Time to cut ship emissions in the North Atlantic

Designating the North Atlantic as an Emission Control Area could lead to significant air pollution reductions from shipping that would benefit both human health and the environment.

Coordinated efforts to establish a North Atlantic Emission Control Area (Atl-ECA) have been going on for a few years, and in 2023 eleven countries and the European Commission submitted a joint paper to the Marine Environment Protection Committee (MEPC) of the International Maritime Organization (IMO), updating progress in this work.

Designating the North Atlantic sea area as an Emission Control Area would impose stricter regulations aimed at reducing emissions of sulphur oxides (SOx), fine particulate matter (PM2.5), and nitrogen oxides (NOx).

The proposed Atl-ECA would include the territorial seas and exclusive economic zones of Spain, Portugal, France, the United Kingdom, Ireland, Iceland, the Faroe Islands, and Greenland, with potential expansion to include the Azores and Madeira archipelagos of Portugal and the Canary Islands of Spain (see Figure 1).

Figure 1. Established and proposed Emission Control Areas Note: Map does not show the entirety of some ECAs. Source: THEICCT.ORG

In June 2024, the International Council on Clean Transportation (ICCT) published a study that assesses the potential emission reductions of such a North Atlantic ECA. The results of the study are intended to be part of a new joint submission to the IMO’s MEPC proposing to designate the Atl-ECA.

According to the study, the Atl-ECA designation could lead to significant air pollutant emission reductions. In 2030, if distillate fuel is used to comply with the ECA regulations, there could be an 82% reduction in SOx emissions, a 64% reduction in PM2.5, and a 36% reduction in black carbon (BC) emissions when compared to a scenario without ECA regulations. Moreover, if the outermost regions of Portugal and Spain join the Atl-ECA, additional emission cuts could be achieved and air pollution near these islands could be significantly reduced.

Application of IMO’s Tier III NOx emission standards is expected to reduce expected NOx emissions by about 3% in 2030 if they apply only to ships built in 2027 or later. However, applying Tier III standards to engines on all ships could result in up to 71% NOx reductions.

In order to investigate different possible pathways, the study used the following scenarios and assumptions:
Business-As-Usual (2030): This assumes no Atl-ECA implementation in the study area. Consequently, vessels are expected to use fuel as predicted by the ICCT’s global maritime fuel demand and emissions projection model – Polaris.

MGO Mix: This scenario assumes that the fleet operating on VLSFO (very low sulphur fuel oil) will switch to MGO (marine gas oil, also known as distillates). Ships already using distillates, LNG (liquified natural gas), and methanol are not expected to change behaviour. Ships predicted to have installed scrubbers will need to adjust performance to achieve the 0.1% fuel sulphur content, instead of the 0.5% sulphur content in the BAU scenario.

ULSFO Mix: This scenario is similar to the MGO Mix scenario, with the distinction that ships operating on VLSFO will switch to ULSFO (ultra-low sulphur fuel oil) instead of MGO. It is assumed that the sulphur content of ULSFO does not exceed 0.1% while other properties and emissions remain similar to VLSFO.

MGO Max: In this scenario, it is assumed that scrubbers are not allowed as an alternative sulphur compliance method and ship owners utilise only MGO for compliance. In this case, no ships will have scrubber installations in 2030.
Scrubber Max: This assumes that all ships currently using HFO (heavy fuel oil) with scrubbers will continue to do so. Ships currently operating on VLSFO will install scrubbers and use HFO instead of opting for 0.1% sulphur-compliant fuels. Like all other scenarios, the ships already using MGO, LNG, and methanol for compliance are not expected to change behaviour.

Figure 2 shows the expected reductions in SOx, PM2.5, and BC emissions across the four different scenarios.

Figure 2. Emissions in the proposed Atl-ECA (excluding outermost regions) by compliance scenario and reductions in emissions compared with the BAU scenario.

Looking at ship types and movements, the study found that 88% of the vessels sailing in the proposed Atl-ECA, along with 94% of the ships operating in the Azores, Madeira, and Canary Islands, are already navigating in other established or proposed ECAs.

Out of 17,640 ships found in the Atl-ECA area in 2021, 76% also navigated in the North Sea ECA and 74% in the Mediterranean Sea SECA, where the 0.1% fuel sulphur requirements will apply in 2025. Furthermore, 87% of vessels recorded in the outermost regions were also sailing within the Atl-ECA region. Similarly, 88% were sailing in the Mediterranean Sea SECA, 63% in the North Sea ECA, and 61% in the North American ECA (61%).

This information is important, as ships operating in existing ECAs will already bunker low-sulphur fuels or use HFO with scrubbers. Newer ships will also have installed NOx reduction technologies if they are subject to Tier III requirements in the North American, Baltic Sea, or North Sea ECAs. Consequently, most ships navigating the proposed Atl-ECA and outermost regions would not require significant technical modifications following the designation of such an ECA.

The study concludes that the biggest reductions in emissions can be achieved when ships use distillate fuels such as MGO to comply with the ECA. Using ULSFO or HFO with scrubbers is not as effective at reducing SOx, PM, or BC. The use of ULSFO produces 9% more SOx, 55% more PM2.5, and 36% more BC emissions compared to distillates. While scrubbers are shown to be equally effective as distillates in reducing SOx emissions, they generate 17% more PM2.5 and 32% more BC emissions.

Based on these findings, the authors of the report present some recommendations to the Atlantic ECA member states:

• Include the full exclusive economic zones of Spain, Portugal, France, the United Kingdom, Ireland, Iceland, Faroe Islands, and Greenland in the geographic scope of the Atl-ECA. This would strategically connect the surrounding established or proposed ECAs, creating the largest low-emission shipping zone in the world.
• Consider including the outermost regions of Portugal (Azores and Madeira) and Spain (Canary Islands) in the geographic scope of the Atl-ECA, as the analysis shows that 94% of the traffic crossing these islands is already shipping in other existing or proposed Emission Control Areas.
• Incentivise the use of distillates over ultra-low sulphur fuel oil or scrubbers for ECA compliance in the national waters of Atl-ECA member states.
• Consider restricting the use of scrubbers in the national waters and ports of Atl-ECA member states to reduce BC and PM and to avoid scrubber discharges.
• The findings of this study will be used in a follow-up analysis to estimate ambient concentrations of air pollutants and the related environmental and health impacts.
• Moreover, the results of these studies, as well as additional work by Porto University, are intended to be a part of a submission in 2025 to the IMO’s Marine Environment Protection Committee on designating a North Atlantic ECA.

The ICCT report “From concept to impact: Evaluating the potential for emissions reduction in the proposed North Atlantic Emission Control Area under different compliance scenarios” by L. Osipova, P. Ferrini Rodrigues, F. Carvalho, and K. Gore can be downloaded at: https://theicct.org/wp-content/uploads/2024/06/ID-146-–-Atlantic-ECA_final-1.pdf