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Author Topic: Aberthaw Power Station and Decarbonisation  (Read 39305 times)
Bmblbzzz
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« Reply #300 on: August 08, 2022, 11:01:05 am »

Wasn't the Chinese component of Hinkley Point cancelled and the contract given elsewhere? Or am I imagining that (and if so, why?)
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stuving
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« Reply #301 on: August 08, 2022, 12:21:17 pm »

Wasn't the Chinese component of Hinkley Point cancelled and the contract given elsewhere? Or am I imagining that (and if so, why?)

Because that was Sizewell, and news items about it always bung in a mention of Hinkley? CGN are still 1/3 partners in Hinkley, with EDF (prop E Macron), and I don't think there's a serious plan to buy them out.
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Red Squirrel
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« Reply #302 on: August 08, 2022, 02:45:19 pm »

As an aside, members will have noted that France has had to turn down the wick on its nuclear power stations recently. Specifically, those which use river water for cooling: it seems the temperatures are currently high enough to risk damage to river life:

https://www.theguardian.com/business/2022/aug/03/edf-to-reduce-nuclear-power-output-as-french-river-temperatures-rise

I read somewhere that one of the objections to Sizewell C is that it will raise the temperature of the sea locally, though in this case the problem relates to the growth of phytoplankton in the balmy discharge.

https://tasizewellc.org.uk/wp-content/uploads/2021/06/g-Ecological-Impacts140679253.pdf

Shame they can't build power stations where people live; we could add the waste heat to local heat networks:

https://www.energyservicebristol.co.uk/business/heat-networks/





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broadgage
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« Reply #303 on: August 08, 2022, 05:01:14 pm »

I am not convinced that drought is the main reason for the substantial reduction in French nuclear output. The output has been well below the historical norm for more than a year, including during times of normal rainfall.
The underlying reason is reported to be stress cracking and corrosion in a large number of nuclear power stations. The French are trying hard not to publicise this since they hope to sell nuclear power stations to the UK (United Kingdom) and elsewhere.

Better to blame the weather rather than defective design or construction.

As a result France have been regularly importing expensive electricity from us. I think that mainland Europe are in a panic over gas and electricity for the coming winter. Various energy saving measures are being enacted or proposed.

And what is being done in the UK ? nothing much.
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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU (Diesel Multiple Unit) is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
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« Reply #304 on: August 08, 2022, 05:42:37 pm »

All river-cooled power stations (and some sea-cooled ones too) have, for a very long time now, operated with outlet temperature limits. And in the summer they often have to reduce exhaust heat by that route - which is why they have cooling towers as back-up. This year, in France, the drought is such that some of them may be short of water for those too.

There hasn't been any secret about how many of the French nuclear generators are "in need of repair", and this goes back to last year. That is why our grid's usual fix of the French electrons has been replaced by us feeding them a little (actually 1.68 GW (Great Western) now). The heatwave effects just add to that. If you think about it, needing more repair is exactly what you would expect as they get older - it happened to ours as well.

I did see a suggestion that the feeding of electricity that way is a virtual gas pipeline, to help France and Germany build their reserves using terminal capacity in the UK (United Kingdom). They are short of this, while we have some that we have replaced by the Norwegian pipeline. So if we burn gas on their behalf they have more of it to send down the salt mines.  But I doubt that's more than an accidental result of what had to happen anyway.
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TonyK
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« Reply #305 on: August 08, 2022, 08:59:55 pm »

As an aside, members will have noted that France has had to turn down the wick on its nuclear power stations recently. Specifically, those which use river water for cooling: it seems the temperatures are currently high enough to risk damage to river life:

https://www.theguardian.com/business/2022/aug/03/edf-to-reduce-nuclear-power-output-as-french-river-temperatures-rise

That's a very sensible idea, and might also save a few euros in fuel.

