Providing grid stability and decarbonising the final few percent

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Mart
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Re: Providing grid stability and decarbonising the final few percent

#11

Post by Mart »

Stinsy wrote: Mon May 19, 2025 4:30 pm
Mart wrote: Mon May 19, 2025 3:47 pm Interesting point Stinsy. I'm very interested in carbon removal, but crucially at the moment, it's far cheaper to reduce CO2 by displacing FF's with RE. But there has to come a tipping point where the economics shift in favour of some sort of carbon capture and storage.

The global temp targets (like the 1.5C that's next to impossible now) are based on reaching net zero emissions, and then preventing the continued temp rise, due to the lag behind CO2 levels, of 20 or so years. But carbon removal is very expensive, with suggestions that this is something that will be deployed in the second half of this century ...... once we work out how to do it more efficiently and cheaper.

For now, I'd go with the general definition of net zero leccy as being 95% low carbon, and then just keep moving more and more energy demand over to leccy, with the 'true' decarbonisation being the move away from FF's for transport, space heating etc etc.

Maybe while this is all happening CAES will become economically viable at TWh scale, displacing much of that hard to beat last 5%? :xx:
We also have to bare in mind that China generates something like 60% of their electricity from Coal. Them shifting a few percentage points to renewables will have a vastly bigger impact than the UK shifting our last few percentage points.

I'm not in favour of "carbon capture" as I believe that to be fraud. However once the grid is 98% renewable we'll get a better return by looking at aviation, or other sectors before we decarbonise the last bit.

We need a pragmatic, not dogmatic, approach.
Yes, don't get me wrong, I too think that CCS for FF's is a con/scam. What I meant was that the target temp max's that we hear about for this century, aren't just based on getting to zero CO2 emissions, but also rely heavily on carbon removal. The hope being that large scale carbon capture will be viable after 2050, to prevent temps from rising too much more. If anything, that's what I find scariest - even if the World can get off its FF addiction, that still won't be enough to 'save' us, without also finding a way to remove CO2 from the environment. We are in a really bad situation.

Regarding China and coal, there is some good news. Following the news that Q1 saw a ~5% reduction in coal generation in China, despite a ~1% rise in leccy demand (v's Q1 2024), it also looks like coal consumption fell over the last rolling 1yr, for the first time. So China may well have peaked on leccy emissions earlier than the 2030 target. They also appear to have peaked on oil consumption last year (due to BEV rollouts). They are now rolling out RE generation much faster than leccy demand is rising, so the decline should (hopefully) accelerate. Effectively, China is starting to use coal (as we use gas) to balance out an ever larger RE generation fleet.
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Ken
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Re: Providing grid stability and decarbonising the final few percent

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Post by Ken »

John_S wrote: Mon May 19, 2025 11:02 pm
Ken wrote: Mon May 19, 2025 9:36 am
What is not mentioned is that overbuilding of PV and wind is probably a good partual solution and a fig of 130% overbuild is often proposed as the ideal amount.
Has anyone considered what changes will be needed to the constraint payment mechanism with 130% overbuild?
John,
Curtailment is not linked to supply and demand but the inability of the system, wires and transformers, to trasmit from supply to demand. This problem is well recognised and there are many large and small infrastructure upgrades in the pipeline. So in a way this is a temporary and artificial
situation which is hoped will be largely sorted by 2030 .

If/when we get to real supply being more than demand, bearing in mind storage, export and demand management (eg TOU tariffs) then the excess will not be able to aquire a contract in the market and will have to curtail of its own accord and cost. The excess could be bid into the market at a minus amount but if the wholesale price becomes negative they will loose the CfD support. I do not envisage this actually happening to a meaningful extent.
_

What seems to be forgotten is that the fossil fuel Cos are completely understating/ lying about their emissions from the extraction process. The methane released when coal mining and gas extraction (widespread flaring) could be as large as the fuel burning pollution and therefore the pollution saving when shutting down coal mining and plants is much more than envisaged. All the potential EVs could be run on just the waste and energy use of oil and gas industry, this is profound but largely ignored.

There are an increasing number of countries who are getting close to 100% RE. I have this yr been following Portugal and Spain (they seem to operate almost as one) and they are frequently operating at -/+ 100% RE but that is not quite the same as zero gas but the gas is sometimes less than what is being put into hydro storage and/or export. So in effect the gas is being used to give system strength as we may well have to do as the article says.
Ken
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Re: Providing grid stability and decarbonising the final few percent

#13

Post by Ken »

Joeboy wrote: Tue May 20, 2025 6:50 am An article popped up yesterday on my Newsfeed on Denmarks molten salt storage for excess Solar/wind etc.

Seems like a good storage solution?

Related article

https://interestingengineering.com/ener ... 0000-homes
Good perhaps for heat but not leccy
"Hyme Energy reports that the system achieves efficiencies of around 90% for industrial heat applications and between 80% and 90% for co-generation. Power generation alone is estimated at 40% efficiency.

Heat is low value energy as every other form of energy ends up as heat. Leccy is a high value energy and therefore its efficiency is much more important.
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Joeboy
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Re: Providing grid stability and decarbonising the final few percent

#14

Post by Joeboy »

Ken wrote: Tue May 20, 2025 9:48 am
Joeboy wrote: Tue May 20, 2025 6:50 am An article popped up yesterday on my Newsfeed on Denmarks molten salt storage for excess Solar/wind etc.

Seems like a good storage solution?

Related article

https://interestingengineering.com/ener ... 0000-homes
Good perhaps for heat but not leccy
"Hyme Energy reports that the system achieves efficiencies of around 90% for industrial heat applications and between 80% and 90% for co-generation. Power generation alone is estimated at 40% efficiency.

Heat is low value energy as every other form of energy ends up as heat. Leccy is a high value energy and therefore its efficiency is much more important.
Maybe, although if it's curtailment in Summer or 40% efficiency from a low cost plant I'd take the 40%.
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