Recommended pre-operation cleanup procedures for hydrogen fueling station

The stainless steel (SS) tubing and in-line filters are found to be sources of particulates in hydrogen fuel from new hydrogen stations. The internal coating of fueling nozzle can be delaminated during fueling as another particulate source. Organic residues, acetone, heptanes, and C₄Cl₄F₆ isomers are found in new SS tubing, which also emits hydrogen sulfide and carbonyl sulfide. Nitrogen contained in new storage tanks, if not properly removed, can elevate the nitrogen concentration in hydrogen fuel. We find that high pressure hydrogen flow can remove particulates, sulfur compounds and residual organic compounds from SS tubing. However, in-line filters should be cleaned by sonication and nitrogen contained in new storage tank pumped away. It is recommended that internal coating of fueling nozzle or SS tubing should not contain oxygen in chemical composition.     

Assessment of hydrogen supply solutions for hydrogen fueling station: A Shanghai case study

Shanghai is one of the fastest growing regions of hydrogen energy in China. This paper researched feasible hydrogen sources in both internal and external Shanghai. This study comes up 9 hydrogen production methods and 6 transportation routes, ultimately forms 12 hydrogen supply solutions according to local conditions. The total cost in each solution is estimated including processes of hydrogen production, treatments, storage and transportation based on different transport distance. The results indicate that hydrogen supply cost is above 50 CNY/kgH₂ for external hydrogen sources after long-distance transportation to Shanghai, such as hydrogen production from coal in Inner Mongolia and from renewables in Hebei. The total cost of on-site hydrogen production from natural gas can be controlled under 40 CNY/kgH₂. When the price of wind power reduces to 0.5 CNY/kWh, hydrogen production from offshore wind power cooperating with hydrogen pipeline network has the greatest development potential for Shanghai hydrogen supply.     

Development of Korean hydrogen fueling station codes through risk analysis

When hydrogen fueling stations were constructed first time in Korea in 2006, there were no standards for hydrogen fueling stations. Hence the CNG (Compressed Natural Gas) station codes were temporarily adopted. In last three years, from 2006 to 2009, the studies for the development of hydrogen fueling station standards were carried out, with the support of the Korean government. In this study, three research groups cooperated to develop optimized hydrogen fueling station codes through risk analysis of hydrogen production and filling systems. Its results were integrated to develop the codes. In the first step to develop the codes, the standards for CNG stations and hydrogen fueling station were compared with each other and analyzed. By referring to foreign hydrogen fueling station standards, we investigated the potential problems in developing hydrogen fueling station codes based on the CNG station standards. In the second, the results of the high-pressure hydrogen leakage experiment were analyzed, and a numerical analysis was performed to establish the safety distance from the main facilities of a hydrogen fueling station to the protection facilities. In the third, HAZOP (Hazard and Operability) and FTA (Fault Tree Analysis) safety assessments were carried out for the on-site and off-site hydrogen fueling stations—currently being operated in Korea— to analyze the risks in existing hydrogen fueling stations. Based on the study results of the above three groups, we developed one codes for off-site type hydrogen fueling stations and another codes for on-site type hydrogen fueling stations. These were applied from September 2010.     

Simulation of hydrogen leak and explosion for the safety design of hydrogen fueling station in Korea

