Economical assessment comparison for hydrogen reconversion from ammonia using thermal decomposition and electrolysis

Ammonia is a promising alternative for the storage and transport of renewable hydrogen over long distances. In this paper, a techno-economic assessment was conducted to evaluate the levelized cost of hydrogen (LCOH) produced from renewable ammonia feedstocks. Both thermal and electrochemical pathways were analyzed. For the thermal pathway we investigated the decomposition using fixed bed reactor and membrane technology, while alkaline electrolysis was studied for the electrochemical route. We evaluated different process scales corresponding to stationary reconversion in a hydrogen refueling station (1000 kgH 2 /day) or an ammonia import terminal (1500 tNH 3 /year) and mobile on-board reconversion for a heavy-duty truck (22 kgH 2 /day). The results show that currently the cheapest option to produce hydrogen from ammonia is the thermal decomposition with membrane technology for import terminal, fixed bed for the hydrogen refueling station, and electrolysis onboard a truck. The levelized cost of hydrogen for the thermal decomposition methods in an ammonia import terminal lie in the range of hydrogen prices produced from today's mix of renewable energy and water as feedstock in Europe. A sensitivity analysis shows that, regardless of the process scale, the parameters with the highest impact on the levelized cost of hydrogen are the reactor temperature for the membrane technology, and ammonia price for fixed bed and electrolysis technologies. The reconversion costs in the latter case are most sensitive to the cell voltage. A future scenario analysis indicates that ammonia electrolysis reconversion costs can be reduced between 14% and 44%, depending on the process scale.