Hydrogen Refueling Research Articles

Characterization of hydrogen refueling temperature rise of the on-board hydrogen system under different failure modes

Fuel cell vehicles (FCVs) have the advantages of pollution-free, and excellent fuel economy. However, rapid hydrogen filling will cause the temperature inside the hydrogen cylinder to rise rapidly. The failure of some components of the on-board hydrogen system (OBHS) will increase the accident rate of FCVs during rapid refueling. Valves and pipelines are ignored during the hydrogen filling mode establishment, thereinto the automatic tank valve and hydrogen dispenser are prone to failure due to loose parts, sensor failure, and other problems. In this paper, a two-dimensional (2D) planar computational fluid dynamics (CFD) model is established to simulate and analyze three kinds of failures, such as hydrogen filling blockage, excessive hydrogen filling, and excessive hydrogen flow, to study the temperature rise characteristics of the OBHS. The results show that the failures of excessive hydrogen filling and excessive hydrogen flow are more likely to cause the final temperature of the hydrogen cylinders to exceed 358 K. The maximum temperature of the OBHS caused by excessive hydrogen flow rate is 5.7 % (21 K) and 0.8 % (3 K) higher than hydrogen filling blockage and excessive hydrogen filling, respectively. This indicates that, contrary to what other studies have not found, the hydrogen filling flow has a greater impact on the temperature rise of the hydrogen cylinder than the hydrogen filling pressure and inlet pipe diameter.

Carbon abatement cost evolution in the forthcoming hydrogen valleys by following different hydrogen pathways

The need to develop a forthcoming hydrogen economy emphasises the emerging concept of ‘hydrogen valleys', where hydrogen production and consumption are being developed. This study assesses the Levelized Cost of Hydrogen (LCOH) and Carbon Abatement Cost (CAC) for various hydrogen end-use applications within the context of a hydrogen valley located in the southern Italy over different time horizons (Today 2023, Mid-Term 2030, Long-Term 2050). Examined applications include blending into the gas grid, reconversion into electricity for grid balancing by means of fuel cells, hydrogen refuelling stations for fuel cell electric vehicles (FCEVs), synthetic methane production, and electro-fuel synthesis. Employing a parametric approach, the study compares LCOH and decarbonisation costs across different pathways. Results indicate current LCOH production values of 3.66–4.90 €/kgH2, projected to decrease to 1.41–1.94 €/kgH2 by 2050. Decarbonisation cost analysis identifies blending and FCEV scenarios as the most cost-effective, contrasting with Power-to-Power scenarios, particularly in the mid and long terms.

An ADMM-enabled robust optimization framework for self-healing scheduling of smart grids integrated with smart prosumers

Enhancing the reliability of energy networks and minimizing downtime is crucial, making self-healing smart grids indispensable for ensuring a continuous power supply and fortifying resilience. As smart grids increasingly incorporate decentralized prosumers, innovative coordination strategies are essential to fully exploit their potential and improve system self-healing capabilities. To address this need, this paper presents a novel bi-level strategy for managing the self-healing process within a smart grid influenced by Hydrogen Refueling Stations (HRSs), Electric Vehicle Charging Stations (EVCSs), and energy hubs. This approach taps into the combined potential of these prosumers to boost system self-healing speed and reliability. In the initial stage, the Smart Grid Operator (SGO) conducts self-healing planning during emergencies, communicating required nodal capacities to prevent forced load shedding and outlining incentives for smart prosumers. Subsequently, prosumers schedule their activities and contribute flexible capacities to the SGO. Bridging the first and second stages, an adaptive Alternating Direction Method of Multipliers (ADMM) algorithm ensures convergence between the SGO and prosumer schedules within a decentralized framework. This strategy underwent implementation on a 118-node distribution system using GAMS. Results demonstrate that the proposed concept reduces Forced Load Shedding (FLS) by 32.04% and self-healing costs by 17.48% through effective utilization of smart prosumers' flexible capacities. Furthermore, outcomes indicate that the SGO reduces FLS by 6.69% by deploying Mobile Electrical Energy Storages (MEESs) and Mobile Fuel Cell Trucks (MFCTs) to critical nodes.

