France
Allowable Hydrogen Permeation Rate From Road Vehicle Compressed Gaseous Storage Systems In Garages- Part 1- Introduction, Scenarios, and Estimation of an Allowable Permeation Rate
Sep 2009
Publication
The paper presents an overview of the main results of the EC NOE HySafe activity to estimate an allowable hydrogen permeation rate for automotive legal requirements and standards. The work was undertaken as part of the HySafe internal project InsHyde.<br/>A slow long term hydrogen release such as that due to permeation from a vehicle into an inadequately ventilated enclosed structure is a potential risk associated with the use of hydrogen in automotive applications. Due to its small molecular size hydrogen permeates through the containment materials found in compressed gaseous hydrogen storage systems and is an issue that requires consideration for containers with non-metallic (polymer) liners. Permeation from compressed gaseous hydrogen storage systems is a current hydrogen safety topic relevant to regulatory and standardisation activities at both global and regional levels.<br/>Various rates have been proposed in different draft legal requirements and standards based on different scenarios and the assumption that hydrogen dispenses homogeneously. This paper focuses on the development of a methodology by HySafe Partners (CEA NCSRD. University of Ulster and Volvo Technology) to estimate an allowable upper limit for hydrogen permeation in automotive applications by investigating the behaviour of hydrogen when released at small rates with a focus on European scenario. The background to the activity is explained. reasonable scenarios are identified a methodology proposed and a maximum hydrogen permeation rate from road vehicles into enclosed structures is estimated The work is based on conclusions from the experimental and numerical investigations described by CEA NCSRD and the University of Ulster in related papers.
Comparisons of Helium and Hydrogen Releases in 1 M3 and 2 M3 Two Vents Enclosures: Concentration Measurements at Different Flow Rates and for Two Diameters of Injection Nozzle
Oct 2015
Publication
This work presents a parametric study on the similitude between hydrogen and helium distribution when released in the air by a source located inside of a naturally ventilated enclosure with two vents. Several configurations were experimentally addressed in order to improve knowledge on dispersion. Parameters were chosen to mimic operating conditions of hydrogen energy systems. Thus the varying parameters of the study were mainly the source diameter the releasing flow rate the volume and the geometry of the enclosure. Two different experimental set-ups were used in order to vary the enclosure's height between 1 and 2 m. Experimental results obtained with helium and hydrogen were compared at equivalent flow rates determined with existing similitude laws. It appears for the plume release case that helium can suitably be used for predicting hydrogen dispersion in these operating designs. On the other hand – when the flow turns into a jet – non negligible differences between hydrogen and helium dispersion appear. In this case helium – used as a direct substitute to hydrogen – will over predict concentrations we would get with hydrogen. Therefore helium concentration read-outs should be converted to obtain correct predictions for hydrogen. However such a converting law is not available yet.
Cell Failure Mechanisms in PEM Water Electrolyzers
Sep 2011
Publication
PEM water electrolysis offers an efficient and flexible way to produce “green-hydrogen” from renewable (intermittent) energy sources. Most research papers published in the open literature on the subject are addressing performances issues and to date very few information is available concerning the mechanisms of performance degradation and the associated consequences. Results reported in this communication have been used to analyze the failure mechanisms of PEM water electrolysis cells which can ultimately lead to the destruction of the electrolyzer. A two-step process involving firstly the local perforation of the solid polymer electrolyte followed secondly by the catalytic recombination of hydrogen and oxygen stored in the electrolysis compartments has been evidenced. The conditions leading to the onset of such mechanism are discussed and some preventive measures are proposed to avoid accidents.
