5 ms·

Time scale is also something I want to know about. "Can I remove CO2 from the air and turn it into something valuable in a way that is cost effective?" is one q

Time scale is also something I want to know about. "Can I remove CO2 from the air and turn it into something valuable in a way that is cost effective?" is one question. Another question is, "Can I remove CO2 from the air and turn it into something valuable faster than a tree?"

ben_w 2y ago
As this is more of "can we make carbon sequestering commercially viable, or at least less lossy", I'm less worried about that and would be more concerned about the global market for ethylene being "316.8 Million Tonnes in the year 2023"*, compared to the tens of gigatons of CO2 emissions — though on the plus side, I'm optimistic about removing most of those emissions and this kind of thing is still fine for the last 10%. As for "less lossy" even if it's not always a commercial winner alone: my guess would be there's always going to be an easier way to get CO2 than "from the air", unless you're on Venus or Mars: take tree (or coal), cut up, put chips in oven, set on fire. Much higher CO2 concentration than air, likely to make most things that need CO2 much easier. * https://finance.yahoo.com/news/global-ethylene-industry-report-2024-091700936.html# https://finance.yahoo.com/news/global-ethylene-industry-repo...
- r-bryan 2y ago
  A little stoichometry suggests that, ignoring oxygen, hydrogen, and energy input, the cited worldwide market for C2H4 would be satisfied by just about 1 gigaton of CO2. So if "we need to process gigatons of CO2 annually", that ethylene's gonna pile up.
sampo 2y ago
> "Can I remove CO2 from the air and turn it into something valuable faster than a tree?" In some climate zones, grasslands do it better than forests. https://climatechange.ucdavis.edu/climate/news/grasslands-more-reliable-carbon-sink-than-trees https://climatechange.ucdavis.edu/climate/news/grasslands-mo...
- criddell 2y ago
  A tree gives you wood. What are the valuable outputs of grasslands?
  - Kostic 2y ago
    Chernozem.
    - thechao 2y ago
      https://en.wikipedia.org/wiki/Chernozem https://en.wikipedia.org/wiki/Chernozem
  - lupusreal 2y ago
    Does bamboo count?
    - criddell 2y ago
      Maybe. I know it actually is grass, but are bamboo growths called grasslands?
  - nostromo 2y ago
    You can make it into a carbon-neutral heating fuel. You can make paper products including things like cardboard and packaging. You can put livestock on it and produce meat. Or if you just want to sequester carbon, you can harvest it and bury it deep in the ground.
  - sampo 2y ago
    > What are the valuable outputs of grasslands? If you use grasslands for grazing cattle you get meat, or also wool with sheep. Sequestering carbon into grassland soil (or into any soil, really) makes them better at absorbing and retaining rainwater, reducing the risks of catastrophic floods in the watershed area.
    - criddell 2y ago
not2b 2y ago
My guess is that it would be much more effective to capture and remove CO2 directly at the source, for example at a cement plant. While this could be done at a fossil fuel plant as well, it seems a lot less attractive: you give back most of the energy you just got from burning the fuel.
Suppafly 2y ago
They should sell it to people for their car tires with a specially colored valve cap like they do for nitrogen. It'd be stupid, but so is paying extra for a slightly higher nitrogen content and people do that.
- jandrese 2y ago
  That sort of application is just spitting into the ocean when you're talking about global CO2 emissions and sequestration.
  - BenjiWiebe 2y ago
    Plus it all comes out of the tires in the end anyways.
danbruc 2y ago
I have not thought about this too carefully so I might be overlooking something. With that out of the way, a quick search indicates that we burn about 90 % of gas, oil, and coal for one purpose or another. Let's round this and pretend we burn it all. To undo this we will essentially need the same amount of energy again that we got out of it when we burned it, we would need to use all the energy coming from fossil fuels to undo burning them. Conservation of energy essentially. Which makes it obvious that the entire idea is pretty pointless, burn fossil fuels to generate energy to then use it to unburn fossil fuels. To do it with renewable energy, we still need the same capacity as the fossil fuel capacity and when we have that - ignoring issues like fluctuations in renewable sources - it makes more sense to just use the renewable sources directly instead of using them to undo burning fossil fuels. If you want to use the process to pull carbon out of the atmosphere, then you first have to replace all fossil fuels with renewable ones, then you can use additional renewable capacity to remove carbon. Add additional 10 % capacity to the world energy capacity to undo one year of carbon emissions every decade, at least to a first approximation. To come back to the initial question, you essentially need an industry the same order of magnitude as the fossil fuel industry to have a meaningful impact. Not going to happen anytime soon.
- TSiege 2y ago
  The point that you're missing is that changes this equation a bit is that burning fossil fuels wastes most of the energy as heat another waste of energy is the amount of FFs we use to ship FFs to other places. So together that means we don't need the same amount of electric power to do the same amount of work. That being said, keeping fossil fuels in the ground will always be better than removing CO2 for the reasons you said. We also seem to be growing energy demands instead of shrinking or stabilizing them which also makes the transition harder.
- axus 2y ago
  Lots of solar on-site that doesn't need to transfer it's power elsewhere could be used; maybe the real winner would be 100% solar-powered solar panel factory :)
- toss1 2y ago
  >>we would need to use all the energy coming from fossil fuels to undo burning them This would true if we need to re-create the original molecule with it's stored energy (plus losses of course). However, it seems this is a misapprehension of the task. Instead of trying to recover the entire hydrocarbon molecule, we're "just" trying to extract or recombine the CO2 reactant. Without doing the chemistry or the math, it seems likely that a variety of methods of either preferentially attracting CO2, or combining it into simpler lower-energy-dense molecules to be collected, would require less energy as was in the original hydrocarbon, often substantially less. Seems it should be an inequality, not an equality. Or am I missing something?
userabchn 2y ago
Have there been any recent developments in "lab-grown wood"? The last time I looked into it there had been some research on it (also at MIT), but there didn't seem to have been any updates for a few years.

