[jauntywundrkind]

Water electrolysis will produce hydrogen. Of course then you also need to compress it. And the fuel cell itself is yet another even more woeful knefficiency. But maybe solar continues to get cheaper to the point where we don't care about the inefficiency. Not likely, not what I believe, but maybe it could work out. For a sea plane especially, it feels like you have what you need in abundance for this infrastructure: water, and open space for solar.

MIT also talked up a solar thermochemical hydrogen production system ~9 months ago, which claims a 40% efficiency. One still needs to compress that down but still a huge leap if that promise can be delivered on. https://news.mit.edu/2023/mit-design-harness-suns-heat-produ...

There is something really compelling about hydrogen, as the most energy dense fuel we can use, that is in mass abundance, that doesn't pollute. Conceptually it's very very cool. I'd love like heck to see X-33 or Venture Star designs dusted off with modern compositeaterial sciences, see something like Skylon make it to the sky. But it does seem incredibly cumbersome & hard & weighty to make infrastructure & fuel storage for. It doesn't seem likely. It seems like an illogical investment given the downsides difficulties & inefficiencies. But I still allow: maybe.