Publications

An accidental hydrogen release in equipment enclosures may result in the presence of a detonable mixture in a confined environment. Numerical simulation is potentially a useful tool for damage assessment in these situations. To assess the value of CFD techniques numerical simulation of detonation was performed for two realistic scenarios. The first scenario starts with a pipe failure in an electrolyzer resulting in a leak of 42 g of hydrogen. The second scenario deals with a failure in a reformer where 84 g of hydrogen is released. In both cases dispersion patterns were first obtained from separate numerical simulation and were then used as initial condition in a detonation simulation based upon the reactive Euler's equations. Energy was artificially added in a narrow region to simulate detonative ignition. In the electrolyzer ignition was assumed to occur 500 ms after beginning of the release. Results show a detonation failing on the top and bottom side but propagating left and right before eventually failing also. Average impulse was 500 Ns/m². For the reformer three cases were simulated with ignition 1.0 1.4 and 2.0 seconds after the beginning of the release. In two cases the detonation wave failed everywhere except in the direction of the release in which it continued propagating until reaching the side wall. In the third the detonation failed everywhere at first but later a deflagration to detonation transition occurred resulting in a strong wave that propagated rapidly toward the side wall. In all three cases the consequences are more serious than in the electrolyzer.

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.

The study focuses on converting current industrial natural gas heating technologies to use 100% hydrogen considering the evidence which must be available before a decision on the UK’s decarbonisation pathway for heating could be made. The aim of the study is to assess the technical requirements and challenges associated with industrial hydrogen conversion and estimate the associated costs and timeframes.

This report and any attachment is freely available on the Hy4Heat website here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.

The telecommunication sector plays a significant role in shaping the global economy and the way people share information and knowledge. At present the telecommunication sector is liable for its energy consumption and the amount of emissions it emits in the environment. In the context of off-grid telecommunication applications off-grid base stations (BSs) are commonly used due to their ability to provide radio coverage over a wide geographic area. However in the past the off-grid BSs usually relied on emission-intensive power supply solutions such as diesel generators. In this review paper various types of solutions (including in particular the sustainable solutions) for powering BSs are discussed. The key aspects in designing an ideal power supply solution are reviewed and these mainly include the pre-feasibility study and the thermal management of BSs which comprise heating and cooling of the BS shelter/cabinets and BS electronic equipment and power supply components. The sizing and optimization approaches used to design the BSs’ power supply systems as well as the operational and control strategies adopted to manage the power supply systems are also reviewed in this paper.

This work dedicated to a mathematical description of energy transition scenarios consists of three main parts. The first part describes modern trends and problems of the energy sector. A large number of charts reflecting the latest updates in energy are provided. The COVID-2019 pandemic’s impacts on the energy sector are also included. The second part of the paper is dedicated to the analysis of energy consumption and the structure of the world fuel and energy balance. Furthermore a detailed description of energy-efficient technologies is given. Being important and low-carbon hydrogen is discussed including its advantages and disadvantages. The last part of the work describes the mathematical tool developed by the authors. The high availability of statistical data made it possible to identify parameters used in the algorithm with the least squares method and verify the tool. Performing several not complicated steps of the algorithm the tool allows calculating the deviation of the average global temperature of the surface atmosphere from preindustrial levels in the 21st century under different scenarios. Using the suggested mathematical description the optimal scenario that makes it possible to keep global warming at a level below 1.7 ◦C was found.

Hydrogen transportation systems require very high pressure hydrogen storage containers to enable sufficient vehicle range for practical use. Current proposed designs have pressures up to 70 MPa with leakage due to damage or deterioration at such high pressures a great safety concern. Accurate models are needed to predict the flammability envelopes around such leaks which rapidly vary with time. This paper compares CFD predictions of jet flows for low pressure jets with predictions using the integral turbulent buoyant jet model. The results show that the CFD model predicts less entrainment and that the turbulent Schmidt number should be smaller with 0.55 giving better results. Then CFD predictions for very high pressure flows are compared with analytical models for choked flows that generate underexpanded jets into the ambient to evaluate the effects of the model assumptions and the effects of real exit geometries. Real gas effects are shown to accelerate the blowdown process and that real flow effects in the CFD model slow the flow rate and increase the exit temperature.

