No, it’s entirely feasible, it’s just that it probably requires about 5 times as much energy input as it produces. What sounds ridiculous is the claim of 70% efficiency. The “water gas” reaction (with carbon monoxide and steam) has of course been known for many many decades and Fischer Tropsch since the 20’s.
It takes a lot of energy to take either water or carbon dioxide apart and F-T requires something like 60+ atmospheres of pressure.
If the reaction heat from a nuclear reactor could be used to boil the water and produce the energy inputs for the F-T part, more and more of this becomes feasible.
Either this or a similar process has been discussed for making jet fuel on aircraft carriers. While the cost may seem expensive, the cost difference appears to go down when the cost of shipping additional jet fuel on a separate AOE (fuel and munitions fleet auxiliary) is taken into account.
I believe the show was called "NAZI Wonder Weapons of 1996." It was in keeping with that theory always pushed on the History Channel that all Der Fuehrer needed was more time!
Steam engines were modestly popular on American rivers a century or two in the past. Now? I don’t think so.