At present, ammonia is mostly formed through reforming of natural gas (CH4). A 1,000 ton per day plant is said to consume about 35 GJ of natural gas to produce 1 ton of ammonia (22.5 GJ of enthalpy). About 50% of extra energy is wasted. If 1 ton ammonia is produced through water electrolysis, 22.5 GJ of electricity is necessary theoretically. Here again, extra electric energy must be wasted. The author discusses roughly how the efficiency depends upon the process size and the renewable energy cost.