Ammonia Emissions from a Fertilizer Plant and Implications for a Hydrogen Economy

Abstract

Ammonia has emerged as a promising hydrogen carrier in the transition to a low-carbon energy system, but its environmental impact depends on the accuracy of reported emissions. Recent studies suggest that emissions from industrial processes may be underestimated, raising concerns about the true scale of nitrogen release, as ammonia quickly reacts in the atmosphere to form harmful particulate matter and nitrous oxide. This thesis quantifies ammonia emissions from the AdvanSix facility in Hopewell, Virginia, using mobile atmospheric measurements and Gaussian plume modeling. A series of downwind transects were conducted to measure ammonia concentration and estimate emission rates. Under ambitious climate scenarios, hydrogen could account for 4–7% of global energy consumption by 2050 [27], with ammonia serving as the primary medium for its long-distance transport. Intercontinental hydrogen trade is projected to be primarily ammonia-based, up to approximately 65 Mt per year by 2060 [9]. Global ammonia production is projected to increase by nearly 40% by 2050 [16], driven by population growth, agricultural demand, and emerging energy applications. Leakages and undesired reactions across the ammonia value chain could result in 0.5–5% of nitrogen being lost to the environment as reactive nitrogen compounds, including NH3, NxO, and N2O. At the scale of a growing ammonia-based energy economy, even small fractional losses would represent a meaningful increase in atmospheric nitrogen loading, which makes emissions reporting from industrial facilities all the more critical. The calculated emission rates generally ranged from approximately 9–10 g/s, with most transects falling within ±10% of the yearly reported values from AdvanSix. A final emission lower-bound of 10.1±2.4 g/s, with an upper-bound of 12.6±3.9 g/s was found. Additional analysis showed that emission estimates were relatively insensitive to source height assumptions but more sensitive to source representation and sampling completeness. Overall, the results suggest that the facility is likely slightly under-reporting its ammonia emissions. This thesis demonstrates the effectiveness of mobile plume measurements as an independent method for validating industrial emissions reporting and highlights their importance for assessing the environmental implications of a growing ammonia-based energy system.