France
Global Energy Review 2020- The Impacts of the Covid-19 Crisis on Global Energy Demand and CO2 Emissions
Apr 2020
Publication
In response to the exceptional circumstances stemming from the coronavirus pandemic the annual IEA Global Energy Review has expanded its coverage to include real-time analysis of developments to date in 2020 and possible directions for the rest of the year. In addition to reviewing 2019 energy and CO2 emissions data by fuel and country for this section of the Global Energy Review we have tracked energy use by country and fuel over the past three months and in some cases – such as electricity – in real time. Some tracking will continue on a weekly basis. The uncertainty surrounding public health the economy and hence energy over the rest of 2020 is unprecedented. This analysis therefore not only charts a possible path for energy use and CO2 emissions in 2020 but also highlights the many factors that could lead to differing outcomes. We draw key lessons on how to navigate this once-in-a-century crisis.
Link to Document on IEA websitte
Link to Document on IEA websitte
Statistics, Lessons Learned and Recommendations from Analysis of HIAD 2.0 Database
Mar 2022
Publication
The manuscript firstly describes the data collection and validation process for the European Hydrogen Incidents and Accidents Database (HIAD 2.0) a public repository tool collecting systematic data on hydrogen-related incidents and near-misses. This is followed by an overview of HIAD 2.0 which currently contains 706 events. Subsequently the approaches and procedures followed by the authors to derive lessons learned and formulate recommendations from the events are described. The lessons learned have been divided into four categories including system design; system manufacturing installation and modification; human factors and emergency response. An overarching lesson learned is that minor events which occurred simultaneously could still result in serious consequences echoing James Reason's Swiss Cheese theory. Recommendations were formulated in relation to the established safety principles adapted for hydrogen by the European Hydrogen Safety Panel considering operational modes industrial sectors and human factors. This work provide an important contribution to the safety of systems involving hydrogen benefitting technical safety engineers emergency responders and emergency services. The lesson learned and the discussion derived from the statistics can also be used in training and risk assessment studies being of equal importance to promote and assist the development of sound safety culture in organisations.
Challenges and Important Considerations When Benchmarking Single-cell Alkaline Electrolyzers
Nov 2021
Publication
This study outlines an approach to identifying the difficulties associated with the bench-marking of alkaline single cells under real electrolyzer conditions. A challenging task in the testing and comparison of different catalysts is obtaining reliable and meaningful benchmarks for these conditions. Negative effects on reproducibility were observed due to the reduction in conditioning time. On the anode side a stable passivation layer of NiO can be formed by annealing of the Ni foams which is even stable during long-term operation. Electrical contact resistance and impedance measurements showed that most of the contact resistance derived from the annealed Ni foam. Additionally analysis of various overvoltages indicated that most of the total overvoltage comes from the anode and cathode activation overpotential. Different morphologies of the substrate material exhibited an influence on the performance of the alkaline single cell based on an increase in the ohmic resistance.
Hydrogen as a Clean and Sustainable Energy Vector for Global Transition from Fossil-Based to Zero-Carbon
Dec 2021
Publication
Hydrogen is recognized as a promising and attractive energy carrier to decarbonize the sectors responsible for global warming such as electricity production industry and transportation. However although hydrogen releases only water as a result of its reaction with oxygen through a fuel cell the hydrogen production pathway is currently a challenging issue since hydrogen is produced mainly from thermochemical processes (natural gas reforming coal gasification). On the other hand hydrogen production through water electrolysis has attracted a lot of attention as a means to reduce greenhouse gas emissions by using low-carbon sources such as renewable energy (solar wind hydro) and nuclear energy. In this context by providing an environmentally-friendly fuel instead of the currently-used fuels (unleaded petrol gasoline kerosene) hydrogen can be used in various applications such as transportation (aircraft boat vehicle and train) energy storage industry medicine and power-to-gas. This article aims to provide an overview of the main hydrogen applications (including present and future) while examining funding and barriers to building a prosperous future for the nation by addressing all the critical challenges met in all energy sectors.
The Future of Hydrogen
Jun 2019
Publication
At the request of the government of Japan under its G20 presidency the International Energy Agency produced this landmark report to analyse the current state of play for hydrogen and to offer guidance on its future development.
The report finds that clean hydrogen is currently enjoying unprecedented political and business momentum with the number of policies and projects around the world expanding rapidly. It concludes that now is the time to scale up technologies and bring down costs to allow hydrogen to become widely used. The pragmatic and actionable recommendations to governments and industry that are provided will make it possible to take full advantage of this increasing momentum.
Hydrogen and energy have a long shared history – powering the first internal combustion engines over 200 years ago to becoming an integral part of the modern refining industry. It is light storable energy-dense and produces no direct emissions of pollutants or greenhouse gases. But for hydrogen to make a significant contribution to clean energy transitions it needs to be adopted in sectors where it is almost completely absent such as transport buildings and power generation.
The Future of Hydrogen provides an extensive and independent survey of hydrogen that lays out where things stand now; the ways in which hydrogen can help to achieve a clean secure and affordable energy future; and how we can go about realising its potential.
Link to Document on IEA Website
The report finds that clean hydrogen is currently enjoying unprecedented political and business momentum with the number of policies and projects around the world expanding rapidly. It concludes that now is the time to scale up technologies and bring down costs to allow hydrogen to become widely used. The pragmatic and actionable recommendations to governments and industry that are provided will make it possible to take full advantage of this increasing momentum.
Hydrogen and energy have a long shared history – powering the first internal combustion engines over 200 years ago to becoming an integral part of the modern refining industry. It is light storable energy-dense and produces no direct emissions of pollutants or greenhouse gases. But for hydrogen to make a significant contribution to clean energy transitions it needs to be adopted in sectors where it is almost completely absent such as transport buildings and power generation.
The Future of Hydrogen provides an extensive and independent survey of hydrogen that lays out where things stand now; the ways in which hydrogen can help to achieve a clean secure and affordable energy future; and how we can go about realising its potential.