Genome-wide Transcriptome Analysis of Hydrogen Production in the Cyanobacterium Synechocystis: Towards the Identification of New Players
Dec 2012
Publication
We report the development of new tools and methods for facile integration and meaningful representation of high throughput data generated by genome-wide analyses of the model cyanobacterium Synechocystis PCC6803 for future genetic engineering aiming at increasing its level of hydrogen photoproduction. These robust tools comprise new oligonucleotide DNA microarrays to monitor the transcriptomic responses of all 3725 genes of Synechocystis and the SVGMapping method and custom-made templates to represent the metabolic reprogramming for improved hydrogen production. We show for the first time that the AbrB2 repressor of the hydrogenase-encoding operon also regulates metal transport and protection against oxidative stress as well as numerous plasmid genes which have been overlooked so far. This report will stimulate the construction and global analysis of hydrogen production mutants with the prospect of developing powerful cell factories for the sustainable production of hydrogen as well as investigations of the probable role of plasmids in this process.
Indoor Use of Hydrogen, Knowledge Gaps and Priorities for the Improvement of Current Standards on Hydrogen, a Presentation of HyIndoor European Project
Sep 2013
Publication
To develop safety strategies for the use of hydrogen indoors the HyIndoor project is studying the behaviour of a hydrogen release deflagration or non-premixed flame in an enclosed space such as a fuel cell or its cabinet a room or a warehouse. The paper proposes a safety approach based on safety objectives that can be used to take various scenarios of hydrogen leaks into account for the safe design of Hydrogen and Fuel Cell (HFC) early market applications. Knowledge gaps on current engineering models and unknown influence of specific parameters were identified and prioritized thereby re-focusing the objectives of the project test campaign and numerical simulations. This approach will enable the improvement of the specification of openings and use of hydrogen sensors for enclosed spaces. The results will be disseminated to all stakeholders including hydrogen industry and RCS bodies.
Autonomous Hydrogen Production for Proton Exchange Membrane Fuel Cells PEMFC
Apr 2020
Publication
This paper focuses on hydrogen production for green mobility applications (other applications are currently under investigation). Firstly a brief state of the art of hydrogen generation by hydrolysis with magnesium is shown. The hydrolysis performance of Magnesium powder ball–milled along with different additives (graphite and transition metals TM = Ni Fe and Al) is taken for comparison. The best performance was observed with Mg–10 wt.% g mixtures (95% of theoretical hydrogen generation yield in about 3 min). An efficient solution to control this hydrolysis reaction is proposed to produce hydrogen on demand and to feed a PEM fuel cell. Tests on a bench fitted with a 100 W Proton Exchange Membrane (PEM) fuel cell have demonstrated the technological potential of this solution for electric assistance applications in the field of light mobility.
Strategies for the Sampling of Hydrogen at Refuelling Stations for Purity Assessment
Aug 2021
Publication
Hydrogen delivered at hydrogen refuelling station must be compliant with requirements stated in different standards which require specialized sampling device and personnel to operate it. Currently different strategies are implemented in different parts of the world and these strategies have already been used to perform 100s of hydrogen fuel sampling in USA EU and Japan. However these strategies have never been compared on a large systematic study. The purpose of this paper is to describe and compare the different strategies for sampling hydrogen at the nozzle and summarize the key aspects of all the existing hydrogen fuel sampling including discussion on material compatibility with the impurities that must be assessed. This review highlights the fact it is currently difficult to evaluate the impact or the difference these strategies would have on the hydrogen fuel quality assessment. Therefore comparative sampling studies are required to evaluate the equivalence between the different sampling strategies. This is the first step to support the standardization of hydrogen fuel sampling and to identify future research and development area for hydrogen fuel sampling.
Investigations on Pressure Dependence of Coriolis Mass Flow Meters Used at Hydrogen Refueling Stations
Sep 2020
Publication
In the framework of the ongoing EMPIR JRP 16ENG01 ‘‘Metrology for Hydrogen Vehicles’’ a main task is to investigate the influence of pressure on the measurement accuracy of Coriolis Mass Flow Meters (CFM) used at Hydrogen Refueling Stations (HRS). At a HRS hydrogen is transferred at very high and changing pressures with simultaneously varying flow rates and temperatures. It is clearly very difficult for CFMs to achieve the current legal requirements with respect to mass flow measurement accuracy at these measurement conditions. As a result of the very dynamic filling process it was observed that the accuracy of mass flow measurement at different pressure ranges is not sufficient. At higher pressures it was found that particularly short refueling times cause significant measurement deviations. On this background it may be concluded that pressure has a great impact on the accuracy of mass flow measurement. To gain a deeper understanding of this matter RISE has built a unique high-pressure test facility. With the aid of this newly developed test rig it is possible to calibrate CFMs over a wide pressure and flow range with water or base oils as test medium. The test rig allows calibration measurements under the conditions prevailing at a 70 MPa HRS regarding mass flows (up to 3.6 kg min−1) and pressures (up to 87.5 MPa).
