ADVANCING SUSTAINABLE MARITIME OPERATIONS: TECHNOLOGICAL, ECONOMIC, AND POLICY INSIGHTS INTO REDUCING NOX, SOX, AND CO₂ EMISSIONS FROM MARINE ENGINES

Abstract

The maritime transport sector underpins over 80% of global trade by volume but is also a significant source of air pollutants and greenhouse gases, contributing approximately 3% of global CO₂ emissions. This research evaluates the effectiveness, feasibility, and policy relevance of major emission reduction strategies for marine engines in the context of IMO 2020 and the 2023 IMO GHG Strategy. Literature review and simulation results show that Selective Catalytic Reduction (SCR) achieves 85–90% NOₓ reduction, while Exhaust Gas Recirculation (EGR) provides moderate reductions of 30–50%. Wet scrubbers offer 95–98% SOₓ removal, but washwater discharge raises environmental concerns. Alternative fuels, including LNG, methanol, and biofuels, provide partial CO₂ reductions (15–25%), while Carbon Capture and Storage (CCS) demonstrates >90% capture efficiency in pilot trials but remains immature for marine application. The analysis confirms that no single technology ensures comprehensive compliance; rather, hybrid solutions such as LNG combined with SCR offer the strongest integrated pathway. Economic analysis highlights the high CAPEX of retrofits but shows improved long-term returns when combined with regulatory incentives and carbon pricing. The research emphasizes the crucial role of digitalization, AI-driven monitoring, and IoT-enabled systems for emissions management. Findings suggest that technological adoption, guided by regulatory clarity and global equity mechanisms, is essential to align shipping with the Paris Agreement and Sustainable Development Goals (SDGs).