An inter-laboratory comparison between 13 international laboratories for eight components relevant for hydrogen fuel quality assessment

The quality of the hydrogen delivered by refuelling stations is critical for end-users and society. The purity of the hydrogen dispensed at hydrogen refuelling points should comply with the technical specifications included in the ISO 14687:2019 and EN 17124:2022 standards. Once laboratories have set up methods, they need to verify their performances, for example through participation in interlaboratory comparisons. Due to the challenge associated with the production of stable reference materials and transport of these which are produced in hydrogen at high pressure (>10 bar), interlaboratory comparisons have been organized in different steps, with increasing extent.This study describes an inter-laboratory comparison exercise for hydrogen fuel involving a large number of participants (13 laboratories), completed in less than a year and included eight key contaminants of hydrogen fuel at level close to the ISO14687 threshold. These compounds were selected based on their high probability of occurrence or because they have been found in hydrogen fuel samples. For the results of the intercomparison, it appeared that fully complying with ISO 21087:2019 is still challenging for many participants and highlighted the importance of organising these types of exercises. Many laboratories performed corrective actions based on their results, which in turn significantly improved their performances.

Study on the characteristics of a novel wrap-around cooled diaphragm compressor for hydrogen refueling station

This study introduces a novel wrap-around cooled diaphragm compressor, designed for employment in hydrogen refilling station. The performance of this innovative compressor is evaluated using a specially developed experimental platform. The analysis focused on the impact of pressure ratio and suction gas temperature on the compressor's performance, and the cooling effect is assessed under varying temperatures of the cooling medium. The findings indicate that both the isentropic and volumetric efficiencies of the diaphragm compressor decrease with an increase in pressure ratio, with maximum values reaching 70% and 65% respectively. Under constant pressure ratio conditions, the exhaust temperature is found to increase with the rise in suction temperature. For a given suction temperature, a higher-pressure ratio resulted in a higher exhaust temperature. Furthermore, the cooling effect of the wrap-around cooling pipeline is found to be more pronounced under high pressure ratio conditions, with a maximum temperature reduction of 189.5 °C.

Economic analysis of hydrogen production and refueling station via molten-medium-catalyzed pyrolysis of natural gas process

The urgent need for sustainable energy solutions has been underscored by escalating greenhouse gas emissions and the global commitment to net-zero emissions. Clean hydrogen energy, despite its potential for the global low-carbon transition, faces challenges such as high production and transport costs and significant carbon emissions. Herein, we investigate the molten-medium-catalyzed pyrolysis of natural gas (MPN) for hydrogen production and refueling. We highlight the urgent environmental and economic motivations for cleaner energy, specifically addressing the existing challenges faced by traditional hydrogen production methods. Our research introduces an innovative integrated system for onsite hydrogen production, showcasing its economic advantages, carbon emission reduction potential, and compatibility with current infrastructures. The study meticulously evaluates the MPN technology's economic feasibility, including a detailed analysis of cost drivers and the market value of by-product carbon materials. Furthermore, we stress the importance of further research to optimize the technology and promote its adoption for a low-carbon future. This investigation presents MPN as a promising alternative, potentially revolutionizing the hydrogen supply chain and contributing significantly to global decarbonization efforts.

Thermodynamic modeling and analysis of cascade hydrogen refuelling with three-stage pressure and temperature for heavy-duty fuel cell vehicles

Recently, the development of heavy-duty fuel cell vehicles (HDFCVs) has received intense attention. Unlike the refuelling protocol of SAE J2601 for light-duty fuel cell vehicles, the SAE J2601-2 for HDFCVs does not propose a specific filling strategy but only specifies the limits that need to be observed for safety. Refuelling data for HDFCVs at hydrogen refuelling station (HRS) shows that refuelling parameters are often set conservatively, resulting in long refuelling time. To shorten the refuelling time, energy consumption and power demand of the cooling system, we establish a detailed three-stage pressure filling model to study the effects of pressure ramp rate (PRR), initial pressure, number of onboard tanks and precooling temperature on the filling time. Then, a three-stage temperature precooling method is proposed simultaneously, whose cooling energy and power of the heat exchanger are compared with the single-stage temperature precooling method. Research shows that three-stage and two-stage pressure filling can reduce the average pressure difference between the station-side and the vehicle-side storage tanks, thereby reducing the Joule-Thomson heat generated by the reduction valve throttling and the heat exchanger energy consumption. Increasing the PRR and initial pressure can significantly and directly shorten the filling time. Increasing the number of onboard tanks and decreasing precooling temperature have little effect on the filling time but reduce the final hydrogen temperature in the onboard tank, which is beneficial to increase the PRR further to shorten the filling time. Within the ambient temperature range set in this article, compared with the single-stage temperature precooling method, the three-stage temperature precooling method can reduce the maximum peak cooling power by 16.69%–17.38% without increasing the total cooling energy of the heat exchanger and onboard tank's final hydrogen temperature, reducing equipment investment in cooling systems. This research is significant for optimizing HRS design and operation strategies.

