7 ms·

This is a cool idea, but it comes with a weird perverse incentive problem. The authors estimate that a "CC CNF" power plant would produce $835 of electricity a

This is a cool idea, but it comes with a weird perverse incentive problem. The authors estimate that a "CC CNF" power plant would produce $835 of electricity and over $225,000 of nanotubes from a single metric ton of methane. At this point, economically, this is no longer a power plant: it is a carbon nanotube factory that has the side-effect of producing power. And if nanotubes are so valuable, the power generation part starts to look like a distraction: why not just pull the electricity off the grid and convert methane/CO2/coal/oil straight into nanotubes for less cost and complexity? So really, this doesn't seem to be about power plants, so much as a (maybe) cheap way to make nanotubes from carbon. If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made.

duaneb 10y ago
> If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made. Is this really a shorter path than just planting more trees, which is both cheap and extremely low maintenance?
- vkou 10y ago
  Trees can sequester a bounded amount of carbon from the air. Burning fossil fuels can release an almost unbounded amount of carbon into the air.
  - duaneb 10y ago
    > Trees can sequester a bounded amount of carbon from the air. So plant more trees? It's a continual process. It's not like you can plant a tree and say "Ok, I'm carbon neutral now!"
    - vkou 10y ago
      We only have so much land to plant trees on. (Which is very quickly shrinking due to urban and agricultural pressure.) The current amount of carbon sequestered in all of the world's forests is ~600 giga-tonnes. If we stopped all of our carbon emissions today, and tried to roll back to pre-industrial CO2 levels, we'd need to sequester ~270 giga-tonnes of carbon. Losing that much agricultural land is unrealistic - expensive as they are, it would be much less painful to switch our entire energy economy to renewables.
      - rosser 10y ago
        Many kind of trees can grow on land that's not agriculturally viable.
        vkou 10y ago
        This is certainly true, but we are talking about absolutely staggering amounts of land. As it stands now, ~30% of our planet's landmasses are covered in forest. Also, some kinds of forest are much better at sequestering carbon - specifically, the tropical rainforests that are being cut and burnt in the tropics. Re-forestation is part of the solution, but it's no panacea.
        rosser 10y ago
        > Re-forestation is part of the solution, but it's no panacea. I hadn't meant to suggest it was. I'm merely saying that any approach to our carbon problem that doesn't include planting trees is inadequate.
        duaneb 10y ago
        > Re-forestation is part of the solution, but it's no panacea. Ahh, I misunderstood, my bad. I thought you were arguing that reforestation was not even worth the effort.
        ageofwant 10y ago
        Spreading a few million tons of powdered iron ore over the southern ocean will capture vast quantities of carbon in the resulting plankton boom, will feed enormous schools of fish and precipitate to the ocean bottom where it will lay captured for millennia. You don't need vast forests to capture carbon. You need one soon to be retired 30 year old panamax ship. A cargo hold full of ore (~50$/ton + 20$ powdering), and a on-board pump/aerator.
    - rosser 10y ago
      Because planting trees is a bad idea on its own merits somehow?
      - DanBC 10y ago
        Yes, it can be. Dense planting means the canopy can prevent rain getting to the ground and the trees take a lot of the water that does get to the ground which means aquifers are not replenished. The dry ground and dry trees pose an increased fire risk. Burning the tree releases any captured carbon, and a bunch of smoke. New forests crowd out and change existing eco systems, meaning many animals are lost to the area.
        ageofwant 10y ago
        I highly doubt temperate or even tropical forest canopies will prevent water from reaching ground level. Gravity does not work that way. Trees shade soil reducing evaporation levels. Trees also significantly reduce surface winds further reducing evaporation. Yes trees do potentially use more water which is exactly what you want, what is the purpose of full aquifers flowing into the sea ? In Australia removal of trees has lead to increased salinity levels affecting 2 Million hectares (In WA alone) of arable land degrading vast swathes of it rendering it unusable for both modern agriculture and pre-agricultural "natural" use. This is precisely because the trees kept the high-salinity water table below surface root levels.
        rosser 10y ago
