Hydrogen Station Research Articles

Review of Developed Methods for Measuring Gas Uptake and Diffusivity in Polymers Enriched by Pure Gas under High Pressure.

Gas emission and diffusion through polymeric materials play crucial roles in ensuring safety and monitoring gas concentrations in technology and industry. Especially, the gas permeation characteristics for O-ring material should be investigated for sealing application in a hydrogen infrastructure. To accommodate the requirements of different environments, we first developed four complementary effective methods for measuring the gas absorption uptake from polymers enriched by pure gas under high pressure and determining the gas diffusivity. The methods included the gravimetric method, the volumetric method, the manometric method, and gas chromatography, which are based on mass, volume, pressure, and volume measurements, respectively. The representative investigated results of the developed methods, such as gas uptake, solubility, and diffusivity are demonstrated. The measuring principles, measuring procedures, measured results, and the characteristics of the methods are compared. Finally, the developed methods can be utilized for testing transport properties, such as the leakage and sealing ability, of rubber and O-ring material under high pressure for hydrogen fueling stations and gas industry.

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.

Analysis of the Hydrogen‐Filling Process of Fixed Station and Skid Station Based on Different Working Conditions

Hydrogen energy is recognized as the most potential renewable energy in the 21st century due to the rising depletion of fossil fuels. Hydrogen refilling stations, as the infrastructure of hydrogen energy, are one of the key components of the entire hydrogen energy industry chain. Analyzing the filling process of hydrogen‐refueling stations (HRS) helps to promote the construction of HRSs. Thus, it promotes the construction of a clean, low‐carbon, safe, and efficient energy system and the high‐quality development of the hydrogen energy industry. In this article, gas cylinders with nominal working pressures of 35 and 70 MPa are filled using three different HRSs, such as single‐stage fixed station, three‐stage fixed station, and skid station. The filling end temperature, filling energy consumption, filling rate, and filling time during the filling process are compared and analyzed. In the results, it is shown that skid station has the advantages of lower filling end temperature and less energy consumption. Thus, in terms of reducing energy loss, the skid‐mounted HRSs can be promoted.

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.

Optimal scheduling of electric-hydrogen integrated charging station for new energy vehicles

In this paper, a novel model of electric-hydrogen integrated charging station (ICS) is proposed, which is composed of battery swapping station (BSS) and hydrogen station (HS). The BSS model, which mainly includes user adaptive response model, battery allocation and scheduling strategy, is established to realize the reasonable management and allocation of batteries. The HS model mainly includes hydrogen production module, hydrogen storage module, hydrogen charging module, fuel cell module and hydrogen scheduling strategy to optimize scheduling from hydrogen production to use. In addition, the BSS can provide energy for HS, and both BSS and HS can feed back the stored energy to the power system during peak load, which is beneficial to the stable operation of the power system. Simulation shows the rationality and correctness of the proposed optimization model. The proposed model and optimization strategy can improve the flexibility and economy of ICS, and help the power system to cut peak and fill valley.

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.

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 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.

Assessing the Quantitative Risk of Urban Hydrogen Refueling Station in Seoul, South Korea, Using SAFETI Model

Hydrogen refueling stations (HRS) operating at high pressures pose a higher risk of leakage than conventional gas stations. Therefore, in this study, a quantitative risk assessment (QRA) was conducted using DNV-GL SAFETI v.8.9. The impact of the shutoff valve was quantitatively assessed, and step-by-step mitigation was applied to propose the minimum installation requirements for the valve necessary to achieve broadly acceptable risk levels. The QRA includes sequence analysis (CA), individual risk (IR), and societal risk (SR), with accident scenarios consisting of catastrophic ruptures and three leak scenarios. The research results indicate that the application of a dual shutoff valve system resulted in an IR of 7.48 × 10−5, effectively controlling the risk below the as low as reasonably practicable (ALARP) criteria of the Health and Safety Executive (HSE). The SR was analyzed based on the ALARP criteria in the Netherlands, and the application of the dual shutoff valve system effectively controlled the risk below the ALARP criteria. Consequently, this study suggests that applying a dual shutoff valve system with a mitigation value exceeding 1.21 × 10−2 can successfully mitigate the risk of urban hydrogen refueling stations to broadly acceptable levels.

