Yeah, concentrating CO2 from atmospheric concentrations is not easy. The benefit is that it actually removes carbon from the atmosphere. Whether it can ever be

Yeah, concentrating CO2 from atmospheric concentrations is not easy. The benefit is that it actually removes carbon from the atmosphere. Whether it can ever be done on a large scale is a question, though. Is there any work on doing that, at a low energy cost? (I mean concentrating CO2, not removing it by weathering rocks?) Yeah, ships are not really weight constrained, unlike airplanes, really cheap sodium batteries should be feasible.