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Modern energy systems are large distributed systems and, as a rule, contain energy storage systems and, in particular, hydrogen batteries and hydrogen production systems. The use of hydrogen for energy transportation has recently been actively studied in a number of scientific projects. To ensure continuous operation of instrumentation and control equipment on long hydrogen pipelines (gas and cryogenic), it is important to ensure constant autonomous power supply to these systems. This can be solved using micromechanical energy microgeneration systems for the uninterrupted operation of various sensors, which are installed in large numbers on almost all elements of the structure and infrastructure. In addition, an important area of scientific research is the revision of the concepts and appearance of traditional devices of modern renewable energy: windmills, solar cells, turbines, etc. Fundamentally new energy devices are on the agenda, capable of recovering mechanical energy of any power and supplying it to the consumer in the form of a given specific energy flow. Collection of chaotically distributed natural energy of the environment (mechanical energy in the form of: vibrations, acoustic vibrations, wave energy, gusts of wind, tornadoes, precipitation, vibrations of the earth's crust, etc.), as well as collection of dissipated energy from artificial sources (iron and automobile highways, airstrips, spaceports, production facilities, etc.) with the help of mechanical microgenerators will allow the recovery and conversion of mechanical energy of various powers, including low power, into a universal energy carrier - hydrogen. Mechanical vibrations of artificial origin are of particular interest due to their widespread use for domestic and industrial purposes in a wide range of vibrations. The energy of mechanical vibrations can be collected and converted into electrical energy using piezoelectric, electromagnetic, triboelectric or electrostatic (capacitive) energy converters. Electrostatic microelectromechanical energy converters are considered the most promising among other energy converters, since their manufacturing processes are based on standard technology for the production of integrated circuits and microelectromechanical systems. Energy conversion by an electrostatic converter is carried out due to an external mechanical force that does work against the force of attraction of the charged electrodes of a variable capacitor. To transfer the received electrical energy to the load of the consuming device, the electrostatic converter is connected to the corresponding electrical circuits (conditioning circuits). Such a system as a whole is a kind of microgenerator or energy collector. Microenergy flow recovery systems integrated into large energy systems will ensure the collection and recovery of significant amounts of energy for remote energy consumers. At the same time, the concept of a distributed mechanical energy recovery system is quite simple: a mechanical energy receiver - a converter into electrical energy - a preliminary electrical storage device - an energy distributor - an electric energy accumulator - an electrolyser - a hydrogen accumulator - a fuel cell. To optimize the operation of the working circuit, including preliminary electrical systems for energy storage and conversion: capacitors and electric energy accumulators, electrolyzers; To ensure their durability and reliability, flexible automatic control of electrical power distribution is necessary. The real work was done to solve that problem. In addition, for extended and large power facilities it is important to ensure widespread sensory control of system parameters. At the same time, if all sensors receive power from an autonomous energy-generating device, then the costs of creating extended communications for instrumentation will be sharply reduced. In addition, the reliability of the control system will significantly increase. The results of studying operation features of a kinetic microgenerator with reduced output voltage are presented. The performance of a multi-stage modified Bennet doubler is compared to a system including a two-stage modified Bennet doubler and a diode-capacitor voltage divider. It is shown that with an increase of the number of stages in the modified Bennet doubler, the conversion of mechanical energy into electrical energy becomes less and less efficient. At the same time, for achieving the maximum energy accumulation rate (power), a two-stage power amplifier based on the Bennet doubler is preferable. It is established that when analyzing the operation of a diode-capacitor voltage divider, it is necessary to take into account the intrinsic (reverse) capacitances of the discharging diodes affecting the divider operation significantly. The divider behavior features while changing the load resistance and the intrinsic capacitances of the discharge diodes are found and analyzed. Analytical expressions linking the main characteristics of the microgenerator as a whole with the parameters of the electronic components used are derived. It is shown that for expanding the range of the "correct" division of the divider, it is necessary to use discharge diodes with minimal intrinsic capacitances, and also that connecting a load to the Bennet doubler as a voltage divider changes the permissible capacitance modulation depth of the variable capacitor. This paper examines the concepts of creating large energy-generating flows based on arrays of micromechanical energy converters placed on optimal energy-efficient receiving surfaces and analyzes the issues of cryogenic production, storage, consumption and transportation of hydrogen. Stationary and mobile cryogenic storage systems for hydrogen are considered. Much attention is paid to the safety of large cryogenic and gas hydrogen systems. [ABSTRACT FROM AUTHOR]

