- Home
- A-Z Publications
- Publications
Publications
Study on Introduction of CO2 Free Energy to Japan with Liquid Hydrogen
Jul 2015
Publication
In Japan both CO2 (Carbon dioxide) emission reduction and energy security are the very important social issues after Fukushima Daiichi accident. On the other hand FCV (Fuel Cell Vehicle) using hydrogen will be on the market in 2015. Introducing large mass hydrogen energy is being expected as expanding hydrogen applications or solution to energy issues of Japan. And then the Japanese government announced the road map for introducing hydrogen energy supply chain in this June2014. Under these circumstances imported CO2 free hydrogen will be one of the solutions for energy security and CO2 reduction if the hydrogen price is affordable. To achieve this Kawasaki Heavy Industries Ltd. (KHI) performed a feasibility study on CO2-free hydrogen energy supply chain from Australian brown coal linked with CCS (Carbon dioxide Capture and Storage) to Japan. In the study hydrogen production systems utilizing brown coal gasification and LH2 (liquid hydrogen) systems as storing and transporting hydrogen are examined. This paper shows the possibility of realizing the CO2 free hydrogen supply chain the cost breakdown of imported hydrogen cost its cost competitiveness with conventional fossil and LH2 systems as key technologies of the hydrogen energy chain.
Fire Spread Scenarios Involving Hydrogen Vehicles
Sep 2021
Publication
Fire spread between vehicles provides a potential risk in parking areas with many vehicles. Several reported very large fires caused the loss of a great number of vehicles. These fires seem to be in contradiction to the European design rules for car parks assuming only a very limited number of vehicles may be on fire at the same time. The fire spread in a car park environment is dependent on many factors of both the vehicles and the structure e.g. the latter has an impact on the rate of fire spread due to reradiation of the vehicles heat release. Therefore a CFD model is established to develop a tool to assess vehicles and better understand fire scenarios in different structures. Further the model enables testing of building design to prevent and mitigate such fires scenarios involving hydrogen vehicles. In this study a real layout of a car park is modelled to investigate the effects of hydrogen emergency releases that have used different TPRD diameters. The results provide insight into the behaviour of hydrogen cars and the release pattern of the TPRD's as well as the temperature development of the concrete ceiling and concrete beams above the cars. It shows that the TPRD diameter has a little effect on the TPRD activation time of the no.1 vehicle when the amount of H2 in the tank is the same. For the surface temperature of the ceiling and beam the peak temperature for a 1mm diameter TPRD release is found highest.
Greenhouse Gas Emissions of Conventional and Alternative Vehicles: Predictions Based on Energy Policy Analysis in South Korea
Mar 2020
Publication
This paper compares the well-to-wheel (WTW) greenhouse gas (GHG) emissions of representative vehicle types–internal combustion engine vehicle (ICEV) hybrid electric vehicle (HEV) plug-in hybrid electric vehicle (PHEV) battery electric vehicle (BEV) and fuel cell electric vehicle (FCEV)–in the future (2030) based on a WTW analysis for the present (2017) and an analysis of various energy policies that could affect future emissions. South Korea was selected as the target region because it has detailed energy policies related to alternative vehicles. The WTW analysis for the present was performed based on three sets of subordinate analyses: (1) life cycle analyses of eight base fuels; (2) life cycle analyses of electricity and hydrogen; and (3) analyses of the fuel economies of seven vehicle types. From the WTW analysis for the present the national average WTW GHG emissions of ICEV-gasoline ICEV-diesel ICEV-liquefied petroleum gas HEV PHEV BEV and FCEV were calculated as 225 233 201 159 133 109 and 55 g-CO2-eq./km respectively. For calculating the WTW GHG emissions in the future two policies regarding electricity production and three policies regarding hydrogen production were analysed. Three cases with varying the degrees of improvements in fuel economies were considered. Six future scenarios were constructed and each scenario represented the case in which each energy policy is enacted. In the reference scenario for compact car the WTW GHG emissions of ICEVs-gasoline HEV PHEV BEV-200 mile FCEV were analysed as 161 110 97 86 and 91 g-CO2-eq./km respectively. The differences between ICEV/HEV and BEV were predicted to decrease in the future mainly due to larger improvements of ICEV/HEV in fuel economies compared to that of BEV. The future life cycle GHG emissions of electricity and hydrogen were calculated according to energy policy. Both two policies regarding power generation were confirmed to increase the benefits of utilizing BEVs but current energy policy regarding hydrogen production were confirmed to decrease the benefits of utilizing FCEVs. Based on the comprehensive results of this study a framework was proposed to evaluate the impacts of an energy policy regarding electricity and hydrogen production on the benefits of using BEVs and FCEVs compared to using HEVs and ICEVs. This framework can also be utilized in other countries when they assess and establish their energy policies.