        > New forests crowd out and change existing eco systems, meaning many animals are lost to the area. I'd be happy with merely replacing some of the forests that we cut down in the first place. You know, if we're going to make arguments premised on human activity altering extant ecosystems, and all...
      - ams6110 10y ago
        Well if you imagine planting trees in vast numbers where there are none today, that will have a rather dramatic environmental impact on any species currently living there. Possibly leading to endangerment or extinctions. A price worth paying, perhaps, but others won't agree.
  - Retric 10y ago
    You can bury trees as a stable carbon sink. The real is storing CO2 is not economical and any other cheap form of carbon could be burned. So really the best option is to leave it in the ground in the first place.
    - andrewflnr 10y ago
      Why would you burn a perfectly good building material? Wood construction is also a stable carbon sink.
      - Retric 10y ago
        Scale, 10 Giga Tons of carbon per year. 36 Gigatons of CO2. 7 billion people. Wood is not 100% carbon and a wood house is ~30 tons of wood. But, there is not a house per person and people don't build new houses every few years.
  - schiffern 10y ago
    > Trees can sequester a bounded amount of carbon from the air. Biochar can be continuously applied on fields to improve degraded soils, and its production from woody biomass is energy positive and inexpensive.
- semi-extrinsic 10y ago
  Don't worry. This whole "making stuff from CO2" business is completely stupid anyway. I say this because the volumes of CO2 capture necessary for the two degree scenario (that we all just committed to in Paris) are so beyond the scale of almost anything we manufacture that it's not even funny. We're talking thousands of Hoover dams full of liquid CO2 that has to be captured, transported and stored every year.
  - deleted 10y ago
    [deleted]
  - ams6110 10y ago
    There were agreements in Paris. Commitments have yet to happen.
    - hugh4 10y ago
      Agreeing to do something impossible is easy. Committing to doing something impossible is no harder. It's just that doing something impossible is tricky.
      - eloff 10y ago
        A more apt description of politics I have not seen.
- lawpoop 10y ago
  Trees only hold carbon until they fall and rot. It's not a permanent solution.
  - sp332 10y ago
    Even old-growth forests sequester carbon over time. http://www.nature.com/nature/journal/v455/n7210/full/nature07276.html http://www.nature.com/nature/journal/v455/n7210/full/nature0...
    - whuh 10y ago
      And then when they fossilize, they sequester even more! ...until, of course, humans come along and unsequester it.
  - dredmorbius 10y ago
    Trees don't vanish into clouds of CO₂ on impact with the ground. Time-to-rot varies, from 50-100 years for a spruce, 200-300 for a pine. I've witnessed downed redwoods myself, over the course of four, nearly five decades, which have failed to decompose even in highly damp conditions. Bogs and swamps are also underappreciated CO₂ sinks.
mikeyouse 10y ago
Right.. 1MT of methane leads to 0.75MT of carbon nanotubes valued at $225,000 -- an implicit price of $300,000/MT for CNTs.. EPA estimates that energy production releases about 8.1 million metric tons of methane annually, so if we convert 1% of the methane to CNTs, we'd have about 61,000 metric tons of carbon nanotubes to dispose of. What happens to the price if you dump 60,000 tons of a previously rare product on the market? What happens if you up the requirement to 10% and you have 600,000MT of nanotubes?
- bduerst 10y ago
  You'd most certainly saturate the market, which is estimated to demand < 10k tons right now: http://www.grandviewresearch.com/industry-analysis/carbon-nanotubes-cnt-market http://www.grandviewresearch.com/industry-analysis/carbon-na...
  - jws 10y ago
    But where would the market go when carbon nanotubes and fibers move from exotic and expensive materials to "cheaper than aluminum". It could displace a lot of aluminum and steel.
    - ams6110 10y ago
      Interesting possibilities, right? Imagine automobiles, bridges, buildings all built with carbon frames at a cost potentially far lower than current aluminum or steel, and also consuming a fraction of the energy to produce?
      - TheSpiceIsLife 10y ago
        I'm generally not a big fan of the drive by pithy comment, but: Space elevator!
      - bduerst 10y ago
        Well carbon fiber doesn't bend, so for car frames it wouldn't be the best choice since crumple zones would be non-existent. There will probably be some good applications, but I don't think it's a full replacement for metals.
Rickasaurus 10y ago
Seems likely this would drive down the cost of carbon nanotubes quite a lot
schiffern 10y ago