Quote
I read somewhere that one of the objections to Sizewell C is that it will raise the temperature of the sea locally, though in this case the problem relates to the growth of phytoplankton in the balmy discharge.

https://tasizewellc.org.uk/wp-content/uploads/2021/06/g-Ecological-Impacts140679253.pdf

I know that dilution is not the solution to pollution, but I find it hard to remember enough physics to work out how much heat would have to be discharged into the sea to make any difference, especially given the currents and tides. Perhaps Sizewell C could be designed so that some of this heat can be used for industry or agriculture. It's been done elsewhere.

Quote
Shame they can't build power stations where people live; we could add the waste heat to local heat networks:

https://www.energyservicebristol.co.uk/business/heat-networks/



That too. The problem is that nobody wants a power station of any type in the neighbourhood, but I'm sure hot water could be piped for relatively long distances with the right pipework.
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« Reply #306 on: August 09, 2022, 04:44:42 pm »

Referring to Tony K's last comment, it almost seems an oxymoron that Iceland has miles and miles of above ground pipework to cool the geothermally heated water so it is at a safe temperature for human and industrial use.
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TonyK
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« Reply #307 on: August 09, 2022, 09:23:32 pm »

Referring to Tony K's last comment, it almost seems an oxymoron that Iceland has miles and miles of above ground pipework to cool the geothermally heated water so it is at a safe temperature for human and industrial use.

'Tis true, I've marvelled at it myself. It is also piped direct to the hot water taps. It sometimes smells a bit sulphurous coming out of the shower head, but they say that's good for the skin, and as a bonus, you can get away with a lot.
« Last Edit: August 10, 2022, 07:29:35 pm by TonyK » Logged

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broadgage
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« Reply #308 on: August 09, 2022, 11:36:33 pm »

The use of waste heat from power stations for domestic heating or industry is frequently proposed and can sound attractive, but seldom makes economic sense.

The first problem is that this waste heat is rejected at a very low temperature, less than blood heat. This slightly warm water is not very effective for domestic heating or industrial purposes.
Try heating a home to say 23 degrees by means of warm water at about 30 degrees. It can be done but requires either underfloor heating or very oversized radiators.

To transport a useful amount of heat at such low temperatures requires huge volumes of water. Very large and expensive pipes that are disruptive to install. Considerable energy used in pumping all that water.

Possible uses include heated swimming pools, heated glasshouses, or thermal desalination of seawater.

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A proper intercity train has a minimum of 8 coaches, gangwayed throughout, with first at one end, and a full sized buffet car between first and standard.
It has space for cycles, surfboards,luggage etc.
A 5 car DMU (Diesel Multiple Unit) is not a proper inter-city train. The 5+5 and 9 car DMUs are almost as bad.
Bmblbzzz
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« Reply #309 on: August 10, 2022, 09:05:57 am »

Referring to Tony K's last comment, it almost seems an oxymoron that Iceland has miles and miles of above ground pipework to cool the geothermally heated water so it is at a safe temperature for human and industrial use.

'Tis true, I've marvelled at it myself. It is also piped direct to the hot water taps. It sometimes smells a bit sulphurous coming out of the shower head, but they say that's good for the skin, and as a bonus, tou can get away with a lot.
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« Reply #310 on: August 10, 2022, 10:21:43 am »

The first problem is that this waste heat is rejected at a very low temperature, less than blood heat. This slightly warm water is not very effective for domestic heating or industrial purposes.

The other way of looking at that is to say that if heat has to be rejected at a higher temperature so it is useable, the electrical output (and thus the efficiency) is reduced. So this heat isn't "free" at all: it has a significant cost in electricity foregone.

In 1972 (I think) I was a lab demonstrator on an OU summer school in Loughborough, and we did a few factory visits (GEC turbines in Derby was one). Two were to power stations; one was Ratcliffe on Soar, mentioned upthread as still in operation. Lasted well, hasn't it? It was only a few years old when I saw it, new and almost shiny. Of course it was impressive, like anything else that's like something familiar but a hundred times bigger. Surprisingly, having seen the boiler (mega-huge), and the turbine (huge), the alternator was almost small by comparison, tacked on the end of the turbine (with an even smaller exciter tacked on the end of that).

