About
In order for ship-owners to comply with the sulphur cap, there are in essence three choices available:
- Switching from high-sulphur fuel oil ('HSFO') to marine gas oil ('MGO'), distillates or low-sulphur fuel oil ('LSFO'), or compliant fuel blends (not exceeding 0.50% sulphur content);
- Installing exhaust gas cleaning systems (commonly referred to as 'scrubbers'), which allow operation on regular HSFO; or
- Retrofitting vessels to use alternative fuels such as LNG, methanol, hydrogen or other sulphur-free fuels.
We have seen that most ship-owners have opted for compliant fuel blends rather than installing scrubbers or retrofitting vessels to use fuels such as LNG. Despite the price difference between LSFO, MGO and HSFO blends, changing to LSFO or MGO has proven to be a viable option that appears to be more reliable than certain scrubbers.
In 2022, the entire Mediterranean Sea was designated as an emission control area, with more stringent controls on sulphur oxide emissions that came into effect from 1 May 2025. During the 82nd session of the Marine Environment Protection Committee (MEPC) in 2024, Canadian Arctic and the Norwegian Sea were designated as Emission Control Areas for Nitrogen and Sulphur Oxides, and Particulate Matter. The 0.10% fuel sulphur content requirement takes effect from 1 March 2026.
During the 83rd session of the MEPC in April 2025, a proposal to designate the entire North-East Atlantic was approved.
The adoption of this ECA was planned for an extraordinary MEPC session in October 2025.. However, the IMO has now stated that the adoption will be delayed by at least 6 months, and adaptation is now scheduled for April 2026 with implementation in September 2028. Once implemented, this EXA will encompass the EEZs and territorial waters of Portugal, Spain, France, the UK, Ireland, Iceland, the Faroe Islands, and Denmark (Greenland) that are not already included in any existing ECAs (excluding the EEZs surrounding Madeira, the Azores, and the Canary Islands). This will establish a continuous ECA throughout the North-East Atlantic, linking the Canadian Arctic, the Norwegian Sea, the North Sea, and the Mediterranean Sea ECAs.
Who does it impact?
All ship-owners, as well as port and flag states, bunker suppliers, charterers, ship builders etc.
Status: In force
Entered into force on 1 January 2020.
Adopted by IMO by several amendments to Annex VI to the International Convention for the Prevention of Pollution from Ships (MARPOL).
Relation to other initiatives and regulations
On 26 October 2018, the IMO’s Marine Environment Protection Committee (MEPC 73) adopted a MARPOL amendment to prohibit the carriage of non-compliant fuel oil for combustion purposes for propulsion or operation on board ships, unless the ship is fitted with an exhaust gas cleaning system ('scrubber'). The regulation entered into force on 1 March 2020.
In addition to MARPOL Annex VI, there are regional mandates in ports and certain territorial waters within e.g. China, Hong Kong and the EU, regarding reduced SOx emissions. These requirements establish maximum allowable limits for sulphur content in fuel oils use by vessels when operating within certain areas and waters and while 'at berth'.
In June 2022, the IMO also released circulars with guidelines on risk and impact assessment when discharging water from exhaust gas cleaning systems, and a set of guidelines with best practices on management and disposal of exhaust gas cleaning system residues and discharge water into port reception facilities.
Participants
Signatory states to MARPOL Annex VI. Implementation is the responsibility of the signatory states.
Thommessen's comments
The IMO 2020 Global Sulphur Cap has significantly reduced the amount of sulphur oxides emanating from ships and is expected to have major health and environmental benefits. The IMO 2020 Global Sulphur Cap is strictly enforced by the world's port state control authorities.
Before the sulphur cap entered into force, we saw a significant increase in ship-owners opting for the installation of exhaust gas cleaning systems ('scrubbers') onboard their ships.
However, the use of exhaust gas cleaning systems has not been uncontroversial and we have seen an increasing number of local regulations prohibiting the use of open-loop systems when ships are operating within certain areas and waters and while 'at berth'. For instance, ports such as the port of Fujairah, port of Gibraltar and port of Singapore, and regulations applicable in the Panama and Suez Canals, as well as the World Heritage Fjords of Norway, all prohibit the use of open loop scrubbers. In July 2025, the 15 state parties to the Convention for the Protection of the Marine Environment of the North-East Atlantic (including Norway) agreed to introduce a ban on open loop discharge from 1 July 2027, and a ban on all discharge from 2029 in inland waters and port areas. Other Member States in the EU may follow suit, and local regulations may be frequently amended.