Comment by dredmorbius

FT can work with pretty much any source of carbon and hydrogen.

The latter might come from an existing hydrocarbon (as with so-called "blue", "grey", "black", or "brown" hydrogen), or from electrolysis, which is not carbon-neutral. If the latter is powered by a carbon-neutral source (surplus renewables, nuclear), it's "green", and carbon-neutral.

CO2 can also be obtained from numerous sources. One prospect suggested when US peak oil was a concern, in the 1960s, was limestone. More recently, the US Naval Research Lab, as well as Google's Project Foghorn, looked at separating CO2 (in the form of carbonic and carbolic acid) from seawater, which is far less energy intensive than direct removal from the atmosphere. I'd looked up the history of research and industrial applications circa 2014, noted here:

<https://web.archive.org/web/20170719101136/https://www.reddi...>

<https://web.archive.org/web/20230601122020/https://old.reddi...>

The US Navy has an interest largely for its carrier fleet. Whilst the carriers themselves are nuclear powered, their aircraft are not, and fuel provisioning for the aircraft fleets is a major logistical hurdle as well as a strategic vulnerability. No need to target the carriers themselves (heavily defended) if the supply tankers can be sunk, something present US adversaries might consider. One prospect would be to effectively recommission older carriers as fuel-synthesis platforms, capable of producing aviation fuel from seawater in situ and not having to transit between fuel depots and the fleet itself. Given the additional costs of transit and strategic significance, the economics should be somewhat more favourable than for civilian use. This was the subject of a number of papers published in the 2010s by the US Naval Research Laboratory (listed above). Earlier research based on other carbon sources was performed at MIT and Brookhaven National Laboratory in the 1970s and 1960s, respectively.