Hydrogen has been used as chemicals and fuels in industries for last decades. Recently, it has become attractive as one of promising green energy candidates in the era of facing with two critical energy issues such as accelerating deterioration of global environment (e.g. carbon dioxide emissions) as well as concerns on the depletion of limited fossil sources. A number of hydrogen fueling stations are under construction to fuel hydrogen-driven vehicles. It would be indispensable to ensure the safety of hydrogen station equipment and operating procedure in order to prevent any leak and explosions of hydrogen: safe design of facilities at hydrogen fueling stations e.g. pressurized hydrogen leak from storage tanks. Several researches have centered on the behaviors of hydrogen ejecting out of a set of holes of pressurized storage tanks or pipes. This work focuses on the 3D simulation of hydrogen leak scenario cases at a hydrogen fueling station, given conditions of a set of pressures, 100, 200, 300, 400 bar and a set of hydrogen ejecting hole sizes, 0.5, 0.7, 1.0 mm, using a commercial computational fluid dynamics (CFD) tool, FLACS. The simulation is based on real 3D geometrical configuration of a hydrogen fueling station that is being commercially operated in Korea. The simulation results are validated with hydrogen jet experimental data to examine the diffusion behavior of leak hydrogen jet stream. Finally, a set of marginal safe configurations of fueling facility system are presented, together with an analysis of distribution characteristics of blast pressure, directionality of explosion. This work can contribute to marginal hydrogen safety design for hydrogen fueling stations and a foundation on establishing a safety distance standard required to protect from hydrogen explosion in Korea being in the absence of such an official requirement.     

Thermodynamical analysis of a hydrogen fueling station via dynamic simulation

This article describes the thermodynamical analysis of a hydrogen (${\text{H}}_2$) fueling station (HFS) with cryopump technology. A dynamic, object-oriented computer model of the HFS is developed in Matlab-Simulink. This model calculates, amongst other thermodynamic properties, the temporal and spatial variation of the ${\text{H}}_2$ temperature and the component temperatures within the HFS. The validation of the computer model with data from a series of measurements at a testing facility confirms a good accuracy of the model. The most important model object is the high pressure pipe through which the ${\text{H}}_2$ flows. The pipe is modeled and validated in different configurations. The thick-walled pipe material is discretized in radial and axial direction. In comparison to measurements the simulations show acceptable accuracy with an radial discretization length of $s<0.0026\text{m}$. In axial direction a discretization length of $l<1.18\text{m}$ is found to deliver acceptable accuracy of the simulations compared to measurements. Based on the simulation results a new method of controlling the ${\text{H}}_2$ temperature by mixing two ${\text{H}}_2$ mass flows with different temperatures is assessed as practicable. The electrical power requirement of the electric heat exchanger in this HFS design is determined. Depending on the load cases it varies between $0.13{\text{kWh}}_{\text{el}}/\left(\text{kg}{\text{H}}_2\right)$ and $0.40{\text{kWh}}_{\text{el}}/\left(\text{kg}{\text{H}}_2\right).$     

A pricing-based location model for deploying a hydrogen fueling station network

We propose an innovative two-step Pricing-Based Location strategy for the rollout of new hydrogen fueling stations. A first model maximizes the profit of a new station with a price p¹ which corresponds to a design capacity supplying a given market share (n¹ customers). According to these findings and with the objective of deploying an extensive network, a second model searches for a suitable location as remote as possible from existing competitors, but as close as possible to just n¹ demand locations. This problem is solved by an agent-based model integrating the Particle Swarm Optimization metaheuristic and a Geographic Information System representing the geospatial distribution of customer demand. We apply this model to the city of Paris by locating additional stations across the city one by one to supply a growing captive fleet of taxis and other transport operators in the future.     

Licensing a fuel cell bus and a hydrogen fueling station in Brazil

The Brazilian Fuel Cell Bus Project is being developed by a consortium comprising 14 national and international partners. The project was initially supported by the GEF/UNDP and MME/FINEP Brazil. The national coordination is under responsibility of MME and EMTU/SP, the São Paulo Metropolitan Urban Transport Company that also controls the bus operation and bus routes. This work reports the efforts done in order to obtain the necessary licenses to operate the first fuel cell buses for regular service in Brazil, as well as the first commercial hydrogen fueling station to attend the vehicles.     

