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As the global shipping industry experiences rapid expansion, the imperative to address greenhouse gas emissions and environmental impact becomes increasingly paramount. Hydrogen has emerged as a pivotal and eco-friendly energy source, offering a pathway towards carbon neutrality and a complete zero-carbon transition in maritime operations. However, the widespread adoption of hydrogen-powered ships hinges on the establishment of robust regulations and technical standards. This paper conducts a comprehensive examination of hydrogen fuel cell (FC) technology in ships, scrutinizing the role of international classification societies and exploring existing standards and regulations within the maritime industry, specifically centered around hydrogen energy. The study outlines a strategic developmental roadmap for a green shipping hydrogen energy system tailored for hydrogen FC-powered ships in China. Emphasizing the differences in hydrogen application between fuel cell vehicles and ships, the paper elucidates technical challenges unique to hydrogen FC-powered ships. Furthermore, it proposes a visionary framework for future technical standards, advocating for the creation of a ship-based hydrogen energy standard system, the development of core technical standards, and a heightened focus on safety regulations. Through comprehensive analysis and compelling argumentation on hydrogen fuel cell ship technology and standards, this paper underscores the indispensable role that technical standards play in propelling the advancement of environmentally friendly shipping. Beyond serving as an informative resource, the paper aims to provide valuable guidance and direction for the future demonstration, application, and promotion of hydrogen fuel cell ship technology. Ultimately, it underscores the pivotal role of technical standards in advancing sustainable maritime transportation. • Analyze hydrogen energy technical standards from the production, storage, safety. • Comparison of hydrogen energy technical differences between vehicles and ships. • Outline the unique challenges of applying hydrogen technology to ship operations. • Constructed a technical standard framework for future hydrogen energy ships. [ABSTRACT FROM AUTHOR]

Hydrogen is considered as a promising fuel in the 21st century due to zero tailpipe CO 2 emissions from hydrogen-powered vehicles. The use of hydrogen as fuel in vehicles can play an important role in decarbonising the transport sector and achieving net-zero emissions targets. However, there exist several issues related to hydrogen production, efficient hydrogen storage system and transport and refuelling infrastructure, where the current research is focussing on. This study critically reviews and analyses the recent technological advancements of hydrogen production, storage and distribution technologies along with their cost and associated greenhouse gas emissions. This paper also comprehensively discusses the hydrogen refuelling methods, identifies issues associated with fast refuelling and explores the control strategies. Additionally, it explains various standard protocols in relation to safe and efficient refuelling, analyses economic aspects and presents the recent technological advancements related to refuelling infrastructure. This study suggests that the production cost of hydrogen significantly varies from one technology to others. The current hydrogen production cost from fossil sources using the most established technologies were estimated at about $0.8–$3.5/kg H 2 , depending on the country of production. The underground storage technology exhibited the lowest storage cost, followed by compressed hydrogen and liquid hydrogen storage. The levelised cost of the refuelling station was reported to be about $1.5–$8/kg H 2 , depending on the station's capacity and country. Using portable refuelling stations were identified as a promising option in many countries for small fleet size low-to-medium duty vehicles. Following the current research progresses, this paper in the end identifies knowledge gaps and thereby presents future research directions. • Technological advancements of hydrogen production, storage and transport are reviewed. • Emissions and economic aspects of production, storage, transport and fuelling are analysed. • Refuelling protocols, temperature rise issue and its control strategies are discussed. • Recent progress of mobile hydrogen refueller is explored. • Challenges of hydrogen production to fuelling and future research directions are presented. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicles (HFCVs), as an important strategic path for global sustainable development and energy transition, have now become an important support for the global energy and transportation sectors. The United Kingdom, Japan, the United States, China, and other countries are vigorously developing HFCVs and increasing the construction of hydrogen stations. Before HFCVs enter the stage of rapid commercialization and development, it is necessary to investigate the factors that influence consumer HFCV adoption. In this paper, meta-analysis used 24 pieces of literature to include in a systematic evaluation of the existing research on the factors that influence consumer willingness to purchase HFCVs, setting influencing factors as the dependent variable, to clarify the specific roles of different influencing factors and to address the problem of mixed and contradictory findings in the literature. The results of the study show that: (1) The influence of gender and age on consumer willingness to purchase HFCVs cannot be judged. (2) Education, individual income, household income, family car number, driving range, knowledge, fuel availability, hydrogen refueling station density, environmental impact, policy incentives and attitudes all have a positive effect on HFCV adoption. (3) Household size, purchase price, fuel cost, maintenance cost and refueling time have a negative effect on HFCV adoption. (4) The purchase price, knowledge, fueling time, hydrogen refueling station density, and policy incentives significantly influence HFCV adoption. This paper provides new research methods and perspectives for the HFCV field and presents theoretical references for future governmental promotion of HFCV. • Meta-analysis of 24 studies conducted for consumers' intention to purchase HFCVs. • Subgroup analysis provides evidence of heterogeneity among estimates. • Household size and the other 4 influencing factors inhibit HFCV adoption. • Education and the other 9 influencing factors promote HFCV adoption. • The purchase price and other 4 influencing factors significantly influence HFCV adoption. [ABSTRACT FROM AUTHOR]

Precooling gaseous hydrogen fuel to a cold temperature before refueling a heavy-duty (HD) hydrogen fuel cell electric vehicle (HFCEV) is essential to avoid overheating the vehicle tank, as well as achieving a high state of charge (SOC). Because a large volume of hydrogen is dispensed during each fill, the need for a shorter fill time amplifies the need to precool each load for refueling a HFCEV. Thus, the design and operation of a precooling unit (PCU), as well as the associated capital and operating costs, plays a pivotal role in any plans for heavy-duty hydrogen refueling stations. In this paper, we present a thermodynamic and technoeconomic analysis of a PCU in a gaseous hydrogen refueling station (HRS) for HD HFCEVs. By employing Argonne National Laboratory's hydrogen station cost optimization and performance evaluation (H2SCOPE) model, the refueling of 50 kg of hydrogen on-board type IV tank at ambient temperatures of 15–45 °C and varying fill rates is simulated. The required degree of precooling temperature to obtain either 100% or the maximum possible SOC is obtained from the simulation. Additionally, the simulation results demonstrate that the average flow rate of hydrogen is approximately 40% lower than the maximum flow rate during a typical fill; which motivates further evaluation of the instantaneous hydrogen mass flow rate profile and suggests the scope of improving precooling unit design. Accordingly, a hybrid strategy of precooling hydrogen has been proposed to address the cooling load by sizing the refrigeration unit for the average flow rate of hydrogen, while supplementing the above average peak hydrogen flow cooling load through thermal buffering. The combined technique enables the downsizing of the original PCU capacity by 25–40% and demonstrates a potential cost reduction of the PCU by approximately 30%, which translates to an installed cost reduction of ∼$125,000 per dispenser. • Hydrogen fill rate during refueling has a strong influence on the precooling load. • Bell-shaped profile of the fill rate advises a scope of improving precooling. • Hybrid strategy of on-demand cooling aided with partial thermal buffer is proposed. • The hybrid precooling approach downsizes the refrigerator capacity by 25–40%. • A potential reduction in the capital cost of precooling unit is 30%. [ABSTRACT FROM AUTHOR]

Hydrogen refueling stations (HRSs) are crucial infrastructures for the advancement of hydrogen energy. To promote and construct HRSs, a cost-benefit analysis is essential. Factors such as hydrogen transportation, storage, production technology, and subsidy policies can impact the costs. This paper aims to analyze the economics of HRSs under four operation modes, ie., on-site hydrogen production, off-site production with pipeline transportation, off-site production with tube trailer, and off-site production with liquid hydrogen tanker. Two life-cycle analysis models, an annualized cost model for hydrogen transportation and a levelized cost model for HRSs, are established for economic assessment. The study reveals that hydrogen supply costs account for over 50% of the LCOH for off-site station, and power costs drive up the LCOH for on-site station. Among the four operation modes, off-site station with pipeline is most economical, and the cost advantage increases as pipeline capacity utilization rate reaches 100%, but decreases as it drops to 20%. off-site station with long tubes is economical within 300 km, and off-site station with liquid hydrogen tankers is more economical within 300km∼1,000 km. On-site hydrogen production by water electrolysis is not economical at a cost of 35.24 CNY/kg. The optimal operation scheme under different hydrogen source distances is proposed. • An annualized cost model for hydrogen transportation modes and A levelized cost model for HRSs were established. • The comprehensive costs analysis throughout the full life cycle was conducted in four different operation modes of HRSs. • The factors affecting HRS costs were analyzed in depth:hydrogen source distance, pipeline utilization, and cost structure. • On-site hydrogen production in integrated station is not yet economically feasible. [ABSTRACT FROM AUTHOR]