Link to Document on IEA Website
Non-combustion Related Impact of Hydrogen Admixture - Material Compatibility
Jun 2020
Publication
The present document is part of a larger literature survey of this WP aiming to establish the current status of gas utilisation technologies in order to determine the impact of hydrogen (H2) admixture on natural gas (NG) appliances. This part focuses on the non-combustion related aspects of injecting hydrogen in the gas distribution networks within buildings including hydrogen embrittlement of metallic materials chemical compatibility and leakage issues. In the particular conditions of adding natural gas and hydrogen (NG / H2) mixture into a gas distribution network hydrogen is likely to reduce the mechanical properties of metallic components. This is known as hydrogen embrittlement (HE) (Birnbaum 1979). This type of damage takes place once a critical level of stress / strain and hydrogen content coexist in a susceptible microstructure. Currently four mechanisms were identified and will be discussed in detail. The way those mechanisms act independently or together is strongly dependent on the material the hydrogen charging procedure and the mechanical loading type. The main metallic materials used in gas appliances and gas distribution networks are: carbon steels stainless steels copper brass and aluminium alloys (Thibaut 2020). The presented results showed that low alloy steels are the most susceptible materials to hydrogen embrittlement followed by stainless steels aluminium copper and brass alloys. However the relative pressures of the operating conditions of gas distribution network in buildings are low i.e. between 30 to 50 mbar. At those low hydrogen partial pressures it is assumed that a gas mixture composed of NG and up to 50% H2 should not be problematic in terms of HE for any of the metallic materials used in gas distribution network unless high mechanical stress / strain and high stress concentrations are applied. The chemical compatibility of hydrogen with other materials and specifically polyethylene (PE) which is a reference material for the gas industry is also discussed. PE was found to have no corrosion issues and no deterioration or ageing was observed after long term testing in hydrogen gas. The last non-combustion concern related to the introduction of hydrogen in natural gas distribution network is the propensity of hydrogen toward leakage. Indeed the physical properties of hydrogen are different from other gases such as methane or propane and it was observed that hydrogen leaks 2.5 times quicker than methane. This bibliographical report on material deterioration chemical compatibility and leakage concerns coming with the introduction of NG / H2 mixture in the gas distribution network sets the basis for the upcoming experimental work where the tightness of gas distribution network components will be investigated (Task 3.2.3 WP3). In addition tightness of typical components that connect end-user appliances to the local distribution line shall be evaluated as well.
Integration of Experimental Facilities: A Joint Effort for Establishing a Common Knowledge Base in Experimental Work on Hydrogen Safety
Sep 2009
Publication
With regard to the goals of the European HySafe Network research facilities are essential for the experimental investigation of relevant phenomena for testing devices and safety concepts as well as for the generation of validation data for the various numerical codes and models. The integrating activity ‘Integration of Experimental Facilities (IEF)’ has provided basic support for jointly performed experimental work within HySafe. Even beyond the funding period of the NoE HySafe in the 6th Framework Programme IEF represents a long lasting effort for reaching sustainable integration of the experimental research capacities and expertise of the partners from different research fields. In order to achieve a high standard in the quality of experimental data provided by the partners emphasis was put on the know-how transfer between the partners. The strategy for reaching the objectives consisted of two parts. On the one hand a documentation of the experimental capacities has been prepared and analysed. On the other hand a communication base has been established by means of biannual workshops on experimental issues. A total of 8 well received workshops has been organised covering topics from measurement technologies to safety issues. Based on the information presented by the partners a working document on best practice including the joint experimental knowledge of all partners with regard to experiments and instrumentation was created. Preserving the character of a working document it was implemented in the IEF wiki website which was set up in order to provide a central communication platform. The paper gives an overview of the IEF network activities over the last 5 years.
Mixed E-learning and Virtual Reality Pedagogical Approach for Innovative Hydrogen Safety Training for First Responders
Oct 2015
Publication
Within the scope of the HyResponse project the development of a specialised training programme is currently underway. Utilizing an andragogy approach to teaching distance learning is mixed with classroom instructors-led activities while hands-on training on a full-scale simulator is coupled with an innovative virtual reality based experience. Although the course is dedicated mainly to first responders provision has been made to incorporate not only simple table-top and drill exercises but also full-scale training involving all functional emergency response organisations at multi-agency cooperation level. The developed curriculum includes basics of hydrogen safety first responders' procedures and incident management expectations
Testing Safety of Hydrogen Components
Sep 2007
Publication
Hydrogen as a new and ecologic energy source is tempting though it creates the challenge of ensuring the safe use of hydrogen for all future consumers. Making sure that a hydrogen vehicle can be simply and safely used by anyone while performing as expected requires that the car be light with built-in safety features. This is achieved by combining high pressure composite cylinders with strict test procedures. Composite cylinders of up to 150 L operated to a maximum of 700 bar are required for vehicle applications. Air Liquide has developed test benches to hydraulically cycle such cylinders at 1400 bar and up to 3500 bar for burst tests. These tests are performed under controlled temperature conditions at ambient and extreme temperatures in order to simulate cylinder aging. Components in gas service such as valves hoses and other pressure devices are tested up to 1400 bars with hydrogen to simulate actual usage conditions. Hydrogen is used as a testing gas instead of nitrogen which is commonly used for such tests because hydrogen interacts with materials (e.g. hydrogen embrittlement) and because hydrogen has a special thermodynamic behaviour ( pressure drop velocity heat exchange…)
Best Practice in Numerical Simulation and CFD Benchmarking. Results from the SUSANA Project
Sep 2017
Publication
Correct use of Computational Fluid Dynamics (CFD) tools is essential in order to have confidence in the results. A comprehensive set of Best Practice Guidelines (BPG) in numerical simulations for Fuel Cells and Hydrogen applications has been one of the main outputs of the SUSANA project. These BPG focus on the practical needs of engineers in consultancies and industry undertaking CFD simulations or evaluating CFD simulation results in support of hazard/risk assessments of hydrogen facilities as well as on the needs of regulatory authorities. This contribution presents a summary of the BPG document. All crucial aspects of numerical simulations are addressed such as selection of the physical models domain design meshing boundary conditions and selection of numerical parameters. BPG cover all hydrogen safety relative phenomena i.e. release and dispersion ignition jet fire deflagration and detonation. A series of CFD benchmarking exercises are also presented serving as examples of appropriate modelling strategies.
Fire Tests Carried Out in FCH JU FIRECOMP Project, Recommendations and Application to Safety of Gas Storage Systems
Sep 2017
Publication
In the event of a fire composite pressure vessels behave very differently from metallic ones: the material is degraded potentially leading to a burst without significant pressure increase. Hence such objects are when necessary protected from fire by using thermally-activated devices (TPRD) and standards require testing cylinder and TPRD together. The pre-normative research project FireComp aimed at understanding better the conditions which may lead to burst through testing and simulation and proposed an alternative way of assessing the fire performance of composite cylinders. This approach is currently used by Air Liquide for the safety of composite bundles carrying large amounts of hydrogen gas.
On the Use of Hydrogen in Confined Spaces: Results from the Internal Project InsHyde
Sep 2009
Publication
Alexandros G. Venetsanos,
Paul Adams,
Inaki Azkarate,
A. Bengaouer,
Marco Carcassi,
Angunn Engebø,
E. Gallego,
Olav Roald Hansen,
Stuart J. Hawksworth,
Thomas Jordan,
Armin Keßler,
Sanjay Kumar,
Vladimir V. Molkov,
Sandra Nilsen,
Ernst Arndt Reinecke,
M. Stöcklin,
Ulrich Schmidtchen,
Andrzej Teodorczyk,
D. Tigreat,
N. H. A. Versloot and
L. Boon-Brett
The paper presents an overview of the main achievements of the internal project InsHyde of the HySafe NoE. The scope of InsHyde was to investigate realistic small-medium indoor hydrogen leaks and provide recommendations for the safe use/storage of indoor hydrogen systems. Additionally InsHyde served to integrate proposals from HySafe work packages and existing external research projects towards a common effort. Following a state of the art review InsHyde activities expanded into experimental and simulation work. Dispersion experiments were performed using hydrogen and helium at the INERIS gallery facility to evaluate short and long term dispersion patterns in garage like settings. A new facility (GARAGE) was built at CEA and dispersion experiments were performed there using helium to evaluate hydrogen dispersion under highly controlled conditions. In parallel combustion experiments were performed by FZK to evaluate the maximum amount of hydrogen that could be safely ignited indoors. The combustion experiments were extended later on by KI at their test site by considering the ignition of larger amounts of hydrogen in obstructed environments outdoors. An evaluation of the performance of commercial hydrogen detectors as well as inter-lab calibration work was jointly performed by JRC INERIS and BAM. Simulation work was as intensive as the experimental work with participation from most of the partners. It included pre-test simulations validation of the available CFD codes against previously performed experiments with significant CFD code inter-comparisons as well as CFD application to investigate specific realistic scenarios. Additionally an evaluation of permeation issues was performed by VOLVO CEA NCSRD and UU by combining theoretical computational and experimental approaches with the results being presented to key automotive regulations and standards groups. Finally the InsHyde project concluded with a public document providing initial guidance on the use of hydrogen in confined spaces.
