Matthew J. Palys*, Anatoliy Kuznetsov, Joel Tallaksen, Michael Reese, Prodromos Daoutidis, University of Minnesota, USA
15th Annual NH3 Fuel Conference, Pittsburgh, PA, October 31, 2018
NH3 Energy+ Topical Conference at the AIChE Annual Meeting
Small-scale, distributed production of ammonia better enables the use of renewable energy for its synthesis than the current paradigm of large-scale, centralized production. Pursuant to this idea, a small-scale Haber-Bosch process has been installed at the West Central Research and Outreach Center (WCROC) in Morris, MN  and there is ongoing work on an absorbent-enhanced process at the University of Minnesota , . Using renewables to make ammonia would greatly improve the sustainability of fertilizer production, which currently accounts for 1% of total global energy consumption . The promise of renewable-powered, distributed ammonia production for sustainability is in fact not limited to fertilizer, because ammonia also has potential as an energy-dense, carbon-neutral fuel. For example, using ammonia produced from renewable energy for nitrogen fertilizer, grain drying fuel and tractor fuel at the WCROC farm would reduce more than 90% of the fossil energy footprint associated with corn production .
In this light, we envision a distributed sustainable agricultural (farm) energy system (DSAE) fundamentally based on the idea of ammonia as not only a fertilizer, but also a fuel and a method of energy storage. Specifically, this system will use only renewable energy to produce ammonia for use as fertilizer and agricultural fuel (for cropping equipment and grain drying) at the scale of a single farm or an agricultural cooperative. It will also use renewables to meet local power and heat demands in a manner synergistic to distributed ammonia production; the difference in power and heat (hourly) and ammonia (monthly or biannually) demand time scales gives rise to opportunities for temporally flexible ammonia production and locally controllable power generation using ammonia. Heat integration will also be possible due to the exothermic nature of ammonia synthesis. Continue reading