The joint consideration of hydrogen supply chain networks and electric power systems can promote hydrogen-fueled transportation and the penetration of renewable energy. This paper develops a low-carbon scheduling approach for an Integrated Hydrogen Transport and Energy System (IHTES). To reduce carbon emissions, the environmental cost from the hydrogen supply chain network and electric power system is jointly minimized with the operational cost of IHTES. To consider the timeliness of hydrogen deliveries, hydrogen transport via tube trailers is innovatively modeled as an extended vehicle routing problem with time windows, and delays are penalized. The scheduling problem is formulated as a mixed-integer linear programming problem so that it can be efficiently solved using the branch-and-cut method. Case studies illustrate and validate the proposed model, and demonstrate the computational efficiency of our approach. Carbon emissions are reduced by 47.8% when the emission cost is co-optimized with the operational cost. The operational cost of the hydrogen supply chain network is reduced by 7.3% when the timeliness of hydrogen deliveries is modeled. • Emission-operation optimization of Integrated Hydrogen Transport and Energy System. • The timeliness of hydrogen deliveries is modeled with delays penalized. • The scheduling problem is formulated as a mixed-integer linear programming problem. [ABSTRACT FROM AUTHOR]

In order to ensure the safety of hydrogen refueling systems and fuel cell vehicles under various filling conditions, the filling parameters are usually set very conservatively, leading to waste energy consumption and investment. The lumped parameter hydrogen gas model and one-dimension tank wall model of the hydrogen filling process previously proposed by our team were extended and improved to the entire hydrogen refueling system by considering the Joule-Thomson effect, kinetic energy and using a more accurate model of the heat transfer coefficients between the inner tank wall and hydrogen gas and between the outer tank wall and ambient. Based on our validated model, the effects of constant and two-stage average pressure ramp rates (APRRs) and precooling/inlet temperatures on refueling performances were investigated, respectively. Compared with the optimal filling strategy of the reference paper, where a constant APRR is the best, our two-stage APRRs can further reduce the cooling power for various inlet temperatures without increasing the cooling energy. For example, maximum cooling power can be reduced by 23.8% at the inlet temperature of −20 °C. Compared with the previous research result obtained using a constant inlet temperature solved by the analytical solution, the two-stage inlet temperatures can further reduce the cooling power by 16.3% at an APRR of 0.428 MPa/s without increasing the cooling energy. • A thermodynamic model for a hydrogen refueling system is improved and well validated. • Joule-Thomson effect, kinetic energy and accurate heat transfer model are considered. • Effects of two-stage average pressure ramp rates and inlet temperatures are studied. • Two-stage strategies can reduce cooling power without increasing cooling energy. [ABSTRACT FROM AUTHOR]

With the rise of the hydrogen energy industry, countries worldwide have introduced relevant policies to elevate the development of the hydrogen energy industry to the height of national energy strategy, and hydrogen energy will become a significant factor affecting the future industrial structure and national competitiveness. The path of technology evolution can trace the history of technology development and predict the trend of technology development, which can help to grasp the first opportunity of technological innovation and lead the direction of technological development. However, there are fewer studies on technology evolution in hydrogen energy. The existing studies mainly use bibliometrics to mine a single technology, and the studies using text mining suffer from the defect that keywords are difficult to decipher. Given this, this paper conducts research on identifying the technology evolution path in the field of hydrogen energy, adopts text mining methods to mine patent data, and introduces document vectorization and phrase mining algorithms to improve the mining depth while increasing the interpretability of the results. It is found that the hydrogen energy industry is in a period of rapid development; the succession and integration of hydrogen energy technologies are good, and the technological development trend focuses on hydrogen storage materials, hydrogen fuel cell vehicles, and green hydrogen preparation. • Identify the mesh evolution path of hydrogen energy technology using text mining. • Introduce a phrase-mining algorithm to make interpreting the results easier. • Analyze the overall development trend of hydrogen energy technology. • Explore the technological themes and evolution patterns in the field of hydrogen energy. [ABSTRACT FROM AUTHOR]

Hydrogen fuel has shown promise as a clean, alternative fuel aiding in the reduction of fossil fuel dependence within the transportation sector. However, hydrogen refueling stations and infrastructure remains a barrier and are a prerequisite for consumer adoption of low-cost and low-emission fuel cell electric vehicles (FCEVs). The costs for FCEV fueling include both station capital costs and operation and maintenance (O&M) costs. Contributing to these O&M costs, unscheduled maintenance is presently more costly and more frequent than for similar gasoline fueling infrastructure and is asserted to be a limiting factor in achieving FCEV customer acceptance and cost parity. Unscheduled maintenance leads to longer station downtime, therefore, causing an increase in missed fueling opportunities, which forces customers to seek refueling at other operable stations that may be significantly farther away. This research proposes a framework for a hydrogen station prognostics health monitoring (H2S PHM) model that can minimize unexpected downtime by predicting the remaining useful life for primary hydrogen station components within the major station subsystems. The H2S PHM model is a data-driven statistical model, based on O&M data collected from 34 retail hydrogen stations located in the U.S. The primary subcomponents studied are the dispenser, compressor, and chiller. The remaining useful life calculations are used to decide whether or not maintenance should be completed based on the prediction and expected future station use. This paper presents the background, method, and results for the H2S PHM model as for a means for improving station availability and customer confidence in FCEVs and hydrogen infrastructure. • Hydrogen station reliability is a key contributor to market success. • Mean fills between failure and station availability are lower than conventional technologies. • A prognostics health monitoring system can improve hydrogen station availability. • Estimated remaining useful life of primary components assists in maintenance decisions. [ABSTRACT FROM AUTHOR]

Argentina has a wide availability of renewable resources, which provides important advantages for the hydrogen vector incorporation. The province of Córdoba is an excellent model case for the study of the rapid incorporation of hydrogen as fuel, to replace 20% V/V of natural gas consumed in vehicular use. This does not involve major changes in infrastructure or modifications to the vehicles. This paper computes and analyzes the levelized cost of hydrogen with the emissions associated for each part of the complete hydrogen supply chain. Two different production sources were used: renewable energies sources and the Argentine electrical grid; and two production pathways: in situ and centralized production. Comparing the same volume of proposed hydrogen compressed natural gas and current CNG, a cost decrease in the majority of the scenarios and a CO 2 eq emission reduction ranging from 19.5 to 8.2% are achieved, even if the hydrogen is produced using the carbon-intensive grid electricity. • The Production of hydrogen to replace part of the CNG used in vehicles is proposed. • Levelized cost of hydrogen and the emissions associated was assessed. • The study includes the entire supply chain from production to the filling station. • The use of HCNG results in a reduction of emissions in all the studied scenarios. • The new fuel is economically favorable, becoming relevant for rapid energy transition. [ABSTRACT FROM AUTHOR]

World's energy demand is majorly met by fossil fuels. An increase in the demand for energy and the depletion of fossil fuels leads to look for the alternate source of energy. Hydrogen is one of the most viable alternate sources of alternate energy. This paper presents the performance study of a Compression Ignition engine using a fuel combination of diesel and hydrogen-diesel. The performance parameters have been analyzed with two input factors, load and Compression Ratio and three output responses, Brake Thermal efficiency (BTE), Brake Specific Fuel Consumption (BSFC) and Volumetric efficiency. The experimental results indicate the improvement in BTE, reduction in BSFC and volumetric efficiency. The BTE was improved by 6.38%, BSFC was reduced by 4.87% and Volumetric efficiency got reduced by 1.89% when hydrogen-diesel fuel is used in place of neat diesel. The experiments have been designed with the help of Design Expert® 13.0.5 using Response Surface Method. The experiments are conducted using Optimal (Custom) design. Mathematical relations are developed between the process parameters and the input factors using regression analysis. The optimal solution has been obtained using the desirability approach. The confirmation experiments have been performed on the optimal solution to verify with the experiment results. Results of the confirmation test shows that the developed mathematical are appropriate for the use in CI engine. • Use of Hydrogen (H 2) as alternate fuel in CI engine. • Experimental investigation of CI engine's performance parameters using Diesel and Hydrogen fuels. • Optimization of CI engine's performance parameters using Response Surface Method. • Performance parameters of H 2 fuelled CI Engine increased at higher compression ratio under varying load condition. [ABSTRACT FROM AUTHOR]

The most challenging aspect of developing a green hydrogen economy is long-distance oceanic transportation. Hydrogen liquefaction is a transportation alternative. However, the cost and energy consumption for liquefaction is currently prohibitively high, creating a major barrier to hydrogen supply chains. This paper proposes using solid nitrogen or oxygen as a medium for recycling cold energy across the hydrogen liquefaction supply chain. When a liquid hydrogen (LH2) carrier reaches its destination, the regasification process of the hydrogen produces solid nitrogen or oxygen. The solid nitrogen or oxygen is then transported in the LH2 carrier back to the hydrogen liquefaction facility and used to reduce the energy consumption cooling gaseous hydrogen. As a result, the energy required to liquefy hydrogen can be reduced by 25.4% using N 2 and 27.3% using O 2. Solid air hydrogen liquefaction (SAHL) can be the missing link for implementing a global hydrogen economy. • The energy required to liquefy hydrogen reduces by 25.4% with N 2 and 27.3% with O 2. • Solid O 2 is a better hydrogen liquefaction energy carrier than solid N 2. • Solid N 2 is selected as the energy carrier due to the risk explosion using O 2. • The solid N 2 occupies 44.5% of the liquid H 2 tank volume. [ABSTRACT FROM AUTHOR]