CFD Simulations of the Refueling of Long Horizontal H2 Tanks
Sep 2021
Publication
The understanding of physical phenomena occurring during the refueling of H2 tanks used for hydrogen mobility applications is the key point towards the most optimal refueling protocol. A lot of experimental investigations on tank refueling were performed in the previous years for different types and sizes of tank. Several operating conditions were tested through these experiments. For instance the HyTransfer project gave one of the major outputs on the understanding of the physical phenomena occurring during a tank refueling. From a numerical perspective the availability of accurate numerical tools is another key point. Such tools could be used instead of the experimental set-ups to test various operating conditions or new designs of tanks and injectors. The use of these tools can reduce the cost of the refueling protocol development in the future. However they first need to be validated versus experimental data. This work is dedicated to CFD (Computational Fluid Dynamics) modeling of the hydrogen refueling of a long horizontal 530L type IV tank. As of now the number of available CFD simulations for such a large tank is low as the computational cost is significant which is often considered as a bottleneck for this approach. The simulated operating conditions correspond to one of the experimental campaigns performed in the framework of the HyTransfer project. The 3D CFD model is presented. In a first validation step the CFD results are compared with experimental data. Then a deeper insight into the physics predicted by the CFD is provided. Finally two other methodologies with the aim to reduce the computational cost have been tested.
Numerical Redesign of 100kw MGT Combustor for 100% H2 Fueling
Jan 2014
Publication
The use of hydrogen as energy carrier in a low emission microturbine could be an interesting option for renewable energy storage distributed generation and combined heat & power. However the hydrogen using in gas turbine is limited by the NOx emissions and the difficulty to operate safely. CFD simulations represent a powerful and mature tool to perform detailed 3-D investigation for the development of a prototype before carrying out an experimental analysis. This paper describes the CFD supported redesign of the Turbec T100 microturbine combustion chamber natural gas-fired to allow the operation on 100% hydrogen.
Investigation of an Intensified Thermo-Chemical Experimental Set-Up for Hydrogen Production from Biomass: Gasification Process Integrated to a Portable Purification System—Part II
Jun 2022
Publication
Biomass gasification is a versatile thermochemical process that can be used for direct energy applications and the production of advanced liquid and gaseous energy carriers. In the present work the results are presented concerning the H2 production at a high purity grade from biomass feedstocks via steam/oxygen gasification. The data demonstrating such a process chain were collected at an innovative gasification prototype plant coupled to a portable purification system (PPS). The overall integration was designed for gas conditioning and purification to hydrogen. By using almond shells as the biomass feedstock from a product gas with an average and stable composition of 40%-v H2 21%-v CO 35%-v CO2 2.5%-v CH4 the PPS unit provided a hydrogen stream with a final concentration of 99.99%-v and a gas yield of 66.4%.
