Torulf,
It would become useless if ultra-cheap fusion comes around, because its would be easier to use electricity instead of light (this does not forbid ultra cheap photovoltaics). It would work like this: a reversible scrubber would remove CO2 from air or water and provide pure CO2 to the next stage. CO2 would be converted into CO (+O2) with electricity or CH4 (using hydrogen), CH4 or CO and H2 would be polymerized using Fischer-Tropsch process or free radical chemistry. I’m not sure if I mentioned this before but a F2 reactor would make a nifty free radical polymerizer: all you need to do is cool the reactor with light hydrocarbons (CH4) and the x-ray flux will polymerize it into oil and hydrogen (the hydrogen can be extracted via a proton membrane and feed back into the second stage.)
The CO2 capturing device produces one thing not mentioned: waste and lots of it! Once you absorb the CO2 what do you do with it, shove it somewhere? My problem with carbon sequestering is that no one wants to pay to sequester CO2, its would be better if CO2 could be made into a product like oil which turned into plastic and composites both sequesters carbon and makes a profit.
