Developing a framework for effective accounting GHG emissions from international shipping for sustainable marine fuel and onboard carbon capture: Case study of methanol

This study introduces a novel framework for accurately accounting for greenhouse gas (GHG) emissions in the international shipping sector, with a specific focus on sustainable marine fuel and onboard carbon capture systems (OCCS), using methanol as a case study. The framework proposes the integration of a carbon source factor and a carbon fate factor to effectively measure and report GHG emissions from shipping activities. By examining methanol as sustainable marine fuel, alongside the implementation of OCCS, this research aims to demonstrate the significant potential for reducing life cycle GHG emissions. When OCCS was applied to 49 case ships, not only were Carbon Intensity Indicator (CII) ratings D or E removed, but the proportion of ships rated A or B was confirmed to increase noticeably from 10 % to 41 %. The findings highlight the critical role of renewable feedstocks and effective carbon management strategies in decarbonizing the shipping industry. The proposed framework offers valuable insights for ship owners, industry regulators, and policymakers, guiding the transition towards sustainable shipping practices and contributing to the global efforts against climate change. This study underscores the importance of developing clear guidelines and standards for GHG emissions accounting in shipping, ensuring consistent and transparent reporting to facilitate effective policy formulation and regulatory compliance.