(44b) Green Ammonia for Sustainable Energy and Agriculture

Ammonia is the basis of synthetic nitrogen fertilizer production and is thus the backbone of modern agriculture. Its large-scale production using the classic Haber-Bosch process, with hydrogen obtained from fossil fuels, is responsible for 1-2% of both global energy consumption and CO 2 emmissions. Reducing the carbon intensity of ammonia production is critical to a more sustainable agricultural system. Furthermore, ammonia’s relative ease of storage and transportation (compared to hydrogen), and its potential use as a power/heat generation or transportation fuel with no associated carbon emissions at the point of use, give it considerable promise as a sustainable energy vector, provided it can be produced in a low emissions manner. For these reasons, green ammonia, i.e., ammonia synthesized from hydrogen obtained from water electrolysis and nitrogen obtained from air using renewable electricity, is currently
receiving world-wide attention from governments, industry, non-governmental organizations, and private investors. Green ammonia requires more distributed siting and smaller-scale production facilities than traditional ammonia due the inherently localized nature of renewable resources and the relative lack of economies of scale for electrolysis technologies. Optimal design and deployment are critical factors for its economic competitiveness.

In this talk, I will describe recent advances in the production, deployment, and utilization of green ammonia that address these challenges. These include:

* The concurrent design and scheduling of ammonia synthesis processes that operate dynamically, as a framework for accounting for the intermittency of the main feedstock (wind or solar irradiance) to minimize the levelized cost of production.

* A supply chain optimization framework for optimal placement of distributed, modular, ammonia production facilities to meet local fertilizer demands.

* The optimal design of a green ammonia-based system where ammonia is used as fertilizer, grain drying fuel, tractor fuel, and energy storage medium on a farm, as an illustration of the potential benefits from the synergistic use of ammonia across multiple sectors.

* The optimal design, scheduling, and operation of islanded renewable microgrids which utilize ammonia for energy storage.
The results I will discuss document the transformative potential of green ammonia toward sustainability in the agriculture and energy sectors. I will also address some outstanding challenges on deploying green ammonia production at scale, as well as adopting its utilization across multiple sectors.