A Study on the Impact of Slow Steaming on Containership Operations under the Carbon Intensity Indicator Regulation

A Study on the Impact of Slow Steaming on Containership Operations under the Carbon Intensity Indicator Regulation

As there is growing concern about the environmental impact of greenhouse gas emissions from ships, the International Maritime Organization (IMO) has introduced several regulations targeting reductions in carbon dioxide emissions of 50% by 2050. This study pays particular attention to the carbon intensity indicator (CII) and investigates the impact of slow steaming, one of the short-term measures in the regulation, on containership operations. To this end, a dataset of 8 containerships with various ages and sizes was collected. Based on operation data in 2021, the CII ratings of the containerships were estimated in the business-as-usual scenario for the 2023-2030 period. Then, the speed reductions required to keep the minimum CII rating were calculated for individual containerships. Finally, working day losses resulting from the speed reductions were calculated. The findings in this study were threefold. First, it was found that containerships will undergo degradation in the CII rating every 3 or 4 years without slow steaming. Second, a speed reduction of 2 knots between 2023 and 2030 is required to keep the minimum CII rating. Finally, speed reductions result in the loss of as many as 6 or 7 working days per year.