>If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made. I'm sure most people are picturing factories here, but using low/appropriate tech as well is essential. Building soil and woody biomass can absorb enormous amounts of carbon. The question essentially becomes, how much biomass per hectare are we talking about? Absorbing the 350 teratonnes of human emitted carbon [1] over the 11.7 billion hectares of Earth's non-tundra land surface [2] works out to 30 tonnes of carbon per hectare. If you exclude deserts it's 42 tonnes per hectare, but the technology already exists to successfully "green" deserts. That's 30 trees per hectare, at 1 tonne per tree.[3] Or 3 kg per square meter of soil carbon, the equivalent of 25 cm of topsoil Soil carbon is stored up to 40 meters down by deep rooted plants, so in practice this isn't a problem. [4] Most of our land management is via agricultural, so agricultural reform is the only lever long enough to make a dent. Practically this means switching from soil destroying tillage to soil building cover crops, long-distance imported fertilizer to in-situ fertility produced by soil organisms[5], and ecologically unstable monocultures to resiliant polyculture and agroforestry systems. If you run the numbers trying to use factories alone the cost is astronomical. It's larger* than the world's global energy infrastructure, because thermodynamics is working against you. An overhaul of agriculture using modern environmental biology is the only thing with a lever long enough to make the numbers close. Plus it simultaneously solves the existential risks posed by our laughably unsustainable food production system and the collapse of ecosystem services by habitat destruction.[6] [1] http://petrolog.typepad.com/climate_change/2010/01/cumulative-emissions-of-co2.html http://petrolog.typepad.com/climate_change/2010/01/cumulativ... [2] http://cnx.org/contents/TWFXbERo@1/The-main-biomes http://cnx.org/contents/TWFXbERo@1/The-main-biomes [3] http://cabiblog.typepad.com/hand_picked/2011/06/ever-wondered-how-much-carbon-is-stored-in-a-tree.html http://cabiblog.typepad.com/hand_picked/2011/06/ever-wondere... [4] http://www.soilquality.org.au/factsheets/organic-carbon http://www.soilquality.org.au/factsheets/organic-carbon [5] https://www.youtube.com/watch?v=x2H60ritjag https://www.youtube.com/watch?v=x2H60ritjag [6] http://unctad.org/en/PublicationsLibrary/ditcted2012d3_en.pdf http://unctad.org/en/PublicationsLibrary/ditcted2012d3_en.pd... [PDF, 5.2MB]
- reitanqild 10y ago
  > Absorbing the 350 teratonnes of human emitted carbon ... And that was the first time I ever saw anyone throwing a number for how many tonnes we are really talking about in any debate I have seen either here or on AT. Congrats! More numbers, less politics! (Not saying it is correct, I haven't verified, -but unlike "celebrity X says we should do something now" this is something that can be measured and discussed rationally.)
the8472 10y ago
> why not just pull the electricity off the grid and convert methane/CO2/coal/oil straight into nanotubes for less cost and complexity? The power plant also produces waste heat which presumably is useful for the reaction. So a combined plant that produces electricity and CNTs with zero carbon emissions is likely more efficient than using electricity to a) heat the whole thing b) pull CO2 out of the air c) run electrolysis.
voiper1 10y ago
The price for nanotubes will quickly drop: > Using the new method, the researchers estimate that it would cost just $2,000/ton to produce .. so at .75tons, it would still generate double the revenue from CNTs than from electricity. But still revenue is 1/3 energy and 2/3 CNT so it's still significantly a power plant.
Derpdiherp 10y ago
And potentially creating a heap of new problems seems as there is a good deal of research which suggests that carbon nanotubes are genotoxic and carcinogenic. Disposal of it could be just as costly as Asbestos with just as adverse side effects. I fully understand that some people getting cancer is less of a problem than our planet becoming uninhabitable, but it most certainly can't be swept under the carpet and forgotten about. http://www.ncbi.nlm.nih.gov/pubmed/23751780 http://www.ncbi.nlm.nih.gov/pubmed/23751780 http://www.ncbi.nlm.nih.gov/pubmed/16686422 http://www.ncbi.nlm.nih.gov/pubmed/16686422 http://www.ncbi.nlm.nih.gov/pubmed/20795897 http://www.ncbi.nlm.nih.gov/pubmed/20795897
rbanffy 10y ago
> If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere We already do that. It's called food. Pretty much all carbon you see on your plate came from CO2 floating in the atmosphere. And, BTW, if we remove all CO2 from the atmosphere to make cars, batteries and bridges, we'll eventually realize those things are not very nutritious.

