Low-Pressure Electrolytic Ammonia Production for Ammonia-Based Energy Storage

J. Thakare
United States

Keywords: energy storage, ammonia, chemical synthesis, electrlytic synthesis


The two North Dakota universities are developing a 300°C-capable proton exchange electrolyte (300°C-PEE) for low-pressure (15-psi) electrolytic ammonia (LPEA) synthesis from water, nitrogen, and electricity. The 300°C-PEE provides a proton conductivity at 300°C of >10-2 siemens/centimeter, similar to that of a Nafion membrane at 70°C. Combined with an appropriate anode catalyst (for 300°C water electrolysis to yield protons) and cathode catalyst (for reaction of protons with nitrogen to yield ammonia), the 300°C-PEM is projected to enable ammonia production (using low-demand/cost off-peak electricity) at a total energy input of ≤8.5 MWh/ton, the energy requirement for state-of-the-art (2018) high-pressure (1100–3000 psi) Haber Bosch-based ammonia production from natural gas. Stored ammonia can be converted to electricity as needed (via combustion or—ideally—direct ammonia fuel cell) and/or sold as fertilizer or a chemical intermediate. The ability to divert excess power to ammonia production will enable continuous electricity generation unit (EGU) operation at or near-optimal/design capacity, ensuring maximum efficiency and minimum degradation of materials, equipment, and performance due to load cycling-driven stresses. Data and information regarding 300°C-PEE properties and deployment for ammonia synthesis will be presented.