Publications
Linking Ab Initio Data on Hydrogen and Carbon in Steel to Statistical and Continuum Descriptions
Mar 2018
Publication
We present a selection of scale transfer approaches from the electronic to the continuum regime for topics relevant to hydrogen embrittlement. With a focus on grain boundary related hydrogen embrittlement we discuss the scale transfer for the dependence of the carbon solution behavior in steel on elastic effects and the hydrogen solution in austenitic bulk regions depending on Al content. We introduce an approximative scheme to estimate grain boundary energies for varying carbon and hydrogen population. We employ this approach for a discussion of the suppressing influence of Al on the substitution of carbon with hydrogen at grain boundaries which is an assumed mechanism for grain boundary hydrogen embrittlement. Finally we discuss the dependence of hydride formation on the grain boundary stiffness
Dynamic Operation of Fischer-Tropsch Reactors for Power-to-liquid Concepts: A Review
Apr 2022
Publication
The Fischer-Tropsch synthesis (FTS) is considered as a power-to-X (PtX) storage concept for converting temporally available excess energy to fuels or chemical compounds without the need of fossil resources. Fluctuating energy supplies demand a load-flexible energy system and a dynamically operating FTS reactor might be beneficial compared to traditional steady-state operations which rely on expensive upstream buffer capacities. This review provides an overview of recent experimental and simulation studies dealing with dynamic FTS operation and summarizes the main findings. The results are presented the two categories process intensification and PtX application. The review further discusses the experimentally difficult task of wide-ranging product characterization with a high temporal resolution. While dynamic reactor operation is often related to a complicated process control which challenges a save and efficient reactor performance the literature findings indicate that for dynamic FTS operation such concerns might not be as critical as assumed at least within well-known boundaries. Researchers further agree that dynamic operation might be a tool for process intensification. Especially hydrogen pulsing seems to be a potentially beneficial operating technique to remove accumulated liquid products restore initial catalyst activity and increase diesel-range productivity. The main challenge in this context is the prevention of high methane selectivity. A lucid future engineering goal seems to be the combination of the two applications: a robust and reliable FTS reactor in a PtX scenario that not only handles a fluctuating feed but uses such variations for process enhancement.
The Renewable Energy Transition in Africa: Powering Access, Resilience and Prosperity
Mar 2021
Publication
A renewables-based energy transition promises to deliver vast socio-economic benefits to countries across Africa improving energy access creating jobs and boosting energy security. To realise these benefits African countries have an opportunity to leapfrog fossil fuel technologies to a more sustainable climate-friendly power strategy aligned with the Paris Agreement and low-carbon growth.<br/><br/>The Renewable Energy Transition in Africa jointly prepared by Germany's KfW Development Bank Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) and the International Renewable Energy Agency (IRENA) on behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ) explores how African countries can achieve universal energy access within the 2030 Agenda timeframe and identifies four areas of action:<br/><br/>Promote access to energy;<br/>De-risk and promoting private sector investments;<br/>Strengthen and modernise the grid;<br/>Support systemic innovation.<br/>The study also explores the transformational potential of the electricity sector in five Africa countries: Ghana Ivory Coast Morocco Rwanda and South Africa. Specifically developed by IRENA country case studies show the real-life applicability of power sector transformation and demonstrates how countries can:<br/><br/>Take advantage of the abundancy and competitiveness of renewables;<br/>Align ambitious renewable targets in energy and climate plans;<br/>Continue supporting the development of regional markets;<br/>Leverage renewables and distributed energy resources to achieve universal energy access;<br/>Develop tailored power sector transformation plans based on a systemic innovation approach;<br/>Build on policy frameworks for just and inclusive transitions.
