Search Results (264)

Green ammonia has emerged as a promising alternative fuel for maritime decarbonization, owing to its carbon-free combustion, favorable volumetric energy density, and well-established logistics infrastructure compared to other alternatives. However, critical gaps persist in the development of an integrated fuel supply framework, which hinders the large-scale adoption of ammonia-fueled vessels. Therefore, this paper proposes an onshore wind-powered green ammonia plant located along the Gaolan–Yangpu feeder route. The plant comprises PEM electrolysis, nitrogen separation, Haber–Bosch synthesis, and storage facilities. An optimal plant configuration is subsequently derived through hourly simulations based on wind power generation and a priority-based capacity expansion algorithm. Key findings indicate that a stable ammonia supply—synchronized with monsoon wind patterns and capable of fueling vessels with 10 MW propulsion systems consuming around 680 tons per fortnight—requires a 72 MW onshore wind farm, a 63 MW PEM electrolyzer, 3.6 MW of synthesis facility, and 3205 tons of storage. This configuration yields a levelized cost of ammonia (LCOA) of approximately USD 700/ton, with wind turbines and electrolyzers (including replacement costs) accounting for over 70% of the total cost. Sensitivity analysis further shows that wind turbine and electrolyzer prices are the primary factors affecting ammonia costs. Although variations in operational parameters may significantly alter final configuration, they cause only minor (±1%) fluctuations in the levelized cost without significantly altering its overall trend. Full article

Inland Waterway Transport (IWT) is widely recognised as an energy-efficient freight mode, yet its decarbonisation is increasingly constrained not by propulsion technology, but by the absence of infrastructure capable of delivering clean energy where and when it is needed. This paper presents a structured review of over a decade of academic, policy and technical literature, identifying systemic gaps in current decarbonisation strategies. The analysis shows that most pilot projects are vessel-specific, and poorly scalable, with infrastructure planning rarely based on vessel-level energy demand data, leaving energy provision as an afterthought. Current approaches overemphasise technology readiness while neglecting the complexity of aligning supply chains, operational diversity, and infrastructure deployment. This review reframes IWT decarbonisation as a problem of provision, not propulsion. It calls for demand-led, demand driven, fuel agnostic infrastructure models and proposes a roadmap that integrates technical, operational, and policy considerations. Without rethinking energy access as a core design challenge—on par with vessel systems and regulatory standards—the sector risks investing in stranded assets and missing climate and modal shift targets. Aligning vessel operations with dynamic, scalable energy delivery systems is essential to achieve a commercially viable, fully decarbonised IWT sector. Full article

Abnormal tidal levels pose a serious threat to maritime navigation, coastal infrastructure, and human life and property. Therefore, it is crucial to accurately predict tidal levels. However, due to the influence of topography and meteorology, tidal levels exhibit complex and non-stationary characteristics, making high-precision prediction a significant challenge. This study proposes a tidal prediction model, named SVMD-BiLSTM-Residual Decomposition (SBRD), which combines Successive Variational Mode Decomposition (SVMD) and Bidirectional Long Short-Term Memory (BiLSTM) networks. SBRD decomposes non-stationary tidal signals into simpler intrinsic mode functions (IMFs) using SVMD. Each IMF is then independently predicted using a BiLSTM network, and the final prediction is obtained through signal reconstruction. Experimental results show that SBRD accurately predicts tidal levels within a 24 h horizon and maintains robust performance during abnormal tidal events, such as acqua alta. Compared to other models, SBRD achieves the highest prediction accuracy and the lowest error, with a Coefficient of Determination (R²) exceeding 99%, a Mean Absolute Error (MAE) of 1.33 cm or less, and a Root Mean Square Error (RMSE) within 2.13 cm for tidal forecasts within a 24 h horizon. These results demonstrate that SBRD effectively enhances the accuracy of tidal level prediction, contributing to the advancement of marine economic technologies and the prevention and mitigation of marine disasters. Full article