Investigation of pre-cooling strategies for heavy-duty hydrogen refuelling

Green hydrogen presents a promising solution for transitioning from fossil fuels to a clean energy future, particularly with the application of fuel cell electric vehicles (FCEVs). However, the hydrogen refuelling process for FCEVs requires extensive pre-cooling to achieve fast filling times. This study presents experiments and simulations of a hydrogen refuelling station equipped with an adaptable cold-fill unit, aiming to maximize fuelling efficiencies. For this purpose, we developed and experimentally validated simulation models for a hydrogen tank and an aluminium block heat exchanger. Different pre-cooling parameters affect the final tank temperatures during the parallel filling of three 350 L type IV tanks. The results indicate significant potential for optimizing the required cooling energy, with achievable savings of over 50 % depending on the pre-cooling strategy. The optimized pre-cooling strategies and energy savings aid in advancing the refuelling process for FCEVs, effectively contributing to the transition to clean energy.

Hydrogen refueling station location optimization under uncertainty

Hydrogen refueling stations (HRS) are essential for the growth of the hydrogen energy and fuel cell vehicle industry, making the strategic decision of their location and scale critical. This study advances the HRS location optimization problem by integrating network planning and hydrogen scheduling optimization, a novel approach that addresses both where and how big HRSs should be, alongside managing supply relations and hydrogen transportation scheduling. Uniquely, it incorporates uncertainty factors in hydrogen demand, using a two-stage multi-period stochastic programming model designed to minimize both construction and operational costs under variable demand scenarios, while also ensuring customer satisfaction. Our main contributions include the development of this comprehensive model and the introduction of an efficient metaheuristic algorithm to solve it, significantly enhancing computational efficiency. The effectiveness of our approach is demonstrated through numerical experiments, and a sensitivity analysis provides crucial insights, underlining the practical implications for HRS infrastructure development. The findings not only offer a methodological advancement in HRS location selection but also deliver tangible results that can guide industry stakeholders in strategic decision-making, marking a significant step forward in the sustainable development of hydrogen energy infrastructure.

A feasibility study of green hydrogen liquefaction for hydrogen refueling station: Multi-criteria based integrative assessment

Considering an important energy vector, hydrogen (H2) has earned enormous attention due to its cleanliness and potential role in decarbonizing the existing systems, e.g., transportation, industrial sector, and commercial units. This is the reason why developing the H2 economy is one of the most crucial aspects under research and numerous studies forecast that the H2 demand will increase many folds in the near future. However, the production of H2 and its transportation have serious challenges due to the fact of energy and cost intensiveness. In this context, we have made an effort to assess the potential feasibility of producing green H2 and simultaneously integrate it with a liquefaction unit to make it ready for transportation. Moreover, the proposed process is evaluated based on renewable energy resources to estimate the potential solution for future energy goals. The proposed model for liquefied H2 (LH2) production claimed high energy efficiency and the value in terms of specific energy consumption is obtained as 5.418 kWh kg LH2−1 for the capacity of 10 ton per day of LH2. A detailed techno-economic analysis provides levelized cost of LH2 by varying criteria for economic feasibility. Environmental assessment results in the lowest environmental potential during green LH2 production, which reveals that the solid oxide electrolysis system is a potential candidate for green LH2 production. As per multi-criteria decision analysis, results showed that the onshore wind with alkaline water electrolysis and proton exchange membrane water electrolysis have high capabilities to become the potential technology for green LH2 production.