Structures formed during gas mixing following an injection of a gas into atmosphere are analyzed using optic methods based on the detection of density non-uniformities. Methods for determination of fractal parameters for a random distribution of these non-uniformities are described and information revealed on the gas mixing structure is analyzed. The BOS (background oriented schlieren) technique is utilized to obtain the optical image of the forming structures which afterward is processed using the correlation procedure allowing to extract the quantitative information on the mixing. Additionally a possibility to link the characteristics of the injected gas source and the system fractal parameters was demonstrated. The method can be used in the development of the non-contact methods for the evaluation of the gaseous system parameters based on the optical diagnostics and potentially for the obtaining more detailed information of the gaseous turbulence.

The present paper reviews the state-of-the-art of integrated structural integrity monitoring systems applicable to hydrogen on-board applications. Storage safety and costs are key issues for the success of the hydrogen technology considered for replacing the conventional fuel systems in transport applications. An in-service health monitoring procedure for high pressure vessels would contribute to minimize the risks associated to high pressure hydrogen storage and to improve the public acceptance. Such monitoring system would also enable a reduction on design burst criteria enabling savings in material costs and weight. This paper reviews safety and maintenance requirements based on present standards for high pressure vessels. A state-of-the-art of storage media and materials for onboard storage tank is presented as well as of current European programmes on hydrogen storage technologies for transport applications including design safety and system reliability. A technological road map is proposed for the development and validation of a prototype within the framework of the Portuguese EDEN project. To ensure safety an exhaustive test procedure is proposed. Furthermore requirements of a safety on-board monitoring system is defined for filament wound hydrogen tanks.

This paper presents results from laboratory experiments with hydrogen dispersions and explosions in a 3 m long channel. Our objective is to get a better understanding of the phenomena and to develop tools that can analyse hydrogen dispersions and explosions. A total of 5 test series were performed with flow rates of hydrogen from 1.8 dm³/min to 75 dm³/min. The propagation of the combustible hydrogen-air cloud in the channel was observed from high-speed video recordings. The hydrogen-air cloud in the channel behaves as a gravity current and the flow appears to be well described by Froude scaling with a length scale corresponding to the height of a layer of 100 % hydrogen. The Froude numbers observed in the experiments are in good agreement with the theory of "light-fluid intrusion" for gravity currents found in the literature. Numerical simulations with the Flacs code correlate well with the experimental results. The flame propagation indicated that approximately half the height of the channel was filled with combustible mixture. We believe that this Froude scaling can be useful as a tool to analyse the consequences of hydrogen release in buildings channels and tunnels.

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.

The Hydrogen Incident Reporting and Lessons Learned website (www.h2incidents.org) was launched in 2006 as a database-driven resource for sharing lessons learned from hydrogen-related safety events to raise safety awareness and encourage knowledge-sharing. The development of this database its first uses and subsequent enhancements have been described at the Second and Third International Conferences on Hydrogen Safety [1] [2]. Since 2009 continuing work has not only highlighted the value of safety lessons learned but enhanced how the database provides access to another safety knowledge tool Hydrogen Safety Best Practices (http://h2bestpractices.org). Collaborations with the International Energy Agency (IEA) Hydrogen Implementing Agreement (HIA) Task 19 – Hydrogen Safety and others have enabled the database to capture safety event learning’s from around the world. This paper updates recent progress highlights the new “Lessons Learned Corner” as one means for knowledge-sharing and examines the broader potential for collecting analyzing and using safety event information.

Compressed natural gas (CNG) is being increasingly used as a clean transportation fuel. However for further reduction in emissions particularly NOx H-CNG mixture with ~ 20 % hydrogen is recommended. Presently most of the H-CNG mixture is produced by blending hydrogen with CNG. For hydrogen production Steam Methane Reforming (SMR) is a major process accounting for more than 90% of hydrogen production by various industries. In this process natural gas is first reformed to syn gas under severe operating conditions (Pressure 20-30 bar temperature 850-950 deg C) followed by conversion of CO to hydrogen in the shift reactor. Other method of hydrogen production such as electrolysis of water is more expensive. Further there are issues of safety with handling of hydrogen its storage and transportation for blending. In order to overcome these problems a single step compact process for the production of H-CNG gaseous mixture through low severity steam methane reforming of natural gas has been developed. It employs a catalyst containing nickel nickel oxide magnesium oxide and silica and has the capability of producing H-CNG mixture in the desired proportion containing 15-20 vol % hydrogen with nil CO production. The process is flexible and rugged allowing H-CNG production as per the demand. The gaseous H-CNG product mixture can directly be used as automobile fuel after compression. The process can help as important step in safe transition towards hydrogen economy. A demonstration unit is being set up at IOC R&D Centre.