Road transportation is a significant source of CO 2 emissions and energy demand. Consequently, initiatives are being promoted to decrease the sector's emissions and comply with the Paris agreement. This article synthesizes the available information about heavy-duty fuel cell trucks as their deployment needs to be considered a complementary solution to decreasing CO 2 emissions alongside battery electric vehicles. A thorough evaluation of 95 relevant documents determines that the main research topics in the past ten years converge on public policies, hydrogen supply chain, environmental impact, drivetrain technology, fuel cell, and storage tank applications. The identified research gaps relate to expanding collaboration between institutions and governments in developing joint green macro policies focused on hydrogen heavy-duty trucks, scarce research about hydrogen production energy sources, low interest in documenting hydrogen pilot projects, and minimal involvement of logistic companies, which need to plan their diesel freight's conversion as soon as possible. [Display omitted] • A review of 95 papers about hydrogen fuel cell heavy-duty trucks is presented. • A bibliometric analysis shows a 270% growth in published papers from 2019 to 2021. • Six popular topics emerge as leading research areas. • The trendiest topics are environment, hydrogen supply chain, and trucks' drivetrains. • Main research gaps relate to private involvement and government collaboration. [ABSTRACT FROM AUTHOR]

Dealing with the conflict between the temperature/pressure rise and the total mass of hydrogen is a key challenge for rapid hydrogen filling of the hydrogen storage tank (HST). The temperature/pressure rise and total mass of hydrogen cause safety risks because of the former and limited cruise as the result of the latter. Therefore, safe hydrogen filling strategy is essential for the promotion of hydrogen fuel cell vehicles (FCVs). The existing thermodynamic model of the hydrogen storage tank is simplified either in the hydrogen state or the heat conduction of the HST wall, which can be hardly used as the real-time and accurate references for developing the filling strategy. To solve this problem, this paper works out the mathematical expression of a HST thermodynamic model. With the proposed HST thermodynamic model, a variable mass flow hydrogen filling strategy is developed. The results show that at the mass flow (12 g/s), the errors of the thermodynamic model are 7.1% and 6.8% for the temperature and pressure rise, compared with the computational fluid dynamics (CFD) model. At the mass flow (4.84 g/s), the thermodynamic model errors are 8.3% and 7.1% for the temperature and pressure rise, compared with the experimental data. Also, compared with the rule-based hydrogen filling strategies, the final state of charge (SoC) with the new filling strategy improve by 3%, 3.7%, and 2.7% at different initial temperatures, different volumes, and initial SoCs, respectively. • A real-time thermodynamic HST model with strong convergence is proposed. • The wall's unsteady heat transfer and hydrogen real properties are considered. • Variable mass flow is applied in the development of the filling strategy first. • The mass flow is determined by reinforcement learning, not rule-based. [ABSTRACT FROM AUTHOR]

Solar-hydrogen energy systems for spacecraft reliably provide energy for carrying out various kinds of unscheduled work on board and for eliminating emergency situations. Surplus energy is constantly accumulated on board in the form of the chemical energy of cryogenic hydrogen. The article presents too the result of the development of a solar-hydrogen power supply system for spacecraft, the onboard network of which provides slow and fast processes. The paper presents too pulsed and continuous models of voltage converters of the electrical power system of automatic spacecraft. It is proved on the simulation basis that the deviation of frequency characteristics of continuous models from pulse ones is insignificant (not more than 2%), while the use of continuous models to study both frequency and time characteristics of the converter allows us to reduce the simulation time tenfold. [ABSTRACT FROM AUTHOR]

To satisfy the growing refueling demand of hydrogen fuel cell vehicles (HFCVs) with carbon-free hydrogen supply, this paper proposes an integrated planning method of green hydrogen supply chain. First, the k-shorted path method is introduced to analyze HFCV refueling load considering vehicle travel habits and routing diversity. Second, based on it, a two-stage integrated planning model is established to minimize the total investment and operation cost. The construction of hydrogen refueling stations, electrolysis-based hydrogen generation stations and hydrogen pipelines are coordinated with their operating constraints, constituting the green hydrogen supply chain, in which hydrogen storage is also an important part for consideration to address variable renewable power. Then, the proposed model is reformulated as a mixed integer linear programing (MILP) problem solved efficiently. Finally, the case studies are carried out on an urban area in Xi'an China to verify the validity and correctness of the proposed method. The results show that the integrated planning can realize synergy benefits. The influence of electricity prices and k values is also discussed. • Develop two-stage integrated planning method of the green hydrogen supply chain for HFCVs in urban areas. • Employ K-shortest path method to simulate hydrogen fuel cell vehicle (HFCV) refueling loads on a specified road network. • Co-optimize placement of Hydrogen Refueling Stations (HRSs), Hydrogen Generation Stations (HGSs) and hydrogen pipelines. • Use Piecewise linearization solution method for non-convex model. • Conduct Case Study of Pipeline topology and HRS deployment based on real urban transportation network. [ABSTRACT FROM AUTHOR]

The expected increase of hydrogen fuel cell vehicles has motivated the emergence of a significant number of studies on Hydrogen Refuelling Stations (HRS). Some of the main HRS topics are sizing, location, design optimization, and optimal operation. On-site green HRS, where hydrogen is produced locally from green renewable energy sources, have received special attention due to their contribution to decarbonization. This kind of HRS are complex systems whose hydraulic and electric linked topologies include renewable energy sources, electrolyzers, buffer hydrogen tanks, compressors and batteries, among other components. This paper develops a linear model of a real on-site green HRS that is set to be built in Zaragoza, Spain. This plant can produce hydrogen either from solar energy or from the utility grid and is designed for three different types of services: light-duty and heavy-duty fuel cell vehicles and gas containers. In the literature, there is a lack of online control solutions developed for HRS, even more in the form of optimal online control. Hence, for the HRS operation, a Model Predictive Controller (MPC) is designed to solve a weighted multi-objective online optimization problem taking into account the plant dynamics and constraints as well as the disturbances prediction. Performance is analysed throughout 210 individual month-long simulations and the effect of the multi-objective weighting, prediction horizon, and hydrogen selling price is discussed. With the simulation results, this work shows the suitability of MPC for HRS control and its significant economic advantage compared to the rule-based control solution. In all simulations, the MPC operation fulfils all required services. Moreover, results show that a seven-day prediction horizon can improve profits by 57% relative to a one-day prediction horizon; that the battery is under-sized; or that the MPC operation strategy is more resolutive for low hydrogen selling prices. [Display omitted] • Model Predictive control application for green hydrogen refuelling station. • Linear modelling of green hydrogen refuelling station. • Parameter sensitivity analysis of the multi-objective function. • Prediction horizon sensitivity analysis. • Model Predictive Control performance advantage compared to rule-based control. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicles have proliferated in recent years, leading to a subsequent increase in hydrogen fuelling stations (HFSs). Operation and maintenance activities of an HFS prone to undesired events caused by human errors. Estimating and evaluating the risk associated with operators' performance can help to enhance the safety of such operations. The human error assessment and reduction technique (HEART) methodology has been widely used to assess the reliability of human performance. However, this technique is not entirely reliable since it depends on experts' experience and judgment, and the model's final outcome is subject to uncertainty. Besides, the HEART method ignores the dependencies of all the tasks required to assess human error probability (HEP). This paper presents a new integrated methodology for quantifying the impacts of different conditions on the reliability of operators' performances in HFSs. The proposed framework is constructed based on the Bayesian network (BN) for complimenting the application of HEART to deal with the lack of data and experts' judgment. Hence, it reduces the inaccuracy of HEP assessed by HEART by plotting it to a BN and considering the dependencies of all involved tasks. Subsequently, the best-worst method (BWM) is utilised to deal with the subjectivity of expert judgment. The integrated BN-BWM-HEART technique enhances the safety and reliability of the current operation and maintenance practices of an HFS. The results indicate that the integrated BN-BWM-HEART technique has the potential capacity to reduce the uncertainty associated with HEP estimation. So, the outcome of the developed methodology enhances the safety and reliability of operations and maintenance activities in an HFS. • Develop a methodology to improve conventional human reliability assessment techniques. • Minimise the subjectivity from a heterogeneous group of decision-makers. • Assess human errors in hydrogen refuelling stations considering effective factors. • Identify influential factors in operation and maintenance of hydrogen refuelling stations. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell vehicle (HFCV) as an emerging industry with great potential have received great attention in the Yangtze River Delta, China. Under government's promotion of hydrogen energy, whether HFCV can be accepted by consumers is an important topic for future policymaking. Therefore, this study takes consumers' willingness to consume HFCV as the dependent variable and collects questionnaires from 21 cities in the Yangtze River Delta from 2020 to 2021. Based on Ordinary Least Squares (OLS) and Logit Regression, the evaluation was conducted from four perspectives: personal and family situation, environmental awareness, energy attitude and local product confidence. The results show that gender, age and income differences are not necessarily determinants of HFCV purchase, but educational level is a significant factor. Consistent with social-psychological studies, personal awareness of environmental protection and energy attitudes are the key factors that are significant affect HFCV purchase. Lastly, it is found that in the Yangtze River Delta, consumers' confidence in Chinese local hydrogen products is also a significant factor. This paper confirms that HFCV consumers have commonalities with other new energy consumers. However, due to the expectation of greater local production and development, enhancing the social recognition and confidence of local hydrogen technology may be one of the promotion approaches neglected. • Consumer Acceptance for Hydrogen fuel cell vehicle (HFCV) in China is explored. • 600 questionnaires were collected from 21 cities in the Yangtze River Delta. • Psychological constructs such as environmental awareness and energy attitudes are still validated in HFCV consumption. • Improving social confidence in local HFCV technology is an important promotion orientation for China. [ABSTRACT FROM AUTHOR]