Control of a Three-Phase Current Source Rectifier for H2 Storage Applications in AC Microgrids
Mar 2022
Publication
The share of electrical energy from renewable sources has increased considerably in recent years in an attempt to reduce greenhouse gas emissions. To mitigate the uncertainties of these sources and to balance energy production with consumption an energy storage system (ESS) based on water electrolysis to produce hydrogen is studied. It can be applied to AC microgrids where several renewable energy sources and several loads may be connected which is the focus of the study. When excess electricity production is converted into hydrogen via water electrolysis low DC voltages and high currents are applied which needs specific power converters. The use of a three-phase buck-type current source converter in a single conversion stage allows for an adjustable DC voltage to be obtained at the terminals of the electrolyzer from a three-phase AC microgrid. The voltage control is preferred to the current control in order to improve the durability of the system. The classical control of the buck-type rectifier is generally done using two loops that correspond only to the control of its output variables. The lack of control of the input variables may generate oscillations of the grid current. Our contribution in this article is to propose a new control for the buck-type rectifier that controls both the input and output variables of the converter to avoid these grid current oscillations without the use of active damping methods. The suggested control method is based on an approach using the flatness properties of differential systems: it ensures the large-signal stability of the converter. The proposed control shows better results than the classical control especially in oscillation mitigation and dynamic performances with respect to the rejection of disturbances caused by a load step.
Design of Gravimetric Primary Standards for Field-testing of Hydrogen Refuelling Stations
Apr 2020
Publication
The Federal Institute of Metrology METAS developed a Hydrogen Field Test Standard (HFTS) that can be used for field verification and calibration of hydrogen refuelling stations. The testing method is based on the gravimetric principle. The experimental design of the HFTS as well as the description of the method are presented here.
Worst Case Scenario for Delayed Explosion of Hydrogen Jets at a High Pressure: Ignition Position
Sep 2021
Publication
Delayed explosion of free field hydrogen releases at a high pressure is subject of multiple investigation performed by various authors in the past years. These studied considered various parameters such as pressures flow rates etc. and their influence on the resulting overpressure. However the influence of the ignition position on the maximum overpressure was not fully explored. Current investigation addressed by computational fluid dynamics (CFD) simulations and experimental measurement fills this gap. This work demonstrates that the ignition positions corresponding to 55%-65% of H2/air mixture give the maximum overpressure. This observation initially observed numerically and afterword confirmed experimentally. A simple model is also suggested.
Materials for Hydrogen-based Energy Storage - Past, Recent Progress and Future Outlook
Dec 2019
Publication
Michael Hirscher,
Volodymyr A. Yartys,
Marcello Baricco,
José Bellosta von Colbe,
Didier Blanchard,
Robert C. Bowman Jr.,
Darren P. Broom,
Craig Buckley,
Fei Chang,
Ping Chen,
Young Whan Cho,
Jean-Claude Crivello,
Fermin Cuevas,
William I. F. David,
Petra E. de Jongh,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
Yaroslav Filinchuk,
George E. Froudakis,
David M. Grant,
Evan MacA. Gray,
Bjørn Christian Hauback,
Teng He,
Terry D. Humphries,
Torben R. Jensen,
Sangryun Kim,
Yoshitsugu Kojima,
Michel Latroche,
Hai-wen Li,
Mykhaylo V. Lototskyy,
Joshua W. Makepeace,
Kasper T. Møller,
Lubna Naheed,
Peter Ngene,
Dag Noreus,
Magnus Moe Nygård,
Shin-ichi Orimo,
Mark Paskevicius,
Luca Pasquini,
Dorthe B. Ravnsbæk,
M. Veronica Sofianos,
Terrence J. Udovic,
Tejs Vegge,
Gavin Walker,
Colin Webb,
Claudia Weidenthaler and
Claudia Zlotea
Globally the accelerating use of renewable energy sources enabled by increased efficiencies and reduced costs and driven by the need to mitigate the effects of climate change has significantly increased research in the areas of renewable energy production storage distribution and end-use. Central to this discussion is the use of hydrogen as a clean efficient energy vector for energy storage. This review by experts of Task 32 “Hydrogen-based Energy Storage” of the International Energy Agency Hydrogen TCP reports on the development over the last 6 years of hydrogen storage materials methods and techniques including electrochemical and thermal storage systems. An overview is given on the background to the various methods the current state of development and the future prospects. The following areas are covered; porous materials liquid hydrogen carriers complex hydrides intermetallic hydrides electro-chemical storage of energy thermal energy storage hydrogen energy systems and an outlook is presented for future prospects and research on hydrogen-based energy storage
