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The Safe Use of the Existing Natural Gas System for Hydrogen (Overview of the NATURALHY-Project)
Sep 2005
Publication
The transition period towards the situation in which hydrogen will become an important energy carrier will be lengthy (decades) costly and needs a significant R&D effort. It’s clear therefore that the development of a hydrogen system requires a practical strategy within the context of the existing assets. Examining the potential of the existing extensive natural gas chain (transmission - distribution - end user infrastructures and appliances) is a logical first step towards the widespread delivery of hydrogen.
The project will define the conditions under which hydrogen can be mixed with natural gas for delivery by the existing natural gas system and later withdrawn selectively from the pipeline system by advanced separation technologies. Membranes will be developed to enable this separation. The socio-economic and life cycle consequences of this hydrogen delivery approach will be mapped out. By adding hydrogen to natural gas the physical and chemical properties of the mixture will differ from “pure” natural gas. As this may have a major effect on safety issues and durability issues (which also have a safety component) related to the gas delivery and the performance of end use appliances these issues are particularly addressed in the project.
The project is executed by a European consortium of 39 partners (including 15 from the gas industry). In this project set up under the auspices of GERG The European Gas Research Group there are leading roles for N.V. Nederlandse Gasunie (NL) Gaz de France (F) TNO (NL) ISQ (P) the Universities of Loughborough and Warwick (UK) and Exergia (GR). Guidance will be provided by a Strategic Advisory Committee consisting of representatives from relevant (inter)national organizations.
The project started on 1st May 2004 and will run for 5 years. The European Commission has selected the Integrated Project NATURALHY for financial support within the Sixth Framework Programme.
The project will define the conditions under which hydrogen can be mixed with natural gas for delivery by the existing natural gas system and later withdrawn selectively from the pipeline system by advanced separation technologies. Membranes will be developed to enable this separation. The socio-economic and life cycle consequences of this hydrogen delivery approach will be mapped out. By adding hydrogen to natural gas the physical and chemical properties of the mixture will differ from “pure” natural gas. As this may have a major effect on safety issues and durability issues (which also have a safety component) related to the gas delivery and the performance of end use appliances these issues are particularly addressed in the project.
The project is executed by a European consortium of 39 partners (including 15 from the gas industry). In this project set up under the auspices of GERG The European Gas Research Group there are leading roles for N.V. Nederlandse Gasunie (NL) Gaz de France (F) TNO (NL) ISQ (P) the Universities of Loughborough and Warwick (UK) and Exergia (GR). Guidance will be provided by a Strategic Advisory Committee consisting of representatives from relevant (inter)national organizations.
The project started on 1st May 2004 and will run for 5 years. The European Commission has selected the Integrated Project NATURALHY for financial support within the Sixth Framework Programme.
Analysis of Buoyancy-driven Ventilation of Hydrogen from Buildings
Sep 2007
Publication
When hydrogen gas is used or stored within a building as with a hydrogen-powered vehicle parked in a residential garage any leakage of unignited H2 will mix with indoor air and may form a flammable mixture. One approach to safety engineering relies on buoyancy-driven passive ventilation of H2 from the building through vents to the outside. To discover relationships between design variables we combine two types of analysis: (1) a simplified 1-D steady-state analysis of buoyancy-driven ventilation and (2) CFD modelling using FLUENT 6.3. The simplified model yields a closed-form expression relating the H2 concentration to vent area height and discharge coefficient; leakage rate; and a stratification factor. The CFD modelling includes 3-D geometry; H2 cloud formation; diffusion momentum convection and thermal effects; and transient response. We modelled a typical residential two-car garage with 5 kg of H2 stored in a fuel tank; leakage rates of 5.9 to 82 L/min (tank discharge times of 12 hours to 1 week); a variety of vent sizes and heights; and both isothermal and nonisothermal conditions. This modelling indicates a range of the stratification factor needed to apply the simplified model for vent sizing as well as a more complete understanding of the dynamics of H2 movement within the building. A significant thermal effect occurs when outdoor temperature is higher than indoor temperature so that thermocirculation opposes the buoyancy-driven ventilation of H2. This circumstance leads to higher concentrations of H2 in the building relative to an isothermal case. In an unconditioned space such as a residential garage this effect depends on the thermal coupling of indoor air to outdoor air the ground (under a concrete slab floor) and an adjacent conditioned space in addition to temperatures. We use CFD modelling to explore the magnitude of this effect under rather extreme conditions.
Collaborative Activities On Hydrogen Safety under the International Energy Agency’s Hydrogen Implementing
Sep 2005
Publication
In October 2004 the International Energy Agency Hydrogen Implementing Agreement (www.ieahia.org) approved the initiation of a collaborative task on hydrogen safety. During the past twelve months a work plan has been established and several member countries have committed to participate. Because of the nature of the International Energy Agency which is an international agreement between governments it is hoped that such collaboration will complement other cooperative efforts to help build the technology base around which codes and standards can be developed. In this way the new task on hydrogen safety will further the IEA Hydrogen Agreement in fulfilling its mission to accelerate the commercial introduction of hydrogen energy. This paper describes the specific scope and work plan for the collaboration that has been developed to date.
Compatibility of Materials with Hydrogen Particular Case- Hydrogen Assisted Stress Cracking of Titanium Alloys
Sep 2007
Publication
A review of the effect of hydrogen on materials is addressed in this paper. General aspects of the interaction of hydrogen and materials hydrogen embrittlement low temperature effects material suitability for hydrogen service and materials testing are the main subjects considered in the first part of the paper. As a particular case of the effect of hydrogen in materials the hydride formation of titanium alloys is considered. Alpha titanium alloys are considered corrosion resistant materials in a wide range of environments. However hydrogen absorption and the possible associated problems must be taken into account when considering titanium as a candidate material for high responsibility applications. The sensitivity of three different titanium alloys Ti Gr-2 Ti Gr-5 and Ti Gr-12 to the Hydrogen Assisted Stress Cracking phenomena has been studied by means of the Slow Strain Rate Technique (SSRT). The testing media has been sea water and hydrogen has been produced on the specimen surface during the test by cathodic polarization. Tested specimens have been characterized by metallography and scanning electron microscopy. Results obtained show that the microstructure of the materials particularly the β phase content plays an important role on the sensitivity of the studied alloys to the Hydrogen Assisted Stress Cracking Phenomena.
Physics of Spontaneous Ignition of High-Pressure Hydrogen Release and Transition to Jet Fire
Sep 2009
Publication
The main objective of this study is an insight into physical phenomena underlying spontaneous ignition of hydrogen at sudden release from high pressure storage and its transition into the sustained jet fire. This paper describes modelling and large eddy simulation (LES) of spontaneous ignition dynamics in a tube with a rupture disk separating high pressure hydrogen storage and the atmosphere. Numerical experiments carried out by a LES model have provided an insight into the physics of the spontaneous ignition phenomenon. It is demonstrated that a chemical reaction commences in a boundary layer within the tube and propagates throughout the tube cross-section after that. Simulated by the LES model dynamics of flame formation outside the tube has reproduced experimental observation of combustion by high-speed photography including vortex induced “flame separation". It is concluded that the model developed can be applied for hydrogen safety engineering in particular for development of innovative pressure relief devices.
Prediction of the Lift-off, Blow-out and Blow-off Stability Limits of Pure Hydrogen and Hydrogen and Hydrocarbon Mixture Jet Flames
Sep 2007
Publication
The paper presented experimental studies of the liftoff and blowout stability of pure hydrogen hydrogen/propane and hydrogen/methane jet flam es using a 2 mm burner. Carbon dioxide and Argon gas were also used in the study for the comparison with hydrocarbon fuel. Comparisons of the stability of H 2/C3H8 H 2/CH4 H 2/Ar and H 2/CO2 flames showed that H 2/C3H8 produced the highest liftoff height and H 2/CH4 required highest liftoff and blowoff velocities. The non-dimensional analysis of liftoff height approach was used to correlate liftoff data of H 2 H2-C3H8 H 2-CO2 C 3H8 and H2-Ar jet flames tested in the 2 mm burner. The suitability of extending the empirical correlations based on hydrocarbon flames to both hydrogen and hydrogen/ hydrocarbon flames was examined.