ben_w 2y ago

As this is more of "can we make carbon sequestering commercially viable, or at least less lossy", I'm less worried about that and would be more concerned about the global market for ethylene being "316.8 Million Tonnes in the year 2023"*, compared to the tens of gigatons of CO2 emissions — though on the plus side, I'm optimistic about removing most of those emissions and this kind of thing is still fine for the last 10%. As for "less lossy" even if it's not always a commercial winner alone: my guess would be there's always going to be an easier way to get CO2 than "from the air", unless you're on Venus or Mars: take tree (or coal), cut up, put chips in oven, set on fire. Much higher CO2 concentration than air, likely to make most things that need CO2 much easier. * https://finance.yahoo.com/news/global-ethylene-industry-report-2024-091700936.html# https://finance.yahoo.com/news/global-ethylene-industry-repo...

r-bryan 2y ago
A little stoichometry suggests that, ignoring oxygen, hydrogen, and energy input, the cited worldwide market for C2H4 would be satisfied by just about 1 gigaton of CO2. So if "we need to process gigatons of CO2 annually", that ethylene's gonna pile up.

sampo 2y ago

> "Can I remove CO2 from the air and turn it into something valuable faster than a tree?" In some climate zones, grasslands do it better than forests. https://climatechange.ucdavis.edu/climate/news/grasslands-more-reliable-carbon-sink-than-trees https://climatechange.ucdavis.edu/climate/news/grasslands-mo...

criddell 2y ago
A tree gives you wood. What are the valuable outputs of grasslands?
- Kostic 2y ago
  Chernozem.
  - thechao 2y ago
    https://en.wikipedia.org/wiki/Chernozem https://en.wikipedia.org/wiki/Chernozem
- lupusreal 2y ago
  Does bamboo count?
  - criddell 2y ago
    Maybe. I know it actually is grass, but are bamboo growths called grasslands?
- nostromo 2y ago
  You can make it into a carbon-neutral heating fuel. You can make paper products including things like cardboard and packaging. You can put livestock on it and produce meat. Or if you just want to sequester carbon, you can harvest it and bury it deep in the ground.
- sampo 2y ago
  > What are the valuable outputs of grasslands? If you use grasslands for grazing cattle you get meat, or also wool with sheep. Sequestering carbon into grassland soil (or into any soil, really) makes them better at absorbing and retaining rainwater, reducing the risks of catastrophic floods in the watershed area.
  - criddell 2y ago

not2b 2y ago

My guess is that it would be much more effective to capture and remove CO2 directly at the source, for example at a cement plant. While this could be done at a fossil fuel plant as well, it seems a lot less attractive: you give back most of the energy you just got from burning the fuel.

Suppafly 2y ago

They should sell it to people for their car tires with a specially colored valve cap like they do for nitrogen. It'd be stupid, but so is paying extra for a slightly higher nitrogen content and people do that.

jandrese 2y ago
That sort of application is just spitting into the ocean when you're talking about global CO2 emissions and sequestration.
- BenjiWiebe 2y ago
  Plus it all comes out of the tires in the end anyways.

danbruc 2y ago

I have not thought about this too carefully so I might be overlooking something. With that out of the way, a quick search indicates that we burn about 90 % of gas, oil, and coal for one purpose or another. Let's round this and pretend we burn it all. To undo this we will essentially need the same amount of energy again that we got out of it when we burned it, we would need to use all the energy coming from fossil fuels to undo burning them. Conservation of energy essentially. Which makes it obvious that the entire idea is pretty pointless, burn fossil fuels to generate energy to then use it to unburn fossil fuels. To do it with renewable energy, we still need the same capacity as the fossil fuel capacity and when we have that - ignoring issues like fluctuations in renewable sources - it makes more sense to just use the renewable sources directly instead of using them to undo burning fossil fuels. If you want to use the process to pull carbon out of the atmosphere, then you first have to replace all fossil fuels with renewable ones, then you can use additional renewable capacity to remove carbon. Add additional 10 % capacity to the world energy capacity to undo one year of carbon emissions every decade, at least to a first approximation. To come back to the initial question, you essentially need an industry the same order of magnitude as the fossil fuel industry to have a meaningful impact. Not going to happen anytime soon.

TSiege 2y ago
The point that you're missing is that changes this equation a bit is that burning fossil fuels wastes most of the energy as heat another waste of energy is the amount of FFs we use to ship FFs to other places. So together that means we don't need the same amount of electric power to do the same amount of work. That being said, keeping fossil fuels in the ground will always be better than removing CO2 for the reasons you said. We also seem to be growing energy demands instead of shrinking or stabilizing them which also makes the transition harder.
axus 2y ago
Lots of solar on-site that doesn't need to transfer it's power elsewhere could be used; maybe the real winner would be 100% solar-powered solar panel factory :)
toss1 2y ago
>>we would need to use all the energy coming from fossil fuels to undo burning them This would true if we need to re-create the original molecule with it's stored energy (plus losses of course). However, it seems this is a misapprehension of the task. Instead of trying to recover the entire hydrocarbon molecule, we're "just" trying to extract or recombine the CO2 reactant. Without doing the chemistry or the math, it seems likely that a variety of methods of either preferentially attracting CO2, or combining it into simpler lower-energy-dense molecules to be collected, would require less energy as was in the original hydrocarbon, often substantially less. Seems it should be an inequality, not an equality. Or am I missing something?

userabchn 2y ago

Have there been any recent developments in "lab-grown wood"? The last time I looked into it there had been some research on it (also at MIT), but there didn't seem to have been any updates for a few years.