Solar powered residential hydrogen fueling station

This paper presents a conceptual design of a solar powered hydrogen fueling station for a single family home in Wallingford, Connecticut, USA. Sixty high-efficiency monocrystalline silicon photovoltaic (PV) solar panels (Total capacity: 18.9 kW) account for approximately 94.7% of the hydrogen home’s power consumption. The fueling station consists of a 165 bar high pressure electrolyzer for on-site production of 2.24 kg/day of hydrogen, three-bank cascade configuration storage tanks (4.26 kg of H₂ at 350 bar) and a SAE J2600 compliant hydrogen nozzle. The system produces 0.8 kg/day of hydrogen for a fuel cell vehicle with an average commute of 56 km/day (Fuel mileage: 71 km/kg H₂). Safety codes and standards applicable at the facility are described, and a well-to-wheel analysis is performed to contrast the carbon dioxide emissions of conventional gasoline and fuel cell vehicles. The energy efficiency obtained by incorporating a solar-hydrogen system for residential applications is also computed.     

Security risk analysis of a hydrogen fueling station with an on-site hydrogen production system involving methylcyclohexane

Although many studies have looked at safety issues relating to hydrogen fueling stations, few studies have analyzed the security risks, such as deliberate attack of the station by threats such as terrorists and disgruntled employees. The purpose of this study is to analyze security risks for a hydrogen fueling station with an on-site production of hydrogen from methylcyclohexane. We qualitatively conducted a security risk analysis using American Petroleum Institute Standard 780 as a reference for the analysis. The analysis identified 93 scenarios, including pool fires. We quantitatively simulated a pool fire scenario unique to the station to analyze attack consequences. Based on the analysis and the simulation, we recommend countermeasures to prevent and mitigate deliberate attacks.     

Design of a hydrogen compressor for hydrogen fueling stations

Hydrogen compressors dominate the hydrogen refueling station costs. Metal hydride based thermally driven hydrogen compressor (MHHC) is a promising technology for the compression of hydrogen. Selection of metal hydride alloys and reactor design have a great impact on the performance of the thermally driven MHHC. A thermal model is developed to study the performance characteristics of the two-stage MHHC at different operating conditions. The effects of heat source temperature and hydrogen supply pressure on the compression ratio and isentropic efficiency are investigated. Finite volume method is used for discretizing the reaction kinetics, continuity, momentum and energy equations. Metal hydrides selected for this analysis are Mm_0.2La_0.6Ca_0.2Ni₅ and Ti_1.1Cr_1.5Mn_0.4V_0.1. The thermal model was validated with the results extracted from an experimental study. Validation results demonstrated that the numerical results are in good agreement with the data reported in literature.     

Modeling hydrogen production for injection into the natural gas grid: Balance between production,demand and storage

For hydrogen injection into the natural gas grid a model has been developed to obtain a balance between production, demand and storage. Due to the relation between atmospheric temperature and natural gas demand, the variation in the gas demand is very large. Consequently, in case of a more or less constant mole fraction of hydrogen in natural gas the demand for hydrogen will also vary considerably. Injection of ten percent hydrogen into the natural gas (in The Netherlands) requires already the production of about two billion cubic meters of hydrogen per year. Considering the variation in demand, most probably large-scale storage of hydrogen is needed because the flexibility in production is limited for economic and technical reasons. On the other hand, storage of hydrogen will also increase the costs. In this paper, we report on the balance between hydrogen production, demand and storage. A number of variables for controlling the production will be taken into consideration. Also the possibility of production without a buffer will be discussed.     

Tube-trailer consolidation strategy for reducing hydrogen refueling station costs

The rollout of hydrogen fuel cell electric vehicles (FCEVs) requires the initial deployment of an adequate network of hydrogen refueling stations (HRSs). Such deployment has proven to be challenging because of the high initial capital investment, the risk associated with such an investment, and the underutilization of HRSs in early FCEV markets. Because the compression system at an HRS represents about half of the station's initial capital cost, novel concepts that would reduce the cost of compression are needed. Argonne National Laboratory with support from the U.S. Department of Energy's (DOE) Fuel Cell Technologies Office (FCTO) has evaluated the potential for delivering hydrogen in high-pressure tube-trailers as a way of reducing HRS compression and capital costs. This paper describes a consolidation strategy for a high-pressure (250-bar) tube-trailer capable of reducing the compression cost at an HRS by about 60% and the station's initial capital investment by about 40%. The consolidation of tube-trailers at pressures higher than 250 bar (e.g., 500 bar) can offer even greater HRS cost-reduction benefits. For a typical hourly fueling-demand profile and for a given compression capacity, consolidating hydrogen within the pressure vessels of a tube-trailer can triple the station's capacity for fueling FCEVs. The high-pressure tube-trailer consolidation concept could play a major role in enabling the early, widespread deployment of HRSs because it lowers the required HRS capital investment and distributes the investment risk among the market segments of hydrogen production, delivery, and refueling.     