A Rural Hydrogen Transportation Test Bed
Sep 2007
Publication
The University of Missouri-Rolla (UMR) through a hydrogen internal combustion engine vehicle evaluation participation agreement with the Ford Motor Company will establish a commuter bus service and hydrogen refueling at a station in rural Missouri near Ft. Leonard Wood (FLW). Initiated by a request from the U.S. Army Maneuver Support Center at FLW UMR is leading the effort to launch the commuter service between FLW and the neighboring towns of Rolla and Lebanon Missouri each of which are located approximately 40 km from the military base on Interstate-44 highway. The broad research training and education agenda for the rural hydrogen transportation test bed is to develop demonstrate evaluate and promote safe hydrogen-based technologies in a real world environment. With funds provided by the Defense Logistics Agency through the Air Force Research Laboratory this hydrogen initiative will build and operate a hydrogen fueling facility that includes on-site generation of hydrogen through electrolysis as well as selling a range of other traditional and alternative fuels.
Safety of Hydrogen-fueled Motor Vehicles with IC Engines.
Sep 2005
Publication
Clarification of questions of safety represents a decisive contribution to the successful introduction of vehicles fuelled by hydrogen. At the moment the safety of hydrogen is being discussed and investigated by various bodies. The primary focus is on fuel-cell vehicles with hydrogen stored in gaseous form. This paper looks at the safety of hydrogen-fuelled vehicles with an internal combustion engine and liquefied hydrogen storage. The safety concept of BMW’s hydrogen vehicles is described and the specific aspects of the propulsion and storage concepts discussed. The main discussion emphasis is on the utilization of boil-off parking of the vehicles in an enclosed space and their crash behaviour. Theoretical safety observations are complemented by the latest experimental and test results. Finally reference is made to the topic-areas in the field of hydrogen safety in which cooperative research work could make a valuable contribution to the future of the hydrogen-powered vehicle.
Experimental Investigation of Hydrogen Jet Fire Mitigation by Barrier Walls
Sep 2009
Publication
Hydrogen jet flames resulting from ignition of unintended releases can be extensive in length and pose significant radiation and impingement hazards. One possible mitigation strategy to reduce exposure to jet flames is to incorporate barriers around hydrogen storage and delivery equipment. While reducing the extent of unacceptable consequences the walls may introduce other hazards if not properly configured. This paper describes experiments carried out to characterize the effectiveness of different barrier wall configurations at reducing the hazards created by jet fires. The hazards that are evaluated are the generation of overpressure during ignition the thermal radiation produced by the jet flame and the effectiveness of the wall at deflecting the flame.<br/>The tests were conducted against a vertical wall (1-wall configuration) and two “3-wall” configurations that consisted of the same vertical wall with two side walls of the same dimensions angled at 135° and 90°. The hydrogen jet impinged on the center of the central wall in all cases. In terms of reducing the radiation heat flux behind the wall the 1-wall configuration performed best followed by the 3-wall 135° configuration and the 3-wall 90°. The reduced shielding efficiency of the three-wall configurations was probably due to the additional confinement created by the side walls that limited the escape of hot gases to the sides of the wall and forced the hot gases to travel over the top of the wall.<br/>The 3-wall barrier with 135° side walls exhibited the best overall performance. Overpressures produced on the release side of the wall were similar to those produced in the 1-wall configuration. The attenuation of overpressure and impulse behind the wall was comparable to that of the three-wall configuration with 90° side walls. The 3-wall 135° configuration’s ability to shield the back side of the wall from the heat flux emitted from the jet flame was comparable to the 1-wall and better than the 3-wall 90° configuration. The ratio of peak overpressure (from in front of the wall and from behind the wall) showed that the 3-wall 135° configuration and the 3-wall 90° configuration had a similar effectiveness. In terms of the pressure mitigation the 3-wall configurations performed significantly better than the 1-wall configuration
Recent Progress in the Steam Reforming of Bio-Oil for Hydrogen Production: A Review of Operating Parameters, Catalytic Systems and Technological Innovations
Dec 2021
Publication
The present review focuses on the production of renewable hydrogen through the catalytic steam reforming of bio-oil the liquid product of the fast pyrolysis of biomass. Although in theory the process is capable of producing high yields of hydrogen in practice certain technological issues require radical improvements before its commercialization. Herein we illustrate the fundamental knowledge behind the technology of the steam reforming of bio-oil and critically discuss the major factors influencing the reforming process such as the feedstock composition the reactor design the reaction temperature and pressure the steam to carbon ratio and the hour space velocity. We also emphasize the latest research for the best suited reforming catalysts among the specific groups of noble metal transition metal bimetallic and perovskite type catalysts. The effect of the catalyst preparation method and the technological obstacle of catalytic deactivation due to coke deposition metal sintering metal oxidation and sulfur poisoning are addressed. Finally various novel modified steam reforming techniques which are under development are discussed such as the in-line two-stage pyrolysis and steam reforming the sorption enhanced steam reforming (SESR) and the chemical looping steam reforming (CLSR). Moreover we argue that while the majority of research studies examine hydrogen generation using different model compounds much work must be done to optimally treat the raw or aqueous bio-oil mixtures for efficient practical use. Moreover further research is also required on the reaction mechanisms and kinetics of the process as these have not yet been fully understood.
Hydrogen–methane Mixtures: Dispersion and Stratification Studies
Sep 2011
Publication
The study of hydrogen as an alternative fuel clean and “environment friendly” has been in the last years and continues to be object of many studies international projects and standard development. Hydrogen is a fundamental energy carrier to be developed together with other renewable resources for the transition to a sustainable energy system.<br/>But experience has shown how often the introduction and establishment of a new technology does not necessarily pass through radical changes but can be stimulated by slight modifications to the “present situation”.<br/>So the worldwide experience with natural gas as industrial automotive and domestic fuel has been the incentive to the present interest towards hydrogen–methane mixtures. The possible use of existing pipeline networks for mixtures of natural gas and hydrogen offers a unique and cost-effective opportunity to initiate the progressive introduction of hydrogen as part of the development of a full hydrogen system.<br/>The aim of the work presented in this paper is the investigation of the dispersion and stratification properties of hydrogen and methane mixtures. Experimental activities have been carried out in a large scale closed apparatus characterized by a volume of about 25 m3 both with and without natural ventilation. Mixtures of 10%vol. hydrogen – 90%vol. methane and 30%vol. hydrogen – 70%vol. methane have been studied with the help of oxygen sensors and gas chromatography.
Life Cycle Environmental Analysis of a Hydrogen-based Energy Storage System for Remote Applications
Mar 2022
Publication
Energy storage systems are required to address the fluctuating behaviour of variable renewable energy sources. The environmental sustainability of energy storage technologies should be carefully assessed together with their techno-economic feasibility. In this work an environmental analysis of a renewable hydrogen-based energy storage system has been performed making use of input parameters made available in the framework of the European REMOTE project. The analysis is applied to the case study of the Froan islands (Norway) which are representative of many other insular microgrid sites in northern Europe. The REMOTE solution is compared with other scenarios based on fossil fuels and submarine connections to the mainland grid. The highest climate impacts are found in the dieselbased configuration (1090.9 kgCO2eq/MWh) followed by the REMOTE system (148.2 kgCO2eq/MWh) and by the sea cable scenario (113.7 kgCO2eq/MWh). However the latter is biased by the very low carbon intensity of the Norwegian electricity. A sensitivity analysis is then performed on the length of the sea cable and on the CO2 emission intensity of electricity showing that local conditions have a strong impact on the results. The REMOTE system is also found to be the most cost-effective solution to provide electricity to the insular community. The in-depth and comparative (with reference to possible alternatives) assessment of the renewable hydrogen-based system aims to provide a comprehensive overview about the effectiveness and sustainability of these innovative solutions as a support for off-grid remote areas.
