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The article kind of glosses over the fact that one of the inputs to the process is hydrogen. That really makes this whole process a way of converting energy st

The article kind of glosses over the fact that one of the inputs to the process is hydrogen. That really makes this whole process a way of converting energy stored in hydrogen to energy stored in hydrocarbons. This is pretty desirable - hydrocarbon fuels are much easier to work with, fit in with our existing transport - but not really a new source of energy. The problem with sequestering CO2 as hydrocarbons is that you need to put a whole load of energy (embodied in the hydrogen you're combining it with) into the ground and leave it there. Fortunately renewables (especially solar) are heading in the right direction. On a sunny day in an area with lots of solar panels, electricity is essentially free. We're still some way from having enough free energy available to be able to put large amounts of it back into the ground though.

gnode 8y ago
> The problem with sequestering CO2 as hydrocarbons is that you need to put a whole load of energy (embodied in the hydrogen you're combining it with) into the ground and leave it there. If sequestering CO2, combining it with CaO to make CaCO3 (calcium carbonate) makes more sense, and is even exothermic. It's also biologically harmless and can be safely dumped, used in building materials, etc.
- khuey 8y ago
  Isn't CaO largely produced from naturally occuring CaCO3 though? Where do you get a large supply of CaO to react with your sequestered CO2 from?
  - gnode 8y ago
    Apparently when CO2 is injected into hot underground basalt deposits, it is absorbed. https://en.wikipedia.org/wiki/Carbon_sequestration#Mineral_carbonation https://en.wikipedia.org/wiki/Carbon_sequestration#Mineral_c... (last paragraph of section) So I would guess the reason for producing synthetic CaO from CaCO3 is that extracting natural CaO is uneconomical.
    - technicalbard 8y ago
      CaO generally does not exist in natural stone deposits (no alkaline or alkali earths exist as oxides because they are very reactive). You produce CaO from CaCO3 by calcining and driving off the CO2 (which is emitted to the atmosphere).
      - gnode 8y ago
        My understanding (someone correct me if I'm wrong) is that virgin CaO is released from volcanic activity, and the aforementioned underground basalt is an igneous rock that has not been exposed to surface atmospheric conditions, and thus contains some amount of unreacted CaO.
metalliqaz 8y ago
The hydrogen is needed for making fuel, but why would it be needed for sequestering?
- juliangoldsmith 8y ago
  The carbon is sequestered by turning it into fuel.
  - metalliqaz 8y ago
    No, the carbon is sequestered buy pumping it deep underground. There's no reason to make fuel if you don't plan on burning it.
    - juliangoldsmith 8y ago
      That's what you do when you sequester it with calcium oxide. This article is about using carbon dioxide to produce usable fuel, that you would burn. Scaled up it would provide a carbon-neutral solution to long-term energy storage.
      - metalliqaz 8y ago
        The article also mentions sequestering underground, there's just no way to make a profit doing so at the moment.
frandroid 8y ago
I think the important part is that widespread adoption of this would reduce the amount of new CO2 emitted into the atmosphere. Even if it was more expensive to produce than extracting oil from the ground (itself a process which is becoming more and more expensive, see tar sands), states could mandate that an increasing share of all gasoline sold be made from this process.
- soperj 8y ago
  tar sands is becoming less expensive as time goes on, fracking is vastly less expensive and is the main increase of oil in the last decade.
juliangoldsmith 8y ago
> The problem with sequestering CO2 as hydrocarbons is that you need to put a whole load of energy (embodied in the hydrogen you're combining it with) into the ground and leave it there. Why would you be putting energy into the ground? If you're producing hydrocarbons, those will presumably be burned or used for something else (e.g. plastics).
- loeg 8y ago
  It only removes the carbon from the atmosphere if you don't subsequently burn it.
  - tomatotomato37 8y ago
    It burns carbon that was in the air to begin with though. An attempt at a closed loop with gasoline is better than a one way road into the atmosphere
    - loeg 8y ago
      The loop isn't closed — you have to add energy to drive the process.
      - smt88 8y ago
        True, but the new energy could be renewable/clean. In that case, it's like you're using hydrocarbons as a storage and transport mechanism for renewables. Also lets you have nearly net-zero carbon emissions from the billions of hydrocarbon-burning engines in the world.
        Johnny555 8y ago
