IAPH develops its own GHG performance indicator for its Environmental Ship Index (ESI) port incentive scheme for shipowners

GHG performance indicator to apply same ship data reported to IMO, also aligning vessel audit frequency to a yearly basis

This week sees the review, at the eighty-second meeting of the Marine Environment Protection Committee (MEPC82), of the IMO’s Carbon Intensity Indicator (CII) - notably of its capacity to accurately and reliably evaluate the GHG performance of certain types of ships.

In a submission it has made on the energy efficiency of ships, IAPH has welcomed the introduction of the CII as a positive development, but also acknowledges the concerns of the shipping industry and IMO member states about the shortcomings of the indicator in its current form.

IAPH has therefore decided to develop its own GHG performance indicator as part of the forthcoming expansion and revision of the IAPH Environmental Ship Index (ESI) which will become fully operational as of 2026. Owners of the 6,425 container, cargo, cruise and passenger vessels registered on the index are able to benefit from the 80-plus port incentive providers around the globe, because the environmental performance of their fleets exceed IMO emissions standards. Both incentive providers and receivers are now working to adapt their data collection based on the new parameters, ahead of the January 2026 launch.

The ESI GHG performance indicator focuses on fuel transition, with a Well-to-Wake (WtW) approach using the carbon intensity of bunkered fuels. The indicator does not include the distance sailed which, when combined with the operational realities of certain ship segments regarding fuel consumption (e.g. long berthing times or long waiting times before berthing) can lead to low CII.

The approach will work with all future low- and zero-carbon fuels, remaining applicable and appropriate for all ship types and sizes, including the numerous vessels that are under 5,000 gross tonnes registered on the Index.

IAPH technical director Antonis Michail commented : “In our submission to MEPC82, we state that although not directly integrating CII, the ESI GHG module remains close to it and the IMO short-term measure, using the same relevant data sources where applicable. We will adjust the frequency reporting to annually, after data verification by class. The Well-to-Wake (WtW) CO2e intensity values will be retrieved from either the Bunker Delivery Notes (BDNs) certificate of sustainability, or IMO defaults, with the global warming potential (GWP) of the different fuels also being taken into account.”

Further upgrades to IAPH Environmental Ship Index to reward innovations

The changes in ESI will go into effect in 2026, enhancing the current system to comprehensively assess vessels' performance not only on greenhouse gas emissions but also on air emissions (SOx, NOx), at berth performance, as well as ambient and underwater noise. In addition, the planned transition of the Index in 2026 will reward innovation on board, including carbon capture, wind assistance, batteries and air lubrification. This will be achieved through a separate innovation module which will be periodically reviewed to adjust to technological and market realities.

Commenting on these significant upgrades to the Index, IAPH Managing Director Patrick Verhoeven commented “As our highly successful ESI voluntary incentive scheme designed by ports for shipowners expands, IAPH is investing in this practical tool, which can be used here and now to help to decarbonise shipping and reduce emissions of all kinds, both at sea and in and around ports.”

For ports, maritime administrations or shipowners interested in joining the IAPH Environmental Ship Index, please contact IAPH’s ESI Liaison which is the Green Award Foundation (admin@environmentalshipindex.org), copying in IAPH Technical Director Antonis Michail (antonis.michail@iaphworldports.org).

Notes to editors

1. Several world ports voluntarily promote and reward the proactive emission policies of shipping companies that choose to perform beyond legal requirements. They do so, based on established indexes and schemes. Back in 2011, aiming to assist ports in the development and adoption of such voluntary port incentives, IAPH established the Environmental Ship Index (ESI). Since then, ESI has developed to become the standard tool used by world ports to reward and incentivise shipowners with ships that exceed IMO emissions standards.
2. Currently, around 6,500 commercial ships globally are registered in the ESI database and there are more than 80 organizations, predominantly port authorities, that actively provide incentives based on ESI. The ESI scores of participating ships and the types of incentives provided by ports are publicly available on the ESI website.
3. ESI is a voluntary system that provides a numerical representation of the environmental performance of ships regarding air pollutants, CO2 and noise. It currently scores ships on NOx and SOx emissions directly and proportionally, and gives a fixed bonus for documentation and operational energy efficiency performance and the installation of zero-emission technologies at berth.
4. The new upgraded edition of the IAPH Environmental Ship Index (ESI) will become fully operational as of 2026. The proposed calculation for the ESI GHG performance indicator can be found here.