Scenarios for Deployment of Hydrogen in Meeting Carbon Budgets (E4tech)
Nov 2015
Publication
This research considers the potential role of hydrogen in meeting the UK’s carbon budgets. It was written by consultancy E4tech.<br/>The CCC develops scenarios for the UK’s future energy system to assess routes to decarbonisation and to advise UK Government on policy options. Uncertainty to 2050 is considerable and so different scenarios are needed to assess different trajectories targets and technology combinations. Some of these scenarios assess specific technologies or fuels which have the potential to make a significant contribution to future decarbonisation.<br/>Hydrogen is one such fuel. It has been included in limited quantities in some CCC scenarios but not extensively examined in part due to perceived or anticipated higher costs than some other options. But as hydrogen technology is developed and deployed the cost projections and other performance indicators have become more favourable.
Quantification of the Uncertainty of the Peak Pressure Value in the Vented Deflagrations of Air-Hydrogen Mixtures
Sep 2007
Publication
In the problem of the protection by the consequences of an explosion is actual for many industrial application involving storage of gas like methane or hydrogen refuelling stations and so on. A simple and economic way to reduce the peak pressure associated to a deflagration is to supply to the confined environment an opportune surface substantially less resistant then the protected structure typically in stoichiometric conditions the peak pressure reduction is around the 8 bars for a generic hydrocarbon combustion in an adiabatic system lacking of whichever mitigation system. In general the problem is the forecast of the peak pressure value (PMAX) of the explosion. This problem is faced using CFD codes modelling the structure in which the explosion is located and setting the main parameters like concentration of the gas in the mixture the volume available the size of vent area and obstacles (if included) and so on. In this work the idea is to start from empirical data to train a Neural Network (NN) in order to find the correlation among the parameters regulating the phenomenon. Associated to this prediction a fuzzy model will provide to quantify the uncertainty of the predicted value.
Safety Aspects of Land-Use Planning Scenarios for a Future Infrastructure with Hydrogen Re-Fuelling Stations
Sep 2005
Publication
Hydrogen is currently gaining much attention as a possible future substitute for oil in the transport sector. Hydrogen is not a primary energy source but can be produced from other sources of energy. A future hydrogen economy will need the establishment of new infrastructures for producing storing distributing dispensing and using hydrogen. Hydrogen can be produced in large-scale centralized facilities or in smaller scale on-site systems. Large-scale production requires distribution in pipelines or trucks. A major challenge is to plan the new infrastructures to approach an even safer society regarding safe use of hydrogen. The paper will on the basis of some scenarios for hydrogen deployment highlight and evaluate safety aspects related to future hydrogen economy infrastructures.
Experimental Study of Hydrogen Release Accidents in a Vehicle Garage
Sep 2009
Publication
Storing a hydrogen fuel-cell vehicle in a garage poses a potential safety hazard because of the accidents that could arise from a hydrogen leak. A series of tests examined the risk involved with hydrogen releases and deflagrations in a structure built to simulate a one-car garage. The experiments involved igniting hydrogen gas that was released inside the structure and studying the effects of the deflagrations. The “garage” measured 2.72 m high 3.64 m wide and 6.10 m long internally and was constructed from steel using a reinforced design capable of withstanding a detonation. The front face of the garage was covered with a thin transparent plastic film. Experiments were performed to investigate extended-duration (20–40 min) hydrogen leaks. The effect that the presence of a vehicle in the garage has on the deflagration was also studied. The experiments examined the effectiveness of different ventilation techniques at reducing the hydrogen concentration in the enclosure. Ventilation techniques included natural upper and lower openings and mechanical ventilation systems. A system of evacuated sampling bottles was used to measure hydrogen concentration throughout the garage prior to ignition and at various times during the release. All experiments were documented with standard and infrared (IR) video. Flame front propagation was monitored with thermocouples. Pressures within the garage were measured by four pressure transducers mounted on the inside walls of the garage. Six free-field pressure transducers were used to measure the pressures outside the garage.
Assessing the Durability and Integrity of Natural Gas Infrastructures for Transporting and Distributing Mixtures of Hydrogen and Natural Gas
Sep 2005
Publication
Extensive infrastructure exists for the transport of natural gas and it is an obvious step to assess its use for the movement of hydrogen. The Naturalhy project’s objective is to prepare the European natural gas industry for the introduction of hydrogen by assessing the capability of the natural gas infrastructure to accept mixtures of hydrogen and natural gas. This paper presents the ongoing work within both Durability and Integrity Work Packages of the Naturalhy project. This work covers a gap in knowledge on risk assessment required for delivering H2+natural gas blends by means of the existing natural gas grids in safe operation.<br/>Experiments involving several parts of the existing infrastructure will be described that are being carried out to re-examine the major risks previously studied for natural gas including: effect of H2 on failure behaviour and corrosion of transmission pipes and their burst resistance (link to the Work Package Safety) on permeability and ageing of distribution pipes on reliability and ageing of domestic gas meters tightness to H2 of domestic appliances and their connexions. The information will be integrated into existing Durability assessment methodologies originally developed for natural gas.<br/>An Integrity Management Tool will be developed taking account of the effect of hydrogen on the materials properties. The tool should enable a cost effective selection of appropriate measures to control the structural integrity and maintaining equipment. The main measures considered are monitoring non destructive examination (pigging and non pigging) and repair strategies. The tool will cover a number of parameters e.g.: percentage of hydrogen in the gas mixture material of construction operating conditions and condition of cathodic protection. Thus the Integrity Management Tool will yield an inspection and maintenance plan based on the specific circumstances.
Modelling of Lean Uniform and Non-Uniform Hydrogen-Air Mixture Explosions in a Closed Vessel
Sep 2009
Publication
Simulation of hydrogen-air mixture explosions in a closed large-scale vessel with uniform and nonuniform mixture compositions was performed by the group of partners within the EC funded project “Hydrogen Safety as an Energy Carrier” (HySafe). Several experiments were conducted previously by Whitehouse et al. in a 10.7 m3 vertically oriented (5.7-m high) cylindrical facility with different hydrogen-air mixture compositions. Two particular experiments were selected for simulation and comparison as a Standard Benchmark Exercise (SBEP) problem: combustion of uniform 12.8% (vol.) hydrogen-air mixture and combustion of non-uniform hydrogen-air mixture with average 12.6% (vol.) hydrogen concentration across the vessel (vertical stratification 27% vol. hydrogen at the top of the vessel 2.5% vol. hydrogen at the bottom of the vessel); both mixtures were ignited at the top of the vessel. The paper presents modelling approaches used by the partners comparison of simulation results against the experiment data and conclusions regarding the non-uniform mixture combustion modelling in real-life applications.
Towards Hydrogen Safety Education and Training
Sep 2005
Publication
The onset and further development of the hydrogen economy are known to be constrained by safety barriers as well as by the level of public acceptance of new applications. Educational and training programmes in hydrogen safety which are currently absent in Europe are considered to be a key instrument in lifting these limitations and to ensure the safe introduction of hydrogen as an energy carrier. Therefore the European Network of Excellence ‘Safety of Hydrogen as an Energy Carrier’ (NoE HySafe) embarked on the establishment of the e-Academy of Hydrogen Safety. This work is led by the University of Ulster and carried out in cooperation with international partners from five other universities (Universidad Politecnica de Madrid Spain; University of Pisa Italy; Warsaw University of Technology Poland; Instituto Superior Technico Portugal; University of Calgary Canada) two research institutions (Forschungszentrum Karlsruhe and Forschungszentrum Juelich Germany) and one enterprise (GexCon Norway). The development of an International Curriculum on Hydrogen Safety Engineering aided by world-class experts from within and outside NoE HySafe is of central importance to the establishment of the e-Academy of Hydrogen Safety. Despite its key role in identifying the knowledge framework of the subject matter and its role in aiding educators with the development of teaching programmes on hydrogen safety no such curriculum appears to have been developed previously. The current structure of the International Curriculum on Hydrogen Safety Engineering and the motivation behind it are described in this paper. Future steps in the development of a system of hydrogen safety education and training in Europe are briefly described.