Optimal Day-ahead Dispatch of an Alkaline Electrolyser System Concerning Thermal–electric Properties and State-transitional Dynamics
Oct 2021
Publication
Green hydrogen is viewed as a promising energy carrier for sustainable development goals. However it has suffered from high costs hindering its implementation. For a stakeholder who considers both renewable energy and electrolysis units it is important to exploit the flexibility of such portfolios to maximize system operational revenues. To this end an electrolyser model that can characterize its dynamic behavior is required in both electric and thermal aspects. In this paper we develop a comprehensive alkaline electrolyser model that is capable of describing its hydrogen production properties temperature variations and state transitions (among production stand-by and off states). This model is further used to study the optimal dispatch of an electrolyser based on a real-world hybrid wind/electrolyser system. The results show the model can effectively capture the coupling between thermal–electric dynamics and on–off performance of an electrolyser. The flexible operation strategy based on this model is proven to significantly increase daily revenues under different spot price conditions for electricity. Comparing the model with the ones derived from conventional modeling methods reveals this model offers more operating details and highlights several operational features such as the preference for working at partial load conditions although at the expense of more computing resources. It is suggested to use this model in studies related to energy integration operation planning and control scheme development in which the multi-domain dynamic properties of electrolysers in electricity/gas/heat need to be properly characterized. A sensitivity analysis on key parameters of such electrolyser system is also introduced to connect the daily operation with long-term planning.
Combustion Characterization in a Diffusive Gas Turbine Burner for Hydrogen-Compliant Applications
Jun 2022
Publication
The target of net-zero emissions set by the 2015 Paris Agreement has strongly commissioned the energy production sector to promote decarbonization renewable sources exploitation and systems efficiency. In this framework the utilization of hydrogen as a long-term energy carrier has great potential. This paper is concerned with the combustion characterization in a non-premixed gas turbine burner originally designed for natural gas when it is fed with NG-H2 blends featuring hydrogen content from 0 to 50% in volume. The final aim is to retrofit a 40 MW gas turbine. Starting from the operational data of the engine a CFD model of the steady-state combustion process has been developed with reference to the base load NG conditions by reducing the fuel mass-flow rate by up to 17% to target the baseline turbine inlet temperature. When the fuel is blended with hydrogen for a given temperature at turbine inlet an increase in the peak temperature up to 800 K is obtained if no countermeasures are taken. Furthermore the flame results are more intense and closer to the injector in the case of hydrogen blending. The results of this work hint at the necessity of carefully analyzing the possible NOx compensation strategies as well as the increased thermal stresses on the injector.
Towards Computer-Aided Graphene Covered TiO2-Cu(CuxOy) Composite Design for the Purpose of Photoinduced Hydrogen Evolution
May 2021
Publication
In search a hydrogen source we synthesized TiO2-Cu-graphene composite photocatalyst for hydrogen evolution. The catalyst is a new and unique material as it consists of copper-decorated TiO2 particles covered tightly in graphene and obtained in a fluidized bed reactor. Both reduction of copper from Cu(CH3COO) at the surface of TiO2 particles and covering of TiO2-Cu in graphene thin layer by Chemical Vapour Deposition (CVD) were performed subsequently in the flow reactor by manipulating the gas composition. Obtained photocatalysts were tested in regard to hydrogen generation from photo-induced water conversion with methanol as sacrificial agent. The hydrogen generation rate for the most active sample reached 2296.27 µmol H2 h−1 gcat−1. Combining experimental and computational approaches enabled to define the optimum combination of the synthesis parameters resulting in the highest photocatalytic activity for water splitting for green hydrogen production. The results indicate that the major factor affecting hydrogen production is temperature of the TiO2-Cu-graphene composite synthesis which in turn is inversely correlated to photoactivity.
