1) Without emissions pricing/regulations, synthetic liquid fuel costs more to produce than fossil-derived liquid fuels, so it is unprofitable.

2) Even assuming that there were emissions pricing/regulations that kept fossil fuels in the ground, synthetic liquid fuel is much more capital intensive and energy intensive to produce than the corresponding amount of electricity needed to move a car N kilometers.

Synthetic fuels have a place in the future for applications that require high energy density like aircraft, rockets, and long distance shipping. But burning synfuels in legacy internal combustion engine vehicles is, generally speaking, not going to have a lower systemic cost than replacing ICE vehicles with battery electric vehicles and charging them with clean electricity.

A sketch of the problem: the Oryx Gas to Liquids plant is a modern Fischer-Tropsch plant that produces about 34,000 barrels (5.4 million liters) per day of liquid hydrocarbon fuels:

https://qp.com.qa/en/QPActivities/Pages/SubsidiariesAndJoint...

It cost about a billion dollars to build. A corresponding electrical synfuel plant would cost significantly more. You could eliminate the natural gas reformer and desulfurization processes, but would need to add:

1) CO2 separation unit sufficient to extract 14.2 million kilograms of CO2 from the atmosphere, daily (to supply the carbon found in 5.4 million liters of synthetic diesel fuel). Since the air contains ~400 ppm CO2, you need to process about 35.5 billion kilograms of air per day to get sufficient input CO2. Capital costs: wild-ass guesses, because nobody has built anything like this at scale. There's a recent claim that it direct air capture could cost "as low as" $94 per ton of CO2 [1]. That would come to 1.3 million dollars per day.

2) Enough hydrogen per day to turn all that CO2 into liquid fuel. Assuming an empirical "average diesel" formula of C12H24, you need 12 moles of CO2 and 48 moles of H2 to make a mole of diesel: 12 CO2 + 48 H2 -> C12H24 + 12 H2O. In terms of mass, that's .18 kilograms of hydrogen for every kilogram of CO2 -- 2.58 million kilograms of hydrogen per day.

3) A clean source of hydrogen. Electrolysis driven by clean electricity is the only process demonstrated at scale. Assuming it takes 46 kWh of electricity to produce a kilogram of hydrogen from water, and that plant capital costs are $975 per kg-H2/day [1], that's an electricity consumption of 118,860 megawatt hours per day plus an electrolyzer complex cost of $2.5 billion.

4) Electricity to drive the electrolyzers. The very cheapest electricity from hydro, nuclear, or renewable sources is somewhere between $20-$30 per megawatt hour. Such low priced electricity isn't available everywhere; in some countries, even large industrial buyers pay $40 and up. At the lower end that's 2.4 million dollars per day for electricity.

Adding it all up, the electricity and air capture costs alone come to about 69 cents per liter of diesel in costs. That is even though I have tried to make very charitable assumptions about how low the costs could be kept. The wholesale price of diesel in the US is currently about 51 cents per liter:

https://www.eia.gov/dnav/pet/hist/LeafHandler.ashx?n=PET&s=E...

I don't know how to properly amortize the extra capital investments to give a per-liter figure, but keep in mind that just adding the hydrogen electrolyzers triples the capital requirements for the whole complex. Note that I have budgeted nothing for labor either.

Finally, how much transportation do you get out? 5.4 million liters of diesel provides 85 million vehicle-kilometers in a 2019 Chevrolet Cruze:

https://www.fueleconomy.gov/feg/PowerSearch.do?action=alts&p...

118,860,000 kWh of electricity provides 645 million vehicle-kilometers in a Tesla Model 3 (assuming 80% generation-to-battery efficiency):

https://pushevs.com/2017/08/01/tesla-model-3-efficiency-impr...

The battery-electric propulsion solution delivers more than 7 times as much range per kilowatt hour of electricity spent, compared to clean synthetic fuel, and even more per dollar spent.

[1] https://www.sciencemag.org/news/2018/06/cost-plunges-capturi...

[2] https://www.energy.gov/eere/fuelcells/doe-technical-targets-... -- using the "2015 target" numbers for centrally located electrolysis.