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  • Mark Holtom (aka Kingbeard)MarkHoltom@mastodonapp.uk
    Jul 31, 2026, 9:28 AM

    I had a chat/debate with a guy about this, and the info is:
    - it costs 2.4 kWh per kg of CO2.
    - there are 18 of these in the world, and the largest can sequester 8,000 tonnes pa.
    - to operate at scale, it needs to be able to process billions of tonnes. So, it would have to scale to 12,760,000%
    - for 1 Bn tonnes of CO2 the energy cost would be the same as for the whole energy usage of all of the EU combined.

    On the other hand, simply planting trees won't fix this. Too little, too late.

    The only realistic scenarios are to
    - immediately halve our energy consumption.
    - insulate so we don't need as much energy.
    - produce as much energy as we can ourselves (solar, etc.)
    - Then to use as many renewable as possible to the supply of the remainder.

    The picture shows the DAC. There is an arrow pointing to a very small mark on the photo. It is a human standing in front of the DAC. He is tiny by comparison.
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Replies

  • Mark Holtom (aka Kingbeard)MarkHoltom@mastodonapp.uk
    Jul 31, 2026, 9:35 AM

    UPDATED:

    There is research on Carbon Capture Systems here
    web.stanford.edu/group/efmh/ja

    The results in Table 3.4 suggest that carbon capture does not come close to eliminating CO2e emissions from coal or gas power plants. Data from real world projects (Section 3.2.3) indicate even less reduction in CO2e emissions due to carbon capture than Table 3.4 suggests

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  • palaresspalaress@mastodon.online
    Jul 31, 2026, 2:27 PM

    @themadhatter

    I think we will still need those, especially after net zero. To "simply" stop emitting is not enough in the long-term. We need to go below 350ppm CO2 levels again. And therefore I would agree with Conny, that this is one part of the solution.

    But you are right, that this is never an excuse for emitting GHG.

    @connynasch @MarkHoltom

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  • Walter C. Smithstiefel_fan@troet.cafe
    Jul 31, 2026, 5:51 PM

    @palaress @themadhatter @connynasch @MarkHoltom
    Exactly this! It's No excuse to further emit GHGes but it might be one part of the solution to lower the CO2 concentration in the athmosphere.
    Now just always say it won't work, we can't build enough is imho like 40 years ago tell the people renewables won't work, because it's not possible to have enough batteries to stabalize the grid ... 🤷🏼‍♂️

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  • Tired and Angrytired_angry@mastodonapp.uk
    Jul 31, 2026, 3:33 PM

    @MarkHoltom
    I’m always dubious of claims that something “doesn’t work” when it is so new. I’m reminded of a few decades ago when people were decrying early solar PV installations, understandably, because their outputs often seemed like a drop in the ocean in comparison to the businesses which had them on their roofs.
    It seems that planting trees alone won’t save us, insulating everything in sight alone won’t save us. EVs instead of petrol & diesel on their own won’t save us.
    So maybe we shouldn’t discourage development of anything which might eventually help unless there really is no hope, ever, of it being useful.

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  • Tired and Angrytired_angry@mastodonapp.uk
    Jul 31, 2026, 3:49 PM

    @MarkHoltom
    Things which seem obvious, to anyone who’s income doesn’t depend on fossil fuels:
    “We” have to stop burning fossil fuels. This surely includes not setting fire to refineries and tankers full of the stuff with bombs & missiles because of 🤷‍♂️ “disagreements” over whatever.
    “We” have to stop destroying forests & plant more trees!
    Insulate, then insulate some more; to avoid heat loss in winter but also to reduce excess heat gain in summer. Not just homes either!

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  • Z̈oéuint8_t@chaos.social
    Jul 31, 2026, 4:45 PM

    @tired_angry @MarkHoltom one could argue that setting refineries and tankers on fire in Minecraft is beneficial. The cargo would have been burned either way. But increasing the cost of the fossil infrastructure drives adoption of non-fossil alternatives.

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  • TwotiredTwotired@universeodon.com
    Jul 31, 2026, 3:30 PM

    @forthy42 @MarkHoltom Yes! Thank you! This is the key point, IMO.

    Yes, we can burn fossil fuels to release the energy by forming a carbon bond, and then expend more than that amount of energy (because thermodynamics) to break it again, but why? If the geothermal energy is “free”, just skip the fossil fuel and use the geothermal energy as your energy source in the first place.

    Thinking that you can fix the fossil fuel problem if you just find the right carbon capture technology is like thinking you can reach the top of the mountain without having to go uphill if you just find the right path.

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  • robloblawrobloblaw@mastodon.social
    Jul 31, 2026, 6:40 PM

    @Twotired @forthy42 @MarkHoltom
    Yes, entropy says this approach won't scale. Do not argue with entropy.

    Iceland is using the plant to 'make up for' carbon emissions they can't avoid for now (hard to abate emissions). They have a very ambitious net zero target.
    open.spotify.com/episode/0EHq9

    Arguably better to use the money to get higher emissions reductions outside their borders, but at least they are doing something positive.

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  • Carlos Solíscsolisr@hub.azkware.net
    Jul 31, 2026, 1:18 PM
    If our current worldwide hyper-connected economy could survive falling back to literal sailboats, it could have been way easier to halve energy consumption...
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  • robloblawrobloblaw@mastodon.social
    Jul 31, 2026, 6:30 PM

    @MarkHoltom
    I agree with the sentiment of this post, but not the details. Even if we stopped all fossil extraction and usage now, it wouldn't be enough to avoid severe global heating. We need to to be drawing down carbon from the atmosphere too. That won't be technological solutions like the Iceland plant - it will be better management of soils and ecosystems, biochar, enhanced weathering, and building with natural materials.
    1/2

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  • robloblawrobloblaw@mastodon.social
    Jul 31, 2026, 6:30 PM

    @MarkHoltom
    And we will be using more final energy, not less. Fossil energy mostly gets wasted in extraction, refining, transport and use (heat losses). Renewables are much more efficient. We need clean electricity grids that displace transport and industry that is currently fossil powered.

    More final energy use, less primary energy. And much less carbon pollution.
    2/2

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  • David Chisnall (*Now with 50% more sarcasm!*)david_chisnall@infosec.exchange
    Jul 31, 2026, 7:00 PM

    @MarkHoltom

    That 2.4 kWh / kg of CO2 seems fairly comparable to the emissions number for a fossil fuel plant, so simply using the energy to displace fossil fuels would have about the same impact.

    It’s almost certainly going to be important in the future, but generally the advice if you’re in a sinking boat is to plug the hole and then start bailing.

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  • kbalkbal@fedia.io
    Jul 31, 2026, 7:06 PM

    Why does every plan seem to leave out "stop burning fossil fuels"? I think we should do that first. It would mean much less driving, practically no flying, expensive shipping, massive reorganization of global supply chains, and a bunch of other unpopular consequences. Let's do it now.

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