Comprehensive Review of Hydrogen Leakage in Relation to Fuel Cell Vehicles and Hydrogen Refueling Stations: Status, Challenges, and Future Prospects

Comprehensive Review of Hydrogen Leakage in Relation to Fuel Cell Vehicles and Hydrogen Refueling Stations: Status, Challenges, and Future Prospects

Risk assessment of fire and explosion accidents in oil-hydrogen fueling station based on fault tree analysis

Owing to the coexistence of gasoline, diesel, and hydrogen, a specific and thorough risk assessment approach must be promptly implemented for oil-hydrogen fueling stations. Consequently, this study makes innovations in considering the safety issues of the joint construction of gas station and hydrogen refueling station, and undertaking the modeling and analysis of fire and explosion incidents at oil-hydrogen fueling stations based on fault tree analysis. The findings reveal that the risk level for fire and explosion at oil-hydrogen fueling stations is categorized as grade III. In our fault tree analysis model, there are 3240 minimum cut sets and 194 minimum path sets. The probability of fire and explosion incidents occurring at oil-hydrogen fueling stations is calculated to be 0.000265. This indicates that while the possibility of such accidents is low, their potential severity is exceedingly high. Ultimately, it is recommended that the safety of oil-hydrogen fueling stations be enhanced through the reinforcement of emergency management, customer safety education, and electrostatic discharge devices.

Accelerating flammable gas cloud dissipation in hydrogen leakage during refilling hydrogen-powered vehicles via employing canopy fans

Mitigating the hydrogen leakage risk during the refilling process contributes to promoting the hydrogen energy commercialization. In this study, the high-pressure hydrogen leakage and dilution characteristics were analyzed with fans installed on the hydrogen refueling station canopy. Two fan conditions are involved: blowing upwards condition, and blowing downwards condition. The role of leakage pressure, atmospheric wind velocity, and fan conditions on the spatiotemporal evolutionary characteristics of flammable gas clouds (FGC) were discussed. Results showed that the hydrogen distribution is significantly impacted by wind velocity and fan blowing conditions when the hydrogen-powered vehicle is refueled. At a small leakage pressure, under windless conditions, employing fans contribute to the FGC dissipation. At windy conditions the fan blowing upwards does not accelerate the FGC dissipation, but rather increases the its volume and slows down its dilution. At a large leakage pressure, at small wind velocities, fan blowing upwards contributes to FGC dilution. However, at large wind velocities, fan blowing upwards is not effective in accelerating the hydrogen dilution. In all the scenarios, fan blowing downwards always helps to accelerate the hydrogen dilution. This study offers a pragmatic approach to effectively mitigate the risk of hydrogen leakage during the refilling process.

Hydrogen embrittlement behaviors during SSRT tests in gaseous hydrogen for cold-worked type 316 austenitic stainless steel and iron-based superalloy A286 used in hydrogen refueling station

To consider an appropriate evaluation method for hydrogen compatibility, slow strain rate tensile (SSRT) tests were conducted on high strength piping materials, cold-worked type 316 austenitic stainless steel (SUS316CW) and iron-based superalloy A286, used in hydrogen stations for two years.SUS316CW, used at room temperature in 82 MPa gaseous hydrogen, contained 7.8 mass ppm hydrogen. The SSRT test of SUS316CW was conducted in nitrogen at −40 °C. The fracture surface showed dimples, and no hydrogen embrittlement behavior was observed. While, the SSRT test of SUS316CW in 70 MPa gaseous hydrogen at −40 °C showed a slight decrease in reduction area and a brittle fracture morphology in the outer layer. This was considered to be the effect of high-pressure gaseous hydrogen during the SSRT test in addition to the pre-contained hydrogen.A286, used at −40 °C in 82 MPa gaseous hydrogen, contained negligible hydrogen (0.14 mass ppm). SSRT tests were conducted at 150 °C in 70 MPa gaseous hydrogen and in air, and showed a low relative reduction in area (RRA) value. To investigate the decrease in the RRA, we switched the gas from hydrogen to air in the middle of the SSRT test and closely examined the RRA values and fracture morphology including side cracks. The hydrogen embrittlement was found to originate from the elastic deformation region. Stress cycling in the elastic deformation region also accelerated the effect of hydrogen. These were attributed to an increase in the lattice hydrogen content. While in the plastic deformation region, hydrogen trapped in the defects and hydrogen through the generated surface cracks increased the hydrogen content at the crack tips, reducing the RRA value. And there was a good correlation between the crack lengths and RRA values.Then, hydrogen embrittlement mechanism depends on the operating conditions (stress and temperature) of the material, and evaluating the hydrogen compatibility of materials by controlling their hydrogen content and strain according to the service environment is desirable.

