Carbon intensity of “average” ships

Abstract

This paper investigates the carbon intensity of “average” ships, i.e., the ships of different types and sizes which, in 2018, performed an average transport work and emitted an average amount of CO₂, according to the data published in the Fourth IMO GHG Study. The goal of the study is to identify the ship types and sizes which may be regarded as the best and the worst performing with respect to carbon intensity. Using the data available from the Fourth IMO GHG Study, the Carbon Intensity Indicator (CII) is calculated for each of the examined average ships and the obtained values are compared to the CII reference lines valid for 2023, 2024, 2025, and 2026. Based on the calculations, carbon intensity ratings may be assigned to examined ships for four consecutive years. Thus, it is possible to estimate the evolution of carbon intensity of examined fleet segments, provided that no measures for improvement of carbon intensity would be implemented in years to come. The analysis has shown that most of the current merchant fleet would exhibit an “inferior” (label E) performance with respect to the carbon intensity. While some of the examined average ships with “inferior” rating could attain the “moderate” rating (label C) in 2023 by relatively small reductions of 2018 CII values, most of the other ships would require considerably greater improvements. Identification of the “worst performers” would indicate which ships require immediate attention with respect to the carbon intensity. Thus, the outcomes of the study may serve as an input to policy makers when deciding on measures addressing the carbon intensity of maritime shipping.