Analysis of Trends and Emerging Technologies in Water Electrolysis Research Based on a Computational Method: A Comparison with Fuel Cell Research
Feb 2018
Publication
Water electrolysis for hydrogen production has received increasing attention especially for accumulating renewable energy. Here we comprehensively reviewed all water electrolysis research areas through computational analysis using a citation network to objectively detect emerging technologies and provide interdisciplinary data for forecasting trends. The results show that all research areas increase their publication counts per year and the following two areas are particularly increasing in terms of number of publications: “microbial electrolysis” and “catalysts in an alkaline water electrolyzer (AWE) and in a polymer electrolyte membrane water electrolyzer (PEME).”. Other research areas such as AWE and PEME systems solid oxide electrolysis and the whole renewable energy system have recently received several review papers although papers that focus on specific technologies and are cited frequently have not been published within the citation network. This indicates that these areas receive attention but there are no novel technologies that are the center of the citation network. Emerging technologies detected within these research areas are presented in this review. Furthermore a comparison with fuel cell research is conducted because water electrolysis is the reverse reaction to fuel cells and similar technologies are employed in both areas. Technologies that are not transferred between fuel cells and water electrolysis are introduced and future water electrolysis trends are discussed.
HyDeploy2 : Trial Management
May 2021
Publication
The trial management philosophy of the Winlaton trial within HyDeploy2 has been developed to enable the overall objectives of the project to be achieved; the safe demonstration of operating a Gas Distribution Network (GDN) on a blend of natural gas and hydrogen. The approach taken to develop the management philosophy of the Winlaton trial has been to continue the trial management strategies deployed for the Keele trial under HyDeploy albeit with site specific modifications where necessary. This document provides an overview of the management and governance processes associated with the trial itself.<br/>Click on the supplement tab to view the other documents from this report
Alkaline Water Electrolysis Powered by Renewable Energy: A Review
Feb 2020
Publication
Alkaline water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. As conventional electrolyzers are designed for operation at fixed process conditions the implementation of fluctuating and highly intermittent renewable energy is challenging. This contribution shows the recent state of system descriptions for alkaline water electrolysis and renewable energies such as solar and wind power. Each component of a hydrogen energy system needs to be optimized to increase the operation time and system efficiency. Only in this way can hydrogen produced by electrolysis processes be competitive with the conventional path based on fossil energy sources. Conventional alkaline water electrolyzers show a limited part-load range due to an increased gas impurity at low power availability. As explosive mixtures of hydrogen and oxygen must be prevented a safety shutdown is performed when reaching specific gas contamination. Furthermore the cell voltage should be optimized to maintain a high efficiency. While photovoltaic panels can be directly coupled to alkaline water electrolyzers wind turbines require suitable converters with additional losses. By combining alkaline water electrolysis with hydrogen storage tanks and fuel cells power grid stabilization can be performed. As a consequence the conventional spinning reserve can be reduced which additionally lowers the carbon dioxide emissions.