        Efficiency still matters -- Renewable doesn't mean unlimited or cheap -- if it takes 10X more energy to create hydrocarbons than you get back from burning them, maybe it's better to use that energy for more efficient transportation storage systems. Then you can use some of the energy saved for direct carbon sequestration.
guntars 8y ago
In addition to hydrogen, the Fischer–Tropsch requires carbon monoxide and not carbon dioxide. It can be produced from carbon dioxide, it just requires even more energy (comparable to hydrogen production from water) and potentially rare catalysts. Energy wise this process might still be favorable to producing biofuels from plants or algae, so I hope they're successful.
yongjik 8y ago
Yeah I skimmed through the linked article[1] very quickly, and the word "hydrogen" appears only twice. It does seem like they're glossing over the cost of hydrogen, which wouldn't be cheap if they want to produce fuel. (All the energy stored in the fuel basically comes from hydrogen.) [1] https://www.cell.com/joule/fulltext/S2542-4351(18)30225-3 https://www.cell.com/joule/fulltext/S2542-4351(18)30225-3
- xyzzyz 8y ago
  The cheap way to obtain hydrogen is to produce it from natural gas, which is of course missing the whole point of CO_2 sequestration.
  - semi-extrinsic 8y ago
    Well, kinda. You can do methane to hydrogen with CO2 capture and storage. But my big question is why would you want to convert it into hydrocarbons for transport then? Direct air capture (DAC) is a maybe-way-out-in-the-2050s technology, but even assuming it were readily and cheaply available in large scale today, doing DAC straight to storage and then just using oil and gas like we've always done would be a much cheaper and more efficient method than going what you propose. Basically: air->CO2->storage AND (CH3)n->burn versus air->CO2[a] AND (CH3)n->CO2[b] + H2[b] AND CO2[a] + H2[b] -> (CH3)n->burn AND CO2[b]->storage (Obviously not taken to be real well-defined balanced chemical reactions).
    - technicalbard 8y ago
      Why anyone would try to capture CO2 from AIR (at 410 ppm) when you could get it from flue gas (from a power plant), where it exists at tens of thousand of ppm (i.e. %) is beyond me. The technology has been commercially demonstrated to capture CO2 and compress it for about $100/tonne.
IanDrake 8y ago
The real thing this article glosses over is how the hydrogen is produced! 95% of hydrogen is produced by splitting hydrocarbons, not by splitting water. Clearly, the assumption is the hydrogen comes from some miracle carbon-neutral source...but it doesn’t.
- mrfusion 8y ago
  Isn’t the hydrogen included in the $94 Per ton? And it’s still viable.
  - technicalbard 8y ago
    No. The prices they quote are JUST getting the CO2 out of the air. Other technologies for getting CO2 from Flue Gas using amines or ammonia have been commercially demonstrated at scale for similar prices. The hydrogen production, FT reactors, post-treating refinery will cost a lot more. If you want hydrogen from water, you need electricity. A lot of it. Nuclear reactors will be the most viable way to do that.
samatman 8y ago
> The problem with sequestering CO2 as hydrocarbons is that you need to put a whole load of energy (embodied in the hydrogen you're combining it with) into the ground and leave it there. That sounds like a problem into you translate it into "leave rice straw on the fields".
derefr 8y ago
It's kind of funny, really: through human history, we "gained" a lot of "free" energy by burning fossil fuels; now, to fully recover our atmosphere from the externalities of that energy generation, we would have to expend just as much, if not more, than that total amount of energy we ever "gained", to essentially un-burn those same fossil fuels.
- toomuchtodo 8y ago
  > we would have to expend just as much, if not more, than that total amount of energy we ever "gained", to essentially un-burn those same fossil fuels. Ironically enough, our renewable electrification process is like a turbo coming up to speed. There is simply so much energy hitting the Earth from the Sun (if I recall off hand, about an hour of sunlight can power humanity for a year, or thereabouts) that if we continue to rapidly deploy solar and wind, we'll have orders of magnitude more energy than humanity currently requires for a first world lifestyle while also having enough energy to sequestor all of the original carbon burned through fossil fuel based industrialization. "A long way around the block" if you will. https://www.iea.org/publications/renewables2017/ https://www.iea.org/publications/renewables2017/ https://www.energy.gov/eere/articles/4-charts-show-renewable-energy-rise-america https://www.energy.gov/eere/articles/4-charts-show-renewable...
  - growlist 8y ago
    I pray this is the case. I dream of a world where energy is so cheap we could bury our roads in tunnels underground, freeing the surface from their blight.
    - toomuchtodo 8y ago
      Don’t dream, find opportunities to contribute. I myself am working on transitioning out of security engineering into renewable energy/utility storage deployment.
      - rmcpherson 8y ago

