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> re-use the captured carbon I assumes that was the entire point of carbon capture? i.e. instead of introducing more carbon into the atmosphere from oil/etc.

> re-use the captured carbon I assumes that was the entire point of carbon capture? i.e. instead of introducing more carbon into the atmosphere from oil/etc. you just reuse what’s already in it?

kaba0 3y ago
But.. why? The problem is that we put an insane amount of carbon into the atmosphere from million years old plants that was stored there just fine. If we just continue to circulate the existing amounts (and increase it in a tiny bit slower rate because let’s be honest, that’s the reality) we are not even a bit ahead.
- ffhhttt 3y ago
  Because gasoline/diesel/etc. are very energy dense and much easier to store and transport than any alternativd. In some cases e.g. airplane there simply seem to be no other options (unless there is a massive breakthrough in battery tech and possibly out understanding of physics). So ‘clean’ burning synthetic fuels don’t seem like a terrible idea. Of course it all comes down to energy efficiency, but if solar/wind continue growing and carbon capture somehow becomes cost-efficient (assuming free solar/wind energy) it seems like a much better option than continuing oil extraction or even biofuels (which of course is also technically “carbon capture” just not very land/water efficient). > we are not even a bit ahead. Of course. But how does it make it different from every other option? Moving to 100% renewables won’t reverse climate change either .
tsimionescu 3y ago
No, the theoretical point of carbon capture is to take the carbon we released from the ground back into it. Ultimately, there is simply too much CO2 in the atmosphere at the moment. The long term goal has to be to permanently sequester it back into the ground - essentially reversing the last 100-200 years of burning fossil fuels, replacing everything we got from coal, oil, and gas with better alternatives so we can keep living a life that is at least as decent as today's. It is impossible for human civilization as we know it to thrive longer term if we keep the current amount of CO2 (and thus carbon) in any way that is circulating. Of course, capture can and should be the goal after we do the much much easier thing, which is not releasing even 1kg more of the already trapped carbon from the ground.
- ffhhttt 3y ago
  > It is impossible for human civilization as we know it to thrive longer term if we keep the current amount of CO2 (and thus carbon) in any way that is circulating. I’m not sure that true. Han civilizations “thrived” under much worse conditions than we can reasonably expect (by that I mean that technological/economical/social progress historically outweighed environmental factors and I don’t why this won’t be the case in the future)
  - tsimionescu 3y ago
    Han civilization was vastly different from human civilization as we know it today, so it seems you're agreeing with me. I wasn't claiming humans would go extinct, just that there would be a massive upheaval that would entirely change civilization. Also, the Earth has never been as inhospitable to human life as it's expected to be since any known civilization started, so there's no historical precedent to compare to in terms of speed or effects of adaptation.
    - ffhhttt 3y ago
      > Han civilization Sorry. I’m not sure how did I manage to write that, it was supposed to be “civilizations have [thrived]”. > Earth has never been as inhospitable to human life as it's expected to be since any known civilization started, That debatable and very hard to quantify. Also it really depends on the region, e.g. Europe was probably quite worse than now during the “little ice age” or the 600s (coincidentally the Arabian peninsula seems to have thrived during that period due to higher humidity). Climate change was the reason many ancient civilizations collapsed, it seems to have been a pretty regular occurrence and we were only be to break out of that circle in the late middle ages/1500s.
bmer 3y ago
I think you might have a very fundamental misunderstanding on how thermodynamics works? The maximum theoretical efficiency for a combustion engine is about 50%. We'll probably struggle to hit 40%, and that too only after a fair bit of further investment (in particular, materials science investments, and the production of most engineered materials itself requires a fair bit of energy, which generally increases based on the non-standardness/"information-content" of the material (very roughly: "how likely is it that we find a naturally occurring deposit of it on Earth"). So, you cannot really "re-use what's already in it [the atmosphere]". Not sustainably, not while also accommodating growth.
- ffhhttt 3y ago
  > I think you might have a very fundamental misunderstanding on how thermodynamics works? Why would you say that? lol. If we have a large surplus of cheap solar/wind energy during certain periods (which is unavoidable if they share will continue increasing significantly in the future). Of course yeah, that only works if this process becomes relatively cheap and efficient.
  - bmer 3y ago
    > Why would you say that? lol. I'm not entirely sure if you do have a misunderstanding, which is why I asked the question. I'm trying to figure out why you think "carbon capturing" is equivalent to "being able to re-mine hydrocarbons"? Assuming for the moment that the rest of the process is perfect (that is: ignoring that it costs energy to perform carbon capture, ignoring that it costs energy to convert from captured carbon back into some sort of usable hydrocarbon, etc.): it is already very challenging to get to even 50% efficiency in the engines involved in converting a fuel into electricity; whether that engine is an ICE, or a steam engine often used to convert certain renewable sources of energy into other forms. Most of that lost efficiency is due to fundamental constraints of thermodynamics : https://en.wikipedia.org/wiki/Carnot_heat_engine https://en.wikipedia.org/wiki/Carnot_heat_engine (Essentially, useful engines that produce mechanical work from difference in average energy between two bodies operate in cycles. Suppose we start at time 0, and it takes k time ticks for a cycle to start from its initial state X(0), go through its processes, and return back to the initial state: X(k). The fact is that X(0) and X(k) must be different, they cannot be exactly the same, because then that would mean that it is impossible to distinguish between X(0) and X(k), and your engine is not just an engine, but a time machine. (This is why entropy is closely related to the fact that time is an "arrow": always moving in a particular direction.)) All this to say: it is not possible to use a finite source of energy for a "long time", unless the finite source dwarfs by "many orders of magnitudes" (how large the magnitude, determines how much time before it runs out) the energy drained from it per time tick. So even if we got carbon capture working as a way to "recycle fuel" (totally, totally ignoring the fact that it will cost more energy to do the carbon capture and store said captured carbon, than the mechanical work we get out of it (the nuclear fusion problem, except not even technically solvable)) it would not last us for more than a few seconds. (Existing hydrocarbon reservoirs do dwarf our current energy use per time tick, but not by that much, and not if we also want to accommodate material growth, because of the energy cost of also "safely managing" the byproducts of the hydrocarbon->mechanical work process. The sun in particular, massively, massively dwarfs our current use per time tick. This is what makes "renewables" renewable: they have a massive bank of energy banking them. We have an awe-inspiring fusion reactor just throwing energy at us for a while. How do we convert it into usable work?) https://e360.yale.edu/features/three-myths-about-renewable-energy-and-the-grid-debunked https://e360.yale.edu/features/three-myths-about-renewable-e... Putting all that together as the context then, my question to you would be: how can one still use captured carbon as a sort of battery in any meaningful way? Is there a misunderstanding of thermodynamics involved on your part, or could you help me understand where my misunderstanding around thermodynamics lies (I am not an expert, just a novice)?