This paper analyses the planning and operation of an energy district that aims to integrate a hydrogen supply chain for feeding vehicles based on fuel cell technology. A model of an energy district and an optimization algorithm based on the economic parameters are presented and validated leveraging an existing energy district, simulating several scenarios depending on different economic conditions and technical parameters. The model of the energy district evaluates energy balances, distinguishing hydrogen and electrical energy flows; the districts can include an FCEV fleet, electrical loads, energy generators, storage system and an electrolyser for producing hydrogen from the green energy surplus produced in the district as well as drawing energy from the power distribution network. The algorithm, based on MILP, is used for optimizing the flows in the district; indeed, it evaluates all the technical and economic constraints at a certain timestamp and provides optimal scheduling of the energy units. Model and algorithm have been used to evaluate different scenarios that were identified by varying the economic parameters (i.e., prices of electrical energy and hydrogen) as well as district design (i.e., upgrading sizes of the generators and electrolysers). Energy district parameters have been identified exploiting real data collected in an existing district located in Terni (Italy) owned by the local multi-utility ASM Terni S.p.A. It already includes a fleet for waste management, PV plants, office buildings and warehouses. Through parameters combination, 1125 OPEX and 729 CAPEX simulated scenarios have been evaluated and reported; each scenario assesses the daily variation of variables' economic trends covering the timeframe from 2030 to 2050. Results of simulations highlight the most convenient economic contexts as well as the envisioned amount of expenditures for adopting FCEV in the presented district or similar ones. For the case study, the forecasted cost of the hydrogen district, including FCEVs, is fully comparable to current costs, resulting in some cases even cheaper. • Energy district model integrating hydrogen and electrical energy networks. • MILP-based optimized management of hydrogen and electricity flows. • Hydrogen fleet conversion analysed in real district of a waste management company. • Analysis of 91,250 technical-economical scenarios for real fleet conversion. [ABSTRACT FROM AUTHOR]

Hydrogen is considered to be one of the fuels of future and liquid hydrogen (LH2) technology has great potential to become energy commodity beyond LNG. However, for commercial widespread use and feasibility of hydrogen technology, it is of utmost importance to develop cost-effective and safe technologies for storage and transportation of LH2 for use in stationary applications as well as offshore transportation. This paper reviews various aspects of global hydrogen supply chain starting from several ways of production to storage and delivery to utilization. While each these aspects contribute to the overall success and efficiency of the global supply chain, storage and delivery/transport are the key enablers for establishing global hydrogen technology, especially while current infrastructure and technology are being under development. In addition, while all storage options have their own advantages/disadvantages, the LH2 storage has unique advantages due to the familiarity with well-established LNG technology and existing hydrogen technology in space programs. However, because of extremely low temperature constraints, commercialization of LH2 technology for large-scale storage and transportation faces many challenges, which are discussed in this paper along with the current status and key gaps in the existing technology. [Display omitted] • Key characteristics of hydrogen (H 2) as potential "fuel for future" is discussed. • Main components of Hydrogen supply chain (production to utilization) are presented. • Liquid H 2 (LH2) technology has great potential to become energy commodity like LNG. • H 2 -storage and transportation are key enabler for establishing global H 2 -supply chain. • Current status and main technical challenges for large-scale LH2 storage are reviewed. [ABSTRACT FROM AUTHOR]

The fast filling time for hydrogen fuel cell vehicles makes them a user-friendly zero emission alternative to fossil fuel powered vehicles. The filling, by compressing gas into the vehicle tanks, produces heat that can be damaging. There are different protocols, standardized or the intellectual property of station operators, dedicated for different specific applications taking into account the specificity of the vessel and customer requirements. Standard protocols are developed for worst case conditions across a broad range of vehicle tank sizes and configurations. These worst case conditions do not result in the most economical equipment solution for hydrogen fueling. To ensure safety for different existing and future potential protocols a new "Safety Watchdog" approach is suggested in the current paper. This "Safety Watchdog" monitors the fueling process boundary conditions independently from the main process controls. The decoupling between the watchdog and the protocol allows use of protocols that are more economically beneficial while ensuring full safety conditions. The current paper provides a mathematical formulation of the Safety Watchdog as well as its validation versus modeling and field experimental data. • The safety of hydrogen fillings should be insured. • During fillings, compressing hydrogen produces heat in vehicle storage systems. • Stations currently rely on conservative pre-determined tables. • Preventing overheating in vehicle tanks can be dynamic to reduce the final costs. [ABSTRACT FROM AUTHOR]

Recent progress in submerged liquid hydrogen (LH 2) cryopump technology development offers improved hydrogen fueling performance at a reduced cost in medium- and heavy-duty (MDV and HDV) fuel cell vehicle refueling applications at 35 MPa pressure, compared to fueling via gas compression. In this paper, we evaluate the fueling cost associated with cryopump-based refueling stations for different MDV and HDV hydrogen demand profiles. We adapt the Heavy Duty Refueling Station Analysis Model (HDRSAM) tool to analyze the submerged cryopump case, and compare the estimated fuel dispensing costs of stations supplied with LH 2 for fueling Class 4 delivery van (MDV), public transit bus (HDV), and Class 8 truck (HDV) fleets using cryopumps relative to station designs. A sensitivity analysis around upstream costs illustrates the trade-offs associated with H 2 production from onsite electrolysis versus central LH 2 production and delivery. Our results indicate that LH 2 cryopump-based stations become more economically attractive as the total station capacity (kg dispensed per day) and hourly demand (vehicles per hour) increase. Depending on the use case, savings relative to next best options range from about 5% up to 44% in dispensed costs, with more favorable economics at larger stations with high utilization. • New submerged cryopumps offer improved performance for hydrogen refueling stations. • Economic analysis tools have been adapted to model stations with new cryopump. • Cost is mainly driven by hourly fueling demand and station daily capacity. • Liquid pump-based stations are most attractive at larger stations with high utilization. • Up to 44% reduction in dispensing cost is possible with new cryopump for heavy-duty truck stations. [ABSTRACT FROM AUTHOR]

In this paper, the current energy mix and the power generation infrastructure of Turkey have been analyzed and two different hydrogen based alternative scenarios applied on Burdur TIMES energy model to foresee the economic and environmental results in the 2016–2031 time period. An improved RES was created to illustrate the current energy network of Burdur city and to determine the relationships between energy carriers and the respective technologies, and then this structure is specified by the relevant data, including fuel cell-powered land vehicle technologies integrated into the land transportation demand side. This paper analyses the feasibility of hydrogen as an alternative energy carrier in the fuel mix for electricity generation in Burdur City to achieve sustainable economic growth, to improve the energy security by minimizing respective environmental emissions and indicate the possible implications of the introduction of the hydrogen supply chain and respective fuel cell end-use technologies in a city level energy modelling perspective. Burdur is selected as the target city to implement the designated level of land transport passenger demand by hydrogen technologies; and after implementation of hydrogen cars in 2020; it has been evaluated that only 0.09 PJ of hydrogen car activity prevents a total of 43.44 kT CO 2 emission in Burdur, addressing the 8% of the total emission in the base scenario between the analysis time horizon. Finally, hydrogen has been evaluated as a clean, dependable option to diversify the energy mix on the current energy supply system of Burdur. • A reference energy system developed for Burdur City in Turkey. • Hydrogen chain supply specified into the reference energy system. • An integrated optimization model structured for the hydrogen supply chain. • A long-term urban bottom-up energy model created for hydrogen in Turkey. [ABSTRACT FROM AUTHOR]