LES Simulation of Buoyancy Jet From Unintended Hydrogen Release with GASFLOW-MPI
Sep 2017
Publication
Hydrogen leakage is a key safety issue for hydrogen energy application. For hydrogen leakage hydrogen releases with low momentum hence the development of the leakage jet is dominated by both initial momentum and buoyancy. It is important for a computational code to capture the flow characteristics transiting from momentum-dominated jet to buoyancy dominated plume during leakage. GASFLOW-MPI is a parallel computational fluid dynamics (CFD) code which is well validated and widely used for hydrogen safety analysis. In this paper its capability for small scale hydrogen leakage is validated with unintended hydrogen release experiment. In the experiment pure hydrogen is released into surrounding stagnant air through a jet tube on a honeycomb plate with various Froude numbers (Fr). The flow can be fully momentum-dominated at the beginning while the influence of buoyancy increases with the Fr decreases along the streamline. Several quantities of interest including velocity along the centerline radial profiles of the time-averaged H2 mass fraction are obtained to compare with experimental data. The good agreement between the numerical results and the experimental data indicates that GASFLOW-MPI can successfully simulate hydrogen turbulent dispersion driven by both momentum and buoyant force. Different turbulent models i.e. k-ε LES and DES model are analyzed for code performance the result shows that all these three models are adequate for hydrogen leakage simulation k-ε simulation is sufficient for industrial applications while LES model can be adopted for detail analysis for a jet/plume study like entrainment. The DES model possesses both characters of the former two model only the performance of its result depends on the grid refinement.
Cost Optimization of a Stand-Alone Hybrid Energy System with Fuel Cell and PV
Mar 2020
Publication
Renewable energy has become very popular in recent years. The amount of renewable generation has increased in both grid-connected and stand-alone systems. This is because it can provide clean energy in a cost-effective and environmentally friendly fashion. Among all varieties photovoltaic (PV) is the ultimate rising star. Integration of other technologies with solar is enhancing the efficiency and reliability of the system. In this paper a fuel cell–solar photovoltaic (FC-PV)-based hybrid energy system has been proposed to meet the electrical load demand of a small community center in India. The system is developed with PV panels fuel cell an electrolyzer and hydrogen storage tank. Detailed mathematical modeling of this system as well as its operation algorithm have been presented. Furthermore cost optimization has been performed to determine ratings of PV and Hydrogen system components. The objective is to minimize the levelized cost of electricity (LCOE) of this standalone system. This optimization is performed in HOMER software as well as another tool using an artificial bee colony (ABC). The results obtained by both methods have been compared in terms of cost effectiveness. It is evident from the results that for a 68 MWh/yr of electricity demand is met by the 129 kW Solar PV 15 kW Fuel cell along with a 34 kW electrolyzer and a 20 kg hydrogen tank with a LPSP of 0.053%. The LCOE is found to be in 0.228 $/kWh. Results also show that use of more sophisticated algorithms such as ABC yields more optimized solutions than package programs such as HOMER. Finally operational details for FC-PV hybrid system using IEC 61850 inter-operable communication is presented. IEC 61850 information models for FC electrolyzer hydrogen tank were developed and relevent IEC 61850 message exchanges for energy management in FC-PV hybrid system are demonstrated.
Debunking the Myths of Hydrogen Production and Water Consumption
Dec 2020
Publication
In our factsheet where we debunk 3 myths around hydrogen production and water consumption: electrolysis uses vast amounts of water; electrolysis uses freshwater resources only and electrolysis is bound to create water stress in water-scarce regions.
Market Segmentation of Domestic and Commercial Natural Gas Appliances
Jan 2021
Publication
The main goal of the project is to enable the wide adoption of H2NG (hydrogen in natural gas) blends by closing knowledge gaps regarding technical impacts on residential and commercial gas appliances. The project consortium will identify and recommend appropriate codes and standards that should be adapted to answer the needs and develop a strategy for addressing the challenges for new and existing appliances.<br/>This deliverable on market segmentation is part of work package 2 and provides a quantitative segmentation of the gas appliance market in terms of appliance population numbers. It therefore prepares the project partners to perform the subsequent selection of the most representative product types to be tested in the laboratories of the THyGA partners.<br/>The classification is developed to categorise appliances installed in the field based on available statistics calculation methods and estimations. As a result appliance populations are provided for each technology segment that draw a representative picture of the installed end-use appliances within the European Union in 2020.
