Dynamic decarbonization pathways for inland shipping under energy system and policy uncertainties

Inland shipping decarbonization requires coordinated changes in fleets, fuels, infrastructure, and policy that static life cycle assessments cannot capture. This study develops a framework coupling Power-to-X pathways, dynamic hybrid life cycle assessment, a fleet digital twin, and multi-objective optimization. Applied to 2,100 weighted representative vessel records in the Yangtze River Delta from 2025 to 2050 under four policy scenarios, the selected integrated policy knee solution reduces diesel from 99.0% to 15.5% of fleet shaft energy demand. Battery electricity becomes the largest low-carbon pathway (30.3%), followed by hydrogen (22.1%), e-methanol (16.4%), and ammonia (15.6%). Cumulative life cycle emissions are 298.8 Mt CO 2 -eq, 10.4% below business as usual, while net present resource cost is 166.3 billion 2025 USD. Deep inland shipping decarbonization is feasible but back-loaded and depends on coordinated fleet renewal, infrastructure deployment, and fuel diversification.