> re-use the captured carbon I assumes that was the entire point of carbon capture? i.e. instead of introducing more carbon into the atmosphere from oil/etc. you just reuse what’s already in it?

kaba0 3y ago

But.. why? The problem is that we put an insane amount of carbon into the atmosphere from million years old plants that was stored there just fine. If we just continue to circulate the existing amounts (and increase it in a tiny bit slower rate because let’s be honest, that’s the reality) we are not even a bit ahead.

ffhhttt 3y ago
Because gasoline/diesel/etc. are very energy dense and much easier to store and transport than any alternativd. In some cases e.g. airplane there simply seem to be no other options (unless there is a massive breakthrough in battery tech and possibly out understanding of physics). So ‘clean’ burning synthetic fuels don’t seem like a terrible idea. Of course it all comes down to energy efficiency, but if solar/wind continue growing and carbon capture somehow becomes cost-efficient (assuming free solar/wind energy) it seems like a much better option than continuing oil extraction or even biofuels (which of course is also technically “carbon capture” just not very land/water efficient). > we are not even a bit ahead. Of course. But how does it make it different from every other option? Moving to 100% renewables won’t reverse climate change either .

tsimionescu 3y ago

No, the theoretical point of carbon capture is to take the carbon we released from the ground back into it. Ultimately, there is simply too much CO2 in the atmosphere at the moment. The long term goal has to be to permanently sequester it back into the ground - essentially reversing the last 100-200 years of burning fossil fuels, replacing everything we got from coal, oil, and gas with better alternatives so we can keep living a life that is at least as decent as today's. It is impossible for human civilization as we know it to thrive longer term if we keep the current amount of CO2 (and thus carbon) in any way that is circulating. Of course, capture can and should be the goal after we do the much much easier thing, which is not releasing even 1kg more of the already trapped carbon from the ground.

