Scrubber installation and green fuel for inland river ships with non-identical streamflow

Recently, the International Maritime Organization (IMO) and government sectors have enacted several stringent regulations to curb the emissions of ships. Green fuel and scrubber installation are two prevailing adaptation strategies used by ships to reduce emissions. Green fuel leads to a high shipping cost with the consumption of low-sulphur but highly-priced oil, while scrubber installation is a long-term decision, which incurs a high capital cost from the setting up of desulphurization facilities but ensures ships can continue consuming low-priced oil. This paper makes a theoretical and holistic investigation of the strategy choice of a container ship in an inland river by taking into account the impact of streamflow velocity. For the inland shipping service, the sailing speed of a ship is the sum of its engine speed and streamflow velocity. The engine speed determines the fuel consumption, and the sailing speed determines the round-trip time of a ship. We found that the engine speed of a ship increases with respect to the streamflow velocity under both strategies in the sense of cost minimization. Also, the streamflow velocity increases the incentive of a ship to install a scrubber. Finally, numerical experiments based on the Yangtze River are conducted to demonstrate our proposed models.