Germany
Low-Cost and Durable Bipolar Plates for Proton Exchange Membrane Electrolyzers
Mar 2017
Publication
Cost reduction and high efficiency are the mayor challenges for sustainable H2 production via proton exchange membrane (PEM) electrolysis. Titanium-based components such as bipolar plates (BPP) have the largest contribution to the capital cost. This work proposes the use of stainless steel BPPs coated with Nb and Ti by magnetron sputtering physical vapor deposition (PVD) and vacuum plasma spraying (VPS) respectively. The physical properties of the coatings are thoroughly characterized by scanning electron atomic force microscopies (SEM AFM); and X-ray diffraction photoelectron spectroscopies (XRD XPS). The Ti coating (50μm) protects the stainless steel substrate against corrosion while a 50- fold thinner layer of Nb decreases the contact resistance by almost one order of magnitude. The Nb/ Ti-coated stainless steel bipolar BPPs endure the harsh environment of the anode for more than 1000h of operation under nominal conditions showing a potential use in PEM electrolyzers for large-scale H2 production from renewables.
A Novel Emergency Gas-to-Power System Based on an Efficient and Long-Lasting Solid-State Hydride Storage System: Modeling and Experimental Validation
Jan 2022
Publication
In this paper a gas-to-power (GtoP) system for power outages is digitally modeled and experimentally developed. The design includes a solid-state hydrogen storage system composed of TiFeMn as a hydride forming alloy (6.7 kg of alloy in five tanks) and an air-cooled fuel cell (maximum power: 1.6 kW). The hydrogen storage system is charged under room temperature and 40 bar of hydrogen pressure reaching about 110 g of hydrogen capacity. In an emergency use case of the system hydrogen is supplied to the fuel cell and the waste heat coming from the exhaust air of the fuel cell is used for the endothermic dehydrogenation reaction of the metal hydride. This GtoP system demonstrates fast stable and reliable responses providing from 149 W to 596 W under different constant as well as dynamic conditions. A comprehensive and novel simulation approach based on a network model is also applied. The developed model is validated under static and dynamic power load scenarios demonstrating excellent agreement with the experimental results.
Kinetic Parameters Estimation via Dragonfly Algorithm (DA) and Comparison of Cylindrical and Spherical Reactors Performance for CO2 Hydrogenation to Hydrocarbons
Oct 2020
Publication
Climate change and global warming as well as growing global demand for hydrocarbons in industrial sectors make great incentives to investigate the utilization of CO2 for hydrocarbons production. Therefore finding an in-depth understanding of the CO2 hydrogenation reactors along with simulating reactor responses to different operating conditions are of paramount importance. However the reaction mechanisms for CO2 hydrogenation and their corresponding kinetic parameters have been disputable yet. In this regard considering the previously proposed Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism which considered CO2 hydrogenation as a combination of reverse water gas shift (RWGS) and Fischer-Tropsch (FT) reactions and using a one-dimensional pseudo-homogeneous non-isothermal model kinetic parameters of the rate expressions are estimated via fitting experimental and modelling data through a novel swarm intelligence optimization technique called dragonfly algorithm (DA). The predicted reactants conversion using DA algorithm are closer to the experimental data (with about 4% error) comparing to those obtained by the artificial bee colony (ABC) algorithm and are in significant agreement with available literature data. The proposed model is used to assess the effect of reactor configuration on the performance and temperature fluctuations. Results show that axial flow spherical reactor (AFSR) and radial flow spherical reactor (RFSR) exhibiting the same surface area with that of the cylindrical reactor (CR) i.e. AFSR-2 and RFSR-2-i are the most efficient exhibiting hydrocarbons selectivity of 40.330% and 40.286% at CO2 conversion of 53.763% and 53.891%. In addition it is revealed that the location of the jacket has an essential role in controlling the reactor temperature.
