port-based blue economy under the imo net-zero framework: from marpol annex vi to alternative fuels

The international maritime organization’s (imo) net-zero framework represents a fundamental reconfiguration of global maritime climate governance, extending the implications of ship-centric regulation under marpol annex vi toward port systems and blue economy structures. moving beyond efficiency-oriented measures, the framework integrates lifecycle-based greenhouse gas (ghg) fuel intensity standards, compliance mechanisms, and emerging market-based instruments that reshape the operational, economic, and governance roles of ports.this paper reviews the evolution and components of the imo net-zero framework and examines its implications for port-based blue economy development, with emphasis on alternative fuel transition pathways. the analysis focuses on key regulatory instruments, including the greenhouse gas fuel intensity (gfi) standard, well-to-wake lifecycle emissions assessment, and compliance mechanisms involving remedial and surplus units. it highlights how these instruments reposition ports from passive infrastructure providers to active nodes of fuel transition, regulatory enforcement, and emissions accountability under marpol annex vi. the study investigates the economic implications of the net-zero framework for port-based blue economy systems, including compliance-related cost structures, investment requirements for alternative marine fuel infrastructure, and shifts in port competitiveness. attention is given to the role of ports in enabling fuel transition through bunkering infrastructure, lifecycle emissions management, and monitoring, reporting, and verification (mrv) functions.from a governance perspective, the paper identifies challenges affecting implementation, especially in developing port systems where regulatory capacity, financial constraints, and policy coherence remain uneven. the analysis underscores that the effectiveness of the net-zero framework depends not only on global rule-setting but also on the ability of ports and coastal administrations to internalize fuel transition dynamics within blue economy strategies.overall, the imo net-zero framework functions not merely as an environmental compliance regime, but as a catalyst for economic and governance transformation in port-based blue economies, reshaping investment priorities, institutional roles, and development trajectories in the emerging low-carbon maritime system.