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.     

Thermodynamic parametric analysis of refueling heavy-duty hydrogen fuel-cell electric vehicles

Reliable design and safe operation of heavy-duty hydrogen refueling stations are essential for the successful deployment of heavy-duty fuel cell electric vehicles (FCEVs). Fueling heavy-duty FCEVs is different from light-duty vehicles in terms of the dispensed hydrogen quantities and fueling rates, requiring tailored fueling station design for each vehicle class. In particular, the selection and design of the onboard hydrogen storage tank system and the fueling performance requirements influence the safe design of hydrogen fueling stations. A thermodynamic modeling and analysis are performed to evaluate the impact of various fueling parameters and boundary conditions on the fueling performance of heavy-duty FCEVs. We studied the effect of dispenser pressure ramp rate and precooling temperature, initial tank temperature and pressure, ambient temperature, and onboard storage design parameters, such as onboard storage pipe diameter and length, on the fueling rate and final vehicle state-of-charge, while observing prescribed tank pressure and temperature safety limits. An important finding was the sensitivity of the temporal fueling rate profile and the final tank state of charge to the design factors impacting pressure drop between the dispenser and vehicle tank, including onboard storage pipe diameter selection, and flow coefficients of nozzle, valves, and fittings. The fueling rate profile impacts the design and cost of the hydrogen precooling unit upstream of the dispenser.     

Dynamic planning and energy management strategy of integrated charging and hydrogen refueling at highway energy supply stations considering on-site green hydrogen production

The layout of electric vehicles charging stations and hydrogen refueling stations (HRSs) is more and more necessary with the development of electric vehicles (EVs) and progress in hydrogen energy storage technology. Due to the high costs of HRSs and the low demand for hydrogen, it is difficult for independent HRSs to make a profit. This study focuses on the dynamic planning of energy supply stations on highways in the medium and long term, considering the growth of EV charging demand and the change in the proportion of hydrogen fuel cell vehicles (HFCVs). Based on the perspective of renewable energy generators (REGs), this study seeks the dynamic optimal configuration and comprehensive benefits of adding HRS and battery to existing EVCS considering the travel rules of new energy vehicles (NEVs). The results show that (1) It is profitable for REGs to invest in HRSs; (2) The economy of investment in batteries by REGs depends on the source-load matching. It is feasible only when the output of renewable energy is difficult to meet the demand. (3) The business model of REGs producing hydrogen on-site and supplying both electricity and hydrogen is feasible.     

Exact algorithms for incremental deployment of hydrogen refuelling stations

Given the large investments required to establish hydrogen refuelling stations (HRSs) and the difficulty in forecasting the sales of fuel cell electric vehicles, incremental HRS deployment offers an efficient method of establishing hydrogen infrastructure with a sufficient load factor and low financial risk. Considering that some HRSs are already in use, this study assumed that the optimal location of a new HRS maximises its distance from existing HRSs and minimises its distance from customer demand points. Accordingly, a multi-objective location model and efficient exact solution methods were proposed to determine the optimal location of one or two new HRSs. As a case study, the solution methods were applied to supply hydrogen to an increasing captive fleet of taxis in a large metropolis such as Paris with fixed demand points. The methods can be widely applied to effectively install one or two HRSs incrementally.     

Comparative risk assessment of liquefied and gaseous hydrogen refueling stations

Several countries are incentivizing the use of hydrogen (H₂) fuel cell vehicles, thereby increasing the number of H₂ refueling stations (HRSs), particularly in urban areas with high population density and heavy traffic. Therefore, it is necessary to assess the risks of gaseous H₂ refueling stations (GHRSs) and liquefied H₂ refueling stations (LHRSs). This study aimed to perform a quantitative risk assessment (QRA) of GHRSs and LHRSs. A comparative study is performed to enhance the decision-making of engineers in setting safety goals and defining design options. A systematic QRA approach is proposed to estimate the likelihood and consequences of hazardous events occurring at HRSs. Consequence analysis results indicate that catastrophic ruptures of tube trailer and liquid hydrogen storage tanks are the worst accidents, as they cause fires and explosions. An assessment of individual and societal risks indicates that LHRSs present a lower hazard risk than GHRSs. However, both station types require additional safety barrier devices for risk reduction, such as detachable couplings, hydrogen detection sensors, and automatic and manual emergency shutdown systems, which are required for risk acceptance.     