Navigating the green shipping: Stochastic hydrogen hub deployment in inland waterways

The maritime industry is shifting toward sustainability to help combat climate change, given the sector’s significant contribution to global greenhouse gas emissions. This study focuses on the strategic integration of hydrogen fuel—a zero-emission alternative—into inland waterway transport systems. We recognize the operational characteristics of inland shipping networks and the complexities of two-stage financial planning. Consequently, we propose a two-stage stochastic framework for the deployment of hydrogen refueling hubs, taking into account financial uncertainties in the future. This approach contrasts with a myopic strategy and a two-stage deterministic framework, addressing both immediate financial constraints and future uncertainties. We focus on the Yangtze River’s shipping network as a case study, and our analysis validates the superior performance of our proposed two-stage stochastic strategy. This suggests its potential to accommodate volatile future financial uncertainties while ensuring the economic and operational viability of hydrogen integration.

Optimal estimation of MC parameter in SAE J2601 hydrogen refuelling protocol based on modified formula and artificial neural networks

The MC method was officially released in SAE J2601 protocol in 2016 to refuel light-duty hydrogen fuel cell vehicles quickly and safely. For the non-communication MC method, the pressure target for controlling the end of filling is calculated based on the formula of the final hydrogen temperature, which contains a key parameter, MC. SAE has proposed two formulas to estimate the MC parameter. This article proposes a modified formula and artificial neural networks (ANN) model for MC parameter. To generate simulated data for fitting the modified formula and training the ANN model, a hydrogen filling model (0D1D) with a zero-dimensional gas and a one-dimensional tank wall is established and thoroughly verified. In establishing the ANN model, Latin hypercube sampling (LHS) is used to sample independent variables randomly, and genetic algorithms (GA) are used to optimize the initial weights and biases of the ANN. The Sobol sensitivity analysis is used to determine the importance of various initial conditions on the MC parameter. Research shows that the final fueling time and initial pressure have a greater impact on the MC parameter, while the ambient and precooling temperatures have little impact. The modified formula of the MC parameter improves R2 from the original 0.76073 to 0.98132 when fitting the MC simulated data. In situations of short filling time, the modified formula and ANN models of the MC parameter reduce the relative error between the 0D1D model by 13.8 % − 58.8 % and 16.6 % − 82.3 %, respectively, thus improving the calculation accuracy of the final hydrogen temperature and ending pressure target. Moreover, the ANN model can predict the MC parameter during the whole fueling process, while the MC formula utilizes the fixed value when the fueling time is less than 30 s. This work has positive significance for improving refuelling protocol.

Distributionally robust planning method for expressway hydrogen refueling station powered by a wind-PV system

Hydrogen fuel has received widespread attention as one of the critical solutions to global energy issues. The popularization of hydrogen fuel cell vehicles (HFCV) requires the deep integration of transportation and energy fields. Considering the complementarity of wind and PV power in remote areas, this paper proposes a planning model of an expressway hydrogen refueling station, including a hydrogen production system (HPS) powered by a wind-PV system and several hydrogen refueling systems (HRSs). The interaction and operation constraints of hydrogen production, storage, delivery, and demand are employed to complete hydrogen supply chain integration in the deterministic planning model. The spatiotemporal distribution of refueling demand at each HRS is obtained by Monte Carlo Simulation. Furthermore, we consider the impact of uncertainty related to renewable energy generation and refueling demand on planning and depict them by ambiguity sets based on Kullback Leibler divergence. The planning problem is transformed into a data-driven distributionally robust model and solved by Value-at-Risk and sample average approximation method. Results indicate that 1) The proposed model can simultaneously collaborate with the segments of the hydrogen supply chain. 2) The proposed method balances the planning reliability and economic efficiency and enhances solution robustness.