Estimation of an Allowable Hydrogen Permeation Rate From Road Vehicle Compressed Gaseous H2 Storage Systems In Typical Garages, Part 2: CFC Dispersion Calculations Using the ADREA-HF Code and Experimental Validation Using Helium Tests at the Garage Facility
Sep 2009
Publication
The time and space evolution of the distribution of hydrogen in confined settings was investigated computationally and experimentally for permeation from typical compressed gaseous hydrogen storage systems for buses or cars. The work was performed within the framework of the InsHyde internal project of the HySafe NoE funded by EC. The main goal was to examine whether hydrogen is distributed homogeneously within a garage like facility or whether stratified conditions are developed under certain conditions. The nominal hydrogen flow rate considered was 1.087 NL/min based on the then current SAE standard for composite hydrogen containers with a non-metallic liner (type 4) at simulated end of life and maximum material temperature in a bus facility with a volume of 681m3. The release was assumed to be directed upwards from a 0.15m diameter hole located at the middle part of the bus cylinders casing. Ventilation rates up to 0.03 ACH were considered. Simulated time periods extended up to 20 days. The CFD simulations performed with the ADREA-HF code showed that fully homogeneous conditions exist for low ventilation rates while stratified conditions prevail for higher ventilation rates. Regarding flow structure it was found that the vertical concentration profiles can be considered as the superposition of the concentration at the floor (driven by laminar diffusion) plus a concentration difference between floor and ceiling (driven by buoyancy forces). In all cases considered this concentration difference was found to be less than 0.5%. The dispersion experiments were performed at the GARAGE facility using Helium. Comparison between CFD simulations and experiments showed that the predicted concentrations were in good agreement with the experimental data. Finally simulations were performed using two integral models: the fully homogeneous model and the two-layer model proposed by Lowesmith et al. (ICHS-2 2007) and the results were compared both against CFD and the experimental data.
Processes of the Formation of Large Unconfined Clouds Following a Massive Spillage of Liquid Hydrogen on the Ground
Sep 2007
Publication
Because of hydrogen low volumetric energy content under its gaseous form transport and storage of liquid hydrogen will certainly play a major role in any future hydrogen economy. One of the obstacles to the expected development use of hydrogen is the poor state of knowledge on explosion risks in the event of an extensive spillage. INERIS set up a large-scale experiment to study the mechanisms of the formation of the gas cloud resulting from such a spillage and the associated mixing process and turbulence effects. Dispersion tests have been performed with cryogenic helium presenting similar dispersion characteristics than liquid hydrogen (buoyancy). Flowrates up to 3 kg/s have been investigated and the instrumentation allowed the observation and quantification of bouyancy effects including internal turbulence. Those results constitute an originals et of data which can be used as a basis for the development of dispersion software and reinterpretation of other existing databases ([10 11])
Batteries and Hydrogen Technology: Keys for a Clean Energy Future
May 2020
Publication
As governments focus on dealing with the Covid-19 health emergency they are increasingly turning their attention to the impact of shutting down their economies and how to revive them quickly through stimulus measures. Economic recovery packages offer a unique opportunity to create jobs while supporting clean energy transitions around the world.
Energy efficiency and renewable energy like wind and solar PV – the cornerstones of any clean energy transition – are good places to start. Those industries employ millions of people across their value chains and offer environmentally sustainable ways to create jobs and help revitalise the global economy.
But more than just renewables and efficiency will be required to put the world on track to meet climate goals and other sustainability objectives. IEA analysis has repeatedly shown that a broad portfolio of clean energy technologies will be needed to decarbonise all parts of the economy. Batteries and hydrogen-producing electrolysers stand out as two important technologies thanks to their ability to convert electricity into chemical energy and vice versa. This is why they also deserve a place in any economic stimulus packages being discussed today.
Link to Document on IEA Website
Energy efficiency and renewable energy like wind and solar PV – the cornerstones of any clean energy transition – are good places to start. Those industries employ millions of people across their value chains and offer environmentally sustainable ways to create jobs and help revitalise the global economy.
But more than just renewables and efficiency will be required to put the world on track to meet climate goals and other sustainability objectives. IEA analysis has repeatedly shown that a broad portfolio of clean energy technologies will be needed to decarbonise all parts of the economy. Batteries and hydrogen-producing electrolysers stand out as two important technologies thanks to their ability to convert electricity into chemical energy and vice versa. This is why they also deserve a place in any economic stimulus packages being discussed today.
Link to Document on IEA Website
Validation of Leading Point Concept in RANS Simulations of Highly Turbulent Lean Syngas-air Flames with Well-pronounced Diffusional-thermal Effects
Jan 2021
Publication
While significant increase in turbulent burning rate in lean premixed flames of hydrogen or hydrogen-containing fuel blends is well documented in various experiments and can be explained by highlighting local diffusional-thermal effects capabilities of the vast majority of available models of turbulent combustion for predicting this increase have not yet been documented in numerical simulations. To fill this knowledge gap a well-validated Turbulent Flame Closure (TFC) model of the influence of turbulence on premixed combustion which however does not address the diffusional-thermal effects is combined with the leading point concept which highlights strongly perturbed leading flame kernels whose local structure and burning rate are significantly affected by the diffusional-thermal effects. More specifically within the framework of the leading point concept local consumption velocity is computed in extremely strained laminar flames by adopting detailed combustion chemistry and subsequently the computed velocity is used as an input parameter of the TFC model. The combined model is tested in RANS simulations of highly turbulent lean syngas-air flames that were experimentally investigated at Georgia Tech. The tests are performed for four different values of the inlet rms turbulent velocities different turbulence length scales normal and elevated (up to 10 atm) pressures various H2/CO ratios ranging from 30/70 to 90/10 and various equivalence ratios ranging from 0.40 to 0.80. All in all the performed 33 tests indicate that the studied combination of the leading point concept and the TFC model can predict well-pronounced diffusional-thermal effects in lean highly turbulent syngas-air flames with these results being obtained using the same value of a single constant of the combined model in all cases. In particular the model well predicts a significant increase in the bulk turbulent consumption velocity when increasing the H2/CO ratio but retaining the same value of the laminar flame speed.
