Environmental and economic evaluation of ammonia as a fuel for short-sea shipping: A case study

In this study, the environmental and economic effects of the ammonia-diesel dual-fuel engine are evaluated by a case study with the real voyage data of a ship. Thirteen scenarios are formed by three different fuel fractions and three different types of ammonia which are classified according to their production routes (brown, blue, and green ammonia). Brown ammonia has worse (137.7%) or slightly lower (3%) CO₂ emissions than MDO depending on the feedstock. Blue ammonia complies with the IMO 2030 target with a 42.8% CO₂ reduction while green ammonia from solar energy has a similar reduction capacity with blue ammonia, and green ammonia from wind energy provides 79.2% CO₂ reduction and complies with the 2050 target. SO_X and PM emissions are decreased up to 95% by ammonia usage. NO_X emissions are 19.4% lower at 60% ammonia energy fraction than MDO, but it increases 133.1% at 95% ammonia energy fraction. The selective catalytic reduction system is required for high ammonia energy fraction cases. The N₂O emission is an important issue during ammonia usage. The fuel expense analyses show that brown ammonia is cheaper and blue ammonia is slightly higher (8.8%–13.9%) than MDO. Green ammonia does not be feasible recently, due to its significantly high price.