Nitrous Oxide (N2O)

Nitrous oxide is a potent greenhouse gas with an AR5 100-year global warming potential of 265, formed in marine engines mainly during fuel-rich or low-temperature combustion and as a byproduct in some SCR systems. It matters most for ammonia combustion, where N2O formation is a key emissions risk that can offset ammonia’s zero-carbon advantage if not controlled. Well-to-wake accounting under the IMO LCA Guidelines and FuelEU Maritime counts N2O as CO2-equivalent, so engine developers target low-N2O combustion and after-treatment for ammonia and dual-fuel engines.