The construction of hydrogenation infrastructure is important to promote the large-scale development of hydrogen energy industry. The technical performance of hydrogen refueling station (HRS) largely determines the refueling efficiency and cost of hydrogen fuel cell vehicles. This paper systematically lists the hydrogen refueling process and the key equipment applicable in the HRS. It comprehensively reviews the key equipment configuration from the hydrogen supply, compression, storage and refueling of the HRS. On the basis of the parameter selection and quantity configuration method, the process optimization technology related to the equipment utilization efficiency and construction cost was quantitatively evaluated. Besides, the existing problems and prospects are put forward, which lays the foundation for further research on the technical economy of HRSs. • The key equipment and process flow of the HRSs are discussed. • The hydrogen supply system configuration is analyzed from three hydrogen sources. • The configuration and optimization of hydrogen storage vessels are presented. • The compressor configuration matched with hydrogen storage are described. • The empirical and queuing method of hydrogen dispenser configuration are explained. [ABSTRACT FROM AUTHOR]

The utilization of hydrogen energy is important for achieving a low-carbon society. Japan has set ambitious goals for hydrogen stations and fuel cell vehicles, focusing on the introduction and dissemination of self-refueling systems. This paper evaluates public trust in the fuel, equipment, and self-handling technology related to self-refueling hydrogen stations and compares it with that for widespread gasoline stations. To this end, the results of an online survey of 300 people with Japanese driver licenses are reported and analyzed. The results show that trust in the equipment and self-handling is more important for the user than trust in the fuel. In addition, to introduce and disseminate new technology such as hydrogen stations, users must be made aware of the risk of using the technology until it becomes as familiar as existing gasoline station technology. • We surveyed user's trust in various aspects of hydrogen self-refueling stations. • Users were concerned about the complexity of gasoline and hydrogen dispensers. • Positive and negative opinions of hydrogen self-refueling technology were indicated. • Positive people may accept new technologies despite the risks. • Familiarity with technology is an important factor for improving acceptance. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to build the first Energy and Life Cycle Analysis (LCA) comparison between buses with internal combustion engine currently used in the city of Rosario, Province of Santa Fe, Argentina, and some technological alternatives and their variants focusing on buses with an electrical engine powered by compressed hydrogen that feet fuel cells of polymer electrolyte membrane (PEM). This LCA comprehend raw material extraction up to its consumption as fuel. Specifically, hydrogen production considering different production processes from renewable sources called "green hydrogen" (Velazquez Abad and Dodds, 2020) [ 1 ] and non-renewable sources called "grey hydrogen" (Velazquez Abad and Dodds, 2020) [ 1 ]. Renewable sources for hydrogen production are rapid cut densified poplar energy plantation, post-industrial wood residues such as chips pallets, and maize silage. For non-renewable hydrogen production sources are the local electrical power grid from water electrolysis and natural gas from the steam methane reforming process. Buses whose fuel would be renewable hydrogen, produced near the City of Rosario, Province of Santa Fe, Argentina, meet one of the main criteria of sustainability biofuels of the European Union (EU) taken into account Renewable Energy Directive (RED) 2009/28 [ 2 ] and EU RED Directive 2018/2001 [ 3 ] that need significant reduction on net greenhouse gases (GHG) from biomass origin row material respect fossil fuels. At least 70% of GHG would be avoided from its main fossil counterpart of the intern combustion engine (ICE), in the worst and current scenario of the emission factor of the electrical grid of Argentina in the point of use that is about 0.40 kg CO 2eq /kWh with energy and environmental load of 100% in the allocation factor in the hydrogen production stage of the LCA analysis. • Significant GHG emissions avoided by using hydrogen in fuel cell buses. • At least 80% of energy consumption in hydrogen life cycle is due to the hydrogen production stage. • Hydrogen fuel cell vehicles are a sustainable alternative in the decarbonization of transport. • Biomass raw material is very competitive as one option to decarbonize transport. • Biogas reforming technology is 47% less energy demanding than solid biomass gasification. [ABSTRACT FROM AUTHOR]

This paper investigates the optimal planning of microgrids including the hydrogen energy system through mixed-integer linear programming model. A real case study is analyzed by extending the only microgrid lab facility in Austria. The case study considers the hydrogen production via electrolysis, seasonal storage and fueling station for meeting the hydrogen fuel demand of fuel cell vehicles, busses and trucks. The optimization is performed relative to two different reference cases which satisfy the mobility demand by diesel fuel and utility electricity based hydrogen fuel production respectively. The key results indicate that the low emission hydrogen mobility framework is achieved by high share of renewable energy sources and seasonal hydrogen storage in the microgrid. The investment optimization scenarios provide at least 66% and at most 99% carbon emission savings at increased costs of 30% and 100% respectively relative to the costs of the diesel reference case (current situation). • A MILP model for renewable based hydrogen production, seasonal storage and mobility. • A real case study is analyzed by extending a microgrid lab facility in Austria. • Multiple investment optimization scenarios relative to two distinct reference cases. • CO 2 reduction by at least 66% and at most 99% relative to the diesel reference case. • Introducing carbon prices to bridge the cost gap between hydrogen and diesel fuel. [ABSTRACT FROM AUTHOR]

The current research concentrated upon customers' consuming behaviors towards hydrogen vehicle in Jiangsu province, China. This paper discussed the associations between factors related to competitions in industries and customers' consuming behaviors. Different from previous literature, the present study explored whether industrial agglomeration would affect customers willingness to purchase hydrogen vehicles. Results from empirical analysis showed that industrial structure height in a city was positively associated with customers' acceptance towards hydrogen vehicles. This indicated that in addition to economic and environmental factors, the agglomeration of industrial activities from industry competition would increase customers purchase intention for hydrogen vehicle. • Industry agglomeration's impacts on hydrogen vehicle's consumption are discussed. • Housing burden is related to the degree of reluctance to buy hydrogen vehicles. • Willingness to energy-saving products and hydrogen vehicles is correlated. • The economic mechanism behind Chinese hydrogen vehicle industry is discussed. [ABSTRACT FROM AUTHOR]

With the acceleration of the development process of hydrogen fuel cell electric vehicles (HFCEV), it has become very important to maximize the energy stored in the vehicle and to use the vehicle with high efficiency. This paper puts forward how to cooperate with a proton exchange membrane fuel cell (PEMFC) as the primary energy source, a lithium-ion battery (LiB) and a supercapacitor (SCAP) as the energy storage technology. Furthermore, this paper examines the effect of two new control strategies developed for HFCEV in different road models on the vehicle fuel economy and life cycle of the system components. Both control strategies applied to the system can be easily applied to the different HFCEVs with minor changes due to the simplicity of their structure and parameters. The simulation results of the study have indicated that the impact of control strategies created in different road conditions on the power of energy sources, the life cycle of system components, system efficiency and fuel economy parameters of HFCEV. Image 1 • New control strategies developed for a hydrogen fuel cell vehicle. • A vehicle with PEM fuel cell, lithium-ion battery and supercapacitor technologies. • The power sharing between energy storage technologies. • The hydrogen fuel saving in the hydrogen fuel cell vehicles. • Extending the life cycle of system components in the hydrogen fuel cell vehicles. [ABSTRACT FROM AUTHOR]

All new technologies, including automotive technologies, are first purchased by early adopters. These consumers are currently posed with the choice of purchasing a fuel cell vehicle (FCV) or a variety of other alternatively fueled vehicles, including battery electric vehicles (BEVs). For FCVs to be commercially successful they need to carve out their own niche in the automotive market, something which may prove challenging in the face of strong BEV market growth. The results in this paper come from a questionnaire survey of 470 FCV owners and 1550 BEV owners. The paper explores the socio-economic profile, travel patterns, and attitudes of FCV buyers and compares them to the buyers of BEVs. The result suggests that the adopters of BEVs and FCV are similar in gender, level of education, household income, and have similar travel patterns. They have differences in age, ownership of previous alternative fuel vehicles, attitudes towards sustainability, and more FCV owners live in rented homes and apartment buildings. The results of the study suggest that FCVs may appeal to consumers who live in homes where they cannot recharge a BEV or install their own charger. FCVs still have several challenges to overcome, including the lack of hydrogen refueling stations and a lack of FCV models to choose from. [ABSTRACT FROM AUTHOR]

