Sustainable ammonia can be produced today: doing so would use electrolyzers to make hydrogen to feed the traditional Haber-Bosch process. In a very few years, new technologies will skip this hydrogen production phase altogether and make ammonia directly from renewable power in an electrochemical cell. Further down the pipeline, next generation technologies will mimic nature, specifically the nitrogenase enzyme, which produces ammonia naturally.
One of these next generation technologies is currently producing impressive results at the US Department of Energy's (DOE) National Renewable Energy Laboratory (NREL).
Last week, ARPA-E announced funding for eight technologies that aim to make ammonia from renewable electricity, air, and water.
The technological pathways being developed include adaptations of the Haber-Bosch process - seeking improvements in catalysts and absorbents - as well as novel electrochemical processes.
Each of these awards must produce an "end-of-project deliverable." For chemical processes, this will be a "bench scale reactor" that produces >1 kg of ammonia per day; and for electrochemical projects, it will be a "short stack prototype" capable of producing >100 g of ammonia per day.
Earlier this year, the US Department of Energy (DOE) hosted a day-long meeting "to explore the scientific challenges associated with discovering alternative, sustainable processes for ammonia production."
The report that came out of this roundtable discussion presents the participants' views on "the current state-of-the-art and the potential challenges and research opportunities ... for heterogeneous catalysis and homogeneous and enzyme catalysis."