I haven’t done the math but I studied a lot energy stuff for my degree. I can say for sure that’s it’s a hell of a lot more money and work than just reducing emissions in the first place. The below comment is accurate, if cynical; I knew someone who works on it in the states. You collect a bunch of co2 (using energy), then compress it (with energy), then ship it (yep diesel trucks), to salt caves where it is pumped (with energy) into the empty salt lined cave where the pressure causes the salt to sort of seal in a partial melt from the pressure. And hope we don’t accidentally frack it all back out. Needless to say I think it’s a waste of technology, money, and political will that’d be better spent on a plethora of other options.
Here in Iceland, where this is located, we produce more green energy than we consume and can’t store that energy, and the carbon is pumped straight into the basalt below which absorbs it. I think doing it here is a decent way to do research on improving the technology.