Nuclear seems like a good idea for the future - in cross ocean shipping. Sails have too many limitations and nobody has any ideas for what else could even work (at least not that I’ve seen, everything fails the sniff test). It has only been done in air craft carriers and submarines (and maybe ice breakers?) that I know of so this is more the only idea I can come up with that could work. It needs a lot of effort to make is work in the real world though.