Hydrogen for Heating? Decarbonization Options for Households in the European Union in 2050
Mar 2021
Publication
This study compares the cost of several low-greenhouse gas (GHG) or GHG-neutral residential heating technologies in the year 2050: (1) hydrogen boilers (2) hydrogen fuel cells with an auxiliary hydrogen boiler for cold spells (3) air-source heat pumps using renewable electricity and (4) heat pumps with an auxiliary hydrogen boiler for cold spells. The assessment includes low-carbon hydrogen from steam-methane reforming (SMR) using natural gas combined with carbon capture and storage (CCS) or SMR + CCS and zero-carbon hydrogen produced from renewable electricity using electrolysis.
The analysis finds that air-source heat pumps are the most cost-effective residential heating technology in 2050 and are at least 50% lower cost than the hydrogen-only technologies. In a sensitivity analysis we find that even if natural gas costs were 50% lower or renewable electricity prices were 50% higher in 2050 compared to our central assumptions heat pumps would still be more cost-effective than hydrogen boilers or fuel cells. Renewable electrolysis hydrogen can be cost-competitive with SMR + CCS hydrogen in 2050 although electrolysis hydrogen is not produced at scale today. At the same time energy efficiency measures to reduce heat demand would be a more cost-effective strategy for achieving GHG reductions than any of the low-GHG heating pathways we assess in this study.
The analysis shows that all pathways using renewable electricity have a near-zero GHG intensity while SMR + CCS hydrogen could reduce GHG emissions by 69%–93% compared to natural gas if improvements are made in the future to reduce the GHG intensity of this pathway. Quantifying the GHG impact and cost effectiveness of various heating pathways is relevant for European policymakers facing decisions on how to both decarbonize buildings and alleviate energy poverty in line with commitments made in the Renovation Wave Initiative.
The document can be downloaded from the ICCT website
The analysis finds that air-source heat pumps are the most cost-effective residential heating technology in 2050 and are at least 50% lower cost than the hydrogen-only technologies. In a sensitivity analysis we find that even if natural gas costs were 50% lower or renewable electricity prices were 50% higher in 2050 compared to our central assumptions heat pumps would still be more cost-effective than hydrogen boilers or fuel cells. Renewable electrolysis hydrogen can be cost-competitive with SMR + CCS hydrogen in 2050 although electrolysis hydrogen is not produced at scale today. At the same time energy efficiency measures to reduce heat demand would be a more cost-effective strategy for achieving GHG reductions than any of the low-GHG heating pathways we assess in this study.
The analysis shows that all pathways using renewable electricity have a near-zero GHG intensity while SMR + CCS hydrogen could reduce GHG emissions by 69%–93% compared to natural gas if improvements are made in the future to reduce the GHG intensity of this pathway. Quantifying the GHG impact and cost effectiveness of various heating pathways is relevant for European policymakers facing decisions on how to both decarbonize buildings and alleviate energy poverty in line with commitments made in the Renovation Wave Initiative.
The document can be downloaded from the ICCT website
What is Needed to Deliver Carbon-neutral Heat Using Hydrogen and CCS?
