Plus the level of technical protection necessary for refueling. With gasoline, you spill-proof the floor, maybe suck off the fumes, that's it. With ammonia, all

Plus the level of technical protection necessary for refueling. With gasoline, you spill-proof the floor, maybe suck off the fumes, that's it. With ammonia, all connections have to be air-tight. You'll have to vent the tank through a pressure-relief line and then condense the ammonia, because you must not release it into the atmosphere. Ammonia spillage will eat through concrete, many metals and tarmac, so either you get very expensive high-grade stainless steel floors or very expensive ammonia-proof plastic floors. And your ammonia-refueling-station will still stink to high heaven...