Power-to-gas: Amphibious yacht and fueling station

Renewable energy sources are being increasingly adopted, however their efficiency is limited by their intermittent nature leading to a mismatch with peak energy grid loading hours and dumping of excess produced energy. To date, much of the focus in renewable vehicles has been on automobiles. This largely overlooks the contribution from recreational boating to greenhouse gas emissions. We demonstrate that a power-to-gas model utilizing excess renewable energy can support boating activities in Ontario, Canada. As a proof-of-concept, we designed the refueling infrastructure, the fHuel+™ refueling station, and the onboard hydrogen utilization system for a high-speed luxury boat, the Hydronautic+™. The concept is built around a localized hydrogen economy. The present report focuses on the design and implementation of a technology specific to the demonstration site, but the overarching goal is to use this project as a proof of concept applicable to other sites across Canada and the United States.     

The public's acceptance toward building a hydrogen fueling station near their residences: The case of South Korea

South Korea is pushing for advancing the emergence of the hydrogen economy in order to reduce greenhouse gas emissions and promote economic growth. In this regard, a significant expansion of hydrogen charging stations is scheduled, but one of the biggest obstacles to this is the public acceptance of building a hydrogen fueling station near their residences. This article collected the data on the public acceptance toward building a hydrogen fueling station on a nine-point scale from a survey of 1000 people across the country, and analyzed the factors affecting public acceptance employing the ordered probit model. The respondents' approval rate for building a hydrogen fueling station near their residences (48.0%) was slightly higher than twice the opposition rate (23.0%). However, the sum of opposition (23.0%) and neutrality or indifference (29.0%) exceeded half of the total respondents, suggesting that the government's additional efforts were needed to improve acceptance. While some factors positively influenced the public acceptance, others affected it negatively. The various implications that can be obtained from these findings for building hydrogen fueling stations are discussed.     

The cavity profile of a diaphragm compressor for a hydrogen refueling station

A low flow rate and short diaphragm life are the two disadvantages of diaphragm compressors when applied in hydrogen refueling stations. A new generatrix of the cavity profile of a diaphragm compressor was developed in this study to increase the cavity volume and decrease the diaphragm radial stress. A reduction in the diaphragm radial stress that resulted from the new design was validated by experiment and numerical simulation. The volumes of the cavities with different generatrices and the radial stress distribution of the diaphragm were investigated under various design conditions. The results indicated that the volume of the cavity with the new generatrix was approximately 10% larger than that with a traditional generatrix at the same allowable stress and cavity radius. At a similar cavity volume and radius, the radial stress values of the diaphragm in the cavity with the new generatrix were low. The decrease rate of the maximal radial stress of the diaphragm in the cavity with the new generatrix reached 13.8%. In the diaphragm centric region, where additional stress was induced by discharge holes, the maximal radial stress decrease rate reached 19.6%.     

Lessons learned from the installation and operation of Northern California's first 70-MPa hydrogen fueling station

A hydrogen dispensing facility capable of providing rapid 70-MPa vehicle fills became operational in May 2011 as the first such hydrogen dispensing facility in Northern California. The facility is operated by the University of California – Berkeley in support of fuel cell vehicle research with automakers, regional and state agencies, and industrial groups. In addition to storing and dispensing high-pressure hydrogen fuel, the station also incorporates a number of key advances in hydrogen refueling system capabilities, including novel fuel pre-cooling, fuel storage, and system safety systems. Key lessons learned from the construction and initial operation of the station include: 1) extensive initial planning is essential for smooth project development; 2) permitting is a key step and early engagement with local officials is critical; 3) extensive safety reviews may be required; 4) site work should be conducted with careful planning and execution; 5) methodical system commissioning is a key step in the project development process; 6) careful station maintenance and operational planning is critical for minimization of station downtime; and 7) station upkeep and utility expenses can be considerable.     