Hydrogen has the potential to become a powerful energy vector with different applications in many sectors (industrial, residential, transportation and other applications) as it offers a clean, sustainable, and flexible alternative. Hydrogen trains use compressed hydrogen as fuel to generate electricity using a hybrid system (combining fuel cell and batteries) to power traction motors and auxiliaries. This hydrogen trains are fuelled with hydrogen at the central train depot, like diesel locomotives. The main goal of this paper is to perform a techno-economic analysis for a hydrogen refuelling stations using on-site production, based on PEM electrolyser technology in order to supply hydrogen to a 20 hydrogen-powered trains captive fleet. A sensitivity analysis on the main parameters will be performed as well, in order to acquire the knowledge required to take any decisions on implementation regarding electricity cost, hydrogen selling price, number of operation hours and number of trains for the captive fleet.The main methodology considers the evaluation of the project based on the Net Present Value calculation and the sensitivity analysis through standard method using Oracle Crystal Ball. The main result shows that the use of hydrogen as an alternative fuel for trains is a sustainable and profitable solution from the economic, environmental and safety points of view.The economic analysis concludes with the need to negotiate an electricity cost lower than 50 €/MWh, in order to be able to establish the hydrogen selling price at a rate higher than 4.5€/kg. The number of operating hours should be higher than 4800 h per year, and the electrolyser system capacity (or hydrogen refuelling station capacity) should be greater than 3.5 MW in order to reach a Net Present Value of 7,115,391 € with a Return of Investment set to 9 years. The result of the multiparametric sensitivity analysis for the Net Present Value (NPV) shows an 85.6% certainty that the project will have a positive result (i.e. profitability) (NPV> 0). The two main variables with the largest impact on Net Present Value are the electrolyser capacity (or hydrogen refuelling station capacity) and the hydrogen selling price. Moreover, a margin of improvement (higher NPV) could be reached with the monetization of the heat, oxygen by-product and CO 2 emission reduction. • Green hydrogen can be produced using renewable energy source for rail sector. • Hydrogen Multiple Units has several advantages for use in regional transport. • A viability analysis for green hydrogen production and refuelling was performed. • NPV of € 7115 million and a 9-year pay-back were obtained for this facility. • With 85.6% of confidence, the NPV will be positive (multiparametric analysis). [ABSTRACT FROM AUTHOR]

The hydrogen energy is considered to be main power source of transport sector in the future, and a huge amount of funds have been invested into developing hydrogen fuel cell electric vehicles (FCEVs). Since FCEVs are in initial development stage and there're few FCEVs on the road, before their expansion this paper intends to conduct an economic analysis for FCEVs by using the choice experiment method. In the choice experiment, 1072 participants were required to select among two FCEVs and one conventional fuel vehicle. Logit models were estimated and then the results were used to calculate the willingness to pay for FCEVs. Results showed that purchase price, driving range, refueling time, fuel cost, emissions reduction, refueling accessibility are significant influences, and the marginal values for every 200 km improvement in driving range, 5 min reduction in refueling time, RMB 0.5/kilometer reduction in fuel cost, 20% reduction in emissions, and 20% improvement of refueling accessibility were estimated to be RMB 49,091, 12,727, 3818, 47,818, and 12,909, respectively. A range of FCEV configurations were calculated, and compared to a gasoline-powered counterpart the extra value that customers were likely to pay for a FCEV ranged from RMB 20,810 to 95,310. These results have significant implications for promoting FCEVs and contribute to better sustainability in transport sector. • A choice experiment was used to collect public preference data of FCEVs. • A logit model was then used to estimate WTP for main attributes of FCEVs. • Driving range, emissions reduction, and refueling time largely decides WTP for a FCEV. • The WTP for various FCEV configurations was calculated and compared. [ABSTRACT FROM AUTHOR]

In recent years, there has been considerable interest in the development of zero-emissions, sustainable energy systems utilising the potential of hydrogen energy technologies. However, the improper long-term economic assessment of costs and consequences of such hydrogen-based renewable energy systems has hindered the transition to the so-called hydrogen economy in many cases. One of the main reasons for this is the inefficiency of the optimization techniques employed to estimate the whole-life costs of such systems. Owing to the highly nonlinear and non-convex nature of the life-cycle cost optimization problems of sustainable energy systems using hydrogen as an energy carrier, meta-heuristic optimization techniques must be utilised to solve them. To this end, using a specifically developed artificial intelligence-based micro-grid capacity planning method, this paper examines the performances of twenty meta-heuristics in solving the optimal design problems of three conceptualised hydrogen-based micro-grids, as test-case systems. Accordingly, the obtained numeric simulation results using MATLAB indicate that some of the newly introduced meta-heuristics can play a key role in facilitating the successful, cost-effective development and implementation of hydrogen supply chain models. Notably, the moth-flame optimization algorithm is found capable of reducing the life-cycle costs of micro-grids by up to 6.5% as compared to the dragonfly algorithm. Image 1 • A metaheuristic-driven model is proposed to optimally design H 2 -based microgrids. • An energy management strategy is used to facilitate the uptake of fuel cell vehicles. • The performances of twenty metaheuristics are studied in terms of solution quality. • The moth-flame optimizer outperforms the well-respected algorithms in this area. • Levelized costs of electricity and H 2 are found to be well below the present rates. [ABSTRACT FROM AUTHOR]

This paper applies a mixed integer linear programming model developed in GAMS to simulate the integration of Power-to-Gas infrastructure into an industrial manufacturer's energy system subject to the existing thermal and electrical energy demands, as well as a third hydrogen energy profile. This work is novel in that it assesses the challenges and economic incentives available to make feasible the installation of a hydrogen-based energy storage systems within the Province of Ontario from a techno-economic, policy and environmental perspectives. The energy hub analyzed in this work uses electricity from the power grid and solar PVs to meet the manufacturer's demands, while converting the excess to hydrogen gas, which is used across an array of pathways to generate revenue. ThisThis includes a blend ofof hydrogen for fuel cell vehicles (FCVs), hydrogen for forklifts, and the direct injection of hydrogen into the facility's natural gas, adding renewable content to the heating, and manufacturing processes. Our primary objective was to implement a safe design that minimizes capital and operating costs, resulting in a favorable business case for producing hydrogen, and providing ancillary grid services. However, Power-to-Gas creates a net-emission reduction that can be used not only to sell emission allowances in the provincial carboncarbon tax program for up to $30/t-CO 2eq but to assist the Company in achieving their strategic emission reduction targets. Installation of the selected Power-to-Gas system would require a total capital investment of $2,620,448 with the electrolyzers and solar panels accounting for 41% and 17% of the capital costs, respectively. The compressors will account for most of the operating costs which total $237,653 annually. Within the energy hub, 76,073 kg-H 2 has been produced per year for end-use applications. A sensitivity analysis was performed by varying both hydrogen and carbon credit price which predicted a potentialpotential CO 2 offset of 2359.7 tonne/yr with a payback period of as little as 2.8 years. • MILP model optimizing an industrial energy system incorporating new P2G technology. • Costing of a P2G installation and analysis of ROI based on hydrogen revenue streams. • A sensitivity analysis based on environmental and regulatory policy changes. • Determines emission offsets resulting from the use of fuel cell vehicles. • A policy review of the challenges of implementing P2G in Ontario. [ABSTRACT FROM AUTHOR]

Hydrogen has an important role as a smart solution for Smart Grid, as it can play as an energy vector, a storage medium, and a clean fuel cell. The integration of Hydrogen and Smart Grid can minimize the impact on the environment while maximizing sustainability, which indicates that we are developing toward a hydrogen society. There have been already many studies on different aspects of this topic. For a better understanding of the related work, this paper proposed a comprehensive overview of the related work on the integration of Hydrogen and Smart Grid. Related literature is organized and analyzed from four categories, including Hydrogen energy in smart grids, Hydrogen fuel cell electric vehicles, Hydrogen economy in smart grids, and Models for energy system in smart grids. And each subject has been introduced more carefully. What's more, for a clear understanding for readers, we provide overall scenario views for the organization of the related work. • The integration of Hydrogen and Smart Grid is a trend. • The integration will help boost new economy and form hydrogen society. • Four different viewpoints include grid, vehicle, economy and system models. • More than 100 publications are reviewed for the integration. [ABSTRACT FROM AUTHOR]

One of the key challenges that still facing the adoption of renewable energy systems is having a powerful energy storage system (ESS) that can store energy at peak production periods and return it back when the demand exceeds the supply. In this paper, we discuss the costs associated with storing excess energy from power grids in the form of hydrogen using proton exchange membrane (PEM) reversible fuel cells (RFC). The PEM-RFC system is designed to have dual functions: (1) to use electricity from the wholesale electricity market when the wholesale price reaches low competitive values, use it to produce hydrogen and then convert it back to electricity when the prices are competitive, and (2) to produce hydrogen at low costs to be used in other applications such as a fuel for fuel cell electric vehicles. The main goal of the model is to minimize the levelized cost of energy storage (LCOS), thus the LCOS is used as the key measure for evaluating this economic point. LCOS in many regions in United States can reach competitive costs, for example lowest LCOS can reach 16.4¢/kWh in Illinois (MISO trading hub) when the threshold wholesale electricity price is set at $25/MWh, and 19.9¢/kWh in Texas (ERCOT trading hub) at threshold price of $20/MWh. Similarly, the levelized cost of hydrogen production shows that hydrogen can be produced at very competitive costs, for example the levelized cost of hydrogen production can reach $2.54/kg-H 2 when using electricity from MISO hub. This value is close to the target set by the U.S. Department of Energy. Levelized cost of energy storage (LCOS) curves for several regions in the United States. Image 1 • A model to calculate the levelized cost of energy storage for reversible fuel cells. • RFC system as energy storage system can increase the resiliency of the power grids. • RFC can be designed to store electricity and produce hydrogen for other uses. • Roundtrip efficiency and capital cost are key factors that shape the LCOS in RFC. [ABSTRACT FROM AUTHOR]