Optimum sizing of hybrid renewable power systems for on-site hydrogen refuelling stations: Case studies from Türkiye and Spain

One of the main barriers to the adoption of fuel cell vehicles (FCEVs) is the limited availability of hydrogen refuelling stations (HRSs). The presence of these stations is crucial in facilitating the provision of fuel for FCEVs, which rely on hydrogen as a source of power generation. Renewable energy sources offer significant advantages for hydrogen production at these stations, as they are environmentally friendly and can reduce costs. In this study, it is provided a techno-economic analysis of an on-site hydrogen refuelling station powered by a hybrid renewable energy generation system using HOMER software in Niğde, Türkiye, and Zaragoza, Spain. Three different power system scenarios were evaluated to refuel 24 vehicles per day for each region throughout the year. The results of the analysis showed that the most optimal system architecture for Niğde was with a solar panel power generation system, with a levelized cost of hydrogen (LCOH) of 6.15 $/kg and the net present cost (NPC) of $6,832,393. The most optimal system architecture for Zaragoza was a wind turbine-photovoltaic panel power generation system, with an LCOH of 5.83 $/kg and NPC of $6,499,723. The annual amount of CO2 emissions avoided by using renewable resources in hydrogen production was calculated as 2,673,453 kg for Niğde and 2,366,573 kg for Zaragoza. The study also found that the cost of hydrogen production increases with decreasing the HRS production capacity. The use of renewable energy generation systems for hydrogen production will enable countries to achieve net-zero emission targets and reduce the need to import fossil fuels to meet energy demands in the transportation sector. The present study makes several contributions towards the achievement of the United Nations Sustainable Development Goals (3, 7, 11, and 13) and has the potential to facilitate the rapid adoption of FCEVs.

A Study on the Thermal Behavior of Series and Parallel Connection Methods in the Process of Hydrogenation of Ship-Borne Hydrogen Storage Cylinder

As a subdivision of the hydrogen energy application field, ship-borne hydrogen fuel cell systems have certain differences from vehicle or other application scenarios in terms of their structural type, safety, environmental adaptability, and test verification. The connection method of the ship-borne hydrogen storage cylinder (SHSC) is very important for the hydrogen fuel cell ship, and the structural parameters of the SHSC are particularly important in the hydrogen refueling process. To ensure the safe and reliable operation of the hydrogen-powered ship, research on the filling of the SHSC under different connection modes was carried out during refueling. In our study, a thermal flow physical model of the SHSC was established to research the hydrogen refueling process of the series and parallel SHSCs. The influence of series and parallel modes of the SHSCs on the hydrogen refueling process was explored, and the evolution law of the internal flow field, pressure, and temperature of series and parallel SHSCs under different filling parameters was analyzed by numerical simulation. Our results confirmed the superiority of the parallel modular approach in terms of thermal safety during refueling. The results can supply a technical basis for the future development of hydrogen refueling stations and ship-board hydrogenation control algorithms.

