The transportation fuels example is even more exciting, IMO. Transportation fuels are basically simple hydrocarbons that burn with oxygen to turn into CO2 and H2O. There's only engineering, capital, and energy costs that need to be overcome - then we can run that process in reverse and turning our current transportation infrastructure carbon-neutral.
One of the big financial problems for CCS (carbon capture and storage) is that CO2 is essentially worthless. If a market would suddenly arise for concentrated CO2, I do not think we would have much of a problem to fill demand.
As far as my brief research into it goes, it looks like atmospheric CO2 extraction is currently in R&D stages. With current bulk CO2 costs, it could become economically competitive.
