The Need to Amend IMO’s EEDI to Include a Threshold for Performance in Waves (Realistic Sea Conditions) to Achieve the Desired GHG Reductions

Elizabeth Lindstad,Henning Borgen,Osman Turan,Gunnar S Eskeland,Christopher Paalson,Harilaos Psaraftis

doi:10.3390/su11133668

Abstract

The International Maritime Organization (IMO) has established the Energy Efficiency Design Index (EEDI) as the most important policy measure to reduce greenhouse gas (GHG) emissions from shipping. A vessel’s EEDI is based on sea trials at delivery, and vessels cannot exceed a threshold for emitted CO2 per ton-mile, depending on vessel type and size. From other industries such as cars we have learnt that testing methods must reflect realistic operating conditions to deliver the desired emission reductions. Present sea-trial procedures for EEDI adjust to ‘calm water conditions’ only, as a comparative basis, despite calm sea being the exception at sea. We find that this adjustment procedure excessively rewards full bodied ‘bulky’ hulls which perform well in calm water conditions. In contrast, hull forms optimized with respect to performance in realistic sea-conditions are not rewarded with the current EEDI procedures. Our results indicate that without adjusting the testing cycle requirements to also include a threshold for performance in waves (real sea), the desired reductions will be short on targets and GHG emissions could potentially increase.

Highlights

The International Maritime Organization (IMO) has established the Energy Efficiency Design Index (EEDI) as the most important policy measure to reduce greenhouse gas (GHG) emissions from shipping
We show how—under the present adjustments to calm water conditions—that the EEDI requirements will, rather, encourage such improvements as antifouling treatment, lending performance boosts at the EEDI sea trial tests more than designs which deliver improved performance in real operations;
A vessel’s EEDI is based on sea trials at delivery, and vessels cannot exceed a threshold for emitted CO2 per ton-mile, depending on vessel type and size

Summary

Introduction

The International Maritime Organization (IMO) has established the Energy Efficiency Design Index (EEDI) as the most important policy measure to reduce greenhouse gas (GHG) emissions from shipping. The strategy acknowledges the needs for continuous improvements and that a wide range of measures, options and technologies should be investigated to enable the maritime industry to reach the reduction targets It confirms the EEDI as IMO’s single most important policy measure to reduce maritime GHG emissions. The EEDI test measures the emissions per ton nm for a fully loaded vessels when the main engine delivers 75% of its maximum continuous power (MCR) at calm water conditions. This is despite the fact that calm sea is the exception in shipping [14]. The obtained results are summarized in the Concluding Section 6

Model Description

Analysis

Findings

Conclusions