Towards net-zero shipping: A multi-level optimization model for green maritime corridors integrating bunker network, ship routes, and fleet deployment

Green Maritime Corridors (GMCs) have recently gained prominence as a strategic initiative to accelerate the net-zero transition in maritime shipping. However, their implementation is constrained by underdeveloped bunkering infrastructure, fragmented shipping networks, and industry reluctance to invest in green technologies. Although carbon pricing instruments, such as the Emission Trading System (ETS) and FuelEU Maritime (FuelEU), are in place to internalize environmental externalities and encourage emission reductions, their influence has not been quantitatively assessed, particularly under fluctuating carbon prices. To bridge these gaps, this study develops a novel multi-level optimization model that functions as a decision-support tool for stakeholders, simultaneously addressing the strategic investment in bunkering infrastructure, tactical planning of ship routes, and operational deployment of alternative-fuel vessels. By incorporating dynamic carbon pricing policies in ETS and FuelEU, our model evaluates the viability of ammonia and methanol across diverse trade routes. Our findings, based on the LINER-LIB benchmark, reveal that (i) the transition is primarily capital-intensive, highlighting the critical role of sustainable investment; (ii) carbon policies rapidly shift the cost-competitiveness in favour of GMCs, validating the effectiveness of government intervention; and (iii) route-specific characteristics are more decisive than fuel type alone, underscoring the need for customized business models and strategies. This research delivers a comprehensive decision-support framework that directly facilitates the practical implementation of GMCs. By quantifying the interplay between policy, investment, and operations, the study provides actionable insights to give investors the confidence to secure investment in green projects, guide policymakers in designing effective regulations, and enable operators to navigate the energy transition.