pay for it.

There is also a lot more that could be done with dynamic demand management.

Dynamic Demand management on a greater scale than now raises the spectre of compulsory smart metering of domestic supplies, which then leads to poor people being forced to time their days around when electricity happens to be cheap since they can't afford to boil the kettle in the 'rush hour'.

The grid will have to cope with greater intermittency of supply in the future. Germany has way more renewable than we do & don't have power cuts as a result, they've learned to predict and prepare. Energy storage is very expensive and will be the last resort after regional interconnects, etc, etc options have been exhausted. To say that we can't achieve what Germany has already, underestimates British electrical engineering.

We can do it, the question is should we.
There is a reason that German electricity prices are the highest in europe and are still climbing.
German industry has only survived due to cross subsidisation from residential and light commercial supplies which will likely be ruled to be illegal by the EU in the near future.


A barrage with coupled low-capital cost energy intensive industries can extract the energy at reasonable cost and increase the energy independance of the United Kingdom.

However this is rather off-topic - the question was primarily which access point would be preferable.

 

[ChiefPlanner]

There was a short branch from Gowerton (South) to Penclawdd and Llanmorlais at one time.

These days, there would be a great deal of opposition to any railway in the AONB, despite the problems with traffic that the peninsula suffers from every Summer.

On topic, the idea of a barrage between Port Eynon and Ilfracombe is a bit pie in the sky really. Assuming it ever did happen, perhaps Swansea docks would be a good place to bring in materials needed for the construction?

Moving to fantasy island territory, assuming the barrage was ever built and with a railway line operating over it, then it would certainly bring north Devon into the Swansea Bay hinterland economically.

None of this should be taken as a belief that this will ever get off the ground!

I believe there were plans for light railways in the Gower (Colonel Stephens no less !) in the post WW1 era - which came to nothing. I cannot see much urban or economic connectivity between say Port Eynon and Minehead. (on the basis of a Summer only steamer was unable to make money !)

 

[Greenback]

I believe there were plans for light railways in the Gower (Colonel Stephens no less !) in the post WW1 era - which came to nothing. I cannot see much urban or economic connectivity between say Port Eynon and Minehead. (on the basis of a Summer only steamer was unable to make money !)

Quite! I didn't know about the light railways, but I would imagine that any plans would have been linked more to freight than passengers, since the population was pretty low and it was, in those days, quite a poor area. Not the case now, of course!

I agree with Holly, a barrage isn't going to happen, and even if it did, there would not be a railway across it!

 

[johnnychips]

http://www.offshorewind.biz/2013/02/04/uk-severn-barrage-could-be-cheaper-than-offshore-wind/

Here's a link to a more modest Severn Barrage project from Weston to Lavernock Point. This is similar to proposals from about twenty-five years ago. This doesn't seem a rail link on top of it would be a great deal of use either, although possibly with more potential than the one being discussed already.

 

[jopsuk]

Norway has enough issues propping up Germany and Denmark without the UK joining in that mess. As to a European grid - it has geopolitical issues with so much European power being derived from gas produced in or transiting over Russian territory or the territory of its satellites.

We're certainly already connected- a 2GW reversible connection to France (we appear right now to be drawing 1.99GW across this) and 1GW one to the Netherlands (currently drawing 1GW)- see the status at any time here

 

[HSTEd]

We're certainly already connected- a 2GW reversible connection to France (we appear right now to be drawing 1.99GW across this) and 1GW one to the Netherlands (currently drawing 1GW)- see the status at any time here

Yes.
We always draw essentially the entire capacity of those links from Europe. (As I understand it the flows are in the direction of France to England 99% of the time).

But at the moment cutting off those links would not collapse the entire grid in an emergency.
This would not be the case if we were transferring ten times as much power to France and back.

 

[Xenophon PCDGS]

I can't see it being built. Crossing it during a storm would also be "interesting"

One must consider the wind speeds that were prevailing in this sea area on a very recent day, which were the same as when the Tay Bridge disaster occurred.

 

[snowball]

Well, it appears that new calculations have demonstrated that the optimum point for a Severn barrage is far further down stream than previously projected.
It appears the location would be somewhere in the vicinity of Port Eynon-Ilfracombe.

And now Nature has made a timely comment:

http://www.bbc.co.uk/news/uk-england-26277432

An earthquake has been recorded under the Bristol Channel, the British Geological Survey (BGS) has confirmed.

The 4.1 magnitude quake happened at about 13:21 GMT and was felt in Devon, south Wales and Somerset.

The focus was north of Ilfracombe, Devon, and south of the Gower, in Wales, and was at a depth of 3.1 miles (5km).

