ADVOCACY group for the use of liquefied natural gas as a ship fuel, SEA-LNG, has provided analysis that shows how LNG extends compliance under the International Maritime Organization’s Carbon Intensity Indicator (CII) rules, ahead of oil-based fuels.

The IMO measures will require all ships to calculate their Energy Efficiency Existing Ship Index (EEXI) following technical means to improve their energy efficiency and to establish their annual operational carbon intensity indicator (CII) and CII rating. Carbon intensity links the greenhouse gas emissions to the amount of cargo carried over distance travelled.

The amendments to MARPOL Annex VI, known as short-term measures, are expected to enter into force on 1 November 2022, with the requirements for EEXI and CII certification coming into effect from 1 January 2023. This means that the first annual reporting will be completed in 2023, with the first rating given in 2024.

CII thresholds will tighten annually, requiring operators to document vessel performance and demonstrate they have achieved the required threshold for the year.

The analysis from SEA-LNG found that LNG-fuelled vessels will be able to continue operating as normal under the system until after 2030, while fossil LNG blended with bioLNG and renewable synthetic LNG will further extend compliance to 2050 and beyond.

The analysis compared emissions for two identical 180k DWT Capesize vessels, one using conventional, oil-based marine fuels the other using LNG as a marine fuel. The results showed that the LNG-fuelled vessel immediately rated two grades higher than the conventionally fuelled vessel. LNG can be the difference between having a moderate C-rated ship and having a major superior A-rated ship on the IMO’s CII scale.

The IMO is encouraging port authorities, governments and other stakeholders to offer incentives for ships with major superior A or superior B ratings.

LNG-fuelled vessels can also gain improved carbon intensity ratings by adopting drop-in carbon-neutral bioLNG in the short to medium term, or zero-carbon renewable synthetic LNG in the longer term.

For example, the analysis showed that for every 10% increase in the content of these fuels in a blend with traditional LNG, the vessel gains two-years of additional compliance. By using bioLNG and renewable synthetic LNG, a vessel commissioned yesterday, today and in the future can retain a favourable CII rating as major superior A or superior B throughout its lifetime.

John Hatley, SEA-LNG investment committee chairman, said, “Clearly, LNG will offer a competitive advantage to ship owners and operators as charterers prefer engaging the higher-performing A and B rated vessels necessary to meet their own GHG emission reduction commitments.

“Adding bio-LNG or renewable synthetic LNG, both fully interchangeable with fossil LNG in LNG-fuelled vessels and bunkering infrastructure, will enable maintenance of this advantageous rating level over the life of the vessel and ensure that owners are not left with stranded assets.”

In calculating the impact on CII grades of a change of fuel from HFO to LNG, SEA-LNG used a figure of 20% to represent likely emissions reductions across the broad range of vessel performance. This saving figure is derived from the 2nd Lifecycle GHG Emissions study by Sphera, which indicates that LNG-fuelled vessels are capable of achieving a reduction in their carbon footprint of as much as 30% on a tank-to-wake basis, when compared with an otherwise identical conventionally fuelled ship.

Source: SEA-LNG