Sep 2020
Publication
In comparison with the power sector large scale decarbonisation of heat has received relatively little attention at the infrastructural scale despite its importance in the global CO2 emissions landscape. In this study we focus on the regional transition of a heating sector from natural gas-based infrastructure to H2 using mathematical optimisation. A discrete spatio-temporal description of the geographical region of Great Britain was used in addition to a detailed description of all network elements for illustrating the key factors in the design of nation-wide H2 and CO2 infrastructure. We have found that the synergistic deployment of H2 production technologies such as autothermal reforming of methane and biomass gasification with CO2 abatement technologies such as carbon capture and storage (CCS) are critical in achieving cost-effective decarbonisation. We show that both large scale underground H2 storage and water electrolysis provide resilience and flexibility to the heating system competing on cost and deployment rates. The optimal regions for siting H2 production infrastructure are characterised by proximity to: (1) underground H2 storage (2) high demands for H2 (3) geological storage for CO2. Furthermore cost-effective transitions based on a methane reforming pathway may necessitate regional expansions in the supply of natural gas with profound implications for security of supply in nations that are already highly reliant potentially creating an infrastructure lock-in during the near term. We found that the total system cost comprising both investment and operational elements is mostly influenced by the natural gas price followed by biomass price and CapEx of underground caverns. Under a hybrid Regulated Asset Base (RAB) commercial framework with private enterprises delivering production infrastructure the total cost of heat supply over the infrastructure lifetime is estimated as 5.2–8.6 pence per kW h. Due to the higher cost relative to natural gas a Contract for Difference payment between d20 per MW h and d53 per MW h will be necessary for H2-derived heat to be competitive in the market.
Cohesive Zone Modelling of Hydrogen Assisted Fatigue Crack Growth: The Role of Trapping
Apr 2022
Publication
We investigate the influence of microstructural traps in hydrogen-assisted fatigue crack growth. To this end a new formulation combining multi-trap stress-assisted diffusion mechanism-based strain gradient plasticity and a hydrogen- and fatigue-dependent cohesive zone model is presented and numerically implemented. The results show that the ratio of loading frequency to effective diffusivity governs fatigue crack growth behaviour. Increasing the density of beneficial traps not involved in the fracture process results in lower fatigue crack growth rates. The combinations of loading frequency and carbide trap densities that minimise embrittlement susceptibility are identified providing the foundation for a rational design of hydrogen-resistant alloys.
The Decarbonisation of Heat
Mar 2020
Publication
This paper proposes that whilst the exact pathway to decarbonising heat in the UK is not yet clear there are a range of actions that could be taken in the next ten years to shift heat onto the right route to meet our 2050 net zero obligation. We already possess many of the skills and technologies required but there are a number of significant barriers preventing a spontaneous movement towards low carbon heat on the scale required – a starting impulse is needed.<br/><br/>Energy efficiency and low carbon heating have the potential to radically improve the quality of life of not just the poorest in our society but all residents of the United Kingdom. With the right approach the decarbonisation of heat can improve health outcomes for millions create new jobs in manufacturing and construction reduce air pollution in our cities and reduce the burden on our health service. This in addition to leading the world in mitigating the climate emergency.
H21- Leeds City Gate Project Report
Jul 2016
Publication
The H21 Leeds City Gate project is a study with the aim of determining the feasibility from both a technical and economic viewpoint of converting the existing natural gas network in Leeds one of the largest UK cities to 100% hydrogen. The project has been designed to minimise disruption for existing customers and to deliver heat at the same cost as current natural gas to customers. The project has shown that:
The project has provided costs for the scheme and has modelled these costs in a regulatory finance model. In addition the availability of low-cost bulk hydrogen in a gas network could revolutionise the potential for hydrogen vehicles and via fuel cells support a decentralised model of combined heat and power and localised power generation.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
- The gas network has the correct capacity for such a conversion
- It can be converted incrementally with minimal disruption to customers
- Minimal new energy infrastructure will be required compared to alternatives
- The existing heat demand for Leeds can be met via steam methane reforming and salt cavern storage using technology in use around the world today
The project has provided costs for the scheme and has modelled these costs in a regulatory finance model. In addition the availability of low-cost bulk hydrogen in a gas network could revolutionise the potential for hydrogen vehicles and via fuel cells support a decentralised model of combined heat and power and localised power generation.
This report and any attachment is freely available on the ENA Smarter Networks Portal here. IGEM Members can download the report and any attachment directly by clicking on the pdf icon above.