Techno-economic analysis of conventional and advanced high-pressure tube trailer configurations for compressed hydrogen gas transportation and refueling

Transporting compressed gaseous hydrogen in tube trailers to hydrogen refueling stations (HRSs) is an attractive economic option in early fuel cell electric vehicle (FCEV) markets. This study examines conventional (Type I, steel) and advanced (Type IV, composite) high-pressure tube trailer configurations to identify those that offer maximum payload and lowest cost per unit of deliverable payload under United States Department of Transportation (DOT) size and weight constraints. The study also evaluates the impacts of various tube trailer configurations and payloads on the transportation and refueling cost of hydrogen under various transportation distance and HRS capacity scenarios. Composite tube trailers can transport large hydrogen payloads, up to 1100 kg at 7300 psi (500 bar) working pressure, while steel tube trailer configurations are limited by DOT weight regulations and may transport a maximum hydrogen payload of approximately 270 kg. Using steel pressure vessels to transport hydrogen at high pressure is counterproductive because of the rapid increase in vessel weight with wall thickness. The most economic composite tube trailer configuration includes 30-inch-diameter vessels packed in a 3 × 3 array. A linear relationship between the deliverable payload and the capital cost of a composite tube trailer has been developed for configurations with the lowest cost-per-unit payload. The capital cost is approximately $1100 per kg of deliverable hydrogen payload. Considering the entire delivery pathway (including refueling), tube trailer configurations with smaller vessels packed in greater numbers enable higher payload delivery and lower delivery cost in terms of $/kg H₂, when delivering hydrogen over longer distances to large stations. Selection of the appropriate tube trailer configuration and corresponding hydrogen payload can reduce hydrogen delivery cost by up to 16%.     

Manufacturing competitiveness analysis for hydrogen refueling stations

Fuel cell electric vehicles (FCEVs) have now entered the market as zero-emission vehicles. Original equipment manufacturers such as Toyota, Honda, and Hyundai have released commercial cars in parallel with efforts focusing on the development of hydrogen refueling infrastructure to support new FCEV fleets. Persistent challenges for FCEVs include high initial vehicle cost and the availability of hydrogen stations to support FCEV fleets. This study sheds light on the factors that drive manufacturing competitiveness of the principal systems in hydrogen refueling stations, including compressors, storage tanks, precoolers, and dispensers. To explore major cost drivers and investigate possible cost reduction areas, bottom-up manufacturing cost models were developed for these systems. Results from these manufacturing cost models show there is substantial room for cost reductions through economies of scale, as fixed costs can be spread over more units. Results also show that purchasing larger quantities of commodity and purchased parts can drive significant cost reductions. Intuitively, these cost reductions will be reflected in lower hydrogen fuel prices. A simple cost analysis shows there is some room for cost reduction in the manufacturing cost of the hydrogen refueling station systems, which could reach 35% or more when achieving production rates of more than 100 units per year. We estimated the potential cost reduction in hydrogen compression, storage and dispensing as a result of capital cost reduction to reach 5% or more when hydrogen refueling station systems are produced at scale.     

Projecting full build-out environmental impacts and roll-out strategies associated with viable hydrogen fueling infrastructure strategies

A transition from gasoline internal combustion engine vehicles to hydrogen fuel cell electric vehicles (FCEVs) is likely to emerge as a major component of the strategy to meet future greenhouse gas reduction, air quality, fuel independence, and energy security goals. Advanced infrastructure planning can minimize the cost of hydrogen infrastructure while assuring that energy and environment benefits are achieved. This study presents a comprehensive advanced planning methodology for the deployment of hydrogen infrastructure, and applies the methodology to delineate fully built-out infrastructure strategies, assess the associated energy and environment impacts, facilitate the identification of an optimal infrastructure roll-out strategy, and identify the potential for renewable hydrogen feedstocks. The South Coast Air Basin of California, targeted by automobile manufacturers for the first regional commercial deployment of FCEVs, is the focus for the study. The following insights result from the application of the methodology:

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Compared to current gasoline stations, only 11%-14% of the number of hydrogen fueling stations can provide comparable accessibility to drivers in a targeted region.

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To meet reasonable capacity demand for hydrogen fueling, approximately 30% the number of hydrogen stations are required compared to current gasoline stations.

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Replacing gasoline vehicles with hydrogen FCEVs has the potential to (1) reduce the emission of greenhouse gases by more than 80%, reduce energy requirements by 42%, and virtually eliminate petroleum consumption from the passenger vehicle sector, and (2) significantly reduce urban concentrations of ozone and PM2.5.

