General > General Technical Chat
UK power grid situation!!
tggzzz:
--- Quote from: IanB on December 14, 2022, 03:50:20 am ---
--- Quote from: tggzzz on December 13, 2022, 12:31:41 pm ---Storage is the key, and is now more of an issue than generation. Any entity that comes up with a practical way of grid scale energy storage will become as rich as Croesus. Currently the only practical solution is pumped storage hydropower, and the capacity for that is very limited in the UK.
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One of the most promising ideas being investigated here is to turn the electricity into hydrogen (or less easily, ammonia), and store it, and then turn it back to electricity when needed.
For hydrogen it is a case of electrolysis and fuel cells, but storing the hydrogen in large quantities is difficult. Ammonia is easy to store as a liquid in tanks, but electrolysis/fuel cells that work with ammonia is a very emergent technology, far from practical deployment.
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I always like to point out there is less hydrogen (and hence hydrogen bonds) in a 1 litre of hydrogen than in 1 litre of petrol/diesel. Using hydrogen to power aircraft leads to the aircraft looking like a Super Guppy on steroids :)
One example of an SMR being used to generate hydrogen is in the special case of using the hydrogen locally in an industrual process.
Zero999:
--- Quote from: tggzzz on December 13, 2022, 12:31:41 pm ---
--- Quote from: tom66 on December 13, 2022, 11:30:49 am ---
--- Quote from: tggzzz on December 13, 2022, 09:26:04 am ---The "global warming thing" is that extreme weather will become more frequent.
The "wind is always blowing somewhere" is a longstanding mantra od the idiot green fringe that also measures energy in GW. It is easily disprovable, courtesy of gridwatch. I took a year's wind production and plotted the CDF. As a rule of thumb in the UK, if the peak wind output is X GW, then the wind output will be below X% for X% of the time. Example: if the peak output is 10GW, then it will be 0.1GW or less for 1% of the year, i.e. 3 days.
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I don't know if anyone is proposing wind ex storage as a viable grid supply - if they are then you are quite right to shout at them.
The reality is that a purely wind powered grid would require some form of storage.
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I don't know what "wind ex storage" is.
All intermittent (i.e. non-dispatchable) sources imply storage is required.
--- End quote ---
A big problem with wind power in the UK and Northern Europe is, the jet stream tends to be weaker (negative North Atlantic Oscillation (NAO)), when it's cold and most needed and stronger (positive NAO), when it's mild. Long term storage is the only solution, as it's not practical to cover the North Atlantic with wind turbines and even then, if we get an extremely negative NAO winter, like 1963 we're buggered, unless the energy can be stored for years.
https://uip.primavera-h2020.eu/sites/default/files/PRIMAVERA_factsheet_climate_energy_NAO_final.pdf
https://www.metoffice.gov.uk/research/climate/seasonal-to-decadal/gpc-outlooks/ens-mean/nao-description
https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/north-atlantic-oscillation
tggzzz:
Thanks for acknowledging where you made a mistake; too few people do that!
I'll concentrate on the interesting points.
--- Quote from: tom66 on December 13, 2022, 08:08:08 pm ---
--- Quote from: tggzzz on December 13, 2022, 02:26:02 pm ---
--- Quote ---A wind farm can be commissioned in a matter of months, far quicker than any nuclear or gas power plant, but it can generate comparable power to one in good conditions.
--- End quote ---
Nonsense, unless you are using "commissioned" in a non-standard way that you haven't bothered to specify (cf "wind ex storage").
Cherry picking (e.g. "in good conditions") is a bad debating technique, suitable only for politicians and salesmen.
It is true that getting a conventional nuke operating is slower than a wind farm. The SMR approach is yet to be tested.
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I think SMR will turn out to be a pipe dream, but let's see if it happens. It has my support, just like fusion, we need to approach the problem with all options. But we should spend the most effort on things that currently work and can be demonstrated to work. How many commercial SMR plants are there, compared to windfarms full of 20MW turbines?
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Essentially there are more operational SMRs than most people would like. They are,of course, self-propelled and surrounded by coolant.
Repurposing such reactors is one reason to believe their technical characteristics are well understood. Whether the political and commercial aspects work is TBD.
Fusion does have a potential problem: if it works and if is too cheap and if energy consumption continues to increase at the historic 2.9%/year, then in 450 years the oceans will boil (ref: the "Thermodynamic Limits" in https://dothemath.ucsd.edu/2011/07/galactic-scale-energy/ )
--- Quote ---
--- Quote from: tggzzz on December 13, 2022, 02:26:02 pm ---Those are variations on a theme, and nothing fundamental.
100GW with storage is larger than we would require. Without storage we would want something around, say, 1000GW to avoid outages
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No. 1TW would be far too much with current projected demands. I don't think you're appreciating what storage does to resolve the intermittency issue.
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I was presuming the storage problem isn't solved. Solving it has to be a high priority, and (as I said) solving it will lead to the richness of Croesus :)
--- Quote ---
--- Quote from: tggzzz on December 13, 2022, 02:26:02 pm ---No, the UK doesn't. It has 25GW peak capacity, which is very different. In the last year
* On 2nd August it had own to 0GW (zero) output.
* 1.7% of the time it had <1% of the peak output (i.e. <250MW).