Addressing Hydrogen Embrittlement of Metals in the Sae J2579 Fuel Cell Vehicle Tank Standard
Sep 2013
Publication
The SAE Technical Information Report (TIR) J2579 (Technical Information Report for Fuel Systems in Fuel Cell and Other Hydrogen Vehicles) has been created to address the safety performance of hydrogen storage and handling systems on vehicles. Safety qualification of the compressed hydrogen storage system is demonstrated through performance testing on prototype containment vessels. The two performance tests currently included in the SAE J2579 for evaluating unacceptable leakage and burst do not account for the potential effects of hydrogen embrittlement on structural integrity. This report describes efforts to address hydrogen embrittlement of structural metals in the framework of performance-based safety qualification. New safety qualification pathways that account for hydrogen embrittlement in the SAE J2579 include an additional pneumatic performance test using hydrogen gas or materials tests that demonstrate acceptable hydrogen embrittlement resistance of candidate structural metals.
Design of Clean Steel Production with Hydrogen: Impact of Electricity System Composition
Dec 2021
Publication
In Europe electrification is considered a key option to obtain a cleaner production of steel at the same time as the electricity system production portfolio is expected to consist of an increasing share of varying renewable electricity (VRE) generation mainly in the form of solar PV and wind power. We investigate cost-efficient designs of hydrogen-based steelmaking in electricity systems dominated by VRE. We develop and apply a linear cost-minimization model with an hourly time resolution which determines cost-optimal operation and sizing of the units in hydrogen-based steelmaking including an electrolyser direct reduction shaft electric arc furnace as well as storage for hydrogen and hot-briquetted iron pellets. We show that the electricity price following steelmaking leads to savings in running costs but to increased capital cost due to investments in the overcapacity of steel production units and storage units for hydrogen and hot-briquetted iron pellets. For two VRE-dominated regions we show that the electricity price following steel production reduces the total steel production cost by 23% and 17% respectively as compared to continuous steel production at a constant level. We also show that the cost-optimal design of the steelmaking process is dependent upon the electricity system mix.
Digital Navigation of Energy–structure–function Maps for Hydrogen-bonded Porous Molecular Crystals
Feb 2021
Publication
Energy–structure–function (ESF) maps can aid the targeted discovery of porous molecular crystals by predicting the stable crystalline arrangements along with their functions of interest. Here we compute ESF maps for a series of rigid molecules that comprise either a triptycene or a spiro-biphenyl core functionalized with six different hydrogen-bonding moieties. We show that the positioning of the hydrogen-bonding sites as well as their number has a profound influence on the shape of the resulting ESF maps revealing promising structure–function spaces for future experiments. We also demonstrate a simple and general approach to representing and inspecting the high-dimensional data of an ESF map enabling an efficient navigation of the ESF data to identify ‘landmark’ structures that are energetically favourable or functionally interesting. This is a step toward the automated analysis of ESF maps an important goal for closed-loop autonomous searches for molecular crystals with useful functions.
Simulation of Flame Acceleration and DDT in H2-air Mixture with a Flux Limiter Centred Method
Sep 2005
Publication
Flame acceleration and deflagration to detonation transition (DDT) is simulated with a numerical code based on a flux limiter centred method for hyperbolic differential equations. The energy source term is calculated by a Riemann solver for the in homogeneous Euler equations for the turbulent combustion and a two-step reaction model for hydrogen-air. The transport equations are filtered for large eddy simulation (LES) and the sub filter turbulence is modelled by a transport equation for the the turbulent kinetic energy. The flame tracking is handled by the G-equation for turbulent flames. Numerical results are compared to pressure histories from physical experiments. These experiments are performed in a closed circular 4m long tube with inner diameter of 0.107m. The tube is filled with hydrogen-air mixture at 1atm which is at rest when ignited. The ignition is located at one end of the tube. The tube is fitted with an obstruction with circular opening 1m down the tube from the ignition point. The obstruction has a blockage ratio of 0.92 and a thickness of 0.01m. The obstruction creates high pressures in the ignition end of the tube and very high gas velocities in and behind the obstruction opening. The flame experiences a detonation to deflagration transition (DDT) in the super sonic jet created by the obstruction. Pressure build-up in the ignition end of the tube is simulated with some discrepancies. The DDT in the supersonic jet is simulated but the position of the DDT is strongly dependent on the simulated pressure in the ignition end.
Experimental Study on Hydrogen Explosions in a Full-scale Hydrogen Filling Station Model
Sep 2005
Publication
In order for fuel cell vehicles to develop a widespread role in society it is essential that hydrogen refuelling stations become established. For this to happen there is a need to demonstrate the safety of the refuelling stations. The work described in this paper was carried out to provide experimental information on hydrogen outflow dispersion and explosion behaviour. In the first phase homogeneous hydrogen-air-mixtures of a known concentration were introduced into an explosion chamber and the resulting flame speed and overpressures were measured. Hydrogen concentration was the dominant factor influencing the flame speed and overpressure. Secondly high-pressure hydrogen releases were initiated in a storage room to study the accumulation of hydrogen. For a steady release with a constant driving pressure the hydrogen concentration varied as the inlet airflow changed depending on the ventilation area of the room the external wind conditions and also the buoyancy induced flows generated by the accumulating hydrogen. Having obtained this basic data the realistic dispersion and explosion experiments were executed at full-scale in the hydrogen station model. High-pressure hydrogen was released from 0.8-8.0mm nozzle at the dispenser position and inside the storage room in the full-scale model of the refuelling station. Also the hydrogen releases were ignited to study the overpressures that can be generated by such releases. The results showed that overpressures that were generated following releases at the dispenser location had a clear correlation with the time of ignition distance from ignition point.
Initial Assessment of the Impact of Jet Flame Hazard from Hydrogen Cars in Road Tunnels and the Implication on Hydrogen Car Design
Sep 2007
Publication
Underground or partial underground tunnels form a very important part of modern road transportation systems. As the development of hydrogen cars advancing into the markets it is unavoidable in the near future that hydrogen cars would become the users of ordinary road tunnels. This paper discusses potential fire scenarios and fire hazards of hydrogen cars in road tunnels and implications on the fire safety measures and ventilation systems in existing tunnels. The information needed for carry out risk assessment of hydrogen cars in road tunnels are discussed. hydrogen has a low ignition energy and wide flammable range suggesting that leaks have a high probability of ignition and result hydrogen flame. CFD simulations of hydrogen fires in a full scale 5m by 5m square cross-section tunnel were carried out. The effect of the ventilation on controlling the back-layering and the downstream flame are discussed.
Assessment and Evaluation of 3rd Party Risk for Planned Hydrogen Demonstration Facility
Sep 2007
Publication
Potential risk exposure of 3rd parties i.e. people not involved in the actual operation of a plant is often a critical factor to gain authority approval and public acceptance for a development project. This is also highly relevant for development of demonstration facilities for hydrogen production and refuelling infrastructure. This paper presents and discusses results for risk exposure of 3rd parties based on risk assessment studies performed for the planned Hydrogen Technology Research Centre Hytrec in Trondheim. The methodology applied is outlined. Key assumptions and study uncertainties are identified and how these might affect the results are discussed.<br/>The purpose of Hytrec is to build a centre for research development and demonstration of hydrogen as an energy carrier. Hydrogen will be produced both by reforming of natural gas with CO2 capture and by electrolysis of water. The plant also includes a SOFC that will run on natural gas or hydrogen and produce heat and electricity for the Hytrec visitor centre. Hytrec will be located in a populated area without access control. Most of the units will be located within cabinets and modules.<br/>The authors acknowledge the Hytrec project and the Hytrec project partners Statoil Statkraft and DNV for their support and for allowing utilisation of results from the Hytrec QRA in this paper.