Hydrogen is called to play a vital role in the future decarbonization of the electricity industry. Among its multiple applications, this energy carrier may improve the energy storage, replacing or complementing the traditional battery banks thanks to its higher energy density. However, the low efficiency and cost of associated devices as well as the difficulty in transport make unfeasible the implantation of hydrogen storage systems at the residential level. However, emerging paradigms like energy communities may change this concept making viable the installation of hydrogen chains in the domestic sector. This paper focuses on day-ahead scheduling of energy communities with integrated collective hydrogen storage system. To this end, a three-stage methodology is developed in which the first level is focused on individual home energy management, the second level handles with peer-to-peer energy trading among prosumers and the last level determines the energy exchanging profile with the utility grid accounting with the hydrogen chain. To handle with uncertainties from renewable sources, demand and energy price, the Information Gap Decision Theory (IGDT) is employed, by which an uncertainty-aware scheduling program can be obtained minimizing the negative effects of uncertain parameters. A case study is performed on a six-prosumer energy community with electrolysis, hydrogen vessel and fuel-cell, allowing both purchasing and selling energy with the grid. The results serve to prove the effectiveness of the developed methodology as well as demonstrate the possible impact of unknowns in energy community operation, and how the hydrogen chain can help to improve the economy and self-sufficiency of the system. • A three-level operating strategy for ECs is proposed. • A multi-stage methodology for day-ahead scheduling of ECs with collective HSS is developed. • Uncertainties from renewable generation and demand are treated using IGDT. • The impact of uncertainties in the operation of ECs is discussed. • The role of HSS in improving the economy of the community is highlighted. [ABSTRACT FROM AUTHOR]

We report modeling results for hydrogen releases associated with deploying hydrogen fuel cell technology on vessels. This first paper (I) considers hydrogen releases through the vessel Vent Mast from 250-bar hydrogen gas storage tanks, the type of tanks being used for the first hydrogen vessels. A manifolded 10-tank hydrogen storage system, holding 278 kg of hydrogen, can be emptied in ∼10 min for maintenance purposes, with a pressure reduction to half the original pressure (125 bar) realized in 2 min if a rapid pressure reduction is needed, for example in the event of a fire. The time profile for filling a tank is also of interest so as not to exceed the tank thermal limits. The calculations show that a manifolded 10-tank array can be filled with hydrogen to 250-bar pressure in ∼2 h from a 350-bar hydrogen refueling trailer without exceeding the 85 °C temperature limit typical of Type IV hydrogen tanks. Computational fluid dynamic (CFD) modeling shows that when the hydrogen is released out of the 10-tank array and into the Vent Mast in a 5-mph wind blowing horizontally, the effect of the wind on the hydrogen dispersion strongly depends on the hydrogen exit speed. For high release speeds (∼800–900 m/s), the hydrogen flow is strongly momentum-driven, and there is modest cross-wind influence. For low hydrogen exit speeds (∼10 m/s), the hydrogen is readily entrained in the wind flow and blown sideways, with the downstream flammable envelope rising at a positive angle to the horizontal due to buoyancy. To capture the influence of a wind with a downward component (e.g., created by a downdraft near a building), a calculation of a low-velocity (8.6 m/s) hydrogen release was performed with a 5-mph wind pointed downward at a 45° angle. The results show that despite the buoyancy of hydrogen, the wind blows the hydrogen substantially downward for low hydrogen speeds exiting the Vent Mast. • A manifolded 250-bar, 278 kg hydrogen storage system can be emptied in ∼10 min. • A high-velocity hydrogen flow out of a Vent Mast is momentum-driven with modest cross-wind influence. • A low-velocity hydrogen flow out of a Vent Mast is readily entrained in prevailing winds. [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 incorporation of Fuel Cell Electric Vehicles (FCEVs) in public transport is a fundamental step towards the minimization of the emissions due to transportation globally. In-depth studies are required regarding the potential risk from the storage of hydrogen, the transportation of hydrogen to refuelling stations and the refuelling procedure. Thus, it is a prerequisite to establish a holistic baseline which is related to FCEV safety during operation/maintenance, especially to a country in which the sales of these types of vehicles are significantly low. This paper suggests the employment of operational risk management methodology. Relevant experts and stakeholders requested to fill out an "Event-Probability Matrix" per scenario of likely hazards. This research estimates the interest of the local society about technological hazards and the conviction that hydrogen vehicles could be as safe as conventional vehicles. Additional critical scenarios related to the hydrogen storage are analyzed. • A holistic viewpoint for Risk Assessment of an FCEV introduction is presented. • Hazards in 4 stages in the FCEV lifecycle were categorized and assessed. • Storage and the transportation of the hydrogen can be considered a safe procedure. • The risk from human-made hazards could be considered negligible. • Moderate hazards are intended to be eliminated in the near future. [ABSTRACT FROM AUTHOR]