The topic of this paper is to give an historical and technical overview of hydrogen storage vessels and to detail the specific issues and constraints of hydrogen energy uses. Hydrogen as an industrial gas is stored either as a compressed or as a refrigerated liquefied gas. Since the beginning of the last century hydrogen is stored in seamless steel cylinders. At the end of the 60 s tubes also made of seamless steels were used; specific attention was paid to hydrogen embrittlement in the 70 s. Aluminum cylinders were also used for hydrogen storage since the end of the 60 s but their cost was higher compared to steel cylinders and smaller water capacity. To further increase the service pressure of hydrogen tanks or to slightly decrease the weight metallic cylinders can be hoop-wrapped. Then with specific developments for space or military applications fully-wrapped tanks started to be developed in the 80 s. Because of their low weight they started to be used in for portable applications: for vehicles (on-board storages of natural gas) for leisure applications (paint-ball) etc… These fully-wrapped composite tanks named types III and IV are now developed for hydrogen energy storage; the requested pressure is very high (from 700 to 850 bar) leads to specific issues which are discussed. Each technology is described in term of materials manufacturing technologies and approval tests. The specific issues due to very high pressure are depicted. Hydrogen can also be stored in liquid form (refrigerated liquefied gases). The first cryogenic vessels were used in the 60s. In the following the main characteristics of this type of storage will be indicated.

The work was done with respect to hydrogen safety of ITER vacuum vessel in cases of loss of cooling and loss of vacuum accidents. Experiments were conducted at sub-atmospheric pressures from 1 bar to 200 mbar and elevated temperatures up to 300 oC. Hydrogen concentration was changed from lower to upper flammability limits in all the range of pressures and temperatures. The experiments were performed in a spherical explosion bomb equipped with two quartz windows. The flame propagation velocity was measured using pressure method and high speed shadow cinematography. The theoretical flame velocities were calculated by Cantera code using Lutz and Mueller mechanisms. The influence of the initial temperature and pressure conditions on the laminar flame speed SL overall reaction order n and Markstein length LM are presented in this work and compared with the results of a theoretical model.

The viability and public acceptance of the hydrogen and fuel cell (HFC) systems and infrastructure depends on their robust safety engineering design education and training of the workforce regulators and other stakeholders in the state-of-the-art in the field. This can be provided only through building up and maturity of the hydrogen safety engineering (HSE) profession. HSE is defined as an application of scientific and engineering principles to the protection of life property and environment from adverse effects of incidents/accidents involving hydrogen. This paper describes a design framework and overviews a structure and contents of technical sub-systems for carrying out HSE. The approach is similar to British standard BS7974 for application of fire safety engineering to the design of buildings and expanded to reflect on specific for hydrogen safety related phenomena including but not limited to high pressure under-expanded leaks and dispersion spontaneous ignition of sudden hydrogen releases to air deflagrations and detonations etc. The HSE process includes three main steps. Firstly a qualitative design review is undertaken by a team that can incorporate owner hydrogen safety engineer architect representatives of authorities having jurisdiction e.g. fire services and other stakeholders. The team defines accident scenarios suggests trial safety designs and formulates acceptance criteria. Secondly a quantitative safety analysis of selected scenarios and trial designs is carried out by qualified hydrogen safety engineer(s) using the state-of-the-art knowledge in hydrogen safety science and engineering and validated models and tools. Finally the performance of a HFC system and/or infrastructure under the trial safety designs is assessed against predefined by the team acceptance criteria. This performance-based methodology offers the flexibility to assess trial safety designs using separately or simultaneously three approaches: deterministic comparative or combined probabilistic/deterministic.

The Hydrogen Incident and Accident Database (HIAD) is being developed as a repository of systematic data describing in detail hydrogen-related undesired events (incidents or accidents). It is an open web-based information system serving various purposes such as a data source for lessons learnt risk communication and partly risk assessment. The paper describes the features of the three HIAD modules – the Data Entry Module (DEM) the Data Retrieval Module (DRM) and the Data Analysis Module (DAM) – and the potential impact the database may have on hydrogen safety. The importance of data quality assurance process is also addressed.