Study of Hydrogen Diffusion and Deflagration in a Closed System
Sep 2007
Publication
A total of 12 ventilation experiments with various combinations of hydrogen release rates and ventilation speeds were performed in order to study how ventilation speed and release rate effect the hydrogen concentration in a closed system. The experiential facility was constructed out of steel plates and beams in the shape of a rectangular enclosure. The volume of the test facility was about 60m3. The front face of the enclosure was covered by a plastic film in order to allow visible and infrared cameras to capture images of the flame. The inlet and outlet vents were located on the lower front face and the upper backside panel respectively. Hydrogen gas was released toward the ceiling from the center of the floor. The hydrogen gas was released at constant rate in each test. The hydrogen release rate ranged from 0.002 m3/s to 0.02 m3/s. Ventilation speeds were 0.1 0.2 and 0.4 m3/s respectively. Ignition was attempted at the end of the hydrogen release by using multiple continuous spark ignition modules on the ceiling and next to the release point. Time evolution of hydrogen concentration was measured using evacuated sample bottles. Overpressure and impulse inside and outside the facility were also measured. The mixture was ignited by a spark ignition module mounted on the ceiling in eight of eleven tests. In the other three tests the mixture was ignited by spark ignition modules mounted next to the nozzle. Overpressures generated by the hydrogen deflagration in most of these tests were low and represented a small risk to people or property. The primary risk associated with the hydrogen deflagrations studied in these tests was from the fire. The maximum concentration is proportional to the ratio of the hydrogen release rate to the ventilation speed within the range of parameters tested. Therefore a required ventilation speed can be estimated from the assumed hydrogen leak rate within the experimental conditions described in this paper.
Molecular Transport Effects of Hydrocarbon Addition on Turbulent Hydrogen Flame Propagation
Sep 2007
Publication
We analytically investigated the influence of light hydrocarbons on turbulent premixed H2/air atmospheric flames under lean conditions in view of safe handling of H2 systems applications in H2 powered IC engines and gas turbines and also with an orientation towards modelling of H2 combustion. For this purpose an algebraic flame surface wrinkling model included with pressure and fuel type effects is used. The model predictions of turbulent premixed flames are compared with the set of corresponding experimental data of Kido et al. (Kido Nakahara et al. 2002). These expanding spherical flame data include H2–air mixtures doped with CH4 and C3H8 while the overall equivalence ratio of all the fuel/air mixtures is fixed at 0.8 for constant unstretched laminar flame speed of 25 cm/s by varying N2 composition. The model predictions show that there is little variation in turbulent flame speed ST for C3H8 additions up to 20-vol%. However for 50 vol% doping flame speed decreases by as much as 30 % from 250 cm/s that of pure H2–air mixtures for turbulence intensity of 200 cm/s. With respect to CH4 for 50 vol% doping ST reduces by only 6 % cf. pure H2/air mixture. In the first instance the substantial decrease of ST with C3H8 addition may be attributed to the increase in the Lewis number of the dual-fuel mixture and proportional restriction of molecular mobility of H2. That is this decrease in flame speed can be explained using the concept of leading edges of the turbulent flame brush (Lipatnikov and Chomiak 2005). As these leading edges have mostly positive curvature (convex to the unburned side) preferential-diffusive-thermal instabilities cause recognizable impact on flame speed at higher levels of turbulence with the effect being very strong for lean H2 mixtures. The lighter hydrocarbon substitutions tend to suppress the leading flame edges and possibly transition to detonation in confined structures and promote flame front stability of lean turbulent premixed flames. Thus there is a necessity to develop a predictive reaction model to quantitatively show the strong influence of molecular transport coefficients on ST.
Novel Wide-area Hydrogen Sensing Technology
Sep 2007
Publication
Element One Inc. is developing novel indicators for hydrogen gas for applications as a complement to conventional electronic hydrogen sensors or as a low-cost alternative in situations where an electronic signal is not needed. The indicator consists of a thin film coating or a pigment of a transition metal oxide such as tungsten oxide or molybdenum oxide with a catalyst such as platinum or palladium. The oxide is partially reduced in the presence of hydrogen in concentrations as low as 300 parts per million and changes from transparent to a dark colour. The colour change is fast and easily seen from a distance. In air the colour change reverses quickly when the source of hydrogen gas is removed in the case of tungsten oxide or is nearly irreversible in the case of molybdenum oxide. A number of possible implementations have been successfully demonstrated in the laboratory including hydrogen indicating paints tape cautionary decals and coatings for hydrogen storage tanks. These and other implementations may find use in vehicles stationary appliances piping refuelling stations and in closed spaces such as maintenance and residential garages for hydrogen-fuelled vehicles. The partially reduced transition metal oxide becomes semi conductive and increases its electrical conductivity by several orders of magnitude when exposed to hydrogen. The integration of this electrical resistance sensor with an RFID tag may extend the ability of these sensors to record and transmit a history of the presence or absence of leaked hydrogen over long distances. Over long periods of exposure to the atmosphere the indicator’s response may slow due to catalyst degradation. Our current emphasis is on controlling this degradation. The kinetics of the visual indicators is being investigated along with their durability in collaboration with the NASA Kennedy Space Center.
CFD Simulation on Diffusion of Leaked Hydrogen Caused by Vehicle Accident in Tunnels
Sep 2005
Publication
Hydrogen fuel cell vehicles are expected to come into widespread use in the near future. Accordingly many hydrogen carrying vehicles will begin to pass through tunnels. It is therefore important to predict whether risk from leaked hydrogen accidents in tunnels can be avoided. CFD simulation was carried out on diffusion of leaked hydrogen in tunnels. Three areas of tunnels were chosen for study. One is the typical longitudinal and lateral areas of tunnels and the others are underground ventilation facilities and electrostatic dust collectors which were simulated with an actual tunnel. The amount of hydrogen leaked was 60m3 (approximately 5.08 kg) which corresponds to the amount necessary for future fuel cell vehicles to achieve their desired running distance. Analytical periods were the time after leaks began until regions of hydrogen above the low flammability limit had almost disappeared or thirty minutes. We found that leaked hydrogen is immediately carried away from leaking area under existing ventilation conditions. We also obtained basic data on behaviour of leaked hydrogen.
Facilitating the Safest Possible Transition from Fossil to Hydrogen Fuels- Hydrogen Executive Leadership Panel
Sep 2005
Publication
In recent years federal and state safety authorities have worked to bring emergency planners and responders together with industry the scientific community and consumers to ensure high levels of safety with gas and liquid pipelines and more recently with liquefied natural gas terminals. The U.S. Department of Transportation (DOT) is the federal authority on the safe transportation of energy and the National Association of State Fire Marshals (NASFM) represents state-level safety authorities. Together they have produced firefighter safety training materials technical guidance and information for use in communities considering new energy infrastructure and conducted research to support these activities. In 2004 the DOT-NASFM partnership established the Hydrogen Executive Leadership Panel (HELP) to ensure a safe transition from fossil fuels to hydrogen fuel cells. HELP brings together senior policy-level experts from all sectors to understand and recommend mitigation strategies for the risks associated with the transportation and use of hydrogen in motor vehicles. The initial group includes experts from the United States Canada and Europe. HELP will be supported by an advisory committee of emergency planners and responders—individuals well-equipped to describe real-world scenarios of greatest concern—and by a second advisory committee of engineers and scientists who will help translate the real-world scenarios into useful technical solutions. By September 2005 HELP expects to define the initial real-world scenarios of greatest concern and bring together teams of experts to collaborate with automakers energy producers government authorities consumers and public safety officials. Much work lies ahead including creating guidance for hydrogen powered automobiles emergency response safety training establishing test methods to reflect real-world incident scenarios and modifying state and local building and fire codes. The HELP leadership will present its strategic plan and first report at the International Conference on Hydrogen Safety in September 2005.