Hydrogen Dispersion in a Closed Environment
Sep 2017
Publication
The highly combustible nature of hydrogen poses a great hazard creating a number of problems with its safety and handling. As a part of safety studies related to the use of hydrogen in a confined environment it is extremely important to have a good knowledge of the dispersion mechanism.<br/>The present work investigates the concentration field and flammability envelope from a small scale leak. The hydrogen is released into a 0.47 m × 0.33 m x 0.20 m enclosure designed as a 1/15 – scale model of a room in a nuclear facility. The performed tests evaluates the influence of the initial conditions at the leakage source on the dispersion and mixing characteristics in a confined environment. The role of the leak location and the presence of obstacles are also analyzed. Throughout the test during the release and the subsequent dispersion phase temporal profiles of hydrogen concentration are measured using thermal conductivity gauges within the enclosure. In addition the BOS (Background Oriented Schlieren) technique is used to visualise the cloud evolution inside the enclosure. These instruments allow the observation and quantification of the stratification effects.
Some Fundamental Combustion Properties of "Cryogenic" Premixed Hydrogen Air Flames
Sep 2021
Publication
Because of the emergence of the U.E. “green deal” and because of the significant implication of national and regional authorities throughout Europe the “hydrogen” economy is emerging. And with it numerous questions and experimentations. One of them perhaps a key point is the storage and transport of hydrogen. Liquid hydrogen in cryogenic conditions is a possibility already used in the space industry but under a lot of constrains. What may be acceptable in a well-controlled and restrained domain may not be realistic in a wider application closer to the public. Safety should be ensured and there is a need for a better knowledge of the flammable and ignition properties of the “cold” hydrogen mixtures following a cryogenic spillage for instance to select adequate ATEX equipment. The purpose of PRESLHY project [4] is to investigate the ignition fire and explosion characteristics of cryogenic hydrogen spillages and to propose safety engineering methods. The present work is part of it and addresses the measurement of the laminar burning velocity (Sl) flammability limits (FL) minimum ignition energy (MIE)… of hydrogen air mixtures at atmospheric pressure but down to -150°C. To do this a special burner was designed with details given inside this paper together with the experimental results. It is found that the FL domain is reduced when the temperature drops that MIE increases slightly and Sl decreases.
20 Years of Carbon Capture and Storage - Accelerating Future Deployment
Nov 2016
Publication
Carbon capture and storage (CCS) technologies are expected to play a significant part in the global climate response. Following the ratification of the Paris Agreement the ability of CCS to reduce emissions from fossil fuel use in power generation and industrial processes – including from existing facilities – will be crucial to limiting future temperature increases to ""well below 2°C"" as laid out in the Agreement. CCS technology will also be needed to deliver ""negative emissions"" in the second half of the century if these ambitious goals are to be achieved.
CCS technologies are not new. This year is the 20th year of operation of the Sleipner CCS Project in Norway which has captured almost 17 million tonnes of CO2 from an offshore natural gas production facility and permanently stored them in a sandstone formation deep under the seabed. Individual applications of CCS have been used in industrial processes for decades and projects injecting CO2 for enhanced oil recovery (EOR) have been operating in the United States since the early 1970s.
This publication reviews progress with CCS technologies over the past 20 years and examines their role in achieving 2°C and well below 2°C targets. Based on the International Energy Agency’s 2°C scenario it also considers the implications for climate change if CCS was not a part of the response. And it examines opportunities to accelerate future deployment of CCS to meet the climate goals set in the Paris Agreement.
Link to Document on IEA Website
CCS technologies are not new. This year is the 20th year of operation of the Sleipner CCS Project in Norway which has captured almost 17 million tonnes of CO2 from an offshore natural gas production facility and permanently stored them in a sandstone formation deep under the seabed. Individual applications of CCS have been used in industrial processes for decades and projects injecting CO2 for enhanced oil recovery (EOR) have been operating in the United States since the early 1970s.
This publication reviews progress with CCS technologies over the past 20 years and examines their role in achieving 2°C and well below 2°C targets. Based on the International Energy Agency’s 2°C scenario it also considers the implications for climate change if CCS was not a part of the response. And it examines opportunities to accelerate future deployment of CCS to meet the climate goals set in the Paris Agreement.
Link to Document on IEA Website
Fuel Cell Electric Vehicles—A Brief Review of Current Topologies and Energy Management Strategies
Jan 2021
Publication
With the development of technologies in recent decades and the imposition of international standards to reduce greenhouse gas emissions car manufacturers have turned their attention to new technologies related to electric/hybrid vehicles and electric fuel cell vehicles. This paper focuses on electric fuel cell vehicles which optimally combine the fuel cell system with hybrid energy storage systems represented by batteries and ultracapacitors to meet the dynamic power demand required by the electric motor and auxiliary systems. This paper compares the latest proposed topologies for fuel cell electric vehicles and reveals the new technologies and DC/DC converters involved to generate up-to-date information for researchers and developers interested in this specialized field. From a software point of view the latest energy management strategies are analyzed and compared with the reference strategies taking into account performance indicators such as energy efficiency hydrogen consumption and degradation of the subsystems involved which is the main challenge for car developers. The advantages and disadvantages of three types of strategies (rule-based strategies optimization-based strategies and learning-based strategies) are discussed. Thus future software developers can focus on new control algorithms in the area of artificial intelligence developed to meet the challenges posed by new technologies for autonomous vehicles.
Evaluation of the Performance Degradation of a Metal Hydride Tank in a Real Fuel Cell Electric Vehicle
May 2022
Publication
In a fuel cell electric vehicle (FCEV) powered by a metal hydride tank the performance of the tank is an indicator of the overall health status which is used to predict its behaviour and make appropriate energy management decisions. The aim of this paper is to investigate how to evaluate the effects of charge/discharge cycles on the performance of a commercial automotive metal hydride hydrogen storage system applied to a real FCEV. For this purpose a mathematical model is proposed based on uncertain physical parameters that are identified using the stochastic particle swarm optimisation (PSO) algorithm combined with experimental measurements. The variation of these parameters allows an assessment of the degradation level of the tank’s performance on both the quantitative and qualitative aspects. Simulated results derived from the proposed model and experimental measurements were in good agreement with a maximum relative error of less than 2%. The validated model was used to establish the correlations between the observed degradations in a hydride tank recovered from a real FCEV. The results obtained show that it is possible to predict tank degradations by developing laws of variation of these parameters as a function of the real conditions of the use of the FCEV (number of charging/discharging cycles pressures mass flow rates temperatures).
