In the initial IMO Strategy for reducing greenhouse gas (GHG) emissions from ships, the level of ambition for CII of international shipping was quantified by CO2 emissions per transport work, the average of overall international shipping.
This is a severe rule for ships with only short voyage because the greater the navigation distance is, the lower the CO2 emissions per unit transport work are. In addition, short voyage ships might be evaluated as poor in the CII assessment because of the small transport workday, although measures have been taken to improve energy efficiency. Consequently, all ships will refuse short-term navigation, resulting in a conversion to land transport in some areas. This will lead to an increase in CO2 emissions.
Ri Hyok, a researcher at the Faculty of Shipbuilding and Ocean Engineering, has proposed a relatively fair CII calculation method by introducing a correction factor for an ordinary freight vessel, taking short-voyage and long-voyage into account.
He confirmed the accuracy of correction factors with operational data of ships of less than 35 000 DWT.
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