Hmmm, I was looking at Ammonia production CAPEXes just the other day!!!
There is also CSIRO tech that converts Ammonia directly to Hydrogen, it was hailed at the time as a game changer. Not sure what happened with it.
I think if you look at the H content of Ammonia and the proportionate heat values, it could be about half that of petrol (say ~ 21 MJ/kg)