ffhhttt 3y ago
> It is impossible for human civilization as we know it to thrive longer term if we keep the current amount of CO2 (and thus carbon) in any way that is circulating. I’m not sure that true. Han civilizations “thrived” under much worse conditions than we can reasonably expect (by that I mean that technological/economical/social progress historically outweighed environmental factors and I don’t why this won’t be the case in the future)
- tsimionescu 3y ago
  Han civilization was vastly different from human civilization as we know it today, so it seems you're agreeing with me. I wasn't claiming humans would go extinct, just that there would be a massive upheaval that would entirely change civilization. Also, the Earth has never been as inhospitable to human life as it's expected to be since any known civilization started, so there's no historical precedent to compare to in terms of speed or effects of adaptation.
  - ffhhttt 3y ago
    > Han civilization Sorry. I’m not sure how did I manage to write that, it was supposed to be “civilizations have [thrived]”. > Earth has never been as inhospitable to human life as it's expected to be since any known civilization started, That debatable and very hard to quantify. Also it really depends on the region, e.g. Europe was probably quite worse than now during the “little ice age” or the 600s (coincidentally the Arabian peninsula seems to have thrived during that period due to higher humidity). Climate change was the reason many ancient civilizations collapsed, it seems to have been a pretty regular occurrence and we were only be to break out of that circle in the late middle ages/1500s.

bmer 3y ago

I think you might have a very fundamental misunderstanding on how thermodynamics works? The maximum theoretical efficiency for a combustion engine is about 50%. We'll probably struggle to hit 40%, and that too only after a fair bit of further investment (in particular, materials science investments, and the production of most engineered materials itself requires a fair bit of energy, which generally increases based on the non-standardness/"information-content" of the material (very roughly: "how likely is it that we find a naturally occurring deposit of it on Earth"). So, you cannot really "re-use what's already in it [the atmosphere]". Not sustainably, not while also accommodating growth.

ffhhttt 3y ago
> I think you might have a very fundamental misunderstanding on how thermodynamics works? Why would you say that? lol. If we have a large surplus of cheap solar/wind energy during certain periods (which is unavoidable if they share will continue increasing significantly in the future). Of course yeah, that only works if this process becomes relatively cheap and efficient.
- bmer 3y ago
  > Why would you say that? lol. I'm not entirely sure if you do have a misunderstanding, which is why I asked the question. I'm trying to figure out why you think "carbon capturing" is equivalent to "being able to re-mine hydrocarbons"? Assuming for the moment that the rest of the process is perfect (that is: ignoring that it costs energy to perform carbon capture, ignoring that it costs energy to convert from captured carbon back into some sort of usable hydrocarbon, etc.): it is already very challenging to get to even 50% efficiency in the engines involved in converting a fuel into electricity; whether that engine is an ICE, or a steam engine often used to convert certain renewable sources of energy into other forms. Most of that lost efficiency is due to fundamental constraints of thermodynamics : https://en.wikipedia.org/wiki/Carnot_heat_engine https://en.wikipedia.org/wiki/Carnot_heat_engine (Essentially, useful engines that produce mechanical work from difference in average energy between two bodies operate in cycles. Suppose we start at time 0, and it takes k time ticks for a cycle to start from its initial state X(0), go through its processes, and return back to the initial state: X(k). The fact is that X(0) and X(k) must be different, they cannot be exactly the same, because then that would mean that it is impossible to distinguish between X(0) and X(k), and your engine is not just an engine, but a time machine. (This is why entropy is closely related to the fact that time is an "arrow": always moving in a particular direction.)) All this to say: it is not possible to use a finite source of energy for a "long time", unless the finite source dwarfs by "many orders of magnitudes" (how large the magnitude, determines how much time before it runs out) the energy drained from it per time tick. So even if we got carbon capture working as a way to "recycle fuel" (totally, totally ignoring the fact that it will cost more energy to do the carbon capture and store said captured carbon, than the mechanical work we get out of it (the nuclear fusion problem, except not even technically solvable)) it would not last us for more than a few seconds. (Existing hydrocarbon reservoirs do dwarf our current energy use per time tick, but not by that much, and not if we also want to accommodate material growth, because of the energy cost of also "safely managing" the byproducts of the hydrocarbon->mechanical work process. The sun in particular, massively, massively dwarfs our current use per time tick. This is what makes "renewables" renewable: they have a massive bank of energy banking them. We have an awe-inspiring fusion reactor just throwing energy at us for a while. How do we convert it into usable work?) https://e360.yale.edu/features/three-myths-about-renewable-energy-and-the-grid-debunked https://e360.yale.edu/features/three-myths-about-renewable-e... Putting all that together as the context then, my question to you would be: how can one still use captured carbon as a sort of battery in any meaningful way? Is there a misunderstanding of thermodynamics involved on your part, or could you help me understand where my misunderstanding around thermodynamics lies (I am not an expert, just a novice)?