A hydrogen station is one that fills or stores the hydrogen, which is critical to the commercial development of hydrogen energy and fuel cell vehicle industry. Therefore, its location planning becomes an important issue. Similar to the electric vehicle (EV) charging station's planning, several factors are considered including the location, the demand of the fuel, the driving distance, etc. In this paper, multiple data sources are applied to the site selection model, including the existing petrol-refueling station network data, geographic information system (GIS) data, population data and regional economic data. Based on the operation of the genetic algorithm, combined with the idea of the greedy algorithm and the annealing algorithm, we propose a multi-algorithm hybrid solution, which not only can avoid local optimal, but also can converge quickly. On the basis of the site selection scheme of the hydrogen station in California, we have optimized the location scheme in Beijing. Finally, we present the feasibility proposals for hydrogen station location in Beijing, including the appropriate number of hydrogen stations in different regions, the reasonable coverage distance of hydrogen stations, etc. Due to the huge development prospects for hydrogen energy and the urgent need to reduce the construction cost of hydrogen stations in China, this research can quickly optimize the location of the hydrogen station and further explore potential mathematical relationships, which has certain social significance and economic benefits. • Multiple data sources are used for hydrogen station location optimization. • Data includes stations network, GIS and economy data from Beijing. • The results provide hydrogen station planning solution for Beijing. • This research has social significance and economic benefits for hydrogen economics. [ABSTRACT FROM AUTHOR]

One major issue that is source of uncertainty holding back the hydrogen deployment, is the infrastructure development needs and costs. Different studies in the literature tackled this issue in France but partially, assessing either one part of the hydrogen supply chain or the whole supply chain but for one possible delivery pathway. This paper compares five hydrogen pathways, going from the production step up to the fuelling station and tackling pipeline and truck options. In order to capture the time evolution aspect of the infrastructure deployment needs, three demand scenarios are investigated, going from 1% of market penetration up to 15%. Additionally, two scenarios are taken into account when it comes to the location of the hydrogen production sites vis-à-vis the demand centres. According to the results, economies of scale that can be driven by higher market penetration rates have significant impact on lowering the hydrogen cost. • Infrastructure costs are source of uncertainty hampering the hydrogen deployment. • Five hydrogen delivery pathways, going up to the refuelling stations, are compared. • Three scenarios are investigated for the hydrogen demand in passenger mobility. • GIS modelling allowed to visualize a potential infrastructure deployment. • The economies of scale have significant impact on lowering the hydrogen cost. [ABSTRACT FROM AUTHOR]

Engine performance parameters, including fuel conversion efficiency (FCE), power, torque and specific fuel consumption (SFC), can be affected by variables such as ignition timing (IGT), injection timing (IT) and hydrogen volume fraction (H2%). In this paper an engine fueled with different H2/CNG blend rations from 0 to 50% volume under ignition and injection timing at different speeds were investigated. For model validation, the engine operating conditions were simulated using the AVL fire software and compared with experimental results. The statistical comparison showed that there was no significant difference between them. Also, a support vector machine (SVM) was used to study the engine's behavior according to the variables studied. The SVM model predicted the FCE, power, torque, SFC and CO with error of less than 4%. The Genetic Algorithm (GA) was used to find optimal IGT, IT and H2% values to achieve optimum engine performance. Therefore, the results showed that the optimum engine operating conditions depend on the engine speed. Also, the results showed that independent variables (IT, IGT and H2%) maximize the engine performance and minimize SFC and CO emission. So that the optimum use of hydrogen in this research at different engine speeds was between 20% and 30%. • Effect of hydrogen fuel in direct injection engine was studied. • Use of HCNG fuel can improve engine performance and exhaust emissions. • The SVM model could predict the engine performance and CO with error of less than 4%. • Ignition timing, injection timing and hydrogen volume fraction at different engine speeds. [ABSTRACT FROM AUTHOR]

Hydrogen fuel cell electric vehicle (FCEV) can reduce air pollution as well as achieve efficient use of hydrogen energy. Farther travel distance requires larger hydrogen storage pressure, thereby imposing more demanding working conditions on the pressure reducing system. In this paper, a multi-stage high pressure reducing valve (MSHPRV) for hydrogen decompression in FCEV is proposed, and the effects of different structural parameters on its internal flow characteristics are investigated to achieve a better hydrogen decompression process. Results show that compared with perforated plate, multi-stage perforated sleeves and valve core hold the dominant position in hydrogen throttling process. Larger multi-stage perforated sleeve diameter, perforated plate diameter and pressure ratio relate to larger hydrogen kinetic energy, turbulence vortex and energy consumption. However, with the increase of perforated plate stage and perforated plate radius, the turbulent intensity and energy consumption inside MSHPRV decreases correspondingly. This study can provide some technical supports for achieving hydrogen decompression in FCEV when facing harsh working conditions, or help with dealing energy conversion during decompression process. • Demanding conditions are imposed on the pressure reducing system of hydrogen fuel cell electric vehicle. • Multi-stage high pressure reducing valve for hydrogen decompression is proposed. • Effects of different structural parameters on the internal flow characteristics are investigated. • A better hydrogen decompression process is achieved with the parametric results. [ABSTRACT FROM AUTHOR]

Hydrogen vehicles are already a reality, However, consumers will be reluctant to purchase hydrogen vehicles (or any other alternative fuel vehicle) if they do not perceive the existence of adequate refueling infrastructure that reduces the risk of running out of fuel regularly while commuting to acceptable levels. This fact leads to the need to study the minimum requirements in terms of fuel availability required by drivers to achieve a demand for hydrogen vehicles beyond potential early-adopters. This paper studies consumer preferences in relation to the design of urban hydrogen refueling infrastructure. To this end, the paper analyzes the results of a survey carried out in Andalusia, a region in southern Spain, on drivers' current refueling tendencies, their willingness to use hydrogen vehicles and their minimum requirements (maximum distance to be traveled to refuel and number of stations in the city) when establishing a network of hydrogen refueling stations in a city. The results show that consumers consider the existence in cities of an infrastructure with a number of refueling stations ranging from approximately 10 to 20% of the total number of conventional service stations as a requisite to trigger the switch to the use of hydrogen vehicles. In addition, these stations should be distributed in response to the drivers’ preferences to refuel close to home. [ABSTRACT FROM AUTHOR]

Zero-emission vehicle (ZEV) adoption is one of the critical solutions to decarbonize the transportation sector. Among the ZEV fleet in the US, battery electric vehicles (BEV) have been leading the market penetration. However, hydrogen fuel cell electric vehicles (FCEV) have also been increasingly adopted in recent years. Although both technologies have challenges with infrastructure, unlike BEVs that have multiple venues for charging (home, work or public), FCEVs rely solely on fueling at public hydrogen stations, and their availability is a significant factor before the vehicle purchase. Therefore, for the success of FCEV adoption, a need to monitor and understand the driver satisfaction of these stations is extremely critical. This research project introduces a quantitative-qualitative approach for continuous monitoring of hydrogen stations based on the station utilization patterns and to assess their preferability based on driver experiences. To illustrate a proof-of-concept, we collected the hourly utilization data of all the hydrogen fueling stations in California for three months. The time-series data was used to develop a capacity-independent term called "Normalized Relative Utilization Index" (NRUI) that encapsulates the utilization pattern of each station to a single metric. We spatially regressed this metric over the number of FCEVs present in the neighborhood to deduce the relationship. We designed a survey to obtain the refueling experiences of FCEV drivers, where about 100 participants responded with their station preferences. Their answers were used to validate the quantitative approach and identify a "Satisfactory Utilization Range" (SUR) of stations which are preferred by most drivers. Though this project illustrates the analysis of data collected over a small period, this approach is easily scalable with new station installations and can be implemented as a continuous monitoring system with real-time station utilization data. We believe this demand-focused approach could complement the existing supply-side monitoring methods on station performance to provide a smoother fueling experience to drivers. We are also releasing the hourly station capacity dataset that was collected as a part of this study to the research community. • Fuel cell electric vehicles (FCEV) are being increasingly adopted in California. • Important factor to FCEV adoption is the availability of hydrogen fueling stations. • Few studies have focused on understanding the driver preferences of fueling stations. • This paper introduces a novel approach to deduce preferability of fueling stations. • This approach supplements the current methods to deliver a satisfactory experience. [ABSTRACT FROM AUTHOR]