Techno-Economical Assessment for Combined Production of Hydrogen, Heat, and Power from Residual Lignocellulosic Agricultural Biomass in Huesca Province (Spain)

Nowadays, great emphasis is rightly given in the scientific community to hydrogen production from electrolysis. However, to achieve the politically stated target ambitions, all low-carbon sources for hydrogen production must be considered. The present work proposes a local production system of negative carbon hydrogen from lignocellulosic residual biomass using gasification and gas separation through H2-selective membranes as enabling technologies. The feedstock is pruning. In addition, the system produces heat and power for a Renewable Energy Community (REC) to increase the economic feasibility of hydrogen production via their sale. A modular basic plant is sized, based on a simplified system envisaged for RECs under the current regulatory framework in Spain (electrical renewable output of 100 kW). A network of these modular basic plants in the province of Huesca (Aragón) is simulated to create a system of hydrogen refueling stations for mobility in that area. A Levelized Cost of Hydrogen (LCOH) is proposed, comprehending the whole production chain from “field to tank”, which is significant in areas where there is no infrastructure for the production and distribution of hydrogen for automotive purposes. The resulting LCOH for the whole system is 8.90 EUR/kg. Sensitivity analysis potentially values a lower LCOH, which unveils that hydrogen mobility can be largely competitive with diesel one.

A risk‐based evaluation of safe distance for a hydrogen refueling station

AbstractTo ensure the safety of hydrogen refueling stations (HRSs) and protective targets in the surrounding area, this paper has introduced a risk‐based safe distance assessment method for a 35MP HRSs, emphasizing the impact of the station's surrounding area. The findings indicate that the safe distance is determined by vapor cloud explosion (VCE) accident scenarios arising from pipeline leaks (compressor‐hydrogen storage tanks) at 125 m. Therefore, a crucial focus should be placed on safeguarding and maintaining hydrogen pipelines. Furthermore, based on societal risk, the requirement of a 358‐m safe distance specifies that the population gathering within this range should be <500 people, virtually eliminating the possibility of constructing hydrogen stations in urban residential areas. Only in scenarios where VCE risks are not considered, less‐populated surrounding environments might reduce the safe distance of hydrogen stations. Eliminating the risk scenarios of VCE is a crucial approach to lowering the safe distance of HRSs, making establishing such stations in urban centers feasible. Therefore, factors such as open spaces, well‐ventilated facilities, and blast walls become critical elements in reducing the safe distance of HRSs.

Experimental investigation for the operational performance improvement of cryogenic piston-type pump using subcooling effect for liquid hydrogen stations

This paper investigates the impact of subcooling degree and exhaust pressure on the performance of a high-pressure piston pump for pressurizing cryogenic liquid. We fabricate a lab-scale cryogenic liquid pump, conduct experiments with liquid nitrogen, and observe the significant effect of subcooling changes on the pump performance. The lab-scale pump achieves up to 30 bar of exhaust pressure and up to 45.4 g exhaust mass per cycle. This paper introduces the concept of duty cycle for the exhaust mass as a measure of pump performance. The results show that as the subcooling degree and the exhaust pressure increase, the duty cycle and the exhaust mass also increase, improving the pump performance. However, the increase in performance does not happen proportionally, and an optimal subcooling degree must be selected. This paper establishes a generalized computational model to predict the pump performance, achieving the mean absolute errors of 1.8 bar and 0.3 g/s in pressure and mass flow rate, respectively. The model can predict the exhaust mass during one stroke cycle of the pump with an approximation error of 10 %. In addition, the model predicts that pressurizing liquid hydrogen to 900 bar requires subcooling degree and its duty cycle cannot reach 100 % by reduction of specific volume. The findings suggest that subcooling can be used to enhance cryogenic liquid pump performance, and the optimal subcooling degree can be determined during the design of piston pumps to achieve high pressure.

Improvement of MC method in SAE J2601 hydrogen refuelling protocol using dual-zone dual-temperature model