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Existing sources of biomethane in the California South Coast Air Basin can provide up to 30% of the hydrogen fueling demand for a fully built-out hydrogen FCEV scenario.

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A step-wise transition of judiciously located existing gasoline stations to dispense and accommodate the increasing demand for hydrogen addresses proactively key infrastructure deployment challenges including a viable business model, zoning, permitting, and public acceptance.

     

Developing an infrastructure for hydrogen vehicles: a Southern California case study

We have examined the technical feasibility and economics of developing a hydrogen vehicle refueling infrastructure for a specific area where zero emission vehicles are being considered, Southern California. Potential hydrogen demands for zero emission vehicles are estimated. We then assess in detail several near term possibilities for producing and delivering gaseous hydrogen transportation fuel including: (1) hydrogen produced from natural gas in a large, centralized steam reforming plant, and truck delivered as a liquid to refueling stations; (2) hydrogen produced in a large, centralized steam reforming plant, and delivered via small scale hydrogen gas pipeline to refueling stations; (3) by-product hydrogen from chemical industry sources; (4) hydrogen produced at the refueling station via small scale steam reforming of natural gas; and (5) hydrogen produced via small scale electrolysis at the refueling station. The capital cost of infrastructure and the delivered cost of hydrogen are estimated for each hydrogen supply option. Hydrogen is compared to other fuels for fuel cell vehicles (methanol, gasoline) in terms of vehicle cost, infrastructure cost and lifecycle cost of transportation. Finally, we discuss possible scenarios for introducing hydrogen as a fuel for fuel cell vehicles.     

The role of renewable fuel supply in the transport sector in a future decarbonized energy system

Battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs) have been identified as two electromobility options which can help to achieve GHG emission reduction targets in the transport sector. However, both options will also impact the future energy system characterized by integration of various demand sectors and increasing intermittent power generation. The objective of this paper is to examine the optimal mix of both propulsion systems and to analyze the cost for renewable fuel supply. We propose a generic approach for dimensioning of fast charging and hydrogen refueling stations and optimization of the fuel supply system. The model is applied in a case study for passenger cars on German highways. The results indicate that a parallel build-up of stations for both technologies does not increase the overall costs. Moreover, the technology combination is also an optimal solution from the system perspective due to synergetic use of hydrogen but limited efficiency losses. Hence, BEVs and FCEVs should jointly contribute to the decarbonization of the future energy system.     

Hydrogen combustion test in a small gas turbine

Details of the gaseous hydrogen combustion test in a can-type conventional gas-turbine combustor and the operating performance of a 275 PS (202 kW) small gas turbine are provided.Initially, experiments were conducted to determine the configuration of the hydrogen fuel nozzles on a combustor test facility. The kerosene fueled gas turbine combustor was used without modification of the original configuration and dimensions.Secondly, the operation performance of the gas turbine was investigated when the gaseous hydrogen was used as a substitute fuel for kerosene fuel. The kerosene fuel supply system was removed or rendered inoperative and a hydrogen flow metering system was newly installed. The high pressure storage cylinders were used to supply hydrogen to the fuel metering system.Data was obtained on pressure losses of the fuel nozzles, ignition performance, temperature distributions at the combustor outlet, combustion efficiency, liner wall temperature distributions, NO_x emission levels, noise levels, operating performance, etc.     

Overview of the next quarter century vision of hydrogen fuel cell electric vehicles

Last three decades, costumers and manufacturers of automotive sector have been influenced positively by Hydrogen and fuel cells (FCs). The main goal of automakers can be pointed as minimizing the fuel consumption and exhaust emissions while improving the range limits, energy efficiency and latest technology adaptation. Therewithal, electric assisted propulsion systems added to vehicles and are called as electric vehicles (EVs). For that matter, Battery Electric Vehicles (BEVs) and hydrogen Fuel Cell Electric Vehicles (FCEVs) have become the focus of researchers and producers. In this mini foreseen review, overview of the next quarter century vision of FCEVs are expressed and discussed by the helped of previous researches and with future forecast reports. The introduction part is summarized the general approach and future expectations of FCs in detailed. Technical overview is represented for FCs and FCEVs in terms of current state of technology to foreseen expectancy. Infrastructure analysis and future aspects overview part is also discussed for sector's perspective on FCEVs. The near future perspective of the FCEVs, which is seen as the next step in EVs, is discussed in detail in the next quarter century vision. Authors concluded that, between the 2030s-2050s, hydrogen FCEVs will continue their rising demand scale under the circumstances of decreasing expensive technology; enhanced energy optimization; extended range limits and increasing hydrogen refueling stations.     

