1 Gt CO2 is equivalent to 2.3e13 mol of native carbon, (as soot).
Sequestration in this form is possible because it’s biologically inert. Standard enthalpy change of formation for CO2 is -393.5 kJ/mol, so converting the whole 1 Gt CO2 corresponds to 8.9e18 J.
Assuming ~10% efficiency, this would take 10 years at 283 GW power, producing 0.27 Gt carbon and 0.73 Gt O2 as by-product.
Your mileage may vary.
If that wins the prize, that’s $.09 per kW·decade. Not a really great ROI for a fusion-based scheme.
I say mother Nature should definitely be involved.