Hydrogen Embrittlement Mechanism in Fatigue Behavior of Austenitic and Martensitic Stainless Steels
May 2018
Publication
In the present study the influence of hydrogen on the fatigue behavior of the high strength martensitic stainless steel X3CrNiMo13-4 and the metastable austenitic stainless steels X2Crni19-11 with various nickel contents was examined in the low and high cycle fatigue regime. The focus of the investigations were the changes in the mechanisms of short crack propagation. Experiments in laboratory air with uncharged and precharged specimen and uncharged specimen in pressurized hydrogen were carried out. The aim of the ongoing investigation was to determine and quantitatively describe the predominant processes of hydrogen embrittlement and their influence on the short fatigue crack morphology and crack growth rate. In addition simulations were carried out on the short fatigue crack growth in order to develop a detailed insight into the hydrogen embrittlement mechanisms relevant for cyclic loading conditions. It was found that a lower nickel content and a higher martensite content of the samples led to a higher susceptibility to hydrogen embrittlement. In addition crack propagation and crack path could be simulated well with the simulation model.
Blue Hydrogen
Apr 2021
Publication
The urgency of reaching net-zero emissions requires a rapid acceleration in the deployment of all emissions reducing technologies. Near-zero emissions hydrogen (clean hydrogen) has the potential to make a significant contribution to emissions reduction in the power generation transportation and industrial sectors.
As part of the Circular Carbon Economy: Keystone to Global Sustainability series with the Center on Global Energy Policy at Columbia University SIPA this report explores the potential contribution of blue hydrogen to climate mitigation.
The report looks at:
As part of the Circular Carbon Economy: Keystone to Global Sustainability series with the Center on Global Energy Policy at Columbia University SIPA this report explores the potential contribution of blue hydrogen to climate mitigation.
The report looks at:
- Cost drivers for renewable hydrogen and hydrogen produced with fossil fuels and CCS;
- Resource requirements and cost reduction opportunities for clean hydrogen; and
- Policy recommendations to drive investment in clean hydrogen production.
- Blue hydrogen is well placed to kickstart the rapid increase in the utilisation of clean hydrogen for climate mitigation purposes but requires strong and sustained policy to incentivise investment at the rate necessary to meet global climate goals.
Solid-State Hydrogen Storage Systems and the Relevance of a Gender Perspective
Sep 2021
Publication
This paper aims at addressing the exploitation of solid-state carriers for hydrogen storage with attention paid both to the technical aspects through a wide review of the available integrated systems and to the social aspects through a preliminary overview of the connected impacts from a gender perspective. As for the technical perspective carriers to be used for solid-state hydrogen storage for various applications can be classified into two classes: metal and complex hydrides. Related crystal structures and corresponding hydrogen sorption properties are reviewed and discussed. Fundamentals of thermodynamics of hydrogen sorption evidence the key role of the enthalpy of reaction which determines the operating conditions (i.e. temperatures and pressures). In addition it rules the heat to be removed from the tank during hydrogen absorption and to be delivered to the tank during hydrogen desorption. Suitable values for the enthalpy of hydrogen sorption reaction for operating conditions close to ambient (i.e. room temperature and 1–10 bar of hydrogen) are close to 30 kJ·molH2 −1 . The kinetics of the hydrogen sorption reaction is strongly related to the microstructure and to the morphology (i.e. loose powder or pellets) of the carriers. Usually the kinetics of the hydrogen sorption reaction is rather fast and the thermal management of the tank is the rate-determining step of the processes. As for the social perspective the paper arguments that as it occurs with the exploitation of other renewable innovative technologies a wide consideration of the social factors connected to these processes is needed to reach a twofold objective: To assess the extent to which a specific innovation might produce positive or negative impacts in the recipient socioeconomic system and from a sociotechnical perspective to explore the potential role of the social components and dynamics in fostering the diffusion of the innovation itself. Within the social domain attention has been paid to address the underexplored relationship between the gender perspective and the enhancement of hydrogen-related energy storage systems. This relationship is taken into account both in terms of the role of women in triggering the exploitation of hydrogen-based storage playing as experimenter and promoter and in terms of the intertwined impact of this innovation in their current conditions at work and in daily life.