Two vehicle fire tests were conducted to investigate the spread of fire to adjacent vehicles from a hydrogen fuel cell vehicle (HFCV) equipped with a thermal pressure relief device (TPRD) : – 1) an HFCV fire test involving an adjacent gasoline vehicle 2) a fire test involving three adjoining HFCV assuming their transportation in a carrier ship. The test results indicated that the adjacent vehicles were ignited by flames from the interior and exterior materials of the fire origin HFCV but not by the hydrogen flames generated through the activation of TPRD.

The influence of plastic deformation on hydrogen diffusion is of critical significance for hydrogen embrittlement (HE) studies. In this work thermal desorption spectroscope (TDS) slow strain rate test (SSRT) feritscope transmission electron microscope (TEM) and TDS model are used to establish the relationship between plastic deformation and hydrogen diffusion aiming at unambiguously elucidating the effect of pre-existing traps on hydrogen diffusion of hot-rolled S30408. An effective way is developed to deduce hydrogen apparent diffusivity in this paper. Results indicate apparent diffusivities decrease firstly and then increase with increasing plastic strain at room temperature. Hydrogen diffusion changing with plastic deformation is a complicated process involving multiple factors. It is suggested to be divided into two processes controlled by dislocations and strain-induced martensite respectively and the transformation strain is about 20% demonstrated by experiments.

Hydrogen gas pressure is an important test parameter when considering materials for high-pressure hydrogen applications. A large set of data on the effect of hydrogen gas pressure on mechanical properties in gaseous hydrogen experiments was reviewed. The data were analyzed by converting pressures into fugacities (f) and by fitting the data using an f|n| power law. For 95% of the data sets |n| was smaller than 0.37 which was discussed in the context of (i) rate-limiting steps in the hydrogen reaction chain and (ii) statistical aspects. This analysis might contribute to defining the appropriate test fugacities (pressures) to qualify materials for gaseous hydrogen applications.

This latest Hydrogen Council report shows that the cost of hydrogen solutions will fall sharply within the next decade – and sooner than previously expected. As scale up of hydrogen production distribution equipment and component manufacturing continues cost is projected to decrease by up to 50% by 2030 for a wide range of applications making hydrogen competitive with other low-carbon alternatives and in some cases even conventional options.

Significant cost reductions are expected across different hydrogen applications. For more than 20 of them such as long-distance and heavy-duty transportation industrial heating and heavy industry feedstock which together comprise roughly 15% of global energy consumption the hydrogen route appears the decarbonisation option of choice – a material opportunity.

The report attributes this trajectory to scale-up that positively impacts the three main cost drivers:

• Strong fall in the cost of producing low carbon and renewable hydrogen;
• Lower distribution and refuelling costs thanks to higher load utilisation and scale effect on infrastructure utilisation; and
• Dramatic drop in the cost of components for end-use equipment under scaling up of manufacturing.

To deliver on this opportunity supporting policies will be required in key geographies together with investment support of around $70 billion in the lead up to 2030 in order to scale up and achieve hydrogen competitiveness. While this figure is sizable it accounts for less than 5% of annual global spending on energy. For comparison support provided to renewables in Germany totalled roughly $30 billion in 2019.

The study is based on real industry data with 25000 data points gathered and analysed from 30 companies using a rigorous methodology. The data was collected and analytical support provided by McKinsey & Company and it represents the entire hydrogen value chain across four key geographies (US Europe Japan/Korea and China). Data was also reviewed by an independent advisory group comprised of recognised hydrogen and energy transition experts.

You can download the full report from the Hydrogen Council website here

The executive summary can be found here

The Swedish and Finnish steel industry has a world-leading position in terms of efficient blast furnace operations with low CO2 emissions. This is a result of a successful development work carried out in the 1980s at LKAB (Luossavaara-Kiirunavaara Aktiebolag mining company) and SSAB (steel company) followed by the closing of sinter plants and transition to 100% pellet operation at all of SSAB’s five blast furnaces. However to further reduce CO2 emission in iron production a new breakthrough technology is necessary. In 2016 SSAB teamed up with LKAB and Vattenfall AB (energy company) and launched a project aimed at investigating the feasibility of a hydrogen-based sponge iron production process with fossil-free electricity as the primary energy source: HYBRIT (Hydrogen Breakthrough Ironmaking Technology). A prefeasibility study was carried out in 2017 which concluded that the proposed process route is technically feasible and economically attractive for conditions in northern Sweden/Finland. A decision was made in February 2018 to build a pilot plant and construction started in June 2018 with completion of the plant planned in summer 2020 followed by experimental campaigns the following years. Parallel with the pilot plant activities a four-year research program was launched from the autumn of 2016 involving several research institutes and universities in Sweden to build knowledge and competence in several subject areas.

