Green hydrogen can absolutely replace jet fuel. It will take will and logistics, and this week, I'm talking to the company that's working on the logistics part.
I would think this could also be a solution for heavy rail. Diesel locomotives are electric generators driving electric motors. Changing the fuel source to hydrogen fuel cells could drastically reduce the carbon impact of heavy rail.
If they only emitted water -- that's still contrails. Contrails are mainly water vapor at altitude. That won't change, other than they'll be cleaner.
Also, I'd like to see the numbers on the carbon impact of all the hydrogen shipping Mr. Eremenko mentioned. These "Nespresso pods" will be shipped using conventional shipping methods, at least for the near-to-mid-term.
I get it, it's potentially a better solution than SAFs and definitely a better solution than what we're burning now. It definitely belongs in the pool, but I feel there were some omissions in the analysis.
Green hydrogen/ hydro.. Hmm, not close to any water but we do have storms in Chicago more and more often. What about a small gizmo that would sit in a downspout and generate electricity?