CFD Modeling and Consequence Analysis of an Accidental Hydrogen Release in a Large Scale Facility
Sep 2013
Publication
In this study the consequences of an accidental release of hydrogen within large scale (>15000 m3) facilities were modelled. To model the hydrogen release an LES Navier–Stokes CFD solver called fireFoam was used to calculate the dispersion and mixing of hydrogen within a large scale facility. The performance of the CFD modelling technique was evaluated through a validation study using experimental results from a 1/6 scale hydrogen release from the literature and a grid sensitivity study. Using the model a parametric study was performed varying release rates and enclosure sizes and examining the concentrations that develop. The hydrogen dispersion results were then used to calculate the corresponding pressure loads from hydrogen-air deflagrations in the facility.
A Hydrogen Fuelled LH2 Tanker Ship Design
May 2021
Publication
This study provides a detailed philosophical view and evaluation of a viable design for a large liquid hydrogen tanker fuelled by liquid hydrogen. Established methods for determining tank sizing ship stability and ship characteristics were used to evaluate the preliminary design and performance of the liquefied hydrogen tanker named ‘JAMILA’ designed specifically to transport liquid hydrogen. JAMILA is designed around four large liquid hydrogen tanks with a total capacity of ∼280000 m3 and uses the boil-off gas for propulsion for the loaded leg of the journey. The ship is 370 m long 75 m wide and draws 10.012 m at full load. It has a fully loaded displacement tonnage of 232000 tonnes to carry 20000 tonnes of hydrogen. Its propulsion system contains a combined-cycle gas turbine of approximately 50 MW. The volume of the hydrogen cargo pressurised to 0.5 MPa primarily determines the size and displacement of the ship.
A Review of Hydrogen Direct Injection for Internal Combustion Engines: Towards Carbon-Free Combustion
Nov 2018
Publication
A paradigm shift towards the utilization of carbon-neutral and low emission fuels is necessary in the internal combustion engine industry to fulfil the carbon emission goals and future legislation requirements in many countries. Hydrogen as an energy carrier and main fuel is a promising option due to its carbon-free content wide flammability limits and fast flame speeds. For spark-ignited internal combustion engines utilizing hydrogen direct injection has been proven to achieve high engine power output and efficiency with low emissions. This review provides an overview of the current development and understanding of hydrogen use in internal combustion engines that are usually spark ignited under various engine operation modes and strategies. This paper then proceeds to outline the gaps in current knowledge along with better potential strategies and technologies that could be adopted for hydrogen direct injection in the context of compression-ignition engine applications—topics that have not yet been extensively explored to date with hydrogen but have shown advantages with compressed natural gas.
Performance Study on Methanol Steam Reforming Rib Micro-Reactor with Waste Heat Recovery
Mar 2020
Publication
Automobile exhaust heat recovery is considered to be an effective means to enhance fuel utilization. The catalytic production of hydrogen by methanol steam reforming is an attractive option for onboard mobile applications due to its many advantages. However the reformers of conventional packed bed type suffer from axial temperature gradients and cold spots resulting from severe limitations of mass and heat transfer. These disadvantages limit reformers to a low efficiency of catalyst utilization. A novel rib microreactor was designed for the hydrogen production from methanol steam reforming heated by automobile exhaust and the effect of inlet exhaust and methanol steam on reactor performance was numerically analyzed in detail with computational fluid dynamics. The results showed that the best operating parameters were the counter flow water-to-alcohol (W/A) of 1.3 exhaust inlet velocity of 1.1 m/s and exhaust inlet temperature of 773 K when the inlet velocity and inlet temperature of the reactant were 0.1 m/s and 493 K respectively. At this condition a methanol conversion of 99.4% and thermal efficiency of 28% were achieved together with a hydrogen content of 69.6%.