Following that we went to Spondon, which I think is the biggest British power station built to provide process heat first and electricity second. It was smaller (30 MWe) but had a very big water softener. The water inside a steam cycle has to be very pure, so that's usually a closed cycled with a purifier for its make-up water. At Spondon the steam went from the boiler through a single high pressure turbine and then, instead of medium- and low-pressure turbine stages, it went across the canal (actually the Derwent) into British Celanese and never came back. If the plant was shut down (which would be rare), so was the power station - another constraint of this sort of joint operation.

And as for heating homes ... well, this week, one problem with siting a power station to do that should be obvious enough. There is heat to be rejected all year, but heating isn't needed in summer. So some alternative is called for - not a river, obviously! And cities are already uncomfortably hot (heat islands), but guess what happens if you plonk a GW (Great Western) or two of heat engine down in one (or even moderately near)?
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TonyK
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« Reply #311 on: August 10, 2022, 07:59:42 pm »

The first problem is that this waste heat is rejected at a very low temperature, less than blood heat. This slightly warm water is not very effective for domestic heating or industrial purposes.

The other way of looking at that is to say that if heat has to be rejected at a higher temperature so it is useable, the electrical output (and thus the efficiency) is reduced. So this heat isn't "free" at all: it has a significant cost in electricity foregone.


Yet another way to look at that is to see the water as having had the maximum amount of energy used. I'm sure I recall a big heated greenhouse affair in Kent using waste heat from something, and somewhere similar near Preston doing the same thing to grow salads. I can't find anything about it now, so maybe it didn't work out.

Iceland's heating systems use a bit of a mix. Reykjavik has boreholes under streets with water at a comfortable temperature for showering and radiators piped to every home. We were told not to turn the heating down if it got too hot, but to open windows, that being the most efficient way. Pavements are heated from below, making them ice free. The big superheated water plants get water at 200C-plus. That gets used for power production, then piped to Reykjavik to provide district heating to the parts without boreholes. The mineral content means it is corrosive, so uses heat exchangers with clean water and traces of hydrogen sulphide added. When we went there the first time, I wanted to look around the power stations, but was outvoted by my wife, and had to settle for stunning scenery and geysers instead.

We could yet use some of this expertise in the UK (United Kingdom), albeit at a less dramatic scale. Just don't tell anyone that a lot of the heat is from radioactive decay.

Edit: My subsequent reading suggests that all this Icelandic innovation developed out of necessity, and as from recently as the 1970s. Prior to that, Iceland had hydroelectric power developed from the early 20th century, but was largely reliant on imported coal and oil for a lot of power as well as space heating. That changed with the oil crisis 50 years ago, giving limited choices of either paying more, using less, or finding another way. A nation with a lower population than Bristol planned and built the solution, and now attracts energy hungry companies that don't have to rely on a single physical location, like data centres and the dreaded Bitcoin miners. We could yet import energy from their if Icelink ever gets the nod.
« Last Edit: August 11, 2022, 04:30:20 pm by TonyK » Logged

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Red Squirrel
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« Reply #312 on: August 10, 2022, 11:08:50 pm »

As an aside, I understand that the average water temperature of rivers in the UK (United Kingdom) is just under 10 degrees. Bristol think it's worth extracting some of this heat in a water-sourced heat pump located on the edge of the grassed-over bombsite that some call Castle Park. Presumably you could extract a lot more heat, more efficiently, from water at 23 degrees? Or am I showing my ignorance again?
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« Reply #313 on: August 10, 2022, 11:16:17 pm »

As an aside, I understand that the average water temperature of rivers in the UK (United Kingdom) is just under 10 degrees. Bristol think it's worth extracting some of this heat in a water-sourced heat pump located on the edge of the grassed-over bombsite that some call Castle Park. Presumably you could extract a lot more heat, more efficiently, from water at 23 degrees? Or am I showing my ignorance again?
You could extract much more heat more efficiently from water at 23 degrees yes.  Just need a heat pump. 
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CyclingSid
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« Reply #314 on: August 11, 2022, 06:51:02 am »

They did a trial of geothermal energy at Marchwood, opposite Southampton, 50+ years ago. There is something related now opposite the West Quay Shopping Centre when I cycle from the station to the ferry.
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