Numerical investigation of the vortex tube performance in novel precooling methods in the hydrogen fueling station

In the present study, the potential of integrating a Ranque-Hilsch vortex tube (RHVT) in the precooling process for refueling high-pressure hydrogen vehicles in hydrogen refueling stations is investigated. In this regard, two novel precooling processes integrating a vortex tube are proposed to significantly reduce the capital expenditure and operating costs in hydrogen fueling stations. Then a numerical study of the RHVT performance is carried out for a high-pressure hydrogen flow to validate the feasibility of the proposed processes. Obtained results from the numerical simulation show that the energy separation effect also exists in the RHVT with hydrogen flow at the pressure level of tens of megapascals. Moreover, it is found that the energy separation performance of the RHVT improves as the pressure ratio increases. In other words, the temperature drop of the cold exit of RHVT decreases as the pressure ratio decreases in the refueling process, which just matches the slowing-down temperature rise during the cylinder charge. Based on the obtained results, it is concluded that the integration of a RHVT into the precooling process has potential in the hydrogen fueling station.     

Sensing hydrogen transitions in homes through social practices: Cooking,heating, and the decomposition of demand

Hydrogen is increasingly being positioned as an essential part of low-carbon transitions. While the role of hydrogen in decarbonising industrial processes and transportation has received growing attention in recent years, very little research has focused on hydrogen as a fuel for homes. This paper uses theories of social practice to illustrate how the physical and chemical properties of hydrogen may disrupt domestic practices of cooking and heating. It focuses on one specific characteristic of hydrogen, that it burns with a near-invisible flame, and reports on a research project that investigated how one hundred people in the North East of England believed this would change their sensorially mediated social practices of heating and cooking. Participants imagined their practices of cooking would be severely disrupted while their practices of heating would be largely unaffected. The paper concludes by summarising the implications of the research for policy, industry, and researchers interested in hydrogen transitions; that these two key home domestic practices have potentially different transition pathways.     

Development of a new real time responding hydrogen fueling protocol

Current Hydrogen Fueling Protocols (HFPs), such as SAE J2601, have been developed for non-communication and communication. They have problems due to the lack of versatility in their scope of application and the efficiency of their application method. The purpose of this study is to develop a new HFP for communication using a Real Time Responding method with outstanding efficiency and versatility. The new HFP was developed using simple model, that played the role of the engine of HFP, and a rigorous model that played the role as the testbed. This new HFP is founded to be more versatile and efficient compared to the existing HFP and to have excellent convenience, stability, safety, and economic feasibility. It is concluded that the new HFP can perform the function for communication only, while the existing HFP is used for both communication and non-communication.     

Impact of pipelines on cooling demand in the gaseous hydrogen refueling station

Hydrogen precooling is an effective method to realize safe, adequate, and fast filling for fuel cell vehicles. Estimating cooling demand is essential for the precooling unit configuration and energy analysis. Complex pipelines exist between the station's storage tanks and the vehicle cylinder. However, their impact on the cooling demand is often underestimated. In this paper, a thermodynamic model of the whole hydrogen refueling process was established to investigate the impact of pipelines in different positions. Accordingly, the influence of pipelines on the thermodynamic parameters was analyzed. Then the effects on the precooling performance were concluded. The results show that flow resistance before the breakaway increases total cooling demand by 9.9%. Meanwhile, heat dissipation through the pipe, located between the control valve and the heat exchanger, smoothens the cooling demand curve and reduces the total cooling demand by 5.7%. After the break-away, the flow resistance of pipelines significantly changes the mass flow rate curve and cooling demand. Heat absorption from the pipe wall slightly influences the cooling demand but jeopardizes refueling safety.