China, People’s Republic

During the critical period of energy transition the collaborative optimization of the electricity-hydrogentransportation coupling system is of vital importance for achieving efficient energy utilization and sustainable development.This paper proposes a collaborative operation mechanism of Distributed Robust Optimization (DRO) considering carbon emissions. Firstly a Stackelberg game dynamic pricing strategy is constructed for the integrated energy station (IES) and the electricity-hydrogen hybrid charging station (HRS) where the upper-level IES optimizes the electricity price setting strategy and the lower-level HRS dynamically adjusts the electricity purchase-hydrogen production plan. Secondly the Wasserstein distance is used to describe the uncertainties of hydrogen vehicle loads and wind-solar power generation and a bisection algorithm-column constraint generation (BA-C&CG) hybrid algorithm is designed to solve the model. Finally the numerical example verification shows that the daily operation cost of HRS under the proposed mechanism is as low as 1108.53 EUR which is 10.58 % and 7.38 % lower than that of the commonly used stochastic optimization (SO) and robust optimization (RO) respectively. The variance analysis (F = 536.05P < 0.001) confirms that the cost advantage is statistically significant. In terms of carbon emission reduction effect the DRO-Stackelberg game model has the lowest daily carbon cost (6.98EUR). This mechanism effectively balances the economic and robustness of the system and the single dispatch calculation time is only 112.09 s meeting the real-time operation requirements of engineering. It provides technical support for the low-carbon collaborative operation of the electricity-hydrogen-transportation coupling system.

With the IMO’s 2050 decarbonization target hydrogen is a key zero-carbon fuel for shipping but the lack of systematic risk assessment methods for hydrogen-powered marine propulsion systems (under harsh marine conditions) hinders its large-scale application. To address this gap this study proposes an integrated risk evaluation framework by fusing Failure Mode Effects and Criticality Analysis (FMECA) with the Fuzzy Analytic Hierarchy Process (FAHP)—resolving the limitation of traditional single evaluation tools and adapting to the dynamic complexity of marine environments. Scientific findings from this framework confirm that hydrogen leakage high-pressure storage tank valve leakage and inverter overload are the three most critical failure modes with hydrogen leakage being the primary risk source due to its high severity and detection difficulty. Further hazard matrix analysis reveals two key risk mechanisms: one type of failure (e.g. insufficient hydrogen concentration) features “high severity but low detectability” requiring real-time monitoring; the other (e.g. distribution board tripping) shows “high frequency but controllable impact” calling for optimized operations. This classification provides a theoretical basis for precise risk prevention. Targeted improvement measures (e.g. dual-sealed valves redundant cooling circuits AI-based regulation) are proposed and quantitatively validated reducing the system’s overall risk value from 4.8 (moderate risk) to 1.8 (low risk). This study’s core contribution lies in developing a universally applicable scientific framework for marine hydrogen propulsion system risk assessment. It not only fills the methodological gap in traditional evaluations but also provides a theoretical basis for the safe promotion of hydrogen shipping supporting the scientific realization of the IMO’s decarbonization goal.

As a key zero-carbon energy carrier the accurate measurement of liquid hydrogen flow in its industrial chain is crucial. However the ultra-low temperature ultra-low density and other properties of liquid hydrogen can introduce calibration errors. To enhance the measurement accuracy and reliability of liquid hydrogen flow this study investigates the heat and mass transfer within a 1 m3 non-vented storage tank during the calibration process of a liquid hydrogen flow standard device that integrates combined dynamic and static gravimetric methods. The vertical tank configuration was selected to minimize the vapor–liquid interface area thereby suppressing boil-off gas generation and enhancing pressure stability which is critical for measurement accuracy. Building upon research on cryogenic flow standard devices as well as tank experiments and simulations this study employs computational fluid dynamics (CFD) with Fluent 2024 software to numerically simulate liquid hydrogen flow within a non-vented tank. The thermophysical properties of hydrogen crucial for the accuracy of the phase-change simulation were implemented using high-fidelity real-fluid data from the NIST Standard Reference Database as the ideal gas law is invalid under the cryogenic conditions studied. Specifically the Lee model was enhanced via User-Defined Functions (UDFs) to accurately simulate the key phasechange processes involving coupled flash evaporation and condensation during liquid hydrogen refueling. The simulation results demonstrated good agreement with NASA experimental data. This study systematically examined the effects of key parameters including inlet flow conditions and inlet liquid temperature on the flow characteristics of liquid hydrogen entering the tank and the subsequent heat and mass transfer behavior within the tank. The results indicated that an increase in mass flow rate elevates tank pressure and reduces filling time. Conversely a decrease in the inlet liquid hydrogen temperature significantly intensifies heat and mass transfer during the initial refueling stage. These findings provide important theoretical support for a deeper understanding of the complex physical mechanisms of liquid hydrogen flow calibration in non-vented tanks and for optimizing calibration accuracy.

