Space launch technologies
If you have electricity being generated via MSRs (Thorium fuelled - probably LTFR) then you have enough energy to make rocket fuel from water and atmospheric carbon.
The good thing about this notion is that LFTR technology is more than hot enough to use the Haber process to produce hydrogen from water rather than relying on inefficient low temperature electrolysis and the same heat makes it easy to tack on carbon atoms to make methane or longer chain molecules.
If you don't want to use rockets, the most viable of the "we can do it now" technologies is a Lofstrom Loop, but it'd still be a massive engineering undertaking and you'd need to ensure a MASSIVE body of water to act as heat dump if things went wrong.