The need to significantly reduce emissions from the steelmaking sector requires effective and ready-to-use technical solutions. With this aim different decarbonization strategies have been investigated by both researchers and practitioners. To this concern the most promising pathway is represented by the replacement of natural gas with pure hydrogen in the direct reduced iron (DRI) production process to feed an electric arc furnace (EAF). This solution allows to significantly reduce direct emissions of carbon dioxide from the DRI process but requires a significant amount of electricity to power electrolyzers adopted to produce hydrogen. The adoption of renewable electricity sources (green hydrogen) would reduce emissions by 95–100% compared to the blast furnace–basic oxygen furnace (BF–BOF) route. In this work an analytical model for the identification of the minimum emission configuration of a green energy–steel system consisting of a secondary route supported by a DRI production process and a renewable energy conversion system is proposed. In the model both technological features of the hydrogen steel plant and renewable energy production potential of the site where it is to be located are considered. Compared to previous studies the novelty of this work consists of the joint modeling of a renewable energy system and a steel plant. This allows to optimize the overall system from an environmental point of view considering the availability of green hydrogen as an inherent part of the model. Numerical experiments proved the effectiveness of the model proposed in evaluating the suitability of using green hydrogen in the steelmaking process. Depending on the characteristics of the site and the renewable energy conversion system adopted decreases in emissions ranging from 60% to 91% compared to the BF–BOF route were observed for the green energy–steel system considered It was found that the environmental benefit of using hydrogen in the secondary route is strictly related to the national energy mix and to the electrolyzers’ technology. Depending on the reference context it was found that there exists a maximum value of the emission factor from the national electricity grid below which is environmentally convenient to produce DRI by using only hydrogen. It was moreover found that the lower the electricity consumption of the electrolyzer the higher the value assumed by the emission factor from the electricity grid which makes the use of hydrogen convenient.

Synthetic fuels are needed to replace their fossil counterparts for clean transport. Presently their production is still inefficient and costly. To enhance the process of methanol production from CO₂ and H₂ and reduce its cost a particle-resolved numerical simulation tool is presented. A global surface reaction model based on the Langmuir-Hinshelwood-Hougen-Watson kinetics is utilized. The approach is first validated against standard benchmark problems for non-reacting and reacting cases. Next the method is applied to study the performance of methanol production in a 2D fixed-bed reactor under a range of parameters. It is found that methanol yield enhances with pressure catalyst loading reactant ratio and packing density. The yield diminishes with temperature at adiabatic conditions while it shows non-monotonic change for the studied isothermal cases. Overall the staggered and the random catalyst configurations are found to outperform the in-line system.

In recent years various studies have put forward the prospect of relying on low-carbon or renewable gases such as green hydrogen (H2) or biomethane to replace the supply of natural gas. Hydrogen in particular is receiving much attention as a versatile energy carrier that could complement direct electrification in a plethora of end-uses and questions over its production and deployment play an important part in the ongoing discussions around the energy chapters of the European Commission’s Green Deal agenda.

The aim of the short study was to assess the technical feasibility emission savings and cost impacts of the addition of hydrogen to the existing gas transport network the so-called practice of “hydrogen blending” which is currently being discussed as a deployment pathway in the context of the review of the EU Gas Market Regulation (GMR) and the Trans-European Networks for Energy (TEN-E) regulation.

The document can be downloaded from their website

Improving efficiency of hydrogen cooling in cryogenic conditions is important for the wider applications of hydrogen energy systems. The approach investigated in this study is based on a Ranque-Hilsch vortex tube (RHVT) that generates temperature separation in a working fluid. The simplicity of RHVT is also a valuable characteristic for cryogenic systems. In the present work novel shapes of RHVT are computationally investigated with the goal to raise efficiency of the cooling process. Specifically a smooth transition is arranged between a vortex chamber where compressed gas is injected and the main tube with two exit ports at the tube ends. Flow simulations have been carried out using STAR-CCM+ software with the real-gas Redlich-Kwong model for hydrogen at temperatures near 70 K. It is determined that a vortex tube with a smooth transition of moderate size manifests about 7% improvement of the cooling efficiency when compared vortex tubes that use traditional vortex chambers with stepped transitions and a no-chamber setup with direct gas injection.