Advanced Research on the Sustainable Maritime Transportation

With globalization and environmental sustainability growing in importance, the sustainable development of maritime transportation, as the main mode of international trade, is particularly significant. This Special Issue “Advanced Research on Sustainable Maritime Transportation” contains a total of 15 high-quality research papers, covering research on many aspects from green shipping technologies and maritime safety to sustainable port operations, reflecting the multi-dimensional efforts to transform the industry into a low-carbon, efficient, safe, and environmentally friendly one. Hereafter, the research content of these papers will be reviewed according to different themes.

The first theme is green shipping technology. Focusing on this topic, Lebedevas and Milašius [1] studied the challenges in terms of reliability in the transition to low-carbon fuels for maritime diesel engines. By employing statistical and single-zone mathematical models such as IMPULS and AVL BOOST, the study evaluated the combustion cycle parameters and thermal loads of cylinder–piston assemblies for low-carbon fuels, aiming to optimize energy efficiency and reduce harmful emissions. Zhang et al. [2] studied and developed a new fault-tolerant control strategy suitable for permanent magnet synchronous motor drive systems in electric ships. This strategy is based on sinusoidal pulse width modulation with a hierarchical reconstruction of the carrier configuration, which can improve the fault tolerance of the inverter without requiring additional hardware. Xu et al. [3] studied the impact of emission control areas on orders for ecologically designed ships using a difference-in-difference method and a regional-level ship data set. The results show that this implementation significantly increases the number of orders for eco-designed ships. Zhang et al. [4] compared the effectiveness of five machine learning methods in predicting a ship’s carbon intensity index. The study used a variety of models, including artificial neural networks, which had the lowest error among all of them and can provide ship operators with an effective carbon emission management tool. Chen et al. [5] used a multinomial logistic model to analyze the key decision-making factors that influence ship owners when choosing fuel for new ships. The study, based on global new ship order data, revealed that shipowners’ choices are significantly affected by their nationality, ship type, and economic factors. Wei et al. [6] assessed the maturity and suitability of alternative fuels against the International Maritime Organization’s greenhouse gas emission reduction targets by reviewing material compatibility and storage technologies. The results suggest that multi-product ports may have the potential to serve as multi-fuel hubs, while the remaining ports favor specific fuels. Elkafas et al. [7] explored the feasibility of replacing conventional power systems with alternative clean power systems during short sea journeys. The results show that hydrogen-powered proton exchange membrane fuel cells are the best clean power system to ensure zero-emission journeys. Wang et al. [8] developed a nonlinear optimization model to optimize shipping companies’ sailing speed and route deployment strategies under the EU’s new emissions trading system policy. The results show that appropriate speed adjustment and ship deployment can effectively reduce operating costs. Eom et al. [9] developed and implemented a digital twin port model to optimize ship scheduling and port operations. Their research shows that this model can significantly improve operational efficiency and reduce carbon emissions. Tu et al. [10] developed a cost–benefit model based on marginal abatement cost to evaluate the economics of adopting different greenhouse gas emission reduction measures in the shipping industry. The study provides shipping companies and maritime authorities with a comprehensive analytical framework for developing decarbonization strategies.

The second theme is maritime security. Focusing on this topic, Yang et al. [11] used bibliometric analysis methods to systematically review the scientific literature on unmanned surface vessels from 2000 to 2023. This study evaluates the new technology development trends, main research hotspots, and future development directions of unmanned surface vessels, providing important guidance and inspiration for the advancement and cooperation of academia and industry in unmanned surface vessel technology. Xu et al. [12] conducted a systematic and bibliometric review of articles related to maritime transportation safety management from 2011 to 2022, comprehensively evaluating the progress of research on safety risk analysis, emergency management, and resilience measurement. The study points out the key research directions and challenges of maritime safety management and provides a direction and foundation for future research on this topic.

The third theme is sustainable port operations. Lebedevas and Čepaitis [13] explored the potential of using the organic Rankine cycle in maritime transport as an energy-saving solution to recover waste heat on ships. The study used numerical simulation methods to evaluate the energy efficiency potential of different heat sources under various engine load conditions. The results show that the organic Rankine cycle can significantly improve the energy efficiency of the main engine. Drazdauskas and Lebedevas [14] studied the performance of the mixed combustion of ammonia and diesel in marine diesel engines. The study optimized combustion cycle parameters by adjusting the injection stage and pressure, aiming to reduce emissions of greenhouse gases, NOX, and unburned NH3 and providing a practical solution for decarbonizing maritime transport. Wang et al. [15] developed a mixed-integer linear programming model aimed at helping shipping companies optimize their operating strategies in response to the EU’s new marine fuel policy. The study demonstrates the adaptability of the model under fluctuations in fuel prices, ship costs, and fleet size, providing shipping companies with important guidance to effectively reduce costs and comply with EU carbon emission reduction policies.

In summary, this Special Issue not only reveals the latest technologies and methods in the field of sustainable maritime transportation but also highlights the importance of technological innovation and policy adjustment in achieving sustainability goals in this industry. From the application of low-carbon fuels and technological advancements in electric ships to the digital management of ports, as well as adapting and responding to global environmental policies, these studies collectively build a diversified solution framework that provides scientific guidance and a practical direction for the sustainable development of maritime transportation. These studies exemplify how the industry is gradually moving in a more environmentally friendly, safe, and efficient direction consistent with global sustainable development goals.