The substantial expansion of renewable energy sources is creating the foundation to successfully transform the German energy sector (the so-called ' Energiewende'). A by-product of this development is the corresponding capacity demand for the transportation, distribution and storage of energy. Hydrogen produced by electrolysis offers a promising solution to these challenges, although the willingness to invest in hydrogen technologies requires the identification of competitive and climate-friendly pathways in the long run. Therefore, this paper employs a pathway analysis to investigate the use of renewable hydrogen in the German passenger car transportation sector in terms of varying market penetration scenarios for fuel cell-electric vehicles (FCEVs). The investigation focuses on how an H 2 infrastructure can be designed on a national scale with various supply chain networks to establish robust pathways and important technologies, which has not yet been done. Therefore, the study includes all related aspects, from hydrogen production to fueling stations, for a given FCEV market penetration scenario, as well as the CO 2 reduction potential that can be achieved for the transport sector. A total of four scenarios are considered, estimating an FCEV market share of 1–75% by the year 2050. This corresponds to an annual production of 0.02–2.88 million tons of hydrogen. The findings show that the most cost-efficient H 2 supply (well-to-tank: 6.7–7.5 €/kg H2) can be achieved in high demand scenarios (FCEV market shares of 30% and 75%) through a combination of cavern storage and pipeline transport. For low-demand scenarios, however, technology pathways involving LH 2 and LOHC truck transport represent the most cost-efficient options (well-to-tank: 8.2–11.4 €/kg H2). • Pathway analysis to investigate the hydrogen use in fuel cell electric vehicles. • Hydrogen infrastructure design for production and distribution at lowest cost. • Systems investigation for a fuel cell electric vehicle market by the year 2050. • Cost-efficient high-demand hydrogen supply with gas caverns and pipelines. • Cost-efficient low-demand hydrogen supply with truck transport. [ABSTRACT FROM AUTHOR]

Hydrogen infrastructure for fueling vehicles has progressed in the last decade from stations with restricted access and limited operating hours to customer-friendly retail stations open to the public. There are now 121 retail hydrogen stations around the world. In California, the number of public retail hydrogen stations has increased from zero to more than 30 in less than two years, and the annual amount of hydrogen dispensed by retail stations has grown from 27,400 kg in 2015 to nearly 105,000 kg in 2016 and more than 440,000 kg in 2017—an increase of about four times year over year. For more than a decade, government, industry, and academia have studied many aspects of hydrogen infrastructure, from renewable hydrogen production to retail hydrogen station performance. This paper reviews the engineering and deployment of modern hydrogen infrastructure, including the costs, benefits, and operational considerations (including safety, reliability, availability), as well as challenges to the scale-up of hydrogen infrastructure. The results identify hydrogen station reliability as a key factor in the expense of operating hydrogen systems, placing it in the context of the larger reliability engineering field. • The number of retail hydrogen stations increased from zero to over 30 in 2 years. • In 2017 had a fourfold increase in dispensed hydrogen kilograms compared to 2016. • Hydrogen demand should increase exponentially based on the projected vehicle count. • Cost reduction efforts are needed to meet the target of less than $5/kg. • An average maintenance cost of $6/kg indicates a need for reliability improvements. [ABSTRACT FROM AUTHOR]

Abstract Nowadays, the development of hydrogen economy in the transportation sector is hindered by the principal barriers arising from the lack of adequate infrastructure and the small fleet of hydrogen-based road vehicles. This study investigates the potential of small-scale autonomous hydrogen refuelling stations with onsite production via an alkaline electrolysis apparatus powered by a small wind turbine. In this context, an urban area with promising wind resources has been selected. Based on the wind conditions and an indicative hydrogen demand for refuelling light-duty fuel cell electric vehicles such as bicycles, the sizing of the wind turbine and the electrolyser has been theoretically calculated. For supporting the daily hydrogen refuelling demand of the fuel cell electric bicycles, which is estimated at approximately 6 kg, it is calculated that a 50 kW wind turbine should be installed in order to power a 70 kW alkaline electrolyser for producing hydrogen. The capital cost of the hydrogen station is calculated at €248,130, while the retail price of the produced hydrogen is estimated to be more than 50.2 €/kg H2 in order to achieve a positive internal rate of return. Ultimately, the present paper aims at delivering a feasibility study of a small-scale H 2 refuelling station for fuel cell bicycles in order to provide investors with initiatives to implement such schemes in urban environments where problems of low air quality and high traffic are intense. Highlights • Assessment of a small-scale wind power based autonomous hydrogen refuelling station. • Total daily demand of hydrogen for fuel cell electric bicycles equals to 6.8 kg. • A 50 kW wind turbine powers an electrolyser of 70 kW to cover the demand. • The daily hydrogen demand is covered in 322 out of 366 days. • By having a hydrogen retail price of more than 51 €/kg, investment is profitable. [ABSTRACT FROM AUTHOR]

Abstract Hydrogen refuelling stations are important for achieving sustainable hydrogen economy in low carbon transport and fuel cell electric vehicles. The solution presented in this paper provides us with a technology for producing carbon dioxide free hydrogen, which is an approach that goes beyond the existing large-scale hydrogen production technologies that use fossil fuel reforming. Hence, the main goal of this work was to design a hydrogen refuelling station to secure the autonomy of a hydrogen powered bicycle. The bicycle hydrogen system is equipped with a proton exchange membrane fuel cell stack of 300 W, a DC/DC converter, and a metal hydride storage tank of 350 NL of hydrogen. The hydrogen power system was made of readily available commercial components. The hydrogen station was designed as an off-grid system in which the installed proton exchange membrane electrolyzer is supplied with electric energy by direct conversion using photovoltaic cells. With the hydrogen flow rate of 2000 cc min−1 the hydrogen station is expected to supply at least 5 bicycles to be used in 20 km long city tourist routes. Highlights • Design of autonomous HRS is registered under Original Registration 1999 Act. • The HRS is expected to supply 5 bicycles in 20 km long city tourist routes. • The bicycle travelled 66 km with 4.5 g of H 2 stored in the storage tank of 30 bars. • The average consumption was 0.0682 g of H 2 per kilometre. • Presented solar HRS and H 2 bicycle are expected to boost H 2 urban mobility. [ABSTRACT FROM AUTHOR]

Abstract Vehicular use of hydrogen is the first attempt to apply hydrogen energy in consumers' environment in large scale and has raised safety concerns in both public authorities and private bodies such as fire services and insurance companies. This paper analyzes typical accident progressions of hydrogen fuel cell vehicles in a road collision accident. Major hydrogen consequences including impinging jet fires and catastrophic tank ruptures are evaluated separately in terms of accident duration and hazard distances. Results show that in a 70 MPa fuel cell car accident, the hazards associated with hydrogen releases would normally last for no more than 1.5 min due to the empty of the tank. For the safety of general public, a perimeter of 100 m is suggested in the accident scene if no hissing sound is heard. However, the perimeter can be reduced to 10 m once the hissing sound of hydrogen release is heard. Furthermore, risks of fatalities, injuries, and damages are all quantified in financial terms to assess the impacts of the accident. Results show that costs of fatalities and injuries contribute most to the overall financial loss, indicating that the insurance premium of fatalities and injuries should be set higher than that of property loss. Highlights • Typical accident progressions of hydrogen car collision on road are analysed. • Duration and hazard distances of impinging jet fires under vehicle are evaluated. • Hazard distances from onboard hydrogen tank catastrophic rupture are suggested. • Risks of fatalities, injuries, and damages are all quantified in financial terms. [ABSTRACT FROM AUTHOR]

Abstract For the general public to use hydrogen as a vehicle fuel, they must be able to handle hydrogen with the same degree of confidence as conventional liquid and gaseous fuels. For refuelling hydrogen cars, hydrogen is stored at high pressures up to 700 bar. The hazards associated with jet releases from accidental leaks of such highly pressurized storage must be considered since a jet release and dispersion can result in a fire or explosion. Therefore, it is essential to understand the dispersion characteristics of hydrogen to determine the extent of the flammable cloud when released from a high-pressure source. These parameters are very important in the establishment of the safety distances and sizes of hazardous zones. This paper describes the work done by us in modelling of dispersion of accidental releases of hydrogen, using the FRED (Fire Explosion Release Dispersion) software. The dispersion module in FRED is validated against experimental data available in the open literature for steady release and dispersion of cold and ambient hydrogen gas. The validation is performed for a wide range of hole sizes (0.5–4 mm), pressure (1.7–400 bar) and temperature (50–298 K). The model predictions of hydrogen gas jet velocity, concentration decay as a function of distance as well as radial concentration distribution are in good agreement with experiments. Overall, it is concluded that FRED can accurately model accidental release and dispersion of hydrogen in unconfined and open configurations. Highlights • The dispersion module in FRED is validated against experimental data. • Validation is performed for a wide range of hole sizes, pressure and temperature. • Model predictions of hydrogen gas jet velocity, concentration decay as a function of distance. • FRED modelling validation results are in good agreement with experiments. [ABSTRACT FROM AUTHOR]

Abstract The application of fuel cells was an important approach for vehicle industry to deal with the challenges of Energy shortage and environment pollution caused by traditional power machines. Fuel cells, which generate power and torque with zero emissions and high efficiency, are considered as an promising future power machine for vehicles. This paper reviewed previous research model and method for fuel cell, effect of state parameters and structural parameters on the performance of fuel cell，power density and life cycle of fuel cell systems in recent years，Prospected development and application of fuel cell system in the future. [ABSTRACT FROM AUTHOR]