(221g) Analysis of a Nuclear-Powered Ammonia Plant

Ammonia is a potential carbon-free energy carrier that could be used as a transportation fuel. Ammonia is 18% hydrogen by weight and it meets the 2015 freedom car energy density goal of 2.7 kWh/L. Ammonia can be safely stored and transported as a refrigerated or pressurized liquid at temperatures and pressures that are moderate compared with liquid or compressed hydrogen. Ammonia can be decomposed catalytically into hydrogen and nitrogen with no carbon monoxide or carbon dioxide production. No other reactants or shift converters are needed for this decomposition reaction.

Currently, ammonia is produced from natural gas. However, alternative processes are needed if ammonia is used as a transportation fuel. We have been exploring the possibility of using nuclear power to produce ammonia from nitrogen extracted from the air and hydrogen extracted from water. We developed an efficient base-line process design based on existing and emerging technologies. Production costs for the base line design are ~50% less than a conventional plant using domestic natural gas a s the feed, but capital costs are about 4 times greater. The nuclear reactor accounts for ~80% of the total capital cost.

Our preliminary analysis indicates that high capital costs are typical of other energy carriers produced from materials other than fossil fuels. Producing transportation fuels without fossil fuels requires significant amounts of energy, and supplying this energy with nuclear reactor, wind farm, or solar power plant requires a large capital expenditure.