duaneb 10y ago

> If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made. Is this really a shorter path than just planting more trees, which is both cheap and extremely low maintenance?

vkou 10y ago
Trees can sequester a bounded amount of carbon from the air. Burning fossil fuels can release an almost unbounded amount of carbon into the air.
- duaneb 10y ago
  > Trees can sequester a bounded amount of carbon from the air. So plant more trees? It's a continual process. It's not like you can plant a tree and say "Ok, I'm carbon neutral now!"
  - vkou 10y ago
    We only have so much land to plant trees on. (Which is very quickly shrinking due to urban and agricultural pressure.) The current amount of carbon sequestered in all of the world's forests is ~600 giga-tonnes. If we stopped all of our carbon emissions today, and tried to roll back to pre-industrial CO2 levels, we'd need to sequester ~270 giga-tonnes of carbon. Losing that much agricultural land is unrealistic - expensive as they are, it would be much less painful to switch our entire energy economy to renewables.
    - rosser 10y ago
      Many kind of trees can grow on land that's not agriculturally viable.
      - vkou 10y ago
        This is certainly true, but we are talking about absolutely staggering amounts of land. As it stands now, ~30% of our planet's landmasses are covered in forest. Also, some kinds of forest are much better at sequestering carbon - specifically, the tropical rainforests that are being cut and burnt in the tropics. Re-forestation is part of the solution, but it's no panacea.
        rosser 10y ago
        > Re-forestation is part of the solution, but it's no panacea. I hadn't meant to suggest it was. I'm merely saying that any approach to our carbon problem that doesn't include planting trees is inadequate.
        duaneb 10y ago
        > Re-forestation is part of the solution, but it's no panacea. Ahh, I misunderstood, my bad. I thought you were arguing that reforestation was not even worth the effort.
      - ageofwant 10y ago
        Spreading a few million tons of powdered iron ore over the southern ocean will capture vast quantities of carbon in the resulting plankton boom, will feed enormous schools of fish and precipitate to the ocean bottom where it will lay captured for millennia. You don't need vast forests to capture carbon. You need one soon to be retired 30 year old panamax ship. A cargo hold full of ore (~50$/ton + 20$ powdering), and a on-board pump/aerator.
  - rosser 10y ago
    Because planting trees is a bad idea on its own merits somehow?
    - DanBC 10y ago
      Yes, it can be. Dense planting means the canopy can prevent rain getting to the ground and the trees take a lot of the water that does get to the ground which means aquifers are not replenished. The dry ground and dry trees pose an increased fire risk. Burning the tree releases any captured carbon, and a bunch of smoke. New forests crowd out and change existing eco systems, meaning many animals are lost to the area.
      - ageofwant 10y ago
        I highly doubt temperate or even tropical forest canopies will prevent water from reaching ground level. Gravity does not work that way. Trees shade soil reducing evaporation levels. Trees also significantly reduce surface winds further reducing evaporation. Yes trees do potentially use more water which is exactly what you want, what is the purpose of full aquifers flowing into the sea ? In Australia removal of trees has lead to increased salinity levels affecting 2 Million hectares (In WA alone) of arable land degrading vast swathes of it rendering it unusable for both modern agriculture and pre-agricultural "natural" use. This is precisely because the trees kept the high-salinity water table below surface root levels.
      - rosser 10y ago
        > New forests crowd out and change existing eco systems, meaning many animals are lost to the area. I'd be happy with merely replacing some of the forests that we cut down in the first place. You know, if we're going to make arguments premised on human activity altering extant ecosystems, and all...
    - ams6110 10y ago
      Well if you imagine planting trees in vast numbers where there are none today, that will have a rather dramatic environmental impact on any species currently living there. Possibly leading to endangerment or extinctions. A price worth paying, perhaps, but others won't agree.
- Retric 10y ago
  You can bury trees as a stable carbon sink. The real is storing CO2 is not economical and any other cheap form of carbon could be burned. So really the best option is to leave it in the ground in the first place.
  - andrewflnr 10y ago
    Why would you burn a perfectly good building material? Wood construction is also a stable carbon sink.
    - Retric 10y ago
      Scale, 10 Giga Tons of carbon per year. 36 Gigatons of CO2. 7 billion people. Wood is not 100% carbon and a wood house is ~30 tons of wood. But, there is not a house per person and people don't build new houses every few years.
- schiffern 10y ago
  > Trees can sequester a bounded amount of carbon from the air. Biochar can be continuously applied on fields to improve degraded soils, and its production from woody biomass is energy positive and inexpensive.
semi-extrinsic 10y ago
Don't worry. This whole "making stuff from CO2" business is completely stupid anyway. I say this because the volumes of CO2 capture necessary for the two degree scenario (that we all just committed to in Paris) are so beyond the scale of almost anything we manufacture that it's not even funny. We're talking thousands of Hoover dams full of liquid CO2 that has to be captured, transported and stored every year.
- deleted 10y ago
  [deleted]
- ams6110 10y ago
  There were agreements in Paris. Commitments have yet to happen.
  - hugh4 10y ago
    Agreeing to do something impossible is easy. Committing to doing something impossible is no harder. It's just that doing something impossible is tricky.
    - eloff 10y ago
      A more apt description of politics I have not seen.
lawpoop 10y ago
Trees only hold carbon until they fall and rot. It's not a permanent solution.
- sp332 10y ago
  Even old-growth forests sequester carbon over time. http://www.nature.com/nature/journal/v455/n7210/full/nature07276.html http://www.nature.com/nature/journal/v455/n7210/full/nature0...
  - whuh 10y ago
    And then when they fossilize, they sequester even more! ...until, of course, humans come along and unsequester it.
- dredmorbius 10y ago
  Trees don't vanish into clouds of CO₂ on impact with the ground. Time-to-rot varies, from 50-100 years for a spruce, 200-300 for a pine. I've witnessed downed redwoods myself, over the course of four, nearly five decades, which have failed to decompose even in highly damp conditions. Bogs and swamps are also underappreciated CO₂ sinks.

