By simple thermodynamics we can be 100%, not 99%, 100% sure, that the energetic cost of removing CO2 from the freaking atmosphere is higher than the benefit of putting it there in the first place.
If you want the process to be sustainable then it has to be reversible. Burning 1000W worth of fuel only to spend >1000W of electricity to remove it from the atmosphere and turn it back into fuel is clearly a net cost compared to just using 1000W of electricity to cook your food. Or less than that with non-inductive methods, since electric heat pumps can produce more than 1000W of heat from 1000W of electricity by removing some of it from the environment.
A non-sustainable process that converts fuel to CO2 and then into a solid or liquid that isn't fuel could theoretically have positive efficiency, but it is by no means guaranteed to (especially when the competition is heat pumps), even if it did by a small margin it could still cost significantly more, and it implies that you're eventually going to both run out of fuel and convert it all into an enormous amount of industrial waste.
That's very different from benefit. Also I don't see how that's related to what your original comment was arguing for (cost of replacing stoves).
Maybe I should add that I do agree with your conclusion (that replacing the stoves makes sense). I just disagree with the argument from "basic thermodynamics" which gives you "100% confidence".
Oxidizing carbon fuels is a irreversible process, meaning an increase in entropy. Dispersion of CO2 in the atmosphere also increases entropy.
We will always, 100% of the times, expend more energy to reverse a irreversible process than we could possible extract from this irreversible process.
This statement is valid regardless of the path chosen.
Which naturally spawns the argument 'let's not reverse it, let's do CH to CO to Cx, all we have to do is find x'.
The problem is this is not valid because we burn a lot of fuel.
Even if we found x, it would not be enough to sustain our rate of carbon emissions. In 2022 the world consumed 5.8*10^12 liters of crude oil.
So it would be necessary to include y. And z. Etc until n.
Inevitably including a regeneration step Cn + H to CH + n.
Now the path looks like:
CH -> CO -> Cx -> Cy -> (...) -> Cn -> CH
Which is a closed loop, meaning net power loss. With 100% confidence.
Maybe the one who oxidizes CH pays the bill to remove the CO2 emitted. Is it even possible to put such measure worldwide? Logistics would suddenly be prohibitively expensive for all but the most valuable products per weight/volume. Globalization is addicted to fossil fuels.
Well, that is literally all we did and build and invest in the last century or so. The very power grid of the world is based on carbon fuels. We can't run our carbon removal machinery on dirty power or we would be emitting more than we could possible remove.
It becomes 100% clear the winning strategy is not removing CO2 from the atmosphere, it is replacing all machines and appliances that burn carbon. Worldwide.
Again, I agree with your claims about entropy. I also agree with the claim that replacing stoves is generally good.
One still does not imply the other. The question was about what makes sense. That's economically, socially, politically, regionally, etc. Amount of energy extracted via some processes is not the same as benefit. However, benefit is what matters. I guess this discussion isn't moving forward from here.
Yeah, the missing key is seeing power and energy as money, because that's essentially how our economy works.
We can convert one in the other, at different conversion rates granted, but still.
Energy input cost is a line in every company spreadsheet, it can block or allow companies to succeed. Today this line is kept artificially low because we base our economies on a very exothermic open loop CH to CO. Closing this loop is not an option because basic thermodynamics, which is the very logic behind carbon removal.
We have to stop entering this path as much as possible.