The MC method has been published in the SAE J2601 refuelling protocol to safely and quickly refuel hydrogen fuel cell vehicles. This article adopts a dual-zone dual-temperature model that distinguishes the hydrogen temperature from the tank wall temperature to replace the dual-zone single-temperature model of the original MC method. A model (0D1D) of lumped parameter gas (0D) and one-dimensional tank wall (1D) is established simultaneously to verify the modified MC method and generate simulation data. A modified formula to the original MC method for calculating final hydrogen temperature is derived, which contains a correction factor K. The formula and coefficients of the correction factor K are determined by fitting the simulated data from the 0D1D model. The correction factor K is expressed in a piecewise function. The formulas of K are relatively complicated, so another simpler correction factor k is derived, which is a linear function. Research shows that the modified MC method extends its applicability to situations of refuelling times <30 s, while the original MC method is unsuitable. In the conditions set in this article of ambient temperature 0 to 40 °C, precooling temperature −40 to −20 °C and initial pressure 2 to 60 MPa, the modified MC method reduces the errors of final hydrogen temperature between the 0D1D model by 2 to 7 °C compared to the original one, thus improving the calculation accuracy of the pressure target and reaching a more accurate state of charge. In a word, the modified MC method improves the accuracy of refuelling control and has positive significance for the operational safety of hydrogen refuelling stations and the driver's refuelling experience.

Investment of hydrogen refueling station based on compound real options

As the development of hydrogen refueling stations (HRS) is key to the hydrogen industry, it is necessary to study the investment feasibility for potential investors in order to stimulate its investment. We view the HRS investment as a two-stage decision-making process, distinguishing characteristics of off-site HRS from those of on-site HRS. Investors can first decide whether or when to invest in an off-site HRS, and then can accordingly decide whether or when to upgrade from an existing off-site HRS to an on-site HRS, by retrofitting off-site HRS with on-site hydrogen production device. We select natural gas reforming as the technology of on-site hydrogen production device, not only because natural gas reforming is cheaper and maturer, but also because this type of retrofit has been applied in a real case. Since the investment in HRS entails multiple uncertainties, we use a compound real options approach for conducting an appraisal of HRS investment. Accordingly, we use the Chinese case to present a new perspective to the sequential analysis of HRS investment decision-making. Four various scenarios are set for a case study, including one benchmark scenario reflecting the current Chinese hydrogen policies, and three comparative scenarios reflecting potentially improved policies, such as increasing operational subsidy, implementing preferential taxation and stimulating demand. The results show the current scenario is not beneficial to invest in HRS building on the proposed analytical framework and the data collected from the case of China. Furthermore, the increase in demand plays the leading role in improving the probability of HRS investment, followed by the implementation of preferential taxation and increasing operational subsidies. Additionally, the on-site HRS shows its superiority over off-site HRS, because all scenarios suggest upgrading to on-site HRS should be executed immediately once the initial off-site HRS is constructed. Therefore, in the context of Chinese hydrogen market and the selected on-site technology of natural gas reforming, it is necessary to create a more favorable business environment for the layout of on-site HRS.

Subcooled Liquid Hydrogen Technology for Heavy-Duty Trucks

Subcooled liquid hydrogen (sLH2) is an onboard storage, as well as a hydrogen refueling technology that is currently being developed by Daimler Truck and Linde to boost the mileage of heavy-duty trucks, while also improving performance and reducing the complexity of hydrogen refueling stations. In this article, the key technical aspects, advantages, challenges and future developments of sLH2 at vehicle and infrastructure levels will be explored and highlighted.

Energetic assessment on a dual-temperature evaporation refrigeration system for hydrogen pre-cooling

The rapid, safe, and adequate refueling for hydrogen-based fuel cell vehicles relies on deep pre-cooling on the station side, which brings significant energy consumption. Step cooling is an ideal solution for the occasion with a large temperature drop. In this paper, a novel pre-cooling system is proposed by incorporating two-temperature evaporation to realize step cooling in the hydrogen refueling station. The pre-cooling load, system performance, and energy-saving potential are investigated under variable storage configurations and working conditions. The results show that the integral pre-cooling load increases linearly with the ambient temperature. However, the load share and the system performance are affected by the hydrogen intermediate temperature, the optimal value of which exhibits a nearly linear relationship with the ambient temperature. The novel system can save up to 30.2 % electricity relative to the conventional system with a single evaporator.