(427a) Increases in Demand for Fixed Nitrogen from Alternative Energy and Carbon Capture Schemes

Anthropogenic fixed or reactive nitrogen is a key input to modern agriculture; contributing a significant portion of the overall energy consumption and the environmental impact. The commercial process for the production of fixed nitrogen, the Haber-Bosch process, consumes large quantities of fossil fuels and releases large amounts of greenhouse gases. In addition to increases in demand for food agricultural fertilizer because of increasing population and prosperity (94-121×10⁹ kg N/year), projected increases in biofuel production from terrestrial sources and microalgae will further increase demand for production of ammonia. In addition to biomass nutrient needs, commonly used pretreatment methods for lignocellulosic biomass use ammonia to disrupt the plant cellular structure. Likewise, carbon capture schemes will increase demand for fixed nitrogen in the form of amines for chemical absorption. Lastly, there is ongoing research exploring direct use of ammonia as a fossil-fuel substitute in internal combustion engines and in fuel cells. In this paper, various scenarios are analyzed for ammonia demand up to the year 2050, driven by increasing demand for food; mandated use of biofuels; initiation of large-scale carbon capture schemes and the potential use of ammonia as a fuel. Sharp increases in demand, in the order of 10¹² kg/year, are projected even with only partial replacement of diesel and gasoline demand for fuel. The other new applications may still account for an additional demand of 100-200 ×10⁹ kg NH₃/year—almost equivalent to the projected fixed nitrogen demand for food agriculture.