Hi, Liquide ammonia electrolysis requires 7.4 MJ per kg of H2 (gaz) using a standard voltage of 7,7 mV assuming the eletrolysing cell is 100% efficient (a standard steel/pt/ceramic cell is 71% efficient IIRC) To compare Water electrolysis is 130 MJ/H2 kg (gaz) assuming a 100% efficiency and need higher voltage (> 1.23 V) So ammonia electrolysis is approx 94% more efficient than water electrolysis, but the energy needed to get liquid hydrogen should not be forgotten (I'll come back and edit this post with the correct value) As far as I know, ammonia electrolysis is good to make direct H2 feeding for fuel cells, however I'm not sure it'll be enough of a fuel flow to use it in direct engine feeding (calculations must be done to be sure of that) Cheers. Source: http://www.rsc.org/suppdata/cc/c0/c0cc01982h/c0cc01982h.pdf