[village-idiot]

Clarification: I was talking about using excess electricity from shore based solar units. This would give operators somewhere to dump excess power cheaply (preventing negative electricity rates), all while providing fuel that's easy to store and usable in applications where batteries wouldn't work.

Obviously at this point fuel cells cannot produce the power output that diesel engines can at a given weight. But your power estimates on what a hydrogen fuel cell can do are off by a bit. Some quick searching finds portable 1MW fuel cells, existing 11MW power plants, and a planned 80MW power plant that's being constructed soon in South Korea. Obviously the latter probably weight too much for a ship today, but as the weight comes down that becomes a possibility.

[delecti]

> But your power estimates on what a hydrogen fuel cell can do are off by a bit

My estimate didn't assume the ship left the shore with any hydrogen fuel. I (apparently incorrectly) assumed you meant that the ship would generate its own hydrogen during the day from excess solar while it was in transport.

[village-idiot]

Ah yes, that wouldn't work at all.

If solar cells got effective enough to generate that much power, you’d probably be better off with solar + battery anyhow.