The paper provides brief introduction to the National South African Program, branded HySA (Hydrogen South Africa) as well as discusses potential business cases for deployment of hydrogen and fuel cell technology in South Africa. This paper also describes some key activities in the area of hydrogen production and storage within HySA Infrastructure Center of Competence in South Africa. The content of this paper is based on the presentation given during the recent WHEC 2016 Congress in Zaragoza, Spain. More specifically, the discussion of activities at HySA Infrastructure Center of Competence in the paper includes hydrogen production and storage. [ABSTRACT FROM AUTHOR]

In contrast to current petrol engines, fuel cell vehicles require much higher purity fuel during operation to prevent degradation of the fuel cell system. ISO 14687-2 provides a list of 13 different impurities with associated maximum limits that must not be exceeded when providing hydrogen to a fuel cell vehicle. This paper provides a summary of the offline, online and impurity enrichment techniques that can be used for performing quality assurance of fuel cell hydrogen. As a large number of hydrogen refuelling stations are expected to be installed across the globe in the near future, it is not likely that robust purity analysis can be carried out for all hydrogen provided to fuel cell vehicles as a full analysis as specified in ISO 14687-2 can only be performed by a few advanced gas laboratories around the world. Therefore, in addition to summarising analytical methods for hydrogen purity analysis, this paper will propose potential solutions for meeting these anticipated demands for quality assurance. [ABSTRACT FROM AUTHOR]

The demand for clean power source which can be used to run the various types of vehicles on the road is increasing on a daily basis due to the fact that high emissions released from internal combustion engine play a significant role in air pollution and climate change. Fuel cell devices, particularly Proton Exchange Membrane (PEM) type, are strong candidates to replace the internal combustion engines in the transport industry. The PEMFC technology still has many challenges including high cost, low durability and hydrogen storage problems which limit the wide-world commercialization of this technology. In this paper, the fuel cell cost, durability and performances challenges which are associated with using of fuel cell technology for transport applications are detailed and reviewed. Recent developments that deal with the proposed challenges are reported. Furthermore, problems of hydrogen infrastructure and hydrogen storage in the fuel cell vehicle are discussed. [ABSTRACT FROM AUTHOR]

Abstract: The study of compressed hydrogen releases from high-pressure storage systems has practical application for hydrogen and fuel cell technologies. Such releases may occur either due to accidental damage to a storage tank, connecting piping, or due to failure of a pressure release device (PRD). Understanding hydrogen behavior during and after the unintended release from a high-pressure storage device is important for development of appropriate hydrogen safety codes and standards and for the evaluation of risk mitigation requirements and technologies. In this paper, the natural and forced mixing and dispersion of hydrogen released from a high-pressure tank into a partially enclosed compartment is investigated using analytical models. Simple models are developed to estimate the volumetric flow rate through a choked nozzle of a high-pressure tank. The hydrogen released in the compartment is vented through buoyancy induced flow or through forced ventilation. The model is useful in understanding the important physical processes involved during the release and dispersion of hydrogen from a high-pressure tank into a compartment with vents at multiple levels. Parametric studies are presented to identify the relative importance of various parameters such as diameter of the release port and air changes per hour (ACH) characteristic of the enclosure. Compartment overpressure as a function of the size of the release port is predicted. Conditions that can lead to major damage of the compartment due to overpressure are identified. Results of the analytical model indicate that the fastest way to reduce flammable levels of hydrogen concentration in a compartment is by blowing through the vents. Model predictions for forced ventilation are presented which show that it is feasible to effectively and rapidly reduce the flammable concentration of hydrogen in the compartment following the release of hydrogen from a high-pressure tank. [Copyright &y& Elsevier]

Abstract: On-board hydrogen storage systems employing high-pressure metal hydrides promise advantages including high volumetric capacities and cold start capability. In this paper, we discuss the development of a system simulation model in Matlab/Simulink platform. Transient equations for mass balance and energy balance are presented. Appropriate kinetic expressions are used for the absorption/desorption reactions for the Ti1.1CrMn metal hydride. During refueling, the bed is cooled by passing a coolant through tubes embedded within the bed while during driving, the bed is heated by pumping the radiator fluid through same set of tubes. The feasibility of using a high-pressure metal hydride storage system for automotive applications is discussed. Drive cycle simulations for a fuel cell vehicle are performed and detailed results are presented. [ABSTRACT FROM AUTHOR]

Abstract: Odorants have been proposed as a reliable, inexpensive means to enable leak detection for hydrogen systems and increase public safety. However, traditional odorants cause problems for fuel cell systems. This paper examines the use of odorants for fuel cell systems, including the hydrogen storage. Current odorants and potential odorants have negative impacts on fuel cell performance. Odorants also appear to be problematic for most of the advanced hydrogen storage options. If odorants are used, the odorants will probably need to be removed from the hydrogen prior to the storage medium. Current hydrogen detectors are more reliable than the odorant–human detection system and should provide increased safety. [Copyright &y& Elsevier]