Decrease in Hydrogen Embrittlement Susceptibility of 10B21 Screws by Bake Aging
Aug 2016
Publication
The effects of baking on the mechanical properties and fracture characteristics of low-carbon boron (10B21) steel screws were investigated. Fracture torque tests and hydrogen content analysis were performed on baked screws to evaluate hydrogen embrittlement (HE) susceptibility. The diffusible hydrogen content within 10B21 steel dominated the fracture behavior of the screws. The fracture torque of 10B21 screws baked for a long duration was affected by released hydrogen. Secondary ion mass spectroscopy (SIMS) result showed that hydrogen content decreased with increasing baking duration and thus the HE susceptibility of 10B21 screws improved. Diffusible hydrogen promoted crack propagation in high-stress region. The HE of 10B21 screws can be prevented by long-duration baking.
High Purity, Self-sustained, Pressurized Hydrogen Production from Ammonia in a Catalytic Membrane Reactor
Dec 2021
Publication
The combination of catalytic decomposition of ammonia and in situ separation of hydrogen holds great promise for the use of ammonia as a clean energy carrier. However finding the optimal catalyst – membrane pair and operation conditions have proved challenging. Here we demonstrate that cobalt-based catalysts for ammonia decomposition can be efficiently 2 used together with a Pd-Au based membrane to produce high purity hydrogen at elevated pressure. Compared to a conventional packed bed reactor the membrane reactor offers several operational advantages that result in energetic and economic benefits. The robustness and durability of the combined system has been demonstrated for more than 1000 h on stream yielding a very pure hydrogen stream (>99.97 % H2) and recovery (>90 %). When considering the required hydrogen compression for storage/utilization and environmental issues the combined system offers the additional advantage of production of hydrogen at moderate pressures along with full ammonia conversion. Altogether our results demonstrate the possibility of deploying high pressure (350 bar) hydrogen generators from ammonia with H2 efficiencies of circa 75% without any external energy input and/or derived CO2 emissions.
Experimental Characterization and Energy Performance Assessment of a Sorption-Enhanced Steam–Methane Reforming System
Aug 2021
Publication
The production of blue hydrogen through sorption-enhanced processes has emerged as a suitable option to reduce greenhouse gas emissions. Sorption-enhanced steam–methane reforming (SESMR) is a process intensification of highly endothermic steam–methane reforming (SMR) ensured by in situ carbon capture through a solid sorbent making hydrogen production efficient and more environmentally sustainable. In this study a comprehensive energy model of SESMR was developed to carry out a detailed energy characterization of the process with the aim of filling a current knowledge gap in the literature. The model was applied to a bench-scale multicycle SESMR/sorbent regeneration test to provide an energy insight into the process. Besides the experimental advantages of higher hydrogen concentration (90 mol% dry basis 70 mol% wet basis) and performance of CO2 capture the developed energy model demonstrated that SESMR allows for substantially complete energy self-sufficiency through the process. In comparison to SMR with the same process conditions (650 ◦C 1 atm) performed in the same experimental rig SESMR improved the energy efficiency by about 10% further reducing energy needs.
Impact Assessment of Hydrogen Transmission on TD1 Parallel Pipeline Separation Distances
Mar 2021
Publication
The recommended minimum separation distances in IGEM/TD/1 were based on a research programme that studied the different ways in which a failure of one buried natural gas transmission pipeline can affect another similar pipeline installed adjacent to the first taking account of the initial pressure wave propagating through the ground the size of the ground crater produced and the threat of escalation from fire if the second pipeline is exposed. The methodology developed from the research was first published in 2010 and is implemented in a software program (“PROPHET”). The distances in IGEM/TD/1 are generally cautious and are essentially determined by the size of the ground crater produced by pipeline ruptures as predicted by the methodology.
To assess the impact of hydrogen transmission on the recommended separation distances the possibility of one pipeline transporting natural gas and the other transporting hydrogen was considered as well as both pipelines transporting hydrogen. The following steps were carried out to assess the impact of hydrogen transmission on parallel pipeline separation distances drawing on existing knowledge only:
To assess the impact of hydrogen transmission on the recommended separation distances the possibility of one pipeline transporting natural gas and the other transporting hydrogen was considered as well as both pipelines transporting hydrogen. The following steps were carried out to assess the impact of hydrogen transmission on parallel pipeline separation distances drawing on existing knowledge only:
- Estimate the ground pressure loading predicted from a hydrogen pipeline rupture.
- Consider the ground pressure effect on a parallel natural gas or hydrogen pipeline.
- Evaluate available ground crater formation models and assess if existing natural gas model is cautious for hydrogen.
- Consider effects of thermal loading due to hydrogen fires where recommended natural gas separation distances are not met.
- Ground pressure loading: The current natural gas methodology is cautious.
- Ground pressure effects: The current natural gas methodology is applicable (no change for hydrogen).
- Ground crater formation: The current natural gas methodology is cautious for ruptures and applicable for punctures (almost no change for hydrogen).
- Thermal loading: The current natural gas methodology is cautious for the thermal loading from ruptures but not necessarily cautious for punctures. Calculations of the minimum flow velocity required to prevent failure of a natural gas pipeline are not cautious for hydrogen.
Dynamic Model to Expand Energy Storage in Form of Battery and Hydrogen Production Using Solar Powered Water Electrolysis for Off Grid Communities
Feb 2022
Publication
In this model we used a 50 WP photovoltaic panel to produce electrical energy. This electricity production was used directly and stored in a battery. In this design we coupled batteries and hydrogen as a means of storing energy. In case of overcharging the battery it will be attached with water electrolysis to convert the excess amount of chemical energy of the battery into hydrogen energy storage. Hydrogen will be stored as a compacted gas and in chemical storage. We used PEM (proton exchange membrane) electrolysis technologies to breakdown water molecules into hydrogen and oxygen which were then stored in the designed tanks. Different supply voltages were used in our practical readings with an average gaining of 22.8 mL/min on a voltage supply of 2. While using Ansys simulation software we extrapolated hydrogen production until reaching 300 mL/min on 12 V of supply (which represents 220% higher production). By using the second phase of this model hydrogen energy was converted back into electrical energy with the help of a PEM (proton exchange membrane) fuel cell when needed. This model explores the feasibility of energy storage in the form of hydrogen and chemical energy for off-grid communities and remote areas comprising batteries water electrolysis and fuel cells. The main purpose of hydrogen storage in this system is to store and handle the extra energy of system produced through PV panel and utilize it for any desired requirements.
Effect of Hydrogen-storage Pressure on the Detonation Characteristics of Emulsion Explosives Sensitized by Glass Microballoons
Mar 2021
Publication
In this study hydrogen-storage glass microballoons were introduced into emulsion explosives to improve the detonation performance of the explosives. The effect of hydrogen-storage pressure on the detonation characteristics of emulsion explosives was systematically investigated. Detonation velocity experiments shows that the change of sensitizing gas and the increase of hydrogen pressure have different effects on the detonation velocity. The experimental parameters of underwater explosion increase first and then decreases with the increase of hydrogen pressure. The decrease of these parameters indicates that the strength of glass microballoons is the limiting factor to improve the detonation performance of hydrogen-storage emulsion explosives. Compared with the traditional emulsion explosives the maximum peak pressure of shock wave of hydrogen-storage emulsion explosives increases by 10.6% at 1.0 m and 10.2% at 1.2 m the maximum values of shock impulse increase by 5.7% at 1.0 m and 19.4% at 1.2 m. The stored hydrogen has dual effects of sensitizers and energetic additives which can improve the energy output of emulsion explosives.
