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Efficient method to capture carbon dioxide from the atmosphere

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Re: Efficient method to capture carbon dioxide from the atmosphere

#41

Post by jmclnx »

condensedcrab wrote: post #13

Direct air capture imo can’t escape the scaling problem - when the feedstock has CO2 at ~400 ppm the economics simply won’t work out despite various oil companies backing one off systems around the globe. Capturing CO2 at the source (power plant, etc) would be simpler to reach economic viability but without incentives it’s dead on arrival. I believe the IRA infra bill had put a price ~$50/ton of CO2 captured.

I agree, plus were would one store the CO2 ? To get back to "1980", I really doubt puling CO2 from the atmosphere will ever work.

Another concern, who will pay for maintenance ? See this for why you cannot let CO2 escape from underground storage:

https://en.wikipedia.org/wiki/Lake_Nyos_disaster

If stored near a populated area, hundreds of thousands could be kill, including all animals and insects, in a matter of minutes if the "vault" has a catastrophic failure. I would rather live near a nuclear waste site than a CO2 Site.

Re: Efficient method to capture carbon dioxide from the atmosphere

#43

Post by gus_massa »

cjbenedikt wrote: post #18
mnky9800n wrote: post #5

Earlier quoted context omitted.

you can inject it into peridotites and let it mineralize. there is enough exposed peridotite outcrops in the world that we could inject all the co2 produced and store it there indefinitely. this process also produces elemental hydrogen.

Do you have any links on research on that? Serious question.

Someone proposed to make giant beaches of malachite and let the sea break the rocks. Malachite has two -OH that can be replaced by a CO3= and so capture the CO2.

I can't find a good link now, but at least it's the only method I know where it's not obvious that requires a huge amount of energy that makes the whole process net negative.

Re: Efficient method to capture carbon dioxide from the atmosphere

#44

Post by Yizahi »

cyphertruck wrote: post #2

Economics rules everything. How much does this cost vs simply planting trees, when the value of harvesting the trees is included? Since tree farms are generally profitable, and wood is expensive, it seems this method is likely to be economically less efficient.

In the order of importance:

1. Even if we do magic and emit nothing, we still need to remove CO2 from the atmosphere or it will cook us over time, just longer.

2. We would need an enormous area for forests (which i great), which would mean a lot of intervention, like resettling people, demolishing and constructing new buildings, a lot of machinery time to move people to and from the new forests, a lot of planting and forest maintenance involved. And add he work to cut and bury resulting wood. If you would sum all the incidental emissions from this process it would rapidly become much less efficient (if at all).

Without either CO2 capture or a sun shade of some sort, the CO2 levels and temperature will only ever increase, just like now.

Re: Efficient method to capture carbon dioxide from the atmosphere

#45

Post by condiment »

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes.

Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s one-shot. There are interesting proposals to use this for direct capture at industrial facilities and to turn the waste material into bricks for building.

The key advantage of this new material appears to be that it can be heated and reused. That would be very valuable in an interior direct air capture use case. Think about filtering the CO2 from an office or a home to get us back to pre-industrial levels indoors.

Re: Efficient method to capture carbon dioxide from the atmosphere

#46

Post by gonzo41 »

jmclnx wrote: post #41
condensedcrab wrote: post #13

Direct air capture imo can’t escape the scaling problem - when the feedstock has CO2 at ~400 ppm the economics simply won’t work out despite various oil companies backing one off systems around the globe. Capturing CO2 at the source (power plant, etc) would be simpler to reach economic viability but without incentives it’s dead on arrival. I believe the IRA infra bill had put a price ~$50/ton of CO2 captured.

I agree, plus were would one store the CO2 ? To get back to "1980", I really doubt puling CO2 from the atmosphere will ever work. Another concern, who will pay for maintenance ? See this for why you cannot let CO2 escape from underground storage: https://en.wikipedia.org/wiki/Lake_Nyos_disaster If stored near a populated area, hundreds of thousands could be kill, including all animals and insects, in a matter of minu…

Well as far as storing it goes, if you can capture it, turn it into a solid and stick it in the ground.

Imagine you were growing a huge biomass that you harvest, dry out, and then store. We know how the bacteria and processes that stripped co2 from the atmosphere in the past, we just need to do that in a big way. Good thing we have places on earth that are huge and flat and growing algae won't be a problem.

And then we complement that with green energy and an attempt at net zero.

Re: Efficient method to capture carbon dioxide from the atmosphere

#48

Post by yodon »

condiment wrote: post #45

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes. Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s…

Do you have a citation for that 20 years estimate?

Re: Efficient method to capture carbon dioxide from the atmosphere

#49

Post by dylan604 »

roflmaostc wrote: post #4
cyphertruck wrote: post #2

Economics rules everything. How much does this cost vs simply planting trees, when the value of harvesting the trees is included? Since tree farms are generally profitable, and wood is expensive, it seems this method is likely to be economically less efficient.

The problem is you cannot plant enough trees around the globe to offset our CO2 emissions. Also, a forest only absorbs CO2 while alive. Once it dies, it emits CO2 too. You would need to permanently store the wood somewhere (submerging in water, etc). Recent article: https://www.theguardian.com/environment/2025/nov/28/africa-f...

If these forests are planted by humans, why do we think the dead trees would just be left to rot like you suggest vs being harvested for wood? The logic does not compute other than trying to make a ridiculous point.

Re: Efficient method to capture carbon dioxide from the atmosphere

#50

Post by netcraft »

condiment wrote: post #45

At current rates of emissions, we’re only about 20 years away from people needing to install CO2 scrubbers in their homes. Soda lime, or calcium hydroxide, is the current state of the art. We use that in an anesthesia and in saltwater aquariums and in scuba rebreathers. An idealized system can capture 500 mg per gram, but in practice you only capture around 250mg/g. This outperforms the method in the article but it’s…

160F, non toxic, this already sounds like something that could feasibly be used in the home. I would already be interested in installing one. And would absolutely love to see what it would do to school performance.

The hard part is capture and disposal.

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