Comment by StableAlkyne

Comment by StableAlkyne a day ago

17 replies

Trouble is always the economics of production. We've been able to turn CO2 into useful materials for a long time.

Sabatier's reaction has been known for about a century, and that turns CO2 into methane. Also Fischer Tropsch will convert CO (which you can get from poor combustion) into larger hydrocarbons.

Many of the advancements nowadays are in making the catalysts more energy efficient or cheaper.

But I suspect eventually what needs to happen is a combination of regulation (to reduce the amount of fossil derived CO2) and government subsidy (to harm the economics of extracting oil, as the free market doesn't intrinsically penaltize long term harm)

jillesvangurp a day ago

The issue with CO2 is that there's not a lot of it in air. The amount is usually expressed in parts per million. It's a bit over 400 these days. Way up from around 280 where it used to be. Only about 0.04% of air is CO2. Which means that by mass and volume, you need to process enormous amounts of air to get a meaningful amount of CO2. The main issue with that is that it requires enormous amounts of energy and large scale infrastructure that by itself is quite wasteful. Once you have it captured, processing it and up-cycling it is not that hard. It's nice that we have some new ways. But it's not like synthetic fuels and plastics weren't already doable for decades.

Carbon capture of course technically works. But you typically end up dumping the CO2 back in the air for things like fuels and plastics after they are expended. So, it's not that meaningful ultimately. You take fossil carbon, you burn it, you capture it, you create another fuel, and you dump it in the air. Because we simply don't capture the overwhelmingly vast majority of fossil carbon that we process and use. Using the carbon twice is a modest improvement. Three times even better. It's not that much of an improvement. Most carbon capture is stupid like that but it sounds nice if you are trying to green wash your CO2 intensive business. Optics and marketing are the main driver for carbon capture schemes. But technically it's just adding cost to things that are already quite expensive.

Keeping the CO2 captured permanently is a bit hand wavy usually and technically a bit of an afterthought usually. We might do this, we might do that. It's going to be amazing. We could have, and would have, and eventually might do some of it. Or none of it. Or somewhere in between. The real world effectiveness of carbon capture to date is generally piss poor. Some people would say it's a scam. And the real worlds amounts of carbon captured ever are so meaninglessly low that dumping all of it back in atmosphere right now would not have any measurable effects whatsoever relative to the still growing amounts we dump into the atmosphere directly.

Anyway we have great carbon capture machines readily available. All plants and trees do this naturally. Burning that stuff to create CO2 is a bit wasteful and not technically that useful if your goal is to process the carbon further. Wood is basically polymers. Much easier to use that directly. Either as a fuel or as a source of polymers (e.g. cellulose) and other carbo hydrates. Of course farming and forestry are hard work and not that cheap.

  • rafaelmn 20 hours ago

    >Carbon capture of course technically works. But you typically end up dumping the CO2 back in the air for things like fuels and plastics after they are expended. So, it's not that meaningful ultimately. You take fossil carbon, you burn it, you capture it, you create another fuel, and you dump it in the air. Because we simply don't capture the overwhelmingly vast majority of fossil carbon that we process and use. Using the carbon twice is a modest improvement. Three times even better. It's not that much of an improvement. Most carbon capture is stupid like that but it sounds nice if you are trying to green wash your CO2 intensive business. Optics and marketing are the main driver for carbon capture schemes. But technically it's just adding cost to things that are already quite expensive.

    I have heard about a proposal to blow up a huge nuclear bomb in deep sea basalt deposits that would dissolve massive amounts of CO2 to the bottom of the ocean. Bomb scale proposed is SF for now but would be interesting to see a PoC experiment with a large warhead.

    https://www.youtube.com/watch?v=aGPKpx6pMko

    • x______________ 16 hours ago

      It would require 3,000,000x the power of hiroshima or 81gt and the negatives involve steam and other materials going into the atmosphere ( like the recent Hunga Tonga volcanic explosion), radioactive nuclear fallout helping the ocean getting a nice glow, and an ocean full of debris which would likely kill of most ocean life in the region for a while. Not to mention the sudden cooling of our planet by 1.5C affecting climate in unpredictable ways.