Modeling of Hydrogen Flame Dynamics in Narrow Gap with Bendable Walls
Sep 2017
Publication
A concept of volume porosity together with model of moving walls were elaborated and implemented into the COM3D code. Additionally to that a support of real-time data exchange with finite-element code ABAQUS - © Dassault Systèmes provided possibility to perform simulations of the gas-dynamic simultaneously with geometrical adaptation of environmental conditions. Based on the data obtained in the KIT combustion experiments in narrow gaps the authors performed a series of the simulation on the combustion in the corresponding conditions. Obtained numerical results demonstrated good agreement with the observed experimental data. These data were also compared with those obtained in the simulation without wall bending where simulation showed considerably different combustion regime. Application of the developed technique allows to obtain results unreachable without accounting on wall displacements which demonstrates massive over-estimation of the pressures observed during flame propagation.
The Hydrogen Economy - Evaluation of the Materials Science and Engineering Issues
Jan 2005
Publication
The main objectives were to identify materials issues relating to the widespread use of hydrogen as a fuel.
MAIN FINDINGS
MAIN FINDINGS
- Hydrogen is seen by many as the answer to the environmental problems of reliance on fossil fuels for energy needs. A great deal of effort is currently being invested in research into all areas of the hydrogen economy such as fuel cells hydrogen generation transportation and storage.
- Fuel cells have the potential to provide power for a very wide range of applications ranging from small portable electronics devices to large stationary electricity production and vehicles covering the whole range of road vehicles and possibly extending to rail marine and even aviation.
- The main obstacles to achieving a viable hydrogen economy are costs of producing hydrogen from renewable sources issues relating to transportation and storage due to the low energy density of hydrogen gas and the cost and reliability of fuel cells.
- The main material considerations relating to the use of hydrogen are hydrogen embrittlement material properties at cryogenic temperatures (due to use of liquid hydrogen) and permeability.
- A number of new materials are likely to come to prominence in a hydrogen economy; high performance composites are likely to be used extensively for high pressure hydrogen cylinders new materials or combinations of materials may be used for hydrogen pipelines and a range of new materials are currently being considered for hydrogen storage such as metal hydrides and carbon nanotubes.
- Due to the effect of hydrogen on materials it is important to test any materials in the environment in which they would be used. Depending on the type of test this could require the use of very specialist expensive equipment.
Pressurized Hydrogen from Charged Liquid Organic Hydrogen Carrier Systems by Electrochemical Hydrogen Compression
Feb 2021
Publication
We demonstrate that the combination of hydrogen release from a Liquid Organic Hydrogen Carrier (LOHC) system with electrochemical hydrogen compression (EHC) provides three decisive advantages over the state-of-the-art hydrogen provision from such storage system: a) The EHC device produces reduced hydrogen pressure on its suction side connected to the LOHC dehydrogenation unit thus shifting the thermodynamic equilibrium towards dehydrogenation and accelerating the hydrogen release; b) the EHC device compresses the hydrogen released from the carrier system thus producing high value compressed hydrogen; c) the EHC process is selective for proton transport and thus the process purifies hydrogen from impurities such as traces of methane. We demonstrate this combination for the production of compressed hydrogen (absolute pressure of 6 bar) from perhydro dibenzyltoluene at dehydrogenation temperatures down to 240 °C in a quality suitable for fuel cell operation e.g. in a fuel cell vehicle. The presented technology may be highly attractive for providing compressed hydrogen at future hydrogen filling stations that receive and store hydrogen in a LOHC-bound manner.
Mapping of Hydrogen Fuel Quality in Europe
Nov 2020
Publication
As part of FCH-JU funded HyCoRA project running from 2014 to 2017 28 gaseous and 13 particulate samples were collected from hydrogen refuelling stations in Europe. Samples were collected with commercial sampling instruments and analysis performed in compliance with prevailing fuel quality standards. Sampling was conducted with focus on diversity in feedstock as well as commissioning date of the HRS. Results indicate that the strategy for sampling was good. No evidence of impurity cross-over was observed. Parallel samples collected indicate some variation in analytical results. It was however found that fuel quality was generally good. Fourteen analytical results were in violation with the fuel tolerance limits. Therefore eight or 29% of the samples were in violation with the fuel quality requirements. Nitrogen oxygen and organics were the predominant impurities quantified. Particulate impurities were found to be within fuel quality specifications. No correlation between fuel quality and hydrogen feedstock or HRS commissioning date was found. Nitrogen to oxygen ratios gave no indication of samples being contaminated by air. A comparison of analytical results between two different laboratories were conducted. Some difference in analytical results were observed.
