@kgb
I don't know the answer to the first question.
But as to F-T process...
Yes, it is more energy efficient if one can use the hydrogen directly and avoid F-T. But this only works at short range with extremely short term storage schedule.
Hydrogen is a low density gas. So storage and transportation is a big issue for use in vehicles, which do a lot of storing and transporting. Hydrogen also likes to leak out of containers, not dangerously, just enough to lose money.
The options are:
liquid - compress and cool it to 20K [-250C, -423F] (only an option for NASA)
high pressure gas - compress and store as gas (takes huge tanks, and much lower energy storage)
Both of these options suck. They suck almost as much as batteries. So the storage and transport issue kills the efficiency when automotive and vehicle use is considered. Pipeline use to a chemical factory is probably not a problem.
Converting to methane/nat gas is the next step of difficulty in the potential choices. Nat gas is far and away easier to deal with than H2. Methane is a natural feedstock to make any plastic. For transportation, cryogenic liquid methane is plausible. But still too much of a pita to really catch on. Or use compressed gas storage. Again, tank sizing issue. These options are being heavily explored right now due to the cheapness of nat gas. We have several locomotives and heavy equipment designs slated for introduction in a few years to take advantage of nat gas.
Next level is methanol and ethanol synthesis. Liquid, minor change to engine design, good enough energy storage, maybe cheap enough. Methanol can be converted to DME (dimethyl ether) for a good diesel substitute. Methanol is also a good plastics feedstock.
I strongly suspect that the industry may settle for this compromise.
Next level of difficulty is full replacement synthesis. Full synthetic gasolines and diesels and waxes and plastics. This is probably the most capital expensive route, but also provides drop in replacement of fuel for all older vehicles. I doubt the whole industry is converted to this path.
We may end up at a place in between.
25% methanol + 25% ethanol + 50% octane
Here is why we might end up at that kind of strange compromise...
We already run E10-E15, taking that away will hurt the lobby. We will also have oil for a good long while, but everyone understands that we need additional supplement. So as we supplement in methanol and ethanol to higher and higher levels, there will still be a need for full octanes to balance the gasoline formula. So that may come from oil and a few F-T plants, but since full F-T process is expensive, there will be a push to use more and more meth and eth until we hit some backwards compatible limit. Then will come the political decision to completely jump ship to pure meth/eth mixtures or stick with a meth/eth/octane mixture.
But this will take decades of transition before decision point. Forecasting beyond that is difficult, because who really knows? Maybe one day, batteries won't suck. Maybe at that point the politics of oil will be passe and nobody will feel any pressure to switch further.