Magnesium Based Materials for Hydrogen Based Energy Storage: Past, Present and Future
Jan 2019
Publication
Volodymyr A. Yartys,
Mykhaylo V. Lototskyy,
Etsuo Akiba,
Rene Albert,
V. E. Antonov,
Jose-Ramón Ares,
Marcello Baricco,
Natacha Bourgeois,
Craig Buckley,
José Bellosta von Colbe,
Jean-Claude Crivello,
Fermin Cuevas,
Roman V. Denys,
Martin Dornheim,
Michael Felderhoff,
David M. Grant,
Bjørn Christian Hauback,
Terry D. Humphries,
Isaac Jacob,
Petra E. de Jongh,
Jean-Marc Joubert,
Mikhail A. Kuzovnikov,
Michel Latroche,
Mark Paskevicius,
Luca Pasquini,
L. Popilevsky,
Vladimir M. Skripnyuk,
Eugene I. Rabkin,
M. Veronica Sofianos,
Alastair D. Stuart,
Gavin Walker,
Hui Wang,
Colin Webb,
Min Zhu and
Torben R. Jensen
Magnesium hydride owns the largest share of publications on solid materials for hydrogen storage. The “Magnesium group” of international experts contributing to IEA Task 32 “Hydrogen Based Energy Storage” recently published two review papers presenting the activities of the group focused on magnesium hydride based materials and on Mg based compounds for hydrogen and energy storage. This review article not only overviews the latest activities on both fundamental aspects of Mg-based hydrides and their applications but also presents a historic overview on the topic and outlines projected future developments. Particular attention is paid to the theoretical and experimental studies of Mg-H system at extreme pressures kinetics and thermodynamics of the systems based on MgH2 nanostructuring new Mg-based compounds and novel composites and catalysis in the Mg based H storage systems. Finally thermal energy storage and upscaled H storage systems accommodating MgH2 are presented.
Test Campaign on Existing HRS & Dissemination of Results
Apr 2019
Publication
This document is the final deliverable of Tasks 2 & 3 of the tender N° FCH / OP / CONTRACT 196: “Development of a Metering Protocol for Hydrogen Refuelling Stations”. In Task 2 a test campaign was organized on several HRS in Europe to apply the testing protocol defined in Task 1. This protocol requires mainly to perform different accuracy tests in order to determine the error of the complete measuring system (i.e. from the mass flow meter to the nozzle) in real fueling conditions. Seven HRS have been selected to fulfill the requirements specified in the tender. Tests results obtained are presented in this deliverable and conclusions are proposed to explain the errors observed. In the frame of Task 3 results and conclusions have been widely presented to additional Metrology Institutes than those involved in Task 1 in order to get their adhesion on the testing proposed protocol. All the work performed in Tasks 2 & 3 and associated outcomes / conclusions are reported here.
Towards Ecological Alternatives in Bearing Lubrication
Jun 2021
Publication
Hydrogen is the cleanest fuel available because its combustion product is water. The internal combustion engine can in principle and without significant modifications run on hydrogen to produce mechanical energy. Regarding the technological solution leading to compact engines a question to ask is the following: Can combustion engine systems be lubricated with hydrogen? In general since many applications such as in turbomachines is it possible to use the surrounding gas as a lubricant? In this paper journal bearings global parameters are calculated and compared for steady state and dynamic conditions for different gas constituents such as air pentafluoropropane helium and hydrogen. Such a bearing may be promising as an ecological alternative to liquid lubrication.
Characterization of the Inducible and Slow-Releasing Hydrogen Sulfide and Persulfide Donor P*: Insights into Hydrogen Sulfide Signaling
Jun 2021
Publication
Hydrogen sulfide (H2S) is an important mediator of inflammatory processes. However controversial findings also exist and its underlying molecular mechanisms are largely unknown. Recently the byproducts of H2S per-/polysulfides emerged as biological mediators themselves highlighting the complex chemistry of H2S. In this study we characterized the biological effects of P* a slow-releasing H2S and persulfide donor. To differentiate between H2S and polysulfide-derived effects we decomposed P* into polysulfides. P* was further compared to the commonly used fast-releasing H2S donor sodium hydrogen sulfide (NaHS). The effects on oxidative stress and interleukin-6 (IL-6) expression were assessed in ATDC5 cells using superoxide measurement qPCR ELISA and Western blotting. The findings on IL-6 expression were corroborated in primary chondrocytes from osteoarthritis patients. In ATDC5 cells P* not only induced the expression of the antioxidant enzyme heme oxygenase-1 via per-/polysulfides but also induced activation of Akt and p38 MAPK. NaHS and P* significantly impaired menadione-induced superoxide production. P* reduced IL-6 levels in both ATDC5 cells and primary chondrocytes dependent on H2Srelease. Taken together P* provides a valuable research tool for the investigation of H2S and per-/polysulfide signalling. These data demonstrate the importance of not only H2S but also per-/polysulfides as bioactive signaling molecules with potent anti-inflammatory and in particular antioxidant properties.
Hydrogen Fuel Cell Road Vehicles and Their Infrastructure: An Option Towards an Environmentally Friendly Energy Transition
Nov 2020
Publication
The latest pre-production vehicles on the market show that the major technical challenges posed by integrating a fuel cell system (FCS) within a vehicle—compactness safety autonomy reliability cold starting—have been met. Regarding the ongoing maturity of fuel cell systems dedicated to road transport the present article examines the advances still needed to move from a functional but niche product to a mainstream consumer product. It seeks to address difficulties not covered by more traditional innovation approaches. At least in long-distance heavy-duty vehicles fuel cell vehicles (FCVs) are going to play a key role in the path to zero-emissions in one or two decades. Hence the present study also addresses the structuring elements of the complete chain: the latter includes the production storage and distribution of hydrogen. Green hydrogen appears to be one of the potential uses of renewable energies. The greener the electricity is the greater the advantage for hydrogen since it permits to economically store large energy quantities on seasonal rhythms. Moreover natural hydrogen might also become an economic reality pushing the fuel cell vehicle to be a competitive and environmentally friendly alternative to the battery electric vehicle. Based on its own functional benefits for on board systems hydrogen in combination with the fuel cell will achieve a large-scale use of hydrogen in road transport as soon as renewable energies become more widespread. Its market will expand from large driving range and heavy load vehicles
Improved Hydrogen-Production-Based Power Management Control of a Wind Turbine Conversion System Coupled with Multistack Proton Exchange Membrane Electrolyzers
Mar 2020
Publication
This paper deals with two main issues regarding the specific energy consumption in an electrolyzer (i.e. the Faraday efficiency and the converter topology). The first aspect is addressed using a multistack configuration of proton exchange membrane (PEM) electrolyzers supplied by a wind turbine conversion system (WTCS). This approach is based on the modeling of the wind turbine and the electrolyzers. The WTCS and the electrolyzers are interfaced through a stacked interleaved DC–DC buck converter (SIBC) due to its benefits for this application in terms of the output current ripple and reliability. This converter is controlled so that it can offer dynamic behavior that is faster than the wind turbine avoiding overvoltage during transients which could damage the PEM electrolyzers. The SIBC is designed to be connected in array configuration (i.e. parallel architecture) so that each converter operates at its maximum efficiency. To assess the performance of the power management strategy experimental tests were carried out. The reported results demonstrate the correct behavior of the system during transient operation.