mikeyouse 10y ago

Right.. 1MT of methane leads to 0.75MT of carbon nanotubes valued at $225,000 -- an implicit price of $300,000/MT for CNTs.. EPA estimates that energy production releases about 8.1 million metric tons of methane annually, so if we convert 1% of the methane to CNTs, we'd have about 61,000 metric tons of carbon nanotubes to dispose of. What happens to the price if you dump 60,000 tons of a previously rare product on the market? What happens if you up the requirement to 10% and you have 600,000MT of nanotubes?

bduerst 10y ago
You'd most certainly saturate the market, which is estimated to demand < 10k tons right now: http://www.grandviewresearch.com/industry-analysis/carbon-nanotubes-cnt-market http://www.grandviewresearch.com/industry-analysis/carbon-na...
- jws 10y ago
  But where would the market go when carbon nanotubes and fibers move from exotic and expensive materials to "cheaper than aluminum". It could displace a lot of aluminum and steel.
  - ams6110 10y ago
    Interesting possibilities, right? Imagine automobiles, bridges, buildings all built with carbon frames at a cost potentially far lower than current aluminum or steel, and also consuming a fraction of the energy to produce?
    - TheSpiceIsLife 10y ago
      I'm generally not a big fan of the drive by pithy comment, but: Space elevator!
    - bduerst 10y ago
      Well carbon fiber doesn't bend, so for car frames it wouldn't be the best choice since crumple zones would be non-existent. There will probably be some good applications, but I don't think it's a full replacement for metals.