Intelligent Hydrogen Fuel Cell Range Extender for Battery Electric Vehicles
May 2019
Publication
Road transport is recognized as having a negative impact on the environment. Policy has focused on replacement of the internal combustion engine (ICE) with less polluting forms of technology including battery electric and fuel cell electric powertrains. However progress is slow and both battery and fuel cell based vehicles face considerable commercialization challenges. To understand these challenges a review of current electric battery and fuel cell electric technologies is presented. Based on this review this paper proposes a battery electric vehicle (BEV) where components are sized to take into account the majority of user requirements with the remainder catered for by a trailer-based demountable intelligent fuel cell range extender. The proposed design can extend the range by more than 50% for small BEVs and 25% for large BEVs (the extended range of vehicles over 250 miles) reducing cost and increasing efficiency for the BEV. It enables BEV manufacturers to design their vehicle battery for the most common journeys decreases charging time to provide convenience and flexibility to the drivers. Adopting a rent and drop business model reduces the demand on the raw materials bridging the gap in the amount of charging (refueling) stations and extending the lifespan for the battery pack.
Experimental and Theoretical Insights to Demonstrate the Hydrogen Evolution Activity of Layered Platinum Dichalcogenides Electrocatalysts
Mar 2021
Publication
Hydrogen is a highly efficient and clean renewable energy source and water splitting through electrocatalytic hydrogen evolution is a most promising approach for hydrogen generation. Layered transition metal dichalcogenides-based nano-structures have recently attracted significant interest as robust and durable catalysts for hydrogen evolution. We systematically investigated the platinum (Pt) based dichalcogenides (PtS2 PtSe2 and PtTe2) as highly energetic and robust hydrogen evolution electrocatalysts. PtTe2 catalyst unveiled the rapid hydrogen evolution process with the low overpotentials of 75 and 92 mV (vs. RHE) at a current density of 10 mA cm−2 and the small Tafel slopes of 64 and 59 mV/dec in acidic and alkaline medium respectively. The fabricated PtTe2 electrocatalyst explored a better catalytic activity than PtS2 and PtSe2. The density functional theory estimations explored that the observed small Gibbs free energy for H-adsorption of PtTe2 was given the prominent role to achieve the superior electrocatalytic and excellent stability activity towards hydrogen evolution due to a smaller bandgap and the metallic nature. We believe that this work will offer a key path to use Pt based dichalcogenides for hydrogen evolution electrocatalysts.
Effect of Low-Temperature Sensitization on Hydrogen Embrittlement of 301 Stainless Steel
Feb 2017
Publication
The effect of metastable austenite on the hydrogen embrittlement (HE) of cold-rolled (30% reduction in thickness) 301 stainless steel (SS) was investigated. Cold-rolled (CR) specimens were hydrogen-charged in an autoclave at 300 or 450 °C under a pressure of 10 MPa for 160 h before tensile tests. Both ordinary and notched tensile tests were performed in air to measure the tensile properties of the non-charged and charged specimens. The results indicated that cold rolling caused the transformation of austenite into α′ and ε-martensite in the 301 SS. Aging at 450 °C enhanced the precipitation of M23C6 carbides G and σ phases in the cold-rolled specimen. In addition the formation of α′ martensite and M23C6 carbides along the grain boundaries increased the HE susceptibility and low-temperature sensitization of the 450 °C-aged 301 SS. In contrast the grain boundary α′-martensite and M23C6 carbides were not observed in the as-rolled and 300 °C-aged specimens
The Role of Electrofuels under Uncertainties for the Belgian Energy Transition
Jul 2021
Publication
Wind and solar energies present a time and space disparity that generally leads to a mismatch between the demand and the supply. To harvest their maximum potentials one of the main challenges is the storage and transport of these energies. This challenge can be tackled by electrofuels such as hydrogen methane and methanol. They offer three main advantages: compatibility with existing distribution networks or technologies of conversion economical storage solution for high capacity and ability to couple sectors (i.e. electricity to transport to heat or to industry). However the level of contribution of electric-energy carriers is unknown. To assess their role in the future we used whole-energy system modelling (EnergyScope Typical Days) to study the case of Belgium in 2050. This model is multi-energy and multi-sector. It optimises the design of the overall system to minimise its costs and emissions. Such a model relies on many parameters (e.g. price of natural gas efficiency of heat pump) to represent as closely as possible the future energy system. However these parameters can be highly uncertain especially for long-term planning. Consequently this work uses the polynomial chaos expansion method to integrate a global sensitivity analysis in order to highlight the influence of the parameters on the total cost of the system. The outcome of this analysis points out that compared to the deterministic cost-optimum situation the system cost accounting for uncertainties becomes higher (+17%) and twice more uncertain at carbon neutrality and that electrofuels are a major contribution to the uncertainty (up to 53% in the variation of the costs) due to their importance in the energy system and their high uncertainties their higher price and uncertainty.
Energy Modeling Approach to the Global Energy-mineral Nexus: Exploring Metal Requirements and the Well-below 2 °C Target with 100 Percent Renewable Energy
Jun 2018
Publication
Detailed analysis of pathways to future sustainable energy systems is important in order to identify and overcome potential constraints and negative impacts and to increase the utility and speed of this transition. A key aspect of a shift to renewable energy technologies is their relatively higher metal intensities. In this study a bottom-up cost-minimizing energy model is used to calculate aggregate metal requirements in different energy technology including hydrogen and climate policy scenarios and under a range of assumptions reflecting uncertainty in future metal intensities recycling rate and life time of energy technologies. Metal requirements are then compared to current production rates and resource estimates to identify potentially “critical” metals. Three technology pathways are investigated: 100 percent renewables coal & nuclear and gas & renewables each under the two different climate policies: net zero emissions satisfying the well-below 2 °C target and business as usual without carbon constraints resulting together in six scenarios. The results suggest that the three different technology pathways lead to an almost identical degree of warming without any climate policy while emissions peaks within a few decades with a 2 °C policy. The amount of metals required varies significantly in the different scenarios and under the various uncertainty assumptions. However some can be deemed “critical” in all outcomes including Vanadium. The originality of this study lies in the specific findings and in the employment of an energy model for the energy-mineral nexus study to provide better understanding for decision making and policy development.
Innovating Transport Across Australia: Inquiry into Automated Mass Transit
Mar 2019
Publication
Automated and electric mass transit will play a significant role in the connectivity of our cities and regions. But automated mass transit must be placed within the wider context of the optimum transport needs of those cities and regions— transport networks based on shared and multi-modal mobility. Realising the full potential of these networks will require sustained policy development and investment.<br/>This report examines current and future developments in the use of automation and new energy sources in land-based mass transit including rail and road mass transit point-to-point transport using automated vehicles and the role and responsibilities of the Commonwealth in the development of these technologies. It will analyse the opportunities and challenges presented by automation and new energy sources and the role the Australian Government has to play in managing this transport revolution.
Success Stories: A Partnership Dedicated to Clean Energy and Transport in Europe
Dec 2018
Publication
As 2018 marks the ten-year anniversary of the Fuel Cells and Hydrogen Joint Undertaking (FCH JU) it is inspiring to look back over the many accomplishments of the past decade. The projects described in these pages illustrate the approach of continuous learning exemplified by the FCH JU’s projects from creating low-carbon and sustainable solutions enabling market entry for new products developing ‘next generation’ products based on previous research to opening new markets for European expertise in fuel cell and hydrogen (FCH) technology.<br/>The FCH JU’s achievements are due in part to its multi-stakeholder structure: a public-private partnership between industry research and the European Commission. Industry-led research has pioneered new developments in FCH technology and brought many of them to the cusp of commercialisation. Market uptake from public authorities major companies and citizens alike has boosted confidence in these clean technologies establishing hydrogen as a cornerstone of Europe’s energy transition.<br/>DEVELOPING SOLUTIONS FOR A GREENER WORLD<br/>Citizens are at the heart of Europe’s Energy Union a strategy aimed at providing clean secure and affordable energy for all. For some years now and as a signatory to the Paris Agreement in 2015 the EU has been actively targeting reductions in carbon dioxide (CO2) emissions.
Can the Current EU Regulatory Framework Deliver Decarbonisation of Gas?