Hydrogen refuelling stations in the Netherlands: An intercomparison of quantitative risk assessments used for permitting

As of 2003, 15 hydrogen refuelling stations (HRSs) have been deployed in the Netherlands. To become established, the HRS has to go through a permitting procedure. An important document of the permitting dossier is the quantitative risk assessment (QRA) as it assesses the risks of the HRS associated to people and buildings in the vicinity of the HRS. In the Netherlands, a generic prescribed approach exists on how to perform a QRA, however specific guidelines for HRSs do not exist. An intercomparison among the QRAs of permitted HRSs has revealed significant inconsistencies on various aspects of the QRA: namely the inclusion of HRS sub-systems and components, the HRS sub-system and component considerations as predefined components, the application of failure scenarios, the determination of failure frequencies, the application of input parameters, the consideration of preventive and mitigation measures as well as information provided regarding the HRS surroundings and the societal risk. It is therefore recommended to develop specific QRA guidelines for HRSs.     

Economic analysis of near-term California hydrogen infrastructure

A detailed economics model of hydrogen infrastructure in California has been developed and applied to assess several potential fuel cell vehicle deployment rate and hydrogen station technology scenarios. The model accounts for all of the costs in the hydrogen supply chain and specifically examines a network of 68 planned and existing hydrogen stations in terms of economic viability and dispensed hydrogen cost. Results show that (1) current high-pressure gaseous delivery and liquid delivery station technologies can eventually be profitable with relatively low vehicle deployment rates, and (2) the cost per mile for operating fuel cell vehicles can be lower than equivalent gasoline vehicles in both the near and long term.     

Techno-economic evaluation of hydrogen refueling stations with liquid or gaseous stored hydrogen

In this study, different hydrogen refueling station (HRS) architectures are analyzed energetically as well as economically for 2015 and 2050. For the energetic evaluation, the model published in Bauer et al. [1] is used and norm-fitting fuelings according to SAE J2601 [2] are applied. This model is extended to include an economic evaluation. The compressor (gaseous hydrogen) resp. pump (liquid hydrogen) throughput and maximum pressures and volumes of the cascaded high-pressure storage system vessels are dimensioned in a way to minimize lifecycle costs, including depreciation, capital commitment and electricity costs. Various station capacity sizes are derived and energy consumption is calculated for different ambient temperatures and different station utilizations. Investment costs and costs per fueling mass are calculated based on different station utilizations and an ambient temperature of +12 °C. In case of gaseous trucked-in hydrogen, a comparison between 5 MPa and 20 MPa low-pressure storage is conducted. For all station configurations and sizes, a medium-voltage grid connection is applied if the power load exceeds a certain limit. For stations with on-site production, the electric power load of the hydrogen production device (electrolyzer or gas reformer) is taken into account in terms of power load. Costs and energy consumption attributed to the production device are not considered in this study due to comparability to other station concepts. Therefore, grid connection costs are allocated to the fueling station part excluding the production device. The operational strategy of the production device is also considered as energy consumption of the subsequent compressor or pump and the required low-pressure storage are affected by it. All station concepts, liquid truck-supplied hydrogen as well as stations with gaseous truck-supplied or on-site produced hydrogen show a considerable cost reduction potential. Long-term specific hydrogen costs of large stations (6 dispensers) are 0.63 €/kg – 0.76 €/kg (dependent on configuration) for stations with gaseous stored hydrogen and 0.18 €/kg for stations with liquid stored hydrogen. The study focuses only on the refueling station and does not allow a statement about the overall cost-effectiveness of different pathways.     

Current standards and configurations for the permitting and operation of hydrogen refueling stations

The literature lacks a systematic analysis of HRS equipment and operating standards. Researchers, policymakers, and HRS operators could find this information relevant for planning the network's future expansion. This study is intended to address this information need by providing a comprehensive strategic overview of the regulations currently in place for the construction and maintenance of hydrogen fueling stations.A quick introduction to fundamental hydrogen precautions and hydrogen design is offered. The paper, therefore, provides a quick overview of hydrogen's safety to emphasize HRS standards, rules, and regulations. Both gaseous and liquid safety issues are detailed, including possible threats and installation and operating expertise.After the safety evaluation, layouts, equipment, and operating strategies for HRSs are presented, followed by a review of in-force regulations: internationally, by presenting ISO, IEC, and SAE standards, and Europeanly, by reviewing the CEN/CENELEC standards. A brief and concise analysis of Italy's HRS regulations is conducted, with the goal of identifying potential insights for strategic development and more convenient technology deployment.     