Some Issues Concerning the CFD Modelling of Confined Hydrogen Releases
Sep 2017
Publication
In SUSANA E.U. project a rather broad CFD benchmarking exercise was performed encompassing a number of CFD codes a diversity of turbulence models... It is concluded that the global agreement is good. But in this particular situation the experimental data to compare with were known to the modelers. In performing this exercise the present authors explored the influence of some modelling choices which may have a significant impact on the results (apart from the traditional convergence testing and mass conservation) especially in the situation where little relevant data are available. The configuration investigated is geometrically simple: a vertical round hydrogen jet in a square box. Nevertheless modelling aspects like the representation of the source and of the boundary conditions have a rather strong influence on the final results as illustrated in this communication. In other words the difficulties may not be so much in the intrinsic capabilities of the code (which SUSANA tends to show) but more in the physical representation the modelers have. Even in the specific situation addressed in this communication although looking simple it may not be so obvious to grasp correctly the leading physical processes.
Prospecting Stress Formed by Hydrogen or Isotope Diffused in Palladium Alloy Cathode
Oct 2018
Publication
The objective of this project is to take into account the mechanical constraints formed by diffusion of hydrogen or tritium in watertight palladium alloy cathode. To know the origin of these it was necessary to discriminating the damaging effects encountered. Effectively hydrogen and isotope induce deformation embrittlement stress corrosion cracking and cathodic corrosion in different regions of cathode. Palladium can be alloyed with silver or yttrium to favourably increase diffusion and reduce these constraints. Effects of electrochemical factors temperature cathode structure adsorbed transient complex of palladium and porous material support are given to estimate and to limit possible damage.
Blind-prediction: Estimating the Consequences of Vented Hydrogen Deflagrations for Homogeneous Mixtures in a 20-foot ISO Container
Sep 2017
Publication
Trygve Skjold,
Helene Hisken,
Sunil Lakshmipathy,
Gordon Atanga,
Marco Carcassi,
Martino Schiavetti,
James R. Stewart,
A. Newton,
James R. Hoyes,
Ilias C. Tolias,
Alexandros G. Venetsanos,
Olav Roald Hansen,
J. Geng,
Asmund Huser,
Sjur Helland,
Romain Jambut,
Ke Ren,
Alexei Kotchourko,
Thomas Jordan,
Jérome Daubech,
Guillaume Lecocq,
Arve Grønsund Hanssen,
Chenthil Kumar,
Laurent Krumenacker,
Simon Jallais,
D. Miller and
Carl Regis Bauwens
This paper summarises the results from a blind-prediction study for models developed for estimating the consequences of vented hydrogen deflagrations. The work is part of the project Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations (HySEA). The scenarios selected for the blind-prediction entailed vented explosions with homogeneous hydrogen-air mixtures in a 20-foot ISO container. The test program included two configurations and six experiments i.e. three repeated tests for each scenario. The comparison between experimental results and model predictions reveals reasonable agreement for some of the models and significant discrepancies for others. It is foreseen that the first blind-prediction study in the HySEA project will motivate developers to improve their models and to update guidelines for users of the models.
Energy Transition in France
May 2022
Publication
To address the climate emergency France is committed to achieving carbon neutrality by 2050. It plans to significantly increase the contribution of renewable energy in its energy mix. The share of renewable energy in its electricity production which amounts to 25.5% in 2020 should reach at least 40% in 2030. This growth poses several new challenges that require policy makers and regulators to act on the technological changes and expanding need for flexibility in power systems. This document presents the main strategies and projects developed in France as well as various recommendations to accompany and support its energy transition policy.
Results of the Pre-normative Research Project PRESLHY for the Safe Use of Liquid Hydrogen
Sep 2021
Publication
Liquid hydrogen (LH2) compared to compressed gaseous hydrogen offers advantages for large-scale transport and storage of hydrogen with higher densities. Although the gas industry has good experience with LH2 only little experience is available for the new applications of LH2 as an energy carrier. Therefore the European FCH JU funded project PRESLHY conducted pre-normative research for the safe use of cryogenic LH2 in non-industrial settings. The central research consisted of a broad experimental program combined with analytical work modelling and simulations belonging to the three key phenomena of the accident chain: release and mixing ignition and combustion. The presented results improve the general understanding of the behavior of LH2 in accidents and provide some design guidelines and engineering tools for safer use of LH2. Recommendations for improvement of current international standards are derived.
Market Segmentation of Domestic and Commercial Natural Gas Appliances
Jan 2021
Publication
The main goal of the project is to enable the wide adoption of H2NG (hydrogen in natural gas) blends by closing knowledge gaps regarding technical impacts on residential and commercial gas appliances. The project consortium will identify and recommend appropriate codes and standards that should be adapted to answer the needs and develop a strategy for addressing the challenges for new and existing appliances.<br/>This deliverable on market segmentation is part of work package 2 and provides a quantitative segmentation of the gas appliance market in terms of appliance population numbers. It therefore prepares the project partners to perform the subsequent selection of the most representative product types to be tested in the laboratories of the THyGA partners.<br/>The classification is developed to categorise appliances installed in the field based on available statistics calculation methods and estimations. As a result appliance populations are provided for each technology segment that draw a representative picture of the installed end-use appliances within the European Union in 2020.
Optimized EMS and a Comparative Study of Hybrid Hydrogen Fuel Cell/Battery Vehicles
Jan 2022
Publication
This paper presents a new Fuel Cell Fuel Consumption Minimization Strategy (FCFCMS) for Hybrid Electric Vehicles (HEVs) powered by a fuel cell and an energy storage system in order to minimize as much as possible the consumption of hydrogen while maintaining the State Of Charge (SOC) of the battery. Compared to existing Energy Management Strategies (EMSs) (such as the well-known State Machine Strategy (SMC) Fuzzy Logic Control (FLC) Frequency Decoupling and FLC (FDFLC) and the Equivalent Consumption Minimization Strategy (ECMS)) the proposed strategy increases the overall vehicle energy efficiency and therefore minimizes the total hydrogen consumption while respecting the constraints of each energy and power element. A model of a hybrid vehicle has been built using the TruckMaker/MATLAB software. Using the Urban Dynamometer Driving Schedule (UDDS) which includes several stops and accelerations the performance of the proposed strategy has been compared with these different approaches (SMC FLC FDFLC and ECMS) through several simulations.
Spin Pinning Effect to Reconstructed Oxyhydroxide Layer on Ferromagnetic Oxides for Enhanced Water Oxidation
Jun 2021
Publication
Producing hydrogen by water electrolysis suffers from the kinetic barriers in the oxygen evolution reaction (OER) that limits the overall efficiency. With spin-dependent kinetics in OER to manipulate the spin ordering of ferromagnetic OER catalysts (e.g. by magnetization) can reduce the kinetic barrier. However most active OER catalysts are not ferromagnetic which makes the spin manipulation challenging. In this work we report a strategy with spin pinning effect to make the spins in paramagnetic oxyhydroxides more aligned for higher intrinsic OER activity. The spin pinning effect is established in oxideFM/oxyhydroxide interface which is realized by a controlled surface reconstruction of ferromagnetic oxides. Under spin pinning simple magnetization further increases the spin alignment and thus the OER activity which validates the spin effect in rate-limiting OER step. The spin polarization in OER highly relies on oxyl radicals (O∙) created by 1st dehydrogenation to reduce the barrier for subsequent O-O coupling.