Jun 2020
Publication
This Energy Insight examines the current regulatory framework and challenges facing the natural gas industry (producers transporters suppliers and consumers) during the transition to a zero-carbon economy. The EU has declared its intention to be climate neutral by 2050 which means that the current level of natural gas usage will no longer be possible. However natural gas is a crucial component of energy supply representing 24 per cent of primary energy supply for the EU27+UK and 36 per cent of residential energy consumption. In some countries the use of natural gas is much higher – around 40 per cent of primary energy supply in Netherlands UK and Italy. The current framework impacting gas addresses two different market failures – natural monopolies for gas transportation and the externalities of Greenhouse Gas Emissions. The framework will not deliver decarbonisation of gas as it does not stimulate either supply or demand for alternatives such as hydrogen nor create the conditions to enable gas networks to transition to a decarbonised future. Policy makers need to prioritise their objectives to take account of the trade-offs involved in designing a new framework. Exclusion of certain low carbon technologies risks driving away investors and reduces the chances of targets being met whilst “picking winners” involves risks because of the many uncertainties involved such as future costs and time required to build new value chains.
Link to Document on Oxford Institute for Energy Studies website
Link to Document on Oxford Institute for Energy Studies website
Advancing Hydrogen: Learning from 19 Plans to Advance Hydrogen from Across the Globe
Jul 2019
Publication
Hydrogen as the International Energy Agency (IEA 2019) notes has experienced a number of ‘false dawns’ - in the 1970s 1990s and early 2000s - which subsequently faded. However this time there is reason to think that hydrogen will play a substantial role in the global energy system. The most important factor driving this renewed focus is the ability of hydrogen to support deep carbon abatement by assisting in those sectors where abatement with non-carbon electricity has so far proven difficult. Hydrogen can also address poor urban air quality energy security and provides a good means of shifting energy supply between regions and between seasons.
In response to these changed conditions many countries states and even cities have developed hydrogen strategies while various interest groups have developed industry roadmaps which fulfil a similar role.
This report summarises 19 hydrogen strategies and aims to help readers understand how nations regions and industries are thinking about opportunities to become involved in this emerging industry. Its prime purpose is to act as a resource to assist those involved in long-term energy policy planning in Australia including those involved in the development of Australia’s hydrogen strategy
The full report can be read on the Energy Network website at this link here
In response to these changed conditions many countries states and even cities have developed hydrogen strategies while various interest groups have developed industry roadmaps which fulfil a similar role.
This report summarises 19 hydrogen strategies and aims to help readers understand how nations regions and industries are thinking about opportunities to become involved in this emerging industry. Its prime purpose is to act as a resource to assist those involved in long-term energy policy planning in Australia including those involved in the development of Australia’s hydrogen strategy
The full report can be read on the Energy Network website at this link here
Techno-Economics Optimization of H2 and CO2 Compression for Renewable Energy Storage and Power-to-Gas Applications
Nov 2021
Publication
The decarbonization of the industrial sector is imperative to achieve a sustainable future. Carbon capture and storage technologies are the leading options but lately the use of CO2 is also being considered as a very attractive alternative that approaches a circular economy. In this regard power to gas is a promising option to take advantage of renewable H2 by converting it together with the captured CO2 into renewable gases in particular renewable methane. As renewable energy production or the mismatch between renewable production and consumption is not constant it is essential to store renewable H2 or CO2 to properly run a methanation installation and produce renewable gas. This work analyses and optimizes the system layout and storage pressure and presents an annual cost (including CAPEX and OPEX) minimization. Results show the proper compression stages need to achieve the storage pressure that minimizes the system cost. This pressure is just below the supercritical pressure for CO2 and at lower pressures for H2 around 67 bar. This last quantity is in agreement with the usual pressures to store and distribute natural gas. Moreover the H2 storage costs are higher than that of CO2 even with lower mass quantities; this is due to the lower H2 density compared with CO2 . Finally it is concluded that the compressor costs are the most relevant costs for CO2 compression but the storage tank costs are the most relevant in the case of H2.
Thermodynamic Assessment of a Solar-Driven Integrated Membrane Reactor for Ethanol Steam Reforming
Nov 2020
Publication
To efficiently convert and utilize intermittent solar energy a novel solar-driven ethanol steam reforming (ESR) system integrated with a membrane reactor is proposed. It has the potential to convert low-grade solar thermal energy into high energy level chemical energy. Driven by chemical potential hydrogen permeation membranes (HPM) can separate the generated hydrogen and shift the ESR equilibrium forward to increase conversion and thermodynamic efficiency. The thermodynamic and environmental performances are analyzed via numerical simulation under a reaction temperature range of 100–400 ◦C with permeate pressures of 0.01–0.75 bar. The highest theoretical conversion rate is 98.3% at 100 ◦C and 0.01 bar while the highest first-law efficiency solar-to-fuel efficiency and exergy efficiency are 82.3% 45.3% and 70.4% at 215 ◦C and 0.20 bar. The standard coal saving rate (SCSR) and carbon dioxide reduction rate (CDRR) are maximums of 101 g·m−2 ·h −1 and 247 g·m−2 ·h −1 at 200 ◦C and 0.20 bar with a hydrogen generation rate of 22.4 mol·m−2 ·h −1 . This study illustrates the feasibility of solar-driven ESR integrated with a membrane reactor and distinguishes a novel approach for distributed hydrogen generation and solar energy utilization and upgradation.
Hydrogen Storage Behavior of Mg-based Alloy Catalyzed by Carbon-cobalt Composites
Feb 2021
Publication
The composites comprised of Co nanoparticle and C nanosheet were prepared though a high-temperature carbonization reaction. The catalysis of Co@C composites on the hydrogen storage behavior of Mg90Ce5Y5 alloy was investigated in detail by XRD SEM TEM PCI and DSC method. Because of the synergistic catalytic function of C and Co in C@Co nanocomposites the Mg90Ce5Y5 alloy with 10 wt.% C@Co shows the excellent hydrogen absorption and desorption performances. Time for releasing hydrogen reduces from 150 min to 11 min with the addition of the C@Co composites at the temperature of 300 °C. Meanwhile the dehydrogenation activation energy also declines from 130.3 to 81.9 kJ mol−1 H2 after the addition of the C@Co composites. This positive effect attributes to the C layer with the high defect density and the Co nanoparticles which reduces the energy barriers for the nucleation of Mg/MgH2 phase and the recombination of hydrogen molecule. Besides the C@Co composites also improve the activation property of the Mg90Ce5Y5 alloy which was fully activated in the first cycle. Moreover the temperature for initial dehydrogenation and the endothermic peak of the alloy hydride were also decreased. Although the addition of the C@Co composites increases the plateau pressures and decreases the value of the decomposition enthalpy these differences are so small that the improvement on thermodynamics can hardly be seen.
Review of Hydrogen Production Techniques from Water Using Renewable Energy Sources and Its Storage in Salt Caverns
Feb 2022
Publication
Hydrogen is becoming an increasingly important energy carrier in sector integration for fuel cell transportation heat and electricity. Underground salt caverns are one of the most promising ways to store the hydrogen obtained from water electrolysis using power generation from renewable energy sources (RES). At the same time the production of hydrogen can be used to avoid energy curtailments during times of low electricity demand or low prices. The stored hydrogen can also be used during times of high energy demand for power generation e.g. with fuel cells to cover the fluctuations and shortages caused by low RES generation. This article presents an overview of the techniques that were used and proposed for using excess energy from RES for hydrogen production from water and its storage techniques especially in underground salt caverns for the aforementioned purpose and its feasibility. This paper compares and summarizes the competing technologies based on the current state-of-the-art identifies some of the difficulties in hydrogen production and storage and discusses which technology is the most promising. The related analysis compares cost and techno-economic feasibility with regard to hydrogen production and storage systems. The paper also identifies the potential technical challenges and the limitations associated with hydrogen integration into the power grid.
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