      ..and to top it off, my money is on "that's exactly how we get Godzilla"..

      There must be better ways.

      • rafaelmn 11 hours ago

        >radioactive nuclear fallout helping the ocean getting a nice glow

        Fun fact - thermonuclear bombs have relatively little fission products - eg. Tsar derived only 3% of its yield from fission. Paper argues there would be no significant radiation impact, and while the ocean life in the region would get wiped author argues global warming will is worse.

        https://www.researchgate.net/publication/387975147_Nuclear_E...

        Anyway would be interesting if they did a smaller scale experiment to measure the impact - always good to have options.

    • maxhille 16 hours ago

      That sounds like a good way to essentially poison our oceans - maybe we should try leaving some part of the planet somewhat intact?

  • rcxdude a day ago

    >Anyway we have great carbon capture machines readily available. All plants and trees do this naturally

    They do, but it also gets released again unless you take extra steps. And it's not all that efficient: you'd need to grow something the size of the amazon, then cut it down and bury it, to have a notable effect. Other proposed options for carbon capture are already more efficient than that, and as you've noted they've still not taken off.

    • chabska 8 hours ago

      > but it also gets released again

      Quite slowly. Lignin, which makes up about 30% of woody biomass, is very difficult to break down biologically. Only a few specialized bacteria and fungi have the enzymes for it.

      We don't need to sequester carbon permanently, we just need to bind enough of it into soil carbon to reduce the concentration of CO2 in the atmosphere. The long residence time of carbon in the soil is sufficient for this purpose.

  • jl6 21 hours ago

    > Wood is basically polymers. Much easier to use that directly.

    Is there a (plausibly economic) direct wood-to-plastic process?

    • PaulHoule 18 hours ago

      It's a pretty big research area to make useful things from lignocelluose which you could get from trees but also crops like switchgrass:

      https://www.sciencedirect.com/science/article/pii/S266689392...

      Like plastics recycling the basic problem is that it competes with plastic monomers and other bottom-of-pyramid substances that cost about 50 cents a pound. For instance you can make ethanol fuel using either strong chemicals under harsh conditions and mild conditions or with enzymes under mild conditions. Either way it doesn't work economically, you can use $30 of enzyme to make $1 of fuel, but hey, sometimes you get a radical cost reduction.

  • triceratops 18 hours ago

    > Which means that by mass and volume, you need to process enormous amounts of air to get a meaningful amount of CO2

    Dumb question: does it make a difference if you locate someplace windy?

    • jvm___ 17 hours ago

      It's 400 parts per million.

      Take a million bags of rice, then take out 400 and dye the grains black. Dump them back in the main pile and mix it all together.

      Now process it and extract the 400 bags of black rice. Also there's dust and sand and other colors of rice mixed in.

      Wind won't really help you at the volumes of air that you need to capture and filter. Running it in the windy desert will find less C02 than Times Square so where you run your system matters as well.

  • pfdietz 20 hours ago

    > Anyway we have great carbon capture machines readily available. All plants and trees do this naturally.

    The Achilles Heels of this are two: (1) the very low efficiency of photosynthesis, necessitating very large areas of land (PV with BEVs is ~100x more land efficient than ICEs with biofuels), and (2) the enormous amounts of water required, as plants transpire water through the pores that admit the CO2 in the first place.

somedude895 18 hours ago

Good luck regulating China and India

  • pfdietz 18 hours ago

    India has great incentive to control CO2 emission: killer heat waves in a somewhat warmer world. And China seems to be slashing their CO2 intensity without external prodding (coal use there seems to have peaked), and facilitating CO2 emission reduction elsewhere.

    • lazide 18 hours ago

      India already has massive incentives to be more effectively regulated than they are now in a dozen other areas. And yet, they remain India.

      China is definitely more effectively regulated than at regulation once the cdentral gov’t steps in, but it only has a limited number of things it can step in on.

      • lazide 15 hours ago

        Wow auto-correct stroke on the second paragraph.

        China is definitely more effectively regulated than India once the central gov’t steps in, but it only has a limited number of things it can step in on (or wants too).