I should have clarified that I know it can work, but not as the perpetual motion kind of system most people seem to envisage or that most projects I'm aware of seem to promote.

Everyone seems to think that carbon capture can be this little add-on when it actually needs to be a bare minimum of 1/3 our total energy production to have a meaningful impact over typical human time scales (a century or 2). Making things more complicated, none of that carbon capture energy can come from carbon fuels. I just don't see how we can do both at the same time, except as research projects to set the stage for when have gone a lot further in decarbonising our production for consumption.