An Inter-comparison Exercise on Engineering Models Capabilities to Simulate Hydrogen Vented Explosions
Sep 2013
Publication
A benchmark exercise on vented explosion engineering model was carried out against the maximum overpressures (one or two peaks) of published experiments. The models evaluated are Bauwens et al. (2012-1 and 2012-2) [4 7] models Molkov Vent Sizing Technology 1999 2001 and 2008 models [12 13 6]. The experiments in consideration are Pasman et al. experiments (1974) (30% H2 - 1m3) [1] Bauwens et al. (2012) experiments (64m3) [4] Daubech et al. (2011) experiments (10 to 30% H2 - 1 and 10 m3) [2] and Daubech et al. (2013) [5] experiments (4 m3 – H2 10 to 30%). On this basis recommendations and limits of use of these models are proposed.
Impact of Mechanical Ventilation on Build-up and Concentration Distribution Inside a 1-m3 Enclosure Considering Hydrogen Energy
Sep 2019
Publication
Natural ventilation is an efficient and well-known way to mitigate a hydrogen build-up in the case of an accidental release in confined enclosures. However for some hydrogen energy applications natural ventilation is not possible or is not efficient enough to reach defined safety strategy. Thus mechanical or forced ventilation can be interesting means to avoid critical concentration of hydrogen considering degraded operation and associated potential hazardous events. To better understand the impact of mechanical ventilation on the hydrogen build-up and distribution a dedicated study was led. First accidental release scenarios were experimentally simulated with helium in a 1-m3 enclosure. Several configurations of release and ventilation modes were tested and are presented in this study. Secondly analytical and numerical – Computational Fluid Dynamics – calculation approaches were applied and adjusted to propose a simplified methodology taking into account mechanical ventilation for assessment of hydrogen accumulation and for design optimization of the applications.
Morphological, Structural and Hydrogen Storage Properties of LaCrO3 Perovskite-Type Oxides
Feb 2022
Publication
Recently perovskite-type oxides have attracted researchers as new materials for solid hydrogen storage. This paper presents the performances of perovskite-type oxide LaCrO3 dedicated for hydrogen solid storage using both numerical and experimental methods. Ab initio calculations have been used here with the aim to investigate the electronic mechanical and elastic properties of LaCrO3Hx (x = 0 6) for hydrogen storage applications. Cell parameters crystal structures and mechanical properties are determined. Additionally the cohesive energy indicates the stability of the hydride. Furthermore the mechanical properties showed that both compounds (before and after hydrogenation) are stable. The microstructure and storage capacity at different temperatures of these compounds have been studied. We have shown that storage capacities are around 4 wt%. The properties obtained from this type of hydride showed that it can be used for future applications. XRD analysis was conducted in order to study the structural properties of the compound. Besides morphological thermogravimetric analysis was also conducted on the perovskite-type oxide. Finally a comparison of these materials with other hydrides used for hydrogen storage was carried out.
Energy integration – The Covid-19 Crisis and Clean Energy Progress – Analysis Report
Jun 2020
Publication
The Covid-19 pandemic has dealt a massive blow to countries around the world choking economies and transforming daily life for billions of people. This extraordinary disruption has significantly impacted the energy sector with worrying implications for clean energy transitions. Some key clean energy technologies have been encouragingly resilient to the effects of the crisis but so far there is little to suggest that the dramatic structural progress needed to achieve long-term climate and energy goals will happen in the current turmoil. Unprecedented action and leadership from governments companies and other real-world decision makers will be required to put the world more firmly on a sustainable long-term pathway. The energy sector must achieve dramatic sustained emissions reductions through policy investment and innovation measures across all energy sectors and technologies.
Building on Tracking Clean Energy Progress 2020 and other COVID-19 analysis this article takes stock of how the crisis has affected energy sectors and technologies thus far and explores the potential implications for clean energy transitions over the medium and longer term.
Link to Document on IEA Website
Building on Tracking Clean Energy Progress 2020 and other COVID-19 analysis this article takes stock of how the crisis has affected energy sectors and technologies thus far and explores the potential implications for clean energy transitions over the medium and longer term.
Link to Document on IEA Website
Role of Hydrogen-Charging on Nucleation and Growth of Ductile Damage in Austenitic Stainless Steels
May 2019
Publication
Hydrogen energy is a possible solution for storage in the future. The resistance of packaging materials such as stainless steels has to be guaranteed for a possible use of these materials as containers for highly pressurized hydrogen. The effect of hydrogen charging on the nucleation and growth of microdamage in two different austenitic stainless steels AISI316 and AISI316L was studied using in situ tensile tests in synchrotron X-ray tomography. Information about damage nucleation void growth and void shape were obtained. AISI316 was found to be more sensitive to hydrogen compared to AISI316L in terms of ductility loss. It was measured that void nucleation and growth are not affected by hydrogen charging. The effect of hydrogen was however found to change the morphology of nucleated voids from spherical cavities to micro-cracks being oriented perpendicular to the tensile axis.
Multi-Objective Optimal Design of a Hydrogen Supply Chain Powered with Agro-Industrial Wastes from the Sugarcane Industry: A Mexican Case Study
Jan 2022
Publication
This paper presents an optimization modeling approach to support strategic planning for designing hydrogen supply chain (HSC) networks. The energy source for hydrogen production is proposed to be electricity generated at Mexican sugar factories. This study considers the utilization of existing infrastructure in strategic areas of the country which brings several advantages in terms of possible solutions. This study aims to evaluate the economic and environmental implications of using biomass wastes for energy generation and its integration to the national energy grid where the problem is addressed as a mixed-integer linear program (MILP) adopting maximization of annual profit and minimization of greenhouse gas emissions as optimization criteria. Input data is provided by sugar companies and the national transport and energy information platform and were represented by probability distributions to consider variability in key parameters. Independent solutions show similarities in terms of resource utilization while also significant differences regarding economic and environmental indicators. Multi-objective optimization was performed by a genetic algorithm (GA). The optimal HSC network configuration is selected using a multi-criteria decision technique i.e. TOPSIS. An uncertainty analysis is performed and main economic indicators are estimated by investment assessment. Main results show the trade-off interactions between the HSC elements and optimization criteria. The average internal rate of return (IRR) is estimated to be 21.5% and average payback period is 5.02 years.
International Association for Hydrogen Safety ‘Research Priorities Workshop’, September 2018, Buxton, UK
Sep 2018
Publication
Hydrogen has the potential to be used by many countries as part of decarbonising the future energy system. Hydrogen can be used as a fuel ‘vector’ to store and transport energy produced in low-carbon ways. This could be particularly important in applications such as heating and transport where other solutions for low and zero carbon emission are difficult. To enable the safe uptake of hydrogen technologies it is important to develop the international scientific evidence base on the potential risks to safety and how to control them effectively. The International Association for Hydrogen Safety (known as IA HySAFE) is leading global efforts to ensure this. HSE hosted the 2018 IA HySAFE Biennial Research Priorities Workshop. A panel of international experts presented during nine key topic sessions: (1) Industrial and National Programmes; (2) Applications; (3) Storage; (4) Accident Physics – Gas Phase; (5) Accident Physics – Liquid/ Cryogenic Behaviour; (6) Materials; (7) Mitigation Sensors Hazard Prevention and Risk Reduction; (8) Integrated Tools for Hazard and Risk Assessment; (9) General Aspects of Safety.<br/>This report gives an overview of each topic made by the session chairperson. It also gives further analysis of the totality of the evidence presented. The workshop outputs are shaping international activities on hydrogen safety. They are helping key stakeholders to identify gaps in knowledge and expertise and to understand and plan for potential safety challenges associated with the global expansion of hydrogen in the energy system.