gnode 8y ago

> The problem with sequestering CO2 as hydrocarbons is that you need to put a whole load of energy (embodied in the hydrogen you're combining it with) into the ground and leave it there. If sequestering CO2, combining it with CaO to make CaCO3 (calcium carbonate) makes more sense, and is even exothermic. It's also biologically harmless and can be safely dumped, used in building materials, etc.

khuey 8y ago
Isn't CaO largely produced from naturally occuring CaCO3 though? Where do you get a large supply of CaO to react with your sequestered CO2 from?
- gnode 8y ago
  Apparently when CO2 is injected into hot underground basalt deposits, it is absorbed. https://en.wikipedia.org/wiki/Carbon_sequestration#Mineral_carbonation https://en.wikipedia.org/wiki/Carbon_sequestration#Mineral_c... (last paragraph of section) So I would guess the reason for producing synthetic CaO from CaCO3 is that extracting natural CaO is uneconomical.
  - technicalbard 8y ago
    CaO generally does not exist in natural stone deposits (no alkaline or alkali earths exist as oxides because they are very reactive). You produce CaO from CaCO3 by calcining and driving off the CO2 (which is emitted to the atmosphere).
    - gnode 8y ago
      My understanding (someone correct me if I'm wrong) is that virgin CaO is released from volcanic activity, and the aforementioned underground basalt is an igneous rock that has not been exposed to surface atmospheric conditions, and thus contains some amount of unreacted CaO.

metalliqaz 8y ago

The hydrogen is needed for making fuel, but why would it be needed for sequestering?

juliangoldsmith 8y ago
The carbon is sequestered by turning it into fuel.
- metalliqaz 8y ago
  No, the carbon is sequestered buy pumping it deep underground. There's no reason to make fuel if you don't plan on burning it.
  - juliangoldsmith 8y ago
    That's what you do when you sequester it with calcium oxide. This article is about using carbon dioxide to produce usable fuel, that you would burn. Scaled up it would provide a carbon-neutral solution to long-term energy storage.
    - metalliqaz 8y ago
      The article also mentions sequestering underground, there's just no way to make a profit doing so at the moment.

frandroid 8y ago

I think the important part is that widespread adoption of this would reduce the amount of new CO2 emitted into the atmosphere. Even if it was more expensive to produce than extracting oil from the ground (itself a process which is becoming more and more expensive, see tar sands), states could mandate that an increasing share of all gasoline sold be made from this process.

soperj 8y ago
tar sands is becoming less expensive as time goes on, fracking is vastly less expensive and is the main increase of oil in the last decade.

juliangoldsmith 8y ago

> The problem with sequestering CO2 as hydrocarbons is that you need to put a whole load of energy (embodied in the hydrogen you're combining it with) into the ground and leave it there. Why would you be putting energy into the ground? If you're producing hydrocarbons, those will presumably be burned or used for something else (e.g. plastics).

loeg 8y ago
It only removes the carbon from the atmosphere if you don't subsequently burn it.
- tomatotomato37 8y ago
  It burns carbon that was in the air to begin with though. An attempt at a closed loop with gasoline is better than a one way road into the atmosphere
  - loeg 8y ago
    The loop isn't closed — you have to add energy to drive the process.
    - smt88 8y ago
      True, but the new energy could be renewable/clean. In that case, it's like you're using hydrocarbons as a storage and transport mechanism for renewables. Also lets you have nearly net-zero carbon emissions from the billions of hydrocarbon-burning engines in the world.
      - Johnny555 8y ago
        Efficiency still matters -- Renewable doesn't mean unlimited or cheap -- if it takes 10X more energy to create hydrocarbons than you get back from burning them, maybe it's better to use that energy for more efficient transportation storage systems. Then you can use some of the energy saved for direct carbon sequestration.

