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The Role of Energy Efficiency Regulations

Abstract

The International Maritime Organization (IMO) has implemented three regulatory measures to drive the short-term reduction of CO2 emissions by improving the energy efficiency of the world fleet. The Energy Efficiency Design Index (EEDI) and the Energy Efficiency Existing Ships Index (EEXI) aim to rate the technical efficiency of ship designs by evaluating theoretical emissions from a vessel, its design characteristics, and installed equipment onboard. The Carbon Intensity Index (CII) focuses on the operational efficiency of a vessel, giving an efficiency rating based on reported fuel consumption, emissions, and transport work done throughout a calendar year. In 2013, the EEDI became the first ofthese regulations to enter into force and was applied to newbuilds only. Both the EEXI and the CII were introduced on 1 January 2023 and are applicable fleetwide.

A dedicated Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping (MMMCZCS) working group was established to study the drivers and enablers for onboard energy efficiency. A subgroup of this working group focused on the role of regulations as a driver to reduce emissions from the global fleet. The subgroup investigated the impact of the three IMO measures as well as their implementation challenges and potential for improvement. This investigation was supported by a range of examples provided by MMMCZCS partner organizations.