Three-dimensional Structures of N2-Diluted Stoichiometric H2-O2 Flames in Narrow Channels
Sep 2021
Publication
Flame propagation and acceleration in unobstructed channels/tubes is usually assumed as symmetric. A fully optically accessible narrow channel that allows to perform simultaneous high-speed schlieren visualization from two mutually perpendicular directions was built to asses the validity of the aforementioned assumption. Here we provide experimental evidence of the interesting three-dimensional structures and asymmetries that develop during the acceleration phase and show how these may control detonation onset in N2-diluted stoichiometric H2-O2 mixtures.
Vented Explosion of Hydrogen/Air Mixture: An Inter Comparison Benchmark Exercise
Sep 2017
Publication
Explosion venting is a widely used mitigation solution in the process industry to protect indoor equipment or buildings from excessive internal pressure caused by accidental explosions. However vented explosions are very complicated to model using computational fluid dynamics (CFD). In the framework of a French working group the main target of this investigation is to assess the predictive capabilities of five CFD codes used by five different organizations by means of comparison with recent experimental data. On this basis several recommendations for the CFD modelling of vented explosions are suggested.
Detailed Examination of Deformations Induced by Internal Hydrogen Explosions: Part 1 Experiments
Sep 2019
Publication
In industry handling hydrogen explosion presents a potential danger due to its effects on people and property. In the nuclear industry this explosion which is possible during severe accidents can challenge the reactor containment and it may lead to a release of radioactive materials into the environment. The Three Mile Island accident in the United States in 1979 and more recently the Fukushima accident in Japan have highlighted the importance of this phenomenon for a safe operation of nuclear installations as well as for the accident management.<br/>In 2013 the French Research Agency (ANR) launched the MITHYGENE project with the main aim of improving knowledge on hydrogen risk for the benefit of reactor safety. One of the topics in this project is devoted to the effect of hydrogen explosions on solid structures. In this context CEA conducted a test program with its SSEXHY facility to build a database on deformations of simple structures following an internal hydrogen explosion. Different regimes of explosion propagation have been studied ranging from detonation to slow deflagration. Different targets were tested such as cylinders and plates of variable thickness and diameter. Detailed instrumentation was used to obtain data for the validation of coupled CFD models of combustion and structural dynamics.<br/>This article details the experimental set-up and the results obtained. A companion article focuses on the comparison between these experimental results and the prediction of CFD numerical models
Comparison of Regulations Codes and Standards for Hydrogen Refueling Stations in Japan and France
Sep 2019
Publication
The states of Regulations Codes and Standards (RCS) of hydrogen refueling stations (HRSs) in Japan and France are compared and specified items to understand correspondence and differences among each RCSs for realizing harmonization in RCS. Japan has been trying to reform its RCSs to reduce HRS installation and operation costs as a governmental target. Specific crucial regulatory items such as safety distances mitigation means materials for hydrogen storage and certification of anti-explosion proof equipments are compared in order to identify the origins of the current obstacles for disseminating HRS.
Hot Surface Ignition in Flowing Streams of Hydrogen-Air Mixtures
Sep 2019
Publication
A set of original experiments is presented covering the topic of hydrogen-air mixture ignition by a hot surface. The hot surface is a 30 mm long/10 mm diameter heated coil which temperature is controlled by IR techniques. The coil is placed into the flowing stream of hydrogen air mixtures. The variable parameters are the composition of the flammable atmosphere (4 to 75% H2 v/v) the flow speed (from 0.5 m/s to 30 m/s) and its temperature (from -110°C to ambient). The experimental techniques and results are presented and a tentative interpretation is proposed based on ignition theories and highspeed video recordings. It is shown that the ignition temperature (600°C) is insensitive to flowing conditions which is a very unexpected result.
Towards Non-Mechanical Hybrid Hydrogen Compression for Decentralized Hydrogen Facilities
Jun 2020
Publication
The cost of the hydrogen value chain needs to be reduced to allow the widespread development of hydrogen applications. Mechanical compressors widely used for compressing hydrogen to date account for more than 50% of the CAPEX (capital expenditure) in a hydrogen refuelling station. Moreover mechanical compressors have several disadvantages such as the presence of many moving parts hydrogen embrittlement and high consumption of energy. Non-mechanical hydrogen compressors have proven to be a valid alternative to mechanical compressors. Among these electrochemical compressors allow isothermal and therefore highly efficient compression of hydrogen. On the other hand adsorption-desorption compressors allow hydrogen to be compressed through cooling/heating cycles using highly microporous materials as hydrogen adsorbents. A non-mechanical hybrid hydrogen compressor consisting of a first electrochemical stage followed by a second stage driven by adsorption-desorption of hydrogen on activated carbons allows hydrogen to be produced at 70 MPa a value currently required for the development of hydrogen automotive applications. This system has several advantages over mechanical compressors such as the absence of moving parts and high compactness. Its use in decentralized hydrogen facilities such as hydrogen refuelling stations can be considered
Effects of Purity and Pressure on the Hydrogen Embrittlement of Steels and Other Metallic Materials
Sep 2009
Publication
A study of open literature was performed to determine the effects of high hydrogen purity and gas pressure (in the range of 700-1000 bar) on the hydrogen embrittlement of several metallic materials. A particular focus was given to carbon low-alloy and stainless steels but information on embrittlement of aluminum and copper was included in the study. Additionally the most common test methods were studied and results from similar tests are presented in a manner so as to simplify comparisons of materials. Finally suggestions are provided for future testing necessary to ensure the safety of hydrogen storage at 700 bar.
On the Use of Spray Systems- An Example of R&D Work in Hydrogen Safety for Nuclear Applications
Sep 2007
Publication
The aim of the present work is to investigate the interaction between a water spray and a laminar hydrogen-air flame in the case of steam inerted mixture. A first work is devoted to study the thermodynamics involved in the phenomena via a lumped parameter code. The flow is two- phase and reactive the gas is multi-component the water spray is polydisperse and the droplet size has certainly an influence on the flame propagation. The energy released by the reaction between hydrogen and oxygen vaporizes suspended droplets. The next step of this study will be to consider a drift-flux model for the droplets and air under hypotheses that the velocity and thermal disequilibria are weak. The multi-component feature of the gas will be further taken into account by studying a gas mixture containing hydrogen air and water vapor. A second study concerns an experimental investigation of the effect of droplets on the flame propagation using a spherical vessel. A Schlieren system is coupled to the spherical vessel in order to record the flame propagation on a digital high speed camera. Both studies will help improve our knowledge of safety relevant phenomena.
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