Technologies and Policies to Decarbonize Global Industry: Review and Assessment of Mitigation Drivers Through 2070
Mar 2020
Publication
Jeffrey Rissman,
Chris Bataille,
Eric Masanet,
Nate Aden,
William R. Morrow III,
Nan Zhou,
Neal Elliott,
Rebecca Dell,
Niko Heeren,
Brigitta Huckestein,
Joe Cresko,
Sabbie A. Miller,
Joyashree Roy,
Paul Fennell,
Betty Cremmins,
Thomas Koch Blank,
David Hone,
Ellen D. Williams,
Stephane de la Rue du Can,
Bill Sisson,
Mike Williams,
John Katzenberger,
Dallas Burtraw,
Girish Sethi,
He Ping,
David Danielson,
Hongyou Lu,
Tom Lorber,
Jens Dinkel and
Jonas Helseth
Fully decarbonizing global industry is essential to achieving climate stabilization and reaching net zero greenhouse gas emissions by 2050–2070 is necessary to limit global warming to 2 °C. This paper assembles and evaluates technical and policy interventions both on the supply side and on the demand side. It identifies measures that employed together can achieve net zero industrial emissions in the required timeframe. Key supply-side technologies include energy efficiency (especially at the system level) carbon capture electrification and zero-carbon hydrogen as a heat source and chemical feedstock. There are also promising technologies specific to each of the three top-emitting industries: cement iron & steel and chemicals & plastics. These include cement admixtures and alternative chemistries several technological routes for zero-carbon steelmaking and novel chemical catalysts and separation technologies. Crucial demand-side approaches include material-efficient design reductions in material waste substituting low-carbon for high-carbon materials and circular economy interventions (such as improving product longevity reusability ease of refurbishment and recyclability). Strategic well-designed policy can accelerate innovation and provide incentives for technology deployment. High-value policies include carbon pricing with border adjustments or other price signals; robust government support for research development and deployment; and energy efficiency or emissions standards. These core policies should be supported by labeling and government procurement of low-carbon products data collection and disclosure requirements and recycling incentives. In implementing these policies care must be taken to ensure a just transition for displaced workers and affected communities. Similarly decarbonization must complement the human and economic development of low- and middle-income countries.
The Challenges of Hydrogen Storage on a Large Scale
Sep 2021
Publication
With the growing success of green hydrogen the general trend is for increased hydrogen production and large quantities of storage. Engie’s projects have grown from a few kilos of hydrogen to the quest for large scale production and associated storage – e.g. several tons or tens of tons. Although a positive sign for Engie’s projects it does inevitably result in challenges in new storage methods and in risks management related to such facilities; particularly with hydrogen facilities being increasingly placed in the vicinity of general public sites. For example a leak on hydrogen storage can generate significant thermal and overpressure effects on surrounding people/facilities in the event of ignition. Firewalls can be installed to protect individuals / infrastructure from thermal effects but the adverse result is that this solution can increase the violence of an explosion in case of delayed ignition or confinement. The manner of emergency intervention on a pool fire of hydrogen is also totally different from intervention on compressed gaseous hydrogen. The first part of this presentation will explain different means to store hydrogen in large quantities. The second part will present for each storage the specific risks generated. The third and final part will explain how these risks can be addressed on a technical point of view by safety devices or by other solutions (separation distance passive/active means …).
Using Additives to Control the Decomposition Temperature of Sodium Borohydride
May 2020
Publication
Hydrogen (H2) shows great promise as zero-carbon emission fuel but there are several challenges to overcome in regards to storage and transportation to make it a more universal energy solution. Gaseous hydrogen requires high pressures and large volume tanks while storage of liquid hydrogen requires cryogenic temperatures; neither option is ideal due to cost and the hazards involved. Storage in the solid state presents an attractive alternative and can meet the U.S. Department of Energy (DOE) constraints to find materials containing > 7 % H2 (gravimetric weight) with a maximum H2 release under 125 °C.
