It’s invariably made from fossil fuels.

If you want to make synthetic fuels it’s similar effort and efficiency to make methane as it is to make hydrogen. In fact converting one to the other is trivial and the conversion from methane is how we actually make hydrogen today.

Hydrogen has a lot of issues. It’s a pain to store since it’s corrosive and does not liquify or stay liquified without cooling and extremely strong pressure vessels. Methan is already used pretty commonly. A lot of busses run on methane today.

So we’re taking methane, a fuel that’s used in transit already and that we gave a shortage if right now since it makes fertilizer and the hormuz straight is blocked. We’re taking that precious methane and converting it to hydrogen (not at all green to do this and the carbon goes into the air at this point) and then we’re awkwardly transporting this and storing it in cars with all the problems that has just to burn the hydrogen in the car pretending that we never released co2 in the process.

Now you might say ‘yeah but in theory you could use electricity to make hydrogen’ and I’ll point out that’s grossly inefficient to just using a battery electric vehicle and it’s not at all done at an industrial scale due to the reality that it was always just a way to sell fossil fuels with an obfuscation of where the release of carbon occurs and never intended an actual reasonable way to store electricity.