There are lots of point sources of CO2 that don't require as much energy to extract, but your point stands: the conversion takes a lot of energy (thermodynamics is a harsh mistress).
The tech works quite well though, CRI in Iceland makes methanol (a viable liquid fuel) from CO2 and electrolyzed H2 semi-commercially, taking advantage of cheap and abundant geomthermal electricity.
The tech works quite well though, CRI in Iceland makes methanol (a viable liquid fuel) from CO2 and electrolyzed H2 semi-commercially, taking advantage of cheap and abundant geomthermal electricity.