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Entropy? Never heard of it.
(lemmy.dbzer0.com)
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this post was submitted on 16 Feb 2025
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Just checked the numbers, for those interested.
A gas power plant produces around. 200-300kWh per tonne of CO2.
Capture costs 300-900kWh per tonne captured.
So this is basically non viable using fossil fuel as the power. If you aren't, then storage of that power is likely a lot better.
It's also worth noting that it is still CO2 gas. Long term containment of a gas is far harder than a liquid or solid.
Who says you power that thing with fossil fuels? The real way to do that is via giant nuclear reactors or reactor complexes.
Fission power can be made cheaper per MW by just making the reactors bigger. Economies of scale, the square cube law and all that. The problem with doing this in the commercial power sector is that line losses kill you on distribution. There just aren't enough customers within a reasonable distance to make monster 10 GW or 100 GW reactors viable, regardless of how cheap they might make energy.
But DACC is one of the few applications this might not be a problem for. Just build your monster reactors right next door to your monster DACC plants.
There are 3 use cases I've seen.
Making fossil fuel power stations "clean".
CO2 recovery for long term storage.
CO2 for industrial use.
It's no good for the first, due to energy consumption. This is the main use I've seen it talked up for, as something that can be retrofitted to power plants.
It's poor for the second, since the result is a gas (hard to store long term). We would want it as a solid or liquid product, which this doesn't do.
The last has limited requirements. We only need so much CO2.
The only large scale use case I can see for this is as part of a carbon capture system. Capture and then react to solidify the carbon. However, plants are already extremely good at this, and can do it directly from atmospheric air, using sunlight.
Why wouldn't the device include or feed a compressor to liquidize the CO2? It takes just a little over 5 atm of pressure which is trivial.
You also need to sustain 5 atm, with no leaks for years. Where is it being stored, and who's paying for the maintenance? All it would take would be a bit of civil unrest, or corruption, and the work could be undone in mass.
The only DAC variant i could see working out is if it takes the CO2 from high-concentrated sources (such as portland cement factories) and transforms it into something practical, like liquid fuel or methane.
It could be leading to cheaper methane than from biological sources, because technological processes can have higher efficiency, and therefore lower prices.
Good luck building enough capacity in nuclear power to do that. Nuclear plants tend to be a lot more expensive and take a lot longer to build than anticipated.
Literally only in the US and Europe. Remove the profit motive and don't keep on inefficient construction companies and it's a quick process.
There's no profit motive for large scale carbon capture anyway, so big CC plants and big nuclear plants would need the same political will.
Can you point out a nuclear project that was a quick process? How would removing the profit motive make it quicker?
Sure, China. You can build a nuclear power plant from dirt to operation in 6 months. Not 10 years plus infinite overages, 6 months.
If there's not a perverse profit motive at every stage and instead people are rewarded for getting the job done and getting the job done right, you end up with high quality fast engineering.
Yes, it works as a "plan B" (along with many other things).
Don't loose hope. We can still win. Keep pushing for producing less CO2.
It's also way easier to just stop digging up coal instead of inefficiently trying to get the exhaust from burning it partially back underground.
You would presumably capture the carbon using excess solar and wind power, which is also the cheapest power there is, sometimes going negative
Is your capture number including the cost of liquifying the CO2 for storage?
If you want to capture the CO2 from fossil fuel, it feels like it'd be easier to filter it out before dumping it in the atmosphere in the first place (apart from the obvious option of just not using fossil fuel)
It would, but it takes more energy that gets produced total. You're spending 300wKh to make 220kWh of electricity.
Is that using numbers for carbon capture from the atmosphere? Carbon capture directly on the exhaust of a fossil fuel power plant would probably be an order of magnitude more efficient. Obviously you can't sustain everything by only using fuel combustion, but you could probably reduce to total emissions per kWh quite a bit without even looking at renewables.
Co2 is liquified before storage.
And how do you plan to keep it liquefied, on a large scale, for 100s of years? It's currently done using pressure vessels amd chillers, that require maintenance etc.