Ammonia bunkering is becoming increasingly important in the maritime industry as ammonia is recognized as a viable alternative fuel for reducing carbon emissions in shipping. Bunkering by tank truck plays a crucial role in the early stages of ammonia-fueled ship development. It involves the efficient transportation of ammonia from production facilities to bunkering stations, offering flexibility in refueling vessels at ports, including those lacking extensive infrastructures like pipelines or large storage tanks. However, the safety and regulations surrounding ammonia use in bunkering are paramount to its adoption. This study focuses on analyzing the effectiveness of safeguards designed to reduce the frequency of ammonia releases and mitigate potential leak damage during bunkering operations. We examine how safeguards, such as breakaway couplings and dry disconnect couplings (DDC), can reduce leak occurrences, while excess flow valves (EFVs) and automatic emergency shut-off valves (ESVs) can limit the consequences of such incidents. If the breakaway coupling and DDC are implemented as safeguards in the flexible hose, and maintenance is performed in accordance with ANSI/CGA G-2.1, the probability of hose failure per bunkering operation will be reduced from approximately 10⁻⁵ to 10⁻⁷. Under the worst weather conditions during the day, the probit value (Pr) depends on both the amount of ammonia released and the distance from the release point, with the distance having a greater effect on fatality than the amount of ammonia. The individual risk is analyzed to determine whether the bunkering process using tank trucks is acceptable. The analysis concludes that, with these safeguards in place, the individual risk at a location 20 m from the bunker site can be reduced to the lower limit of the As Low As Reasonably Practicable (ALARP) zone, ensuring a safe and acceptable level of risk for ammonia bunkering operations. The safety integrity level (SIL) of the automatic ESV should be at least 2 or higher, and it should be activated within a few seconds after a gas leak begins. Full article

Maritime ship transportation is not only the core infrastructure of the global logistics system but also is closely related to national security and sustainable development. However, the human factor remains the primary source of risk leading to maritime accidents during ship navigation. In recent years, multi-source data has been recognized as an important means to improve the efficiency of ship operations and navigation safety. In this paper, the major research methods and technical pathways of maritime multi-source data in recent years have been systematically reviewed, and a comprehensive technical framework from data acquisition and preprocessing to practical application has been constructed. Focusing on the data layer, application layer, and system layer, this paper comprehensively analyzes the key technologies of maritime navigation based on multi-source data. At the same time, this paper also highlights the advantages and cutting-edge methods of multi-source data in typical application scenarios—such as track extraction, target recognition, behavior detection, path planning, and collision avoidance—and analyzes their performance and adaptation strategies in different usage contexts. Through the combination of theory and engineering practice, this paper looks forward to the future development of ship intelligence and water transportation systems, providing a theoretical basis and technical support for the construction of intelligent shipping systems. Full article

The article addresses the issue of liquefied natural gas (LNG) distribution as a marine fuel, analyzing both ecological and economic aspects in the context of the Baltic Sea basin. The authors emphasize that LNG plays an increasingly significant role in the global energy balance, and its application in maritime transport is crucial for implementing sustainable development policies and advancing the energy transition. From an ecological perspective, LNG offers a substantial reduction in harmful emissions compared with conventional marine fuels such as marine diesel oil (MDO) and heavy fuel oil (HFO). In particular, the use of LNG results in lower emissions of carbon dioxide (CO₂), sulfur oxides (SO_x), nitrogen oxides (NO_x), and particulate matter (PM). The reduction in these pollutants is essential not only for improving air quality in port and coastal areas but also for mitigating global environmental impacts, including climate change. On the economic side, the article focuses on the cost structure of LNG distribution, highlighting that its price dynamics are subject to significant fluctuations. These variations are driven by geopolitical developments, crude oil price volatility, environmental regulations, and the expansion of bunkering infrastructure. From an economic perspective, LNG prices show significant volatility depending on the year and market conditions. Between 2018 and 2023, LNG prices ranged from approximately 450 to 530 USD/ton, at times exceeding the cost of HFO (400–550 USD/ton) but in some years remaining cheaper. In comparison, MDO prices were consistently the highest, increasing over the analyzed period from 600 USD/ton to over 720 USD/ton. This variability results from geopolitical factors, supply and demand dynamics, and environmental regulations, which highlight the strategic importance of LNG as a transitional fuel in shipping. The purpose of this study is to examine the role of LNG as an alternative fuel for shipping in the Baltic Sea, with particular emphasis on the scale of vessel emissions and the key factors influencing its distribution costs. Full article