Thermodynamic Evaluation of Bi-directional Solid Oxide Cell Systems Including Year-round Cumulative Exergy Analysis
Jun 2018
Publication
Bi-directional solid oxide cell systems (Bi-SOC) are being increasingly considered as an electrical energy storage method and consequently as a means to boost the penetration of renewable energy (RE) and to improve the grid flexibility by power-to-gas electrochemical conversion. A major advantage of these systems is that the same SOC stack operates as both energy storage device (SOEC) and energy producing device (SOFC) based on the energy demand and production. SOEC and SOFC systems are now well-optimised as individual systems; this work studies the effect of using the bi-directionality of the SOC at a system level. Since the system performance is highly dependent on the cell-stack operating conditions this study improves the stack parameters for both operation modes. Moreover the year-round cumulative exergy method (CE) is introduced in the solid oxide cell (SOC) context for estimating the system exergy efficiencies. This method is an attempt to obtain more insightful exergy assessments since it takes into account the operational hours of the SOC system in both modes. The CE method therefore helps to predict more accurately the most efficient configuration and operating parameters based on the power production and consumption curves in a year. Variation of operating conditions configurations and SOC parameters show a variation of Bi-SOC system year-round cumulative exergy efficiency from 33% to 73%. The obtained thermodynamic performance shows that the Bi-SOC when feasible can prove to be a highly efficient flexible power plant as well as an energy storage system.
Review of Release Behavior of Hydrogen & Natural Gas Blends from Pipelines
Aug 2021
Publication
Hydrogen can be used to reduce carbon emissions by blending into other gaseous energy carriers such as natural gas. However hydrogen blending into natural gas has important implications for safety which need to be evaluated. Hydrogen has different physical properties than natural gas and these properties affect safety evaluations concerning a leak of the blended gas. The intent of this report is to begin to investigate the safety implications of blending hydrogen into the natural gas infrastructure with respect to a leak event from a pipeline. A literature review was conducted to identify existing data that will better inform future hazard and risk assessments for hydrogen/natural gas blends. Metrics with safety implications such as heat flux and dispersion behavior may be affected by the overall blend ratio of the mixture. Of the literature reviewed there was no directly observed separation of the hydrogen from the natural gas or methane blend. No literature was identified that experimentally examined unconfined releases such as concentration fields or concentration at specific distances. Computational efforts have predicted concentration fields by modified versions of existing engineering models but the validation of these models is limited by the unavailability of literature data. There are multiple literature sources that measured flame lengths and heat flux values which are both relevant metrics to risk and hazard assessments. These data can be more directly compared to the outputs of existing engineering models for validation.
The paper can be downloaded on their website
The paper can be downloaded on their website
Everything About Hydrogen Podcast: The year-end Round Up! 2020 in Review
Dec 2020
Publication
2020 has been a year for the history books! Some good most of it not so good; but 2020 has been a boom year for the future of hydrogen technologies. Patrick Chris and Andrew do their level best on this episode to talk about all the stories and the highlights of 2020 in under 50 minutes. Have a listen and let us know if we missed anything in our penultimate episode of 2020!
The podcast can be found on their website
The podcast can be found on their website
Hy4Heat Domestic Hydrogen Purge Procedures - Work Package 4
Jun 2021
Publication
The aim of this project was to review the current purge standards for UK domestic installations in particular IGEM/UP/1B and carry out experiments to assess the validity of those standards for use in hydrogen in order to understand and recommend safe purge practices for hydrogen in a domestic environment.
This report provides the results and conclusions relating to the relative safety of purging domestic installations to hydrogen compared to Natural Gas and the implications of releasing any purged gas
into an enclosed volume representing a small room.
The two high-level findings from this work are:
The risks with hydrogen are associated with a wide range of flammability with methane the risks are smaller and mainly in lower concentrations of gas in air. Because of this it is particularly important to ensure hydrogen pipes are appropriately purged.
This report provides the results and conclusions relating to the relative safety of purging domestic installations to hydrogen compared to Natural Gas and the implications of releasing any purged gas
into an enclosed volume representing a small room.
The two high-level findings from this work are:
- changeover to hydrogen will result in an increased risk of flammability inside the installation pipework
- changeover to hydrogen will result in a reduced risk of a build-up of flammable gas in any room where purging occurs.
The risks with hydrogen are associated with a wide range of flammability with methane the risks are smaller and mainly in lower concentrations of gas in air. Because of this it is particularly important to ensure hydrogen pipes are appropriately purged.
No more items...