Decarbonization Synergies From Joint Planning of Electricity and Hydrogen Production: A Texas Case Study
Oct 2020
Publication
Hydrogen (H2) shows promise as an energy carrier in contributing to emissions reductions from sectors which have been difficult to decarbonize like industry and transportation. At the same time flexible H2 production via electrolysis can also support cost-effective integration of high shares of variable renewable energy (VRE) in the power system. In this work we develop a least-cost investment planning model to co-optimize investments in electricity and H2 infrastructure to serve electricity and H2 demands under various low-carbon scenarios. Applying the model to a case study of Texas in 2050 we find that H2 is produced in approximately equal amounts from electricity and natural gas under the least-cost expansion plan with a CO2 price of $30–60/tonne. An increasing CO2 price favors electrolysis while increasing H2 demand favors H2 production from Steam Methane Reforming (SMR) of natural gas. H2 production is found to be a cost effective solution to reduce emissions in the electric power system as it provides flexibility otherwise provided by natural gas power plants and enables high shares of VRE with less battery storage. Additionally the availability of flexible electricity demand via electrolysis makes carbon capture and storage (CCS) deployment for SMR cost-effective at lower CO2 prices ($90/tonne CO2) than for power generation ($180/tonne CO2 ). The total emissions attributable to H2 production is found to be dependent on the H2 demand. The marginal emissions from H2 production increase with the H2 demand for CO2 prices less than $90/tonne CO2 due to shift in supply from electrolysis to SMR. For a CO2 price of $60/tonne we estimate the production weighted-average H2 price to be between $1.30–1.66/kg across three H2 demand scenarios. These findings indicate the importance of joint planning of electricity and H2 infrastructure for cost-effective energy system decarbonization.
Numerical Simulations of Cryogenic Hydrogen Cooling in Vortex Tubes with Smooth Transitions
Mar 2021
Publication
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.
Hydrogen for Cooking: A Review of Cooking Technologies, Renewable Hydrogen Systems and Techno-Economics
Dec 2022
Publication
About 3 billion people use conventional carbon-based fuels such as wood charcoal and animal dung for their daily cooking needs. Cooking with biomass causes deforestation and habitat loss emissions of greenhouse gases and smoke pollution that affects people’s health and well-being. Hydrogen can play a role in enabling clean and safe cooking by reducing household air pollution and reducing greenhouse gas emissions. This first-of-a-kind review study on cooking with hydrogen assessed existing cooking technologies and hydrogen systems in developing country contexts. Our critical assessment also included the modelling and experimental studies on hydrogen. Renewable hydrogen systems and their adoptability in developing countries were analysed. Finally we presented a scenario for hydrogen production pathways in developing countries. Our findings indicated that hydrogen is attractive and can be safely used as a cooking fuel. However radical and disruptive models are necessary to transform the traditional cooking landscape. There is a need to develop global south-based hydrogen models that emphasize adoptability and capture the challenges in developing countries. In addition the techno-economic assumptions of the models vary significantly leading to a wide-ranging levelized cost of electricity. This finding underscored the necessity to use comprehensive techno-economic assumptions that can accurately predict hydrogen costs.
Vented Explosion of Hydrogen/Air Mixture: An Inter Comparison Benchmark Exercise
Sep 2017
Publication
Explosion venting is a widely used mitigation solution in the process industry to protect indoor equipment or buildings from excessive internal pressure caused by accidental explosions. However vented explosions are very complicated to model using computational fluid dynamics (CFD). In the framework of a French working group the main target of this investigation is to assess the predictive capabilities of five CFD codes used by five different organizations by means of comparison with recent experimental data. On this basis several recommendations for the CFD modelling of vented explosions are suggested.
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