This study examines stakeholder perspectives regarding the feasibility, benefits, and challenges associated with the development of multipurpose shipyards that encompass shipbuilding, repair, and recycling within Indonesia’s maritime industry. A convergent mixed-methods approach was utilised to collect quantitative and qualitative data from 37 stakeholders, including managers, employees, shipowners, regulators, subcontractors, academics, and community representatives. The Stakeholder Salience Model and Diffusion of Innovations theory provided the integrated statistical and thematic analysis. Results indicated significant stakeholder support (97.3%) for multipurpose shipyards, with 81.1% expressing positive perceptions and 16.2% very positive perceptions. Results indicate that ship repair (97.3%) and shipbuilding (86.5%) are seen as critical activities, with 59.5% of respondents highlighting the importance of ship recycling. The advantages of the multipurpose yard concept for Indonesia included improved operational efficiency (70.2%), increased market competitiveness (54.1%) and job creation (91.9%). Major challenges identified include technical complexities (62.2%), regulatory ambiguities (45.9%), substantial capital investment (43.2%), and skill shortages (40.5%). The study suggests improvements in governmental regulations, financial support for businesses, and training for the workforce. Phased implementation and stakeholder collaboration can align economic, environmental, and safety objectives, potentially decreasing Indonesia’s dependence on foreign shipping services. This study integrates stakeholder theory with innovation diffusion, providing replicable insights for sustainable practices in shipyards within archipelagic economies like Indonesia, the Philippines, and Vietnam, where similar geographic and infrastructure challenges shape the maritime industries. Full article

Six years after its deployment, SatShipAI, an operational platform combining AI models with Sentinel-1 SAR imagery and AIS data, has provided robust maritime surveillance around Denmark. A meta-analysis of archived outputs, logs, and manual reviews shows stable vessel detection and classification performance over time, including successful cross-sensor application to X-band SAR data without retraining. Key operational challenges included orbit file delays, nearshore detection limits, and emerging infrastructure such as wind farms. The platform proved particularly valuable for detecting offshore “dark” vessels beyond AIS coverage, informing maritime security, traffic management, and emergency response. These findings demonstrate the feasibility, resilience, and adaptability of long-term AI–geospatial systems, offering practical guidance for future autonomous monitoring infrastructure. Full article

Coastal public spaces in large Euro-Mediterranean cities represent critical zones of negotiation between land and sea, where ecological fragilities, infrastructural pressures and social demands intersect. Grounded in the concept of the urban amphibious, this study explores the spatial-functional complexity of city-sea interfaces through the development of CITI4SEA (City-Sea Interface Typological Indicators for Spatial-Ecological Assessment), an original multidimensional framework for the evaluation of coastal public spaces. The methodology builds on a geo-database of 149 coastal municipalities in eight EU Member States and applies a set of indicators to seven major cities (with populations over 500,000 and comprehensive port infrastructure). Through a structured evaluation grid applied to 23 coastal public spaces, the framework enables a cross-comparative analysis of spatial configurations, ecological qualities, and patterns of public use. Results reveal the emergence of transnational clusters based on shared planning logics and degrees of socio-environmental integration, rather than geographic proximity. The study also identifies asymmetries in accessibility, environmental performance and equipment provision. Beyond mapping spatial disparities, the contribution offers a replicable tool for assessing littoral transformations within the broader framework of Integrated Coastal Zone Management (ICZM) and Maritime Spatial Planning (MSP), supporting context-specific strategies for resilient and inclusive coastal governance. Full article

