EEXI would only cut shipping emissions by 1.8%, finds study

EEXI would only cut shipping emissions by 1.8%, finds study

A new working paper by the International Council on Clean Transportation (ICCT) has found that the International Maritime Organization’s (IMO’s) Energy Efficiency Existing Ship Index (EEXI), designed to reduce fuel use and CO2 emissions, would only affect shipping emissions by between 0.8 per cent and 1.8 per cent by 2030.

In the working paper, authors Dan Rutherford, Xiaoli Mao, and Bryan Comer state that the EEXI would make only a small contribution to IMO’s climate goals due to the continuing prevalence of slow steaming, whereby most ships are being operated at engine loads that would be unaffected by the technical efficiency standard the EEXI sets.

To reduce the carbon intensity of shipping, the IMO proposes both a technical approach and an operational approach. The EEXI is a technical approach, proposed by Japan and supported by Norway, Greece, Panama, the United Arab Emirates, the International Chamber of Shipping, BIMCO, and the International Association of Independent Tanker Owners (BIMCO, 2020).

The proposal would apply technical efficiency standards to the existing fleet based upon the approach of the IMO’s Energy Efficiency Design Index (EEDI), which only regulates the carbon intensity of newbuild ships. The working paper states that unlike an operational efficiency standard, the EEXI would limit the amount of CO2 emitted per unit of transport supply (e.g., deadweight tonne-nautical miles), rather than per unit of transport work.

To comply with the EEXI, owners can modify existing ships by installing energy efficiency retrofits, largely done by main engine power limitation (EPL), the paper reports. New ships that can be certified to EEDI targets for 2022 and beyond will meet the EEXI without further modifications. The paper refers to research by MAN & PrimeServ from 2016 that states that EPL is likely to be the easiest way for older ships to meet the EEXI requirements as it requires minimal changes to the ship and does not change the underlying performance of the engine.

However, as EEXI does not limit engine power below what ships already use, the authors believe that it will not result in reductions in ship speed or CO2. They conclude that the main impact of the EEXI would be to codify current business as usual operational efficiency gains due to slow steaming and will not require the majority of ships in the current fleet to change behaviour.

The paper states that: ‘Ships are currently steaming at speeds lower than they were designed for and, as a consequence, are typically using much less than 100 per cent MCR.  ICCT found that the EEXI would only reduce 2030 emissions by 0.8 per cent if evaluated at 75 per cent MCRlim or 1.6 per cent if evaluated at 87 per cent MCRlim from a 2030 baseline without the EEXI. So, while the EEXI is more effective if evaluated at 87 per cent MCRlim, it still is not very effective at reducing absolute emissions from the fleet. Accordingly, a mandatory and stringent operational goal-based measure that targets the potential of further short-term speed reduction is likely to be more effective than the EEXI.’

Next week, the IMO will discuss how to combine operational measures regulating carbon Intensity and the EEXI to decarbonise shipping.

The working paper is part of a forthcoming study to be released in November analysing the effect of the EEXI in reducing shipping’s carbon intensity. The full paper can be downloaded by clicking here.