Nobody thinks they'll get net energy out of this. They're spending energy to make carbon-neutral liquid fuels. The energy would have to come from renewables or nuclear for this to be useful.
No more than 20% if that. That translates into synth gasoline at $30/gallon
This wont be able to decarbonize anything until surplus carbon free energy is generated for it use - that need not take decades with proper governmental policies, but it means this technology will not lead the way.