Fiber Bragg grating (FBG) sensing systems face significant challenges in resolving overlapping spectral signatures when multiple sensors operate within limited wavelength ranges, severely limiting sensor density and network scalability. This study introduces a novel Transformer-based neural network architecture that effectively resolves spectral overlap in both uniform and mixed-linewidth FBG sensor arrays, operating under bidirectional drift. The system uniquely combines dual-linewidth configurations with reflection and transmission mode fusion to enhance demodulation accuracy and sensing capacity. By integrating cloud computing, the model enables scalable deployment and near-real-time inference even in large-scale monitoring environments. The proposed approach supports self-healing functionality through dynamic switching between spectral modes during fiber breaks and enhances resilience against spectral congestion. Comprehensive evaluation across twelve drift scenarios demonstrates exceptional demodulation performance under severe spectral overlap conditions that challenge conventional peak-finding algorithms. This breakthrough establishes a new paradigm for high-density, distributed FBG sensing networks applicable to land monitoring, soil stability assessment, groundwater detection, maritime surveillance, and smart agriculture. Full article

The decarbonization and automation of port operations are emerging as key strategies to enhance the sustainability and efficiency of maritime logistics. This study proposes a simulation-based framework to assess the operational and environmental impacts of transitioning from traditional Internal Combustion Engine (ICE) tractors to Battery Electric Tractors (BET) and Automated Electric Guided Tractors (e-AGT) in Roll-on/Roll-off (Ro–Ro) port terminal operations. The proposed framework is applied to simulate a full vessel turnaround at the Ro–Ro terminal of the Port of Ravenna (Italy). A set of Key Performance Indicators (KPIs) is defined to evaluate turnaround time, vehicle productivity, energy consumption and CO₂ emissions across three scenarios. The results indicate that both BET and e-AGT configurations significantly reduce emissions compared to ICE, with reductions up to 40%. However, the e-AGT scenario reveals operational drawbacks, including increased unloading time and reduced fleet availability due to charging constraints and routing limitations. These findings highlight the environmental potential of automation and electrification but also emphasize the need for integrated planning of fleet size, charging infrastructure and circulation specifications. The proposed framework provides a replicable decision-support tool for port authorities and logistics operators to evaluate alternative handling technologies under realistic conditions. Full article

In response to mounting regulatory and environmental pressures, the maritime sector must urgently improve energy efficiency and reduce greenhouse gas emissions. However, conventional operational interfaces often fail to deliver real-time, actionable insights needed for informed decision-making onboard. This work presents an innovative Augmented Reality (AR) interface integrated with an established shipboard data collection system to enhance real-time monitoring and operational decision-making on commercial vessels. The baseline data acquisition infrastructure is currently installed on over 800 vessels across various ship types, providing a robust foundation for this development. To validate the AR interface’s feasibility and performance, a field trial was conducted on a representative dry bulk carrier. Through hands-free AR smart glasses, crew members access real-time overlays of key performance indicators, such as fuel consumption, engine status, emissions levels, and energy load balancing, directly within their field of view. Field evaluations and scenario-based workshops demonstrate significant gains in energy efficiency (up to 28% faster decision-making), predictive maintenance accuracy, and emissions awareness. The system addresses human–machine interaction challenges in high-pressure maritime settings, bridging the gap between complex sensor data and crew responsiveness. By contextualizing IoT data within the physical environment, the AR-IoT platform transforms traditional workflows into proactive, data-driven practices. This study contributes to the emerging paradigm of digitally enabled sustainable operations and offers practical insights for scaling AR-IoT solutions across global fleets. Findings suggest that such convergence of AR and IoT not only enhances vessel performance but also accelerates compliance with decarbonization targets set by the International Maritime Organization (IMO). Full article