A comprehensive survey of low‐carbon planning and operation of electricity, hydrogen fuel, and transportation networks

AbstractThe trend of global energy systems towards carbon neutrality has led to an escalating interdependency between electricity, hydrogen fuel, and transportation networks. However, the means of surmounting the many challenges confronting the optimal coupling and coordination of electric power, hydrogen fuel, and transportation systems are not sufficiently understood to guide modern infrastructure planning operations. The present work addresses this issue by surveying the extant literature, relevant government policies, and future development trends to evaluate the present state of technology available for coordinating these systems and then determine the most pressing issues that remain to be addressed to facilitate future trends. On the one hand, the users of transportation networks represent flexible consumers of electric power and hydrogen fuel for those connected via devices such as electric vehicles and hydrogen fuel cell vehicles through charging stations and hydrogen refuelling stations. On the other hand, power grids can mitigate the negative effect of random charging behaviours on grid security through time‐of‐use electricity pricing, while excess renewable energy outputs can be applied to generate hydrogen fuel. The findings of this overview offer support for infrastructure planning and operations. Finally, the most urgent issues requiring further research are summarised.

A numerical analysis on the thermal characteristics by filling parameters of high-pressure valve for hydrogen refueling station

Renewable hydrogen plays a critical role in the current energy transition, and can facilitate the decarbonization and de-fossilization of hard-to-abate sectors, such as the industrial, power, transportation and buildings sectors. High pressure hydrogen valve（HPHV）is an important energy storage element for the hydrogen fueling station. Given the problems of large internal pressure fluctuation and long adjustment time of the HPHV during the operation of the current hydrogen fueling system, it is necessary to study the thermal effects of the HPHV. In the study，the pressure、temperature and velocity changes of the HPHV are studied from the aspect of numerical calculation. The hydrogen pressure and temperature changes of the model were simulated and analyzed at the different filling parameters. The accuracy of the simulation model was demonstrated by practice. The influence of the internal taper of the spool on the temperature change of 40°, 50°, 60° and 70° was studied. The influence of outlet pressure of 5 MPa, 10 MPa, 15 MPa, 20 MPa, 25 MPa on the temperature of high-pressure hydrogen valve and the influence of mass flow rate of 0.1 g/s, 0.3 g/s, 0.5 g/s, 0.8 g/s on the velocity field of hydrogen high-pressure valve. The study shows that when the taper was 60°, the optimal decompression performance, small temperature rise, and the performance was stable. The highest speed and the lowest temperature appear near the gap outlet, up to 2500 m/s and 85 K, respectively. The temperature and speed change trends were basically opposite, and the temperature change range of the outlet was 280 K–370 K. The results of this study provide great support for the research and application of ultra-high pressure hydrogen storage and hydrogen refueling, which also provide a theoretical basis for the subsequent development of the hydrogen energy industry and the wide application of hydrogen fuel cell vehicles, and provide ideas for realizing the goal of “dual carbon".

An Exploration of Safety Measures in Hydrogen Refueling Stations: Delving into Hydrogen Equipment and Technical Performance

The present paper offers a thorough examination of the safety measures enforced at hydrogen filling stations, emphasizing their crucial significance in the wider endeavor to advocate for hydrogen as a sustainable and reliable substitute for conventional fuels. The analysis reveals a wide range of crucial safety aspects in hydrogen refueling stations, including regulated hydrogen dispensing, leak detection, accurate hydrogen flow measurement, emergency shutdown systems, fire-suppression mechanisms, hydrogen distribution and pressure management, and appropriate hydrogen storage and cooling for secure refueling operations. The paper therefore explores several aspects, including the sophisticated architecture of hydrogen dispensers, reliable leak-detection systems, emergency shut-off mechanisms, and the implementation of fire-suppression tactics. Furthermore, it emphasizes that the safety and effectiveness of hydrogen filling stations are closely connected to the accuracy in the creation and upkeep of hydrogen dispensers. It highlights the need for materials and systems that can endure severe circumstances of elevated pressure and temperature while maintaining safety. The use of sophisticated leak-detection technology is crucial for rapidly detecting and reducing possible threats, therefore improving the overall safety of these facilities. Moreover, the research elucidates the complexities of emergency shut-off systems and fire-suppression tactics. These components are crucial not just for promptly managing hazards, but also for maintaining the station’s structural soundness in unanticipated circumstances. In addition, the study provides observations about recent technical progress in the industry. These advances effectively tackle current safety obstacles and provide the foundation for future breakthroughs in hydrogen fueling infrastructure. The integration of cutting-edge technology and materials, together with the development of upgraded safety measures, suggests a positive trajectory towards improved efficiency, dependability, and safety in hydrogen refueling stations.