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This [0] AMA from the research group answers most of the questions I am seeing here in the thread. "Technologies range from aqueous amines - the water-rich sol

This [0] AMA from the research group answers most of the questions I am seeing here in the thread. "Technologies range from aqueous amines - the water-rich solvents that run through modern, commercially available capture units - to energy-efficient membranes that filter CO2 from flue gas emitted by power plants. Our newest solvent, EEMPA, can accomplish the task for as little as $47.10 per metric ton - bringing post-combustion capture within reach of 45Q tax incentives." [0] reddit.com/r/askscience/comments/mdouzu/askscience_ama_series_hi_reddit_we_are_scientists/

londons_explore 6y ago
$47.10 per ton smells like someone has calculated the cost of the reagents and cited that as the price... Any estimate of this process cost would never be to 3 Sig fig.
- CharlesW 6y ago
  I don't know why $47.10 is any less credible than $47, but here's more detail on what the estimate represents from TFAMA: "For the $47.10/metric ton carbon capture cost, 48% comes from CAPEX while the remaining is OPEX. The equipment life of a carbon capture unit would be similar to that of a power plant, about 20-30 years. The $47.10/metric ton cost is just for carbon capture, and does not include transportation and sequestration costs."
  - eitland 6y ago
    It is still suspicious to use so exact numbers for a technology that has not yet been tested out at scale at all.
    - phreeza 6y ago
      In my experience, the obsession with correct significant figures is an american high school thing. Why should you deliberately have to choose a number that is not your best guess? Ideally you should include confidence bounds, but if you don't, it shouldn't imply that you are confident to that level.
      - jfim 6y ago
        Because it gives an idea of what range is expected for the actual price. If someone gets an estimate of "about fifty bucks" versus "about $51.04", their reaction to seeing a final price of say $62.17 would be different. The first one implies that it's a rough estimate, while the second one doesn't.
        phreeza 6y ago
        "About" is doing a lot of work, too, no?
        throwawayfire 6y ago
        If someone said "about fifty bucks" and it turns out to be $62.17, I'd immediately understand them to be scamming me.
        jfim 6y ago
        Really depends on what the context is. Maybe for a taxi ride when negotiating a price ahead of time, but pointing at an object, asking for its price, getting an estimate that's off, then getting the actual price before the transaction is completed doesn't feel like a scam.
        Scipio_Afri 6y ago
        Please price estimates for car repairs in dollars and cents and state it's only an estimate all the time.. with variations possible depending on what's discovered that might have been missed it that particular context.
      - adrianmonk 6y ago
        That's definitely where I learned that it was expected. I look at it as one of many possible conventions for communicating precision. For what it is, it works well. But it's not universal, and people who do and don't use it should both keep in mind that the other group exists.
      - 6y ago
  - aaron695 6y ago
    > I don't know why $47.10 is any less credible than $47 It shows a lack of understanding of either basic science or napkin maths. For either reality, science or invention, it matters. https://en.m.wikipedia.org/wiki/Significant_figures https://en.m.wikipedia.org/wiki/Significant_figures
    - deleted 6y ago
      [deleted]
- hansvm 6y ago
  Sig figs are just a crude method to in-band signal some bounds on your estimates. They don't seem super relevant here when communicating an order of magnitude improvement.
- worldofmatthew 6y ago
  I am pretty sure the $0.10 per tree of the Eden reforest project would be far cheaper than $47.10 per ton, to say the least. That would be 471 trees for $47.10.
  - earlyriser 6y ago
    That price is per tree planted and there's not guarantee the tree is going to grow. It's great to plant trees, but even if we could reforest the entire Earth on the good places we'll need other technologies to capture carbon.
  - KptMarchewa 6y ago
    Does the 0.10$ include land acquisition for the forest? If not, the cost could be significantly higher.
    - worldofmatthew 6y ago
      They work with the native communities (that is why around 10% of trees planted are designed as a food source) which allows that 10 cents to cover everything, not just the planting of the trees.
  - sbierwagen 6y ago
    Reforestation only sequesters carbon if the land remains forest forever. If it’s cleared again in the future then that carbon goes right back into the atmosphere.
    - ytpete 6y ago
      Doesn't it depend on what is done with all the wood that was chopped down? If used say for construction, that carbon is staying out of the atmosphere. Or do mature trees not make up the majority of the carbon that is stored in forests?
Aachen 6y ago
Clickable link: https://old.reddit.com/r/askscience/comments/mdouzu/askscience_ama_series_hi_reddit_we_are_scientists/ https://old.reddit.com/r/askscience/comments/mdouzu/askscien...
williesleg 6y ago
Trees and plants consume CO2 and produce O2. By absorbing the CO2 you make less trees. That will kill the plants. Mission accomplished. Assholes.

londons_explore 6y ago

$47.10 per ton smells like someone has calculated the cost of the reagents and cited that as the price... Any estimate of this process cost would never be to 3 Sig fig.