Please do your research before making statements such as those below.
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Do you think that I don't appreciate wind sometimes goes to zero watts? The whole point of storage on such a scale is to make wind power viable (and solar in countries which have good insolation.)
The whole point about overbuilding the amount of wind power is that you store the excess by converting it into hydrogen or hydrocarbon fuel, and then use that fuel when there's no wind. You combine that with demand management, so encouraging usage of energy when it's more readily available, and conservation when it isn't - e.g. EV chargers that run more on excess wind.
If you don't understand how that can work I don't really know what to say.
--- End quote ---
Oh, I completely understand that. What I, and others, don't understand is how to do that economically and in the UK.
After that is solved on the scale of seasons and grids, wind/solar/tidal/etc it becomes practical to remove fossil fuel power stations.
--- Quote ---
--- Quote from: tggzzz on December 13, 2022, 02:26:02 pm ---
--- Quote ---But hopefully Russia's actions show that is increasingly necessary to maintain energy independence which wind power and storage enables. Anyway, I said we'd need more storage, this is not the hard part. There are lots of depleted gas fields, and there will be more come the end of North Sea gas and oil. I'm sure we can figure that bit out. The difficult bit is the syngas stuff, that is the new infrastructure that needs to be built en-masse.
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"I'm sure we can figure that out" is not sufficient.
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Well, the good news is I'm not in charge of grid and power engineering for the UK, so you don't need to rely on me "figuring it out". There are people working in this area that know way more than both of us working this stuff out, and I am summarising research, papers and thought patterns here.
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There have been people working on that for many decades. My father, when he was at the Central Electricity Research Labs, wrote a paper summarising the options. That was 40 years ago ! :(
Hence my wanting to "kick the tyres" before believing that any particular technology is practical.
--- Quote ---In terms of storage, the UK has comparatively little in use right now. About 9 days' gas (see above) whereas NL has around 130 days.
--- End quote ---
That sounds about right.
One viewpoint is that the UK has been "banking" imported gas in various European storage facilities. Let's hope we can "withdraw our deposits" when there is a "run on the banks".
--- Quote ---If we use depleted gas fields, we should be able to achieve capacities similar to Europe.
...
We certainly have no shortage of fields that could be developed for this purpose.
...
There are also inland fields, or converted coal gas mines, available.
--- End quote ---
Maybe. I don't know which locations are practical and economic.
I'm skeptical about storing gas in coal mines; overall capacity and leakage into buildings are two obvious issues..
--- Quote ---It's not yet clear whether natural gas or hydrogen will win here. Natural gas is easier to use, as existing gas boilers, power plants, and industrial processes can use it, and it is easier to store and transport than hydrogen. However, it has greater losses. Current research suggests about 70% conversion efficiency could be achieved with an optimised CH4 conversion system; hydrogen may be able to achieve 80%. The conversion loss is one reason that you need to overbuild the wind power and the storage capacity, because your storage will be less efficient than using the energy directly. The really cool thing about Sabatier is it uses CO2 from the atmosphere, so processes that trap CO2, like fertiliser production via CH4 (a huge amount going into the soil carbon cycle) it is negative for carbon emissions. And even if you burn it in conventional boilers etc., it is effectively carbon neutral if fugitive emissions are kept low enough.
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I'm skeptical about non-commercial uses of hydrogen. Apart from its low energy density, the small molecule size exacerbates leakage, and over time it embrittles metals.
I wonder if the planned test sites will be monitored long enough, or whether success will be declared before the problems have had time to become apparent.
tom66:
--- Quote from: IanB on December 14, 2022, 03:50:20 am ---One of the most promising ideas being investigated here is to turn the electricity into hydrogen (or less easily, ammonia), and store it, and then turn it back to electricity when needed.
For hydrogen it is a case of electrolysis and fuel cells, but storing the hydrogen in large quantities is difficult. Ammonia is easy to store as a liquid in tanks, but electrolysis/fuel cells that work with ammonia is a very emergent technology, far from practical deployment.
--- End quote ---
Yup, ammonia is another useful technology worth investigating. The other advantage is you can use ammonia as fertiliser, which is something we need to stop using fossil fuel gas for, if only for food security. Ammonia can also be directly combusted, though I'm not sure if there are any particularly negative side effects from using this as a fuel or if the efficiency is particularly good compared to CH4. A downside is that ammonia isn't a great compound to have around in huge tanks, due to environmental hazards if it leaks.
IanB:
--- Quote from: tggzzz on December 14, 2022, 08:49:55 am ---One example of an SMR being used to generate hydrogen is in the special case of using the hydrogen locally in an industrial process.
--- End quote ---
For anyone not keeping up with acronyms, SMR is steam methane reforming, which is an industrial process to extract hydrogen from natural gas, producing carbon dioxide as a side product.
In the hydrogen world, there are different "colours" of hydrogen. For instance "grey" hydrogen is produced from reforming where the CO2 is simply discharged to the atmosphere. Then there is "blue" hydrogen, where the reforming process is still used, but the produced CO2 is captured and not released to the atmosphere. Or there is "green" hydrogen, which does not use reforming at all, but instead uses electrolysis of water or some other process that does not create any CO2.
The desire is to move towards green hydrogen, but there are issues of scale and efficiency still to be resolved.
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