The simulation and analysis of leakage and explosion at a renewable hydrogen refuelling station

The number of hydrogen refuelling stations (HRSs) is steadily growing worldwide. In China, the first renewable hydrogen refuelling station has been built in Dalian for nearly 3 years. FLACS software based on computational fluid dynamics approach is used in this paper for simulation and analysis on the leakage and explosion of hydrogen storage system in this renewable hydrogen refuelling station. The effects of wind speed, leakage direction and wind direction on the consequences of the accident are analyzed. The harmful area, lethal area, the farthest harmful distance and the longest lethal distance in explosion accident of different accident scenarios are calculated. Harmful areas after explosion of different equipments in hydrogen storage system are compared. The results show that leakage accident of the 90 MPa hydrogen storage tank cause the greatest harm in hydrogen explosion. The farthest harmful distance caused by explosion is 35.7 m and the farthest lethal distance is 18.8 m in case of the same direction of wind and leakage. Moreover, it is recommended that the hydrogen tube trailer should not be parked in the hydrogen refuelling station when the amount of hydrogen is sufficient.     

Improved safety by crossanalyzing quantitative risk assessment of hydrogen refueling stations

With the goal of building 310 hydrogen refueling stations (HRSs) in Korea by 2022, restrictions, such as location restrictions and separation distances, are being eased, so developing ways to improve technology and safety. As HRSs contain major facilities such as compressors, storage tanks, dispenser, and priority control panels, and a leakage could result in a large fire or explosion caused by an ignition source. To perform quantitative risk assessment, programs, namely, Hy-KoRAM and Phast/Safeti were used in this study. It could determine the damage range and effect on radiant heat and flame length, as well as personal and societal risks, using these programs. The crossanalysis of the two programs also improves the facility's safety and the reliability of the results.     

Energetic evaluation of hydrogen refueling stations with liquid or gaseous stored hydrogen

The future success of fuel cell electric vehicles requires a corresponding infrastructure. In this study, two different refueling station concepts for fuel cell passenger cars with 70 MPa technology were evaluated energetically. In the first option, the input of the refueling station is gaseous hydrogen which is compressed to final pressure, remaining in gaseous state. In the second option, the input is liquid hydrogen which is cryo-compressed directly from the liquid phase to the target pressure. In the first case, the target temperature of −33 °C to −40 °C [1] is achieved by cooling down. In the second option, gaseous deep-cold hydrogen coming from the pump is heated up to target temperature. A dynamic simulation model considering real gas behavior to evaluate both types of fueling stations from an energetic perspective was created. The dynamic model allows the simulation of boil-off losses (liquid stations) and standby energy losses caused by the precooling system (gaseous station) dependent on fueling profiles. The functionality of the model was demonstrated with a sequence of three refueling processes within a short time period (high station utilization). The liquid station consumed 0.37 kWh/kg compared to 2.43 kWh/kg of the gaseous station. Rough estimations indicated that the energy consumption of the entire pathway is higher for liquid hydrogen. The analysis showed the high influence of the high-pressure storage system design on the energy consumption of the station. For future research work the refueling station model can be applied to analyze the energy consumption dependent on factors like utilization, component sizing and ambient temperature.     

Design and operation of a stochastic hydrogen supply chain network under demand uncertainty

The design of a future hydrogen supply chain (HSC) network is challenging due to the: (1) involvement of many echelons in the supply chain network, (2) high level of interactions between the supply chain components and sub-systems, and (3) uncertainty in hydrogen demand. Most of the early attempts to design the future HSC failed to incorporate all these challenges in a single generic optimization framework using mathematical modeling approach. Building on our previous multiperiod MILP model, the model presented in this paper is expanded to take into account uncertainty arising from long-term variation in hydrogen demand using a scenario-based approach. The model also adds another echelon: fueling stations and local distribution of hydrogen. Our results show that the future HSC network is somewhat similar to the existing petroleum infrastructure in terms of production, distribution, and storage. In both situations, the most feasible solution is centralized production plants with truck and rail delivery and small-to-large storage facilities. The main difference is that the future hydrogen supply has the benefits of using distributed forecourt production of hydrogen at local fueling stations via several production technologies. Finally, the performance of the studied models was evaluated using sensitivity and risk analyses.