The transport of natural gas blended with hydrogen is a key strategy for the low-carbon energy transition. However the influence mechanism of its thermo-physical property variations on centrifugal compressor performance remains insufficiently understood. This study systematically investigates the effects of the hydrogen blending ratio (HBR 0–30%) inlet temperature and rotational speed on key compressor parameters (pressure ratio polytropic efficiency and outlet temperature) through numerical simulations. In order to evaluate the influence of hydrogen blending on the performance and stability of centrifugal compressors a three-dimensional model of the compressor was established and the simulation conducted was verified with the experimental data. Results indicate that under constant inlet conditions both the pressure ratio and outlet temperature decrease with increasing HBR while polytropic efficiency remains relatively stable. Hydrogen blending significantly expands the surge margin shifting both surge and choke lines downward and consequently reducing the stable operating range by 27.11% when hydrogen content increases from 0% to 30%. This research provides theoretical foundations and practical guidance for optimizing hydrogen-blended natural gas centrifugal compressor design and operational control.

Clean energy technologies offer promising pathways for low-carbon transitions yet their feasibility remains uncertain particularly in rapidly developing regions. This study develops a Factorial Multi-Stochastic Optimization-driven Equilibrium (FMOE) model to assess the economic and environmental impacts of clean power deployment. Using Small Modular Reactors (SMRs) in Guangdong China as a case study the model reveals that SMRs can reduce system costs and alleviate GDP losses supporting provincial-level Nationally Determined Contributions (NDCs). If offshore wind capital costs fall to 40 % of SMRs’ SMR deployment may no longer be necessary after 2030. Otherwise SMRs could supply 22 % of capacity by 2040. The FMOE model provides a robust adaptable framework for evaluating emerging technologies under uncertainty and supports sustainable power planning across diverse regional contexts. This study offers valuable insights into the resource and economic implications of clean energy strategies contributing to global carbon neutrality and efficient energy system design.

The Yangtze River as the world’s largest clean energy corridor links key economic regions and plays a crucial role in inland waterway transportation. However few studies have comprehensively evaluated the potential of the Yangtze River for cross-regional hydrogen transport. Here we develop a comprehensive integrated power and hydrogen supply chain (IPHSC) optimization model to evaluate the potential of cross-regional hydrogen transport via the Yangtze River. The IPHSC optimization model covers the entire hydrogen production-storage-transportation-utilization chain through cross-sector modeling of energy transportation water scheduling and environmental protection. Results show that in the 2060 carbon neutrality scenario the deployment of 62.2 kilotons of 574 differentiated liquid hydrogen (LH2) carrier ships could enable the transportation of 5018 kilotons (1512 million ton-km) of hydrogen annually meeting nearly 20% of the total electrolytic hydrogen demand across eight riverine provinces. Unlike west-to-east electricity transmission in China the central Yangtze River region is expected to become the main hub for hydrogen exports in the future. Compared with alternative methods such as transmission lines or pipelines LH2 carrier ships offer the lowest energy supply costs at 3 US cents/kWh for electricity and 5 US cents/kWh for hydrogen. Additionally a full-parameter attribution analysis of over 40 factors is conducted to assess variations in supply costs. Our study offers a thorough evaluation of the feasibility and economic benefits of hydrogen transportation via inland waterways providing a comprehensive multi-sectoral coupling assessment framework for regions with well-established inland waterway networks such as Europe and the United States.

Aiming at the problems of poor transient characteristics of converter output DC voltage and large DC current ripple caused by alkaline electrolyzer (AEL) switching operation in the wind power-hydrogen coupled integrated system this paper proposes an interleaved parallel VDCM control method to improve the stable operation of the system. Firstly a refined mathematical-physical model of the wind power-hydrogen coupled integrated system including HD-PMSG interleaved parallel buck and AEL is constructed. Then the VDCM control strategy is introduced into the interleaved parallel buck converter which provides reliable inertia and damping support for the output voltage of the hydrogen production system by simulating the DC motor power regulation characteristics and effectively improving the current ripple of the output current. Meanwhile the influence of rotational inertia and the damping coefficient on the dynamic stability of the system in the control strategy is analyzed based on the small signal method. Finally the proposed method is validated through MATLAB/SIMULINK simulation experiments and RCP + HIL hardware-in-the-loop experiments. The results show that the proposed method can improve the dynamic stability of the wind power-hydrogen coupled integrated system effectively.

This paper proposes a hybrid-mode operation strategy for an offshore hydrogen-producing wind turbine (OHP-WT) capable of grid-following (GFL) and grid-forming (GFM) operation under both normal and low-voltage ride-through (LVRT) conditions. Unlike conventional centralized wind-to-hydrogen (W2H) schemes the proposed turbine-level architecture integrates W2H converters directly into the DC link of a three-level neutral-point-clamped converter. A supervisory power-sharing and mode-switch layer is developed above established GFL and GFM controls to coordinate active and reactive power regulation DC-link balancing and hydrogen-load management according to grid conditions. The proposed strategy is validated through detailed PLECS simulations and real-time hardware-in-the-loop experiments using identical parameters. Results show that the GFL mode achieves accurate power dispatch and shallow-fault LVRT compliance while the GFM mode maintains voltage and frequency stability under weak grid and severe-fault conditions. In all cases maximum-power-point tracking (MPPT) is preserved and hydrogen production continuously absorbs surplus power to stabilize the DC link. The findings demonstrate that the hybrid-mode OHP-WT enables transition between grid support and hydrogen production effectively reducing wind-power curtailment and enhancing offshore grid resilience.