While there are many candidate hydrogen storage materials the vast majority are metal hydrides. Of the hydrides this review focuses solely on sodium borohydride (NaBH4) which is often not covered in other hydride reviews. However as it contains 10.6% (by weight) H2 that can release at 133 ± 3 JK−1mol−1 this inexpensive material has received renewed attention. NaBH4 should decompose to H2g) Na(s) and B(s) and could be recycled into its original form. Unfortunately metal to ligand charge transfer in NaBH4 induces high thermodynamic stability creating a high decomposition temperature of 530 °C. In an effort make H2 more accessible at lower temperatures researchers have incorporated additives to destabilize the structure.
This review highlights metal additives that have successfully reduced the decomposition temperature of NaBH4 with temperatures ranging from 522 °C (titanium (IV) fluoride) to 379 °C (niobium (V) fluoride). We describe synthetic methods employed chemical pathways taken and the challenges of boron derivative formation on H2 cycling. Though no trends can be found across all additives it is our hope that compiling the data here will enable researchers to gain a better understanding of the additives’ influence and to determine how a new system might be designed to make NaBH4 a more viable H2 fuel source.
While there are many candidate hydrogen storage materials the vast majority are metal hydrides. Of the hydrides this review focuses solely on sodium borohydride (NaBH4) which is often not covered in other hydride reviews. However as it contains 10.6% (by weight) H2 that can release at 133 ± 3 JK−1mol−1 this inexpensive material has received renewed attention. NaBH4 should decompose to H2g) Na(s) and B(s) and could be recycled into its original form. Unfortunately metal to ligand charge transfer in NaBH4 induces high thermodynamic stability creating a high decomposition temperature of 530 °C. In an effort make H2 more accessible at lower temperatures researchers have incorporated additives to destabilize the structure.
This review highlights metal additives that have successfully reduced the decomposition temperature of NaBH4 with temperatures ranging from 522 °C (titanium (IV) fluoride) to 379 °C (niobium (V) fluoride). We describe synthetic methods employed chemical pathways taken and the challenges of boron derivative formation on H2 cycling. Though no trends can be found across all additives it is our hope that compiling the data here will enable researchers to gain a better understanding of the additives’ influence and to determine how a new system might be designed to make NaBH4 a more viable H2 fuel source.
CFD Simulations of Large Scale LH2 Dispersion in Open Environment
Sep 2021
Publication
An inter-comparison among partners’ CFD simulations has been carried out within the EU-funded project PRESLHY to investigate the dispersion of the mixture cloud formed from large scale liquid hydrogen release. Rainout experiments performed by Health and Safety Executive (HSE) have been chosen for the work. From the HSE experimental series trial-11 was selected forsimulation due to its conditions where only liquid flow at the nozzle was achieved. During trial-11 liquid hydrogen is spilled horizontally 0.5 m above a concrete pad from a 5 barg tank pressure through a 12 mm (1/2 inch) nozzle. The dispersion takes place outdoors and thus it is imposed to variant wind conditions. Comparison of the CFD results with the measurements at several sensors is presented and useful conclusions are drawn.
Hydrogen Energy Systems: A Critical Review of Technologies, Applications, Trends and Challenges
May 2021
Publication
The global energy transition towards a carbon neutral society requires a profound transformation of electricity generation and consumption as well as of electric power systems. Hydrogen has an important potential to accelerate the process of scaling up clean and renewable energy however its integration in power systems remains little studied. This paper reviews the current progress and outlook of hydrogen technologies and their application in power systems for hydrogen production re-electrification and storage. The characteristics of electrolysers and fuel cells are demonstrated with experimental data and the deployments of hydrogen for energy storage power-to-gas co- and tri-generation and transportation are investigated using examples from worldwide projects. The current techno-economic status of these technologies and applications is presented in which cost efficiency and durability are identified as the main critical aspects. This is also confirmed by the results of a statistical analysis of the literature. Finally conclusions show that continuous efforts on performance improvements scale ramp-up technical prospects and political support are required to enable a cost-competitive hydrogen economy.
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