In the context of mounting climate impacts and growing urgency to meet the Paris Agreement goals, the ocean is now increasingly being recognised not just as a victim of climate change, but as an indispensable part of the solution. Research has demonstrated that readily actionable ocean-based climate solutions can help close the emissions gap (the difference between the greenhouse gas emission reductions needed to limit global warming to 1.5 °C, and projected global emissions considering current national pledges and policies) by providing approximately a third of the mitigation needed to keep the Paris Agreement’s 1.5 °C goal within reach. This mitigation potential (of fully actioning these solutions) is unequally divided across seven key ocean-based action areas (listed in decreasing order of magnitude): phasing out offshore oil and gas; deploying offshore renewable energy infrastructure; decarbonising maritime transport and associated infrastructure; decarbonising ocean and aquatic food value chains; carbon capture and storage; marine and coastal conservation and restoration; and decarbonising coastal tourism. We argue that achieving the full potential of ocean climate solutions will require smart governance, drastically increased financial investment, and international cooperation. Accomplishing this, however, will bring strong co-benefits for biodiversity, food systems, and coastal resilience. The Third United Nations Ocean Conference and 30th United Nations Climate Change Conference of the Parties (COP 30) present rare opportunities to mainstream the ocean into global climate strategies. Full article

As the next generation of time–space infrastructure, low-earth-orbit navigation augmentation (LEO-NA) technology has become a hot research topic, since it can overcome the vulnerabilities and limitations of global navigation satellite systems (GNSSs). Meanwhile, a LEO-NA signal can serve as a better cooperative illuminator to build more powerful passive radar (PR). This paper proposes and investigates a new and promising PR system, LEO-NA signal-based PR (LNAS-PR), which utilizes LEO-NA signals as the illuminator and utilizes an unmanned aerial vehicle (UAV) to carry the receiver. Taking advantage of higher landing power and global coverage, LNAS-PR can be used to detect maritime targets with benefits of low cost and high efficiency. However, new technical challenges of information capture and processing need to be dealt with. Therefore, this paper presents the system model, signal model, and performance analyses within a maritime monitoring scenario, providing a foundation for future in-depth research. Full article

The decarbonization of short sea shipping is emerging as a critical priority for Mediterranean countries. This paper presents key findings from the ELECTRA-GR project, funded by the EEA Financial Mechanism (MIS 5202231), which aimed to evaluate the feasibility, technical readiness, and legislative requirements for the electrification of coastal ferry services in Greece. The study focused on two pilot routes—Salamis–Perama and Chios–Oinousses— representative of the high-frequency, short-distance ferry operations characteristic of the Greek archipelago. A comprehensive assessment was conducted combining technical fleet profiling, stakeholder consultations, legislative analysis, cost–benefit evaluations, and international benchmarking with Norway. For the base scenario of the high-traffic Salamis–Perama route, full electrification yields an annual reduction of approximately 900 tons of CO₂ compared to diesel operation and achieves a Net Present Value (NPV) of €1.6 million over a 15-year period. In contrast, the Chios–Oinousses route, characterized by lower traffic volume, achieves a reduction of 85 tons of CO₂ annually through hybrid conversion, but results in an NPV of €−1.69 million, underscoring the need for financial support mechanisms or targeted subsidies to ensure economic feasibility. The results indicate that electrification of short ferry routes in Greece is technically feasible and environmentally advantageous but faces significant challenges, including inadequate port infrastructure, regulatory gaps, and limited industrial readiness. The study proposes a structured roadmap toward electrification, emphasizing the modernization of shipyards, tailored policy instruments, and public–private cooperation. The findings contribute to the formulation of a scalable strategy for clean maritime transport in peripheral and island regions of Greece. Full article