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Comment by nlitened | Hacker News Reader

Could someone please explain how could carbon capture ever work? To me it looks as if it is a mathematically impossible thing: if you produce energy by releasing carbon, you would need to expend even more energy to capture the same carbon back, so it is impossible — there’s no way to produce required energy to do so. And if you had such an huge and cheap energy source for carbon capture, you wouldn’t burn carbon in the first place — you’d use that energy source instead.

What am I missing? Am I stupid, or the people who talk about carbon capture are ridiculously dishonest?

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You're thinking about energy and not cost.

For example, when solar plus direct air capture can remove a ton of CO2 for cheaper than it costs a container ship not to emit that CO2 then it's reduced cost for the same CO2 outcome even though it's using more total energy.

Regardless of whether it actually makes sense to capture carbon, you'll see a lot of sky-is-falling fanatics and vested interests dismissing it because it caps the price of carbon credits and limits economic damage estimates. You can't price CO2 at $500/ton to necessitate change when it only costs $200/ton to capture it - without quickly going bankrupt that is.

This is why the IPCC not even attempting to evaluate mechanical capture shows they aren't serious about solving the problem. They seemingly exist to push a fear narrative, and having an upper bound on the impact of CO2 limits their ability to do so.

The carbon dioxide is captured and stored, the actual carbon isn't returned to whatever form it was before burning. So theoretically it _can_ work (but, as it turns out, it still doesn't make sense).

I've always thought of carbon capture as something you do later in the timeline, after burning carbon to get you to a society that can make the transition to green energy.

this might be the case for example if you need a certain amount of innovation and that requires a certain critical mass of brains thinking over the problem.

or maybe if you're an accelerationista, you want AI to solve it for you and burning carbon now to train it might make sense.

but I don't think the idea is to ever burn carbon to capture carbon.

As you point out, it probably doesn’t ever make sense to use carbon capture to “offset” energy-related emissions. Probably the only way it would make sense would be as a way to reduce the amount of CO2 in the atmosphere after we’re no longer burning previously sequestered carbon.

You would produce the energy without releasing carbon.

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