Consider the two words: "sustainable" and "fuel". As a locally generated process input, H2 appears to make sense, say for steel production or yes, ammonia. Bu

Consider the two words: "sustainable" and "fuel". As a locally generated process input, H2 appears to make sense, say for steel production or yes, ammonia. But H2 is hard to store; best is to do so cryogenically which uses a lot of energy and is heavy. storig higher temperature H2 is more difficult (those crafty molecules are tiny!). The economics likely work for many industrial processes, but not for transport, much less grid power generation. The "fuel" part doesn't pencil out; I believe H2 fuel story are just a subsidy to the fossil fuel companies in order to get legislation passed. Compared to other fuels Ammonia isn't especially energetic, but for a large vessel with a lot of space it can work. But it's really toxic and harder to manage safely than buker fuel or jet fuel. "Sustainable" doesn't mean just its production but its overall risk to human life. It lacks adequate energy density to drive something like a car much less a plane, even if you were willing to have something as nasty as NH3 in your fragile, weight-sensitive vehicle. Don't take my word for it: Maersk, who is famously commissioning ammonia (and methanol) vessels, has publicly stated that these are not long term solutions but rather (they hope) a way to push the green agenda forward.