Rickasaurus 10y ago

Seems likely this would drive down the cost of carbon nanotubes quite a lot

schiffern 10y ago

>If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere, then maybe, just _maybe_, we can start fixing the mess we made. I'm sure most people are picturing factories here, but using low/appropriate tech as well is essential. Building soil and woody biomass can absorb enormous amounts of carbon. The question essentially becomes, how much biomass per hectare are we talking about? Absorbing the 350 teratonnes of human emitted carbon [1] over the 11.7 billion hectares of Earth's non-tundra land surface [2] works out to 30 tonnes of carbon per hectare. If you exclude deserts it's 42 tonnes per hectare, but the technology already exists to successfully "green" deserts. That's 30 trees per hectare, at 1 tonne per tree.[3] Or 3 kg per square meter of soil carbon, the equivalent of 25 cm of topsoil Soil carbon is stored up to 40 meters down by deep rooted plants, so in practice this isn't a problem. [4] Most of our land management is via agricultural, so agricultural reform is the only lever long enough to make a dent. Practically this means switching from soil destroying tillage to soil building cover crops, long-distance imported fertilizer to in-situ fertility produced by soil organisms[5], and ecologically unstable monocultures to resiliant polyculture and agroforestry systems. If you run the numbers trying to use factories alone the cost is astronomical. It's larger* than the world's global energy infrastructure, because thermodynamics is working against you. An overhaul of agriculture using modern environmental biology is the only thing with a lever long enough to make the numbers close. Plus it simultaneously solves the existential risks posed by our laughably unsustainable food production system and the collapse of ecosystem services by habitat destruction.[6] [1] http://petrolog.typepad.com/climate_change/2010/01/cumulative-emissions-of-co2.html http://petrolog.typepad.com/climate_change/2010/01/cumulativ... [2] http://cnx.org/contents/TWFXbERo@1/The-main-biomes http://cnx.org/contents/TWFXbERo@1/The-main-biomes [3] http://cabiblog.typepad.com/hand_picked/2011/06/ever-wondered-how-much-carbon-is-stored-in-a-tree.html http://cabiblog.typepad.com/hand_picked/2011/06/ever-wondere... [4] http://www.soilquality.org.au/factsheets/organic-carbon http://www.soilquality.org.au/factsheets/organic-carbon [5] https://www.youtube.com/watch?v=x2H60ritjag https://www.youtube.com/watch?v=x2H60ritjag [6] http://unctad.org/en/PublicationsLibrary/ditcted2012d3_en.pdf http://unctad.org/en/PublicationsLibrary/ditcted2012d3_en.pd... [PDF, 5.2MB]

reitanqild 10y ago
> Absorbing the 350 teratonnes of human emitted carbon ... And that was the first time I ever saw anyone throwing a number for how many tonnes we are really talking about in any debate I have seen either here or on AT. Congrats! More numbers, less politics! (Not saying it is correct, I haven't verified, -but unlike "celebrity X says we should do something now" this is something that can be measured and discussed rationally.)

the8472 10y ago

> why not just pull the electricity off the grid and convert methane/CO2/coal/oil straight into nanotubes for less cost and complexity? The power plant also produces waste heat which presumably is useful for the reaction. So a combined plant that produces electricity and CNTs with zero carbon emissions is likely more efficient than using electricity to a) heat the whole thing b) pull CO2 out of the air c) run electrolysis.

voiper1 10y ago

The price for nanotubes will quickly drop: > Using the new method, the researchers estimate that it would cost just $2,000/ton to produce .. so at .75tons, it would still generate double the revenue from CNTs than from electricity. But still revenue is 1/3 energy and 2/3 CNT so it's still significantly a power plant.

Derpdiherp 10y ago

And potentially creating a heap of new problems seems as there is a good deal of research which suggests that carbon nanotubes are genotoxic and carcinogenic. Disposal of it could be just as costly as Asbestos with just as adverse side effects. I fully understand that some people getting cancer is less of a problem than our planet becoming uninhabitable, but it most certainly can't be swept under the carpet and forgotten about. http://www.ncbi.nlm.nih.gov/pubmed/23751780 http://www.ncbi.nlm.nih.gov/pubmed/23751780 http://www.ncbi.nlm.nih.gov/pubmed/16686422 http://www.ncbi.nlm.nih.gov/pubmed/16686422 http://www.ncbi.nlm.nih.gov/pubmed/20795897 http://www.ncbi.nlm.nih.gov/pubmed/20795897

rbanffy 10y ago

> If we can incentivize people to make useful products out of all that CO2 just floating in the atmosphere We already do that. It's called food. Pretty much all carbon you see on your plate came from CO2 floating in the atmosphere. And, BTW, if we remove all CO2 from the atmosphere to make cars, batteries and bridges, we'll eventually realize those things are not very nutritious.