[stephen_g]

Definitely from an energy perspective it doesn’t make a lot of sense - it’s unlikely (due to the thermodynamics of it) that removing a ton of CO2 will ever get to the point where it requires less energy than the energy produced from burning the fuel that created that ton of CO2.

So even with clean energy, unless you have a totally clean grid with significant surplus energy, you’d do better to use the energy to put into displacing fossil fuels, because with the same amount of energy, you’d stop more CO2 being produced than you could remove with it.

[danbruc]

[...] it’s unlikely (due to the thermodynamics of it) that removing a ton of CO2 will ever get to the point where it requires less energy than the energy produced from burning the fuel that created that ton of CO2.

This argument only works if you want to reverse the entire process, turn the carbon dioxide back into something similar to oil or gas. If you would burn pure hydrocarbons with pure oxygen perfectly, it would be as simple as condensing the water in order to get pure carbon dioxide.