COMMERCIAL and non-commercial vessels must comply with the new International Maritime Organization (IMO) 2023 regulations to reduce carbon emissions using energy efficiency indicators.

The two main IMO 2023 measures are the Energy Efficiency Existing Ship Index (EEXI) and the Carbon Intensity Indicator (CII) Rating Scheme.

 IMO 2023 targets ships' efficiency and carbon emissions effective Jan. 1, 2023.

"From Jan. 1, 2023 it is mandatory for all ships to calculate their attained EEXI to measure their energy efficiency and to initiate the collection of data for the reporting of their annual operational CII and CII rating," IMO said.

EEXI is a rating system that assesses the energy performance of existing ships based on energy consumption data and other key metrics such as speed, power and engine size. EEXI is based on the ship's specifications and not its actual operating performance.

Noncompliant vessels that receive an EEXI rating below a certain threshold will face IMO 2023 penalties and restrictions and will be required to modify their engines or systems. EEXI will be assessed at the first International Air Pollution Prevention Certification survey after Jan. 1, 2023..

CII, the new global shipping carbon intensity indicator, is used to rank and monitor the efficiency of individual ships. It links the GHG emissions to the amount of cargo carried and the distance traveled ratio.

The CII rating threshold will become stricter over time and will therefore determine the annual carbon reduction factor needed to ensure compliance. Each vessel will receive a grade from A (good) to E (poor) starting this year.

Ships with three years of D grades or one year receiving an E grade will have to put a corrective action plan in place.