The N₂O production from ammonia and hydrogen as fuels for shipping purposes

Ammonia and hydrogen are considered promising alternative fuel options for shipping purposes. However, the complete passage to these new fuels for power production is not straightforward, especially for the maritime sector. To properly address the issues related to large-scale implementation of alterantive fuels, a holistic approach including techno-economic, environmental, and societal aspects is strongly recommended. Concerning the environmental domain, a useful indicator is the emission of nitrogen oxides (NO_x), which is over 95 % derived from anthropogenic sources. In this regard, some of the oxidized nitrogen would ultimately produce nitrous oxide N₂O, which would offset some of the climatic benefits reached by switching maritime shipping fuels. For these reasons, this work evaluates and compares the emission rate of N₂O (gN₂O/kWh) and the corresponding emission index (gN₂O/kgfuel) of N₂O produced by ammonia and hydrogen, in the framework of shipping purposes, by using the thermo-kinetic mechanism KIBO developed at the University of Bologna. Results give insights and technical indications on the sustainability of these tank-to-wake, zero-carbon fuels.

Keywords: Nitrous oxide, Maritime transportation, Tank-to-wake sustainability, Zero-carbon fuels.