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This argument basically relies on the assumption that it is at least as energy intensive to convert CO2 into something more solid than the energy you get from b

This argument basically relies on the assumption that it is at least as energy intensive to convert CO2 into something more solid than the energy you get from burning hydrocarbons to produce that CO2, but I think that assumption isn’t true. I can’t recall where I saw it and I’m not a chemistry expert but conservation of energy is a thing and there is more potential energy in hydrocarbons than in some simple inert solid molecules containing carbon (which have slightly more potential energy than the CO2 and water produced by combustion). If you can be reasonably efficient then it is possible to extract energy from hydrocarbons without releasing CO2 into the atmosphere. That said, I don’t think there are any sufficiently efficient industrial scale processes to do this.

contravariant 6y ago
You're worrying about the wrong part of the equation, the main problem is going to be what you're going to do with the oxygen. There's a reason why so many things tend to react violently with pure oxygen, to the point that we have an entire vocabulary dedicated just to that one class of reactions.
- dan-robertson 6y ago
  I’m replying to a commenter who claims that it is thermodynamically impossible to extract energy from fossil fuels while capturing the carbon (ie not releasing CO2 into the environment). Obviously some chemistry needs to happen but I claim it is possible to still get net energy out while somehow capturing the CO2. See this page: https://longitudinal.blog/co2-series-part-2-co2-removal/ https://longitudinal.blog/co2-series-part-2-co2-removal/ with the bit that starts “Note: Interestingly, this is all much less than the heat of combustion”
pfdietz 6y ago
Well, when nature does CO2 sequestration, it IS energy positive. The overall reaction silicates + CO2 --> silica + carbonates is mildly exothermic. This is why most of the carbon on Earth is in rocks, not in the atmosphere.

contravariant 6y ago

You're worrying about the wrong part of the equation, the main problem is going to be what you're going to do with the oxygen. There's a reason why so many things tend to react violently with pure oxygen, to the point that we have an entire vocabulary dedicated just to that one class of reactions.

dan-robertson 6y ago
I’m replying to a commenter who claims that it is thermodynamically impossible to extract energy from fossil fuels while capturing the carbon (ie not releasing CO2 into the environment). Obviously some chemistry needs to happen but I claim it is possible to still get net energy out while somehow capturing the CO2. See this page: https://longitudinal.blog/co2-series-part-2-co2-removal/ https://longitudinal.blog/co2-series-part-2-co2-removal/ with the bit that starts “Note: Interestingly, this is all much less than the heat of combustion”

pfdietz 6y ago

Well, when nature does CO2 sequestration, it IS energy positive. The overall reaction silicates + CO2 --> silica + carbonates is mildly exothermic. This is why most of the carbon on Earth is in rocks, not in the atmosphere.