The reference to biology using hydrocarbons as its preferred energy store is one to fat, not fossil fuels.
That’s far from free energy. And life likely wound up that way because its precursors—hydrogen and carbon—are readily available, it’s energy dense both volumetrically and by mass, it’s safe and it can be converted into various forms of energy directly and easily.
Ultimately, the big unknown is the cost of synthesising Jet A. I think it will be low enough that it blows the hydrogen hypothesis out of the water, but I don’t have more than a hunch to go off.
Yes. Most of the available energy is in the hydrogen bonds, but if you want to 'tame' neat hydrogen by binding it to something else, from all the stuff in the periodic table carbon is pretty much the optimal choice.
> Ultimately, the big unknown is the cost of synthesising Jet A. I think it will be low enough that it blows the hydrogen hypothesis out of the water, but I don’t have more than a hunch to go off.
To the extent one of the inputs to synthetic Jet A is hydrogen, it won't be cheaper as such. So the question really is whether the added cost is low enough that the easier logistics of a room-temperature liquid fuel makes the total cost lower. I'm slightly hopeful that this will eventually be the case.
I feel you are suggesting the reason is because it's an ideal energy transport mechanism, while ignoring the (not insignificant) fact that almost all the hydrocarbons we've used so far have been, effectively, free energy.
Or at the least, incur a cost that we have not yet had to contend with.