Both green hydrogen and green ammonia are ways of transporting electricity, which cannot be stored in large quantities. Global production of ammonia is some 150 million tons per year. Green ammonia could directly replace most of this using existing infrastructure.
A cheaper Ammonia production using renewable energy can be produced using Bis(Triflouromethylysulfonyl)imide Electrolyte. This is still experimental but will soon be inductrialized.
ammonia production is about to go through massive reduction in cost due to breakthrough in process see Fuel Positive (NHHH), the machinery to produce 100 ton per year easily fits in a single 20ft container , all you need is air , water and a very little electricity