Renewable energies, such as solar and wind plants, are being widely installed in our society, and efficient utilization of redundant power becomes a challenge in the energy technology. Ammonia is one of the most produced chemicals, which is synthesized artificially from nitrogen and hydrogen, and most of ammonia is currently used for fertilizers maintaining human foodstuff. Now, ammonia is expected to be used as a fuel. Recently, many efforts are reported for the developments of direct-ammonia fuel cells, ammonia-fueled reciprocating engines, ammonia-fueled gas turbines, and ammonia cracker for hydrogen production. Although there are many ways for ammonia utilization as a…