CharlesW 6y ago
I don't know why $47.10 is any less credible than $47, but here's more detail on what the estimate represents from TFAMA: "For the $47.10/metric ton carbon capture cost, 48% comes from CAPEX while the remaining is OPEX. The equipment life of a carbon capture unit would be similar to that of a power plant, about 20-30 years. The $47.10/metric ton cost is just for carbon capture, and does not include transportation and sequestration costs."
- eitland 6y ago
  It is still suspicious to use so exact numbers for a technology that has not yet been tested out at scale at all.
  - phreeza 6y ago
    In my experience, the obsession with correct significant figures is an american high school thing. Why should you deliberately have to choose a number that is not your best guess? Ideally you should include confidence bounds, but if you don't, it shouldn't imply that you are confident to that level.
    - jfim 6y ago
      Because it gives an idea of what range is expected for the actual price. If someone gets an estimate of "about fifty bucks" versus "about $51.04", their reaction to seeing a final price of say $62.17 would be different. The first one implies that it's a rough estimate, while the second one doesn't.
      - phreeza 6y ago
        "About" is doing a lot of work, too, no?
      - throwawayfire 6y ago
        If someone said "about fifty bucks" and it turns out to be $62.17, I'd immediately understand them to be scamming me.
        jfim 6y ago
        Really depends on what the context is. Maybe for a taxi ride when negotiating a price ahead of time, but pointing at an object, asking for its price, getting an estimate that's off, then getting the actual price before the transaction is completed doesn't feel like a scam.
        Scipio_Afri 6y ago
        Please price estimates for car repairs in dollars and cents and state it's only an estimate all the time.. with variations possible depending on what's discovered that might have been missed it that particular context.
    - adrianmonk 6y ago
      That's definitely where I learned that it was expected. I look at it as one of many possible conventions for communicating precision. For what it is, it works well. But it's not universal, and people who do and don't use it should both keep in mind that the other group exists.
    - 6y ago
- aaron695 6y ago
  > I don't know why $47.10 is any less credible than $47 It shows a lack of understanding of either basic science or napkin maths. For either reality, science or invention, it matters. https://en.m.wikipedia.org/wiki/Significant_figures https://en.m.wikipedia.org/wiki/Significant_figures
  - deleted 6y ago
    [deleted]
hansvm 6y ago
Sig figs are just a crude method to in-band signal some bounds on your estimates. They don't seem super relevant here when communicating an order of magnitude improvement.
worldofmatthew 6y ago
I am pretty sure the $0.10 per tree of the Eden reforest project would be far cheaper than $47.10 per ton, to say the least. That would be 471 trees for $47.10.
- earlyriser 6y ago
  That price is per tree planted and there's not guarantee the tree is going to grow. It's great to plant trees, but even if we could reforest the entire Earth on the good places we'll need other technologies to capture carbon.
- KptMarchewa 6y ago
  Does the 0.10$ include land acquisition for the forest? If not, the cost could be significantly higher.
  - worldofmatthew 6y ago
    They work with the native communities (that is why around 10% of trees planted are designed as a food source) which allows that 10 cents to cover everything, not just the planting of the trees.
- sbierwagen 6y ago
  Reforestation only sequesters carbon if the land remains forest forever. If it’s cleared again in the future then that carbon goes right back into the atmosphere.
  - ytpete 6y ago
    Doesn't it depend on what is done with all the wood that was chopped down? If used say for construction, that carbon is staying out of the atmosphere. Or do mature trees not make up the majority of the carbon that is stored in forests?

Aachen 6y ago

Clickable link: https://old.reddit.com/r/askscience/comments/mdouzu/askscience_ama_series_hi_reddit_we_are_scientists/ https://old.reddit.com/r/askscience/comments/mdouzu/askscien...

williesleg 6y ago

Trees and plants consume CO2 and produce O2. By absorbing the CO2 you make less trees. That will kill the plants. Mission accomplished. Assholes.