 

[Xenophon PCDGS]

http://www.offshorewind.biz/2013/02/04/uk-severn-barrage-could-be-cheaper-than-offshore-wind/

Here's a link to a more modest Severn Barrage project from Weston to Lavernock Point. This is similar to proposals from about twenty-five years ago. This doesn't seem a rail link on top of it would be a great deal of use either, although possibly with more potential than the one being discussed already.

Does anyone know what is the maximum sea depth in the area of this and other proposed barrages ?

 

[HSTEd]

And now Nature has made a timely comment:

http://www.bbc.co.uk/news/uk-england-26277432

How is this relevant?

4.1 Magnitude is nothing.

From Wikipedia for a Magnitude 4.0-4.9 earthquake:

Noticeable shaking of indoor objects and rattling noises. Felt by most people in the affected area. Slightly felt outside. Generally causes none to minimal damage. Moderate to significant damage very unlikely. Some objects may fall off shelves or be knocked over.

Forgive me if I believe we can engineer a barrage to laugh at such tremors.
Something falling off a shelf is unlikely to obliterate several tens of millions of tonnes of reinforced concrete and stone

 

[snowball]

How is this relevant?

I wasn't trying to suggest it was a serious problem for the project. I just thought it a spectacular and amusing coincidence and assumed others would find it so too. UK earthquakes only make the national media about once every couple of years, and now within two days of a barrage on this route being mentioned, an earthquake happens on its route!

 

[HSTEd]

I wasn't trying to suggest it was a serious problem for the project. I just thought it a spectacular and amusing coincidence and assumed others would find it so too. UK earthquakes only make the national media about once every couple of years, and now within two days of a barrage on this route being mentioned, an earthquake happens on its route!

A good point.
Sorry

 

[Xenophon PCDGS]

I wasn't trying to suggest it was a serious problem for the project. I just thought it a spectacular and amusing coincidence and assumed others would find it so too.

You can add me to the "others" to whom your posting makes reference to.

 

[lord rathmore]

I doubt that this will be built due to the NIMBY factor and the decades long planning inquiries, stakeholders consultations, and impact assessments.

If however it is built, then yes I agree that the bulk of the construction materials should be delivered by rail, with additional or improved rail links being built if needed.

The completed structure should also carry a rail route.

I doubt that any large electricity consuming facilities will be built in or near the proposed barrage.
Bulk transmission of power is a mature technology and it would probably make more sense to transmit the power via new or existing national grid infrastructure to where needed.

The electrical output of a large tidal power scheme though variable, can be calculated years in advance and is fairly easily accomadated by the national grid.
We are gradually moving towards a european grid, and surplus power can be exported, with imports at times of low production.
Norway in particular has very considerable hydroelectric power, they could import tidal power from us at times of surplus thereby keeping more water in stock behind the dams for later use.

Sorry mate but this is wishful thinking. Transmission over any distance involves losses of power. The longer the distance the greater the losses. You can reduce %age losses by increasing the transmission voltage but there is a limit to the voltage an undersea cable can safely carry. Also, is it such a great idea to rely for your essential power supply on the whim of a foreign country? Tidal barrages sound great in theory like a lot of renewables, but the intermittency is a serious drawback. Sorry passengers this service terminates here now because it's low tide.

 

[HSTEd]

Technically since the barrage would generate on the ebb, it would be "Sorry this service terminates here because it is high tide". :P

But this is a drawback, hence my proposal that it would normally be coupled directly to relatively low capital cost load sinks, so the energy can be captured in the form of ammonia or hydrogen.

 

[JGR]

Transmission losses are not insignificant, but they're not a deal-breaker either.
Any loads such as plants would need to be connected to the main grid for reliability purposes anyway. Trying to match a source with huge daily variations, ie. a tidal barrage, with a set of plants, is unlikely to end well. Varying industrial power consumption to smooth the out peaks only gets you so far, you can't go overboard.

 

[HSTEd]

Any loads such as plants would need to be connected to the main grid for reliability purposes anyway. Trying to match a source with huge daily variations, ie. a tidal barrage, with a set of plants, is unlikely to end well. Varying industrial power consumption to smooth the out peaks only gets you so far, you can't go overboard.

The processes I have in mind, such as relatively low cost PEM electrolysers and SSAS [Solid State Ammonia Synthesis] are known to be stable against rapid and repeated load variations.
They should not suffer major reliability issues from being cycled.
Indeed this is what they are primarily being developed for.

The plants would undoubtedly be connected to teh grid, but only to make use of low cost electricity generated during summer nights, allowing the plants to operate flat out during the 'low season' even when the barrage is not generating.