guntars 8y ago

In addition to hydrogen, the Fischer–Tropsch requires carbon monoxide and not carbon dioxide. It can be produced from carbon dioxide, it just requires even more energy (comparable to hydrogen production from water) and potentially rare catalysts. Energy wise this process might still be favorable to producing biofuels from plants or algae, so I hope they're successful.

yongjik 8y ago

Yeah I skimmed through the linked article[1] very quickly, and the word "hydrogen" appears only twice. It does seem like they're glossing over the cost of hydrogen, which wouldn't be cheap if they want to produce fuel. (All the energy stored in the fuel basically comes from hydrogen.) [1] https://www.cell.com/joule/fulltext/S2542-4351(18)30225-3 https://www.cell.com/joule/fulltext/S2542-4351(18)30225-3

xyzzyz 8y ago
The cheap way to obtain hydrogen is to produce it from natural gas, which is of course missing the whole point of CO_2 sequestration.
- semi-extrinsic 8y ago
  Well, kinda. You can do methane to hydrogen with CO2 capture and storage. But my big question is why would you want to convert it into hydrocarbons for transport then? Direct air capture (DAC) is a maybe-way-out-in-the-2050s technology, but even assuming it were readily and cheaply available in large scale today, doing DAC straight to storage and then just using oil and gas like we've always done would be a much cheaper and more efficient method than going what you propose. Basically: air->CO2->storage AND (CH3)n->burn versus air->CO2[a] AND (CH3)n->CO2[b] + H2[b] AND CO2[a] + H2[b] -> (CH3)n->burn AND CO2[b]->storage (Obviously not taken to be real well-defined balanced chemical reactions).
  - technicalbard 8y ago
    Why anyone would try to capture CO2 from AIR (at 410 ppm) when you could get it from flue gas (from a power plant), where it exists at tens of thousand of ppm (i.e. %) is beyond me. The technology has been commercially demonstrated to capture CO2 and compress it for about $100/tonne.

IanDrake 8y ago

The real thing this article glosses over is how the hydrogen is produced! 95% of hydrogen is produced by splitting hydrocarbons, not by splitting water. Clearly, the assumption is the hydrogen comes from some miracle carbon-neutral source...but it doesn’t.

mrfusion 8y ago
Isn’t the hydrogen included in the $94 Per ton? And it’s still viable.
- technicalbard 8y ago
  No. The prices they quote are JUST getting the CO2 out of the air. Other technologies for getting CO2 from Flue Gas using amines or ammonia have been commercially demonstrated at scale for similar prices. The hydrogen production, FT reactors, post-treating refinery will cost a lot more. If you want hydrogen from water, you need electricity. A lot of it. Nuclear reactors will be the most viable way to do that.

samatman 8y ago

derefr 8y ago

It's kind of funny, really: through human history, we "gained" a lot of "free" energy by burning fossil fuels; now, to fully recover our atmosphere from the externalities of that energy generation, we would have to expend just as much, if not more, than that total amount of energy we ever "gained", to essentially un-burn those same fossil fuels.

toomuchtodo 8y ago
> we would have to expend just as much, if not more, than that total amount of energy we ever "gained", to essentially un-burn those same fossil fuels. Ironically enough, our renewable electrification process is like a turbo coming up to speed. There is simply so much energy hitting the Earth from the Sun (if I recall off hand, about an hour of sunlight can power humanity for a year, or thereabouts) that if we continue to rapidly deploy solar and wind, we'll have orders of magnitude more energy than humanity currently requires for a first world lifestyle while also having enough energy to sequestor all of the original carbon burned through fossil fuel based industrialization. "A long way around the block" if you will. https://www.iea.org/publications/renewables2017/ https://www.iea.org/publications/renewables2017/ https://www.energy.gov/eere/articles/4-charts-show-renewable-energy-rise-america https://www.energy.gov/eere/articles/4-charts-show-renewable...
- growlist 8y ago
  I pray this is the case. I dream of a world where energy is so cheap we could bury our roads in tunnels underground, freeing the surface from their blight.
  - toomuchtodo 8y ago
    Don’t dream, find opportunities to contribute. I myself am working on transitioning out of security engineering into renewable energy/utility storage deployment.
    - rmcpherson 8y ago