Hydrogen-assisted Cracking of GMA Welded 960 & A Grade High-strength Steels
Jan 2020
Publication
High-strength steels with yield strength of 960 MPa are susceptible to hydrogen-assisted cracking (HAC) during welding processing. In the present paper the implant test is used to study HAC in a quenched and tempered steel S960QL and a high-strength steel produced by thermo-mechanical controlled process S960MC. Welding is performed using the gas-metal arc welding process. Furthermore diffusible hydrogen concentration (HD) in arc weld metal is determined. Based on the implant test results lower critical stress (LCS) for complete fracture critical implant stress (σkrit) for crack initiation and embrittlement index (EI) are determined. At HD of 1.66 ml/100 g LCS is 605 MPa and 817 MPa for S960QL and S960MC respectively. EI is 0.30 and 0.46 for S960QL and S960MC respectively. Fracture surfaces of S960QL show higher degradation with reduced deformation. Both higher EI of S960MC and fractography show better resistance to HAC in the HAZ of S960MC compared to S960QL.
Blind-prediction: Estimating the Consequences of Vented Hydrogen Deflagrations for Homogeneous Mixtures in a 20-foot ISO Container
Sep 2017
Publication
Trygve Skjold,
Helene Hisken,
Sunil Lakshmipathy,
Gordon Atanga,
Marco Carcassi,
Martino Schiavetti,
James R. Stewart,
A. Newton,
James R. Hoyes,
Ilias C. Tolias,
Alexandros G. Venetsanos,
Olav Roald Hansen,
J. Geng,
Asmund Huser,
Sjur Helland,
Romain Jambut,
Ke Ren,
Alexei Kotchourko,
Thomas Jordan,
Jérome Daubech,
Guillaume Lecocq,
Arve Grønsund Hanssen,
Chenthil Kumar,
Laurent Krumenacker,
Simon Jallais,
D. Miller and
Carl Regis Bauwens
This paper summarises the results from a blind-prediction study for models developed for estimating the consequences of vented hydrogen deflagrations. The work is part of the project Improving hydrogen safety for energy applications through pre-normative research on vented deflagrations (HySEA). The scenarios selected for the blind-prediction entailed vented explosions with homogeneous hydrogen-air mixtures in a 20-foot ISO container. The test program included two configurations and six experiments i.e. three repeated tests for each scenario. The comparison between experimental results and model predictions reveals reasonable agreement for some of the models and significant discrepancies for others. It is foreseen that the first blind-prediction study in the HySEA project will motivate developers to improve their models and to update guidelines for users of the models.
Economic Analysis of Improved Alkaline Water Electrolysis
Feb 2017
Publication
Alkaline water electrolysis (AWE) is a mature hydrogen production technology and there exists a range of economic assessments for available technologies. For advanced AWEs which may be based on novel polymer-based membrane concepts it is of prime importance that development comes along with new configurations and technical and economic key process parameters for AWE that might be of interest for further economic assessments. This paper presents an advanced AWE technology referring to three different sites in Europe (Germany Austria and Spain). The focus is on financial metrics the projection of key performance parameters of advanced AWEs and further financial and tax parameters. For financial analysis from an investor’s (business) perspective a comprehensive assessment of a technology not only comprises cost analysis but also further financial analysis quantifying attractiveness and supply/market flexibility. Therefore based on cash flow (CF) analysis a comprehensible set of metrics may comprise levelised cost of energy or respectively levelized cost of hydrogen (LCH) for cost assessment net present value (NPV) for attractiveness analysis and variable cost (VC) for analysis of market flexibility. The German AWE site turns out to perform best in all three financial metrics (LCH NPV and VC). Though there are slight differences in investment cost and operation and maintenance cost projections for the three sites the major cost impact is due to the electricity cost. Although investment cost is slightly lower and labor cost is significantly lower in Spain the difference can not outweigh the higher electricity cost compared to Germany. Given the assumption that the electrolysis operators are customers directly and actively participating in power markets and based on the regulatory framework in the three countries in this special case electricity cost in Germany is lowest. However as electricity cost is profoundly influenced by political decisions as well as the implementation of economic instruments for transforming electricity systems toward sustainability it is hardly possible to further improve electricity price forecasts.
A Direct Synthesis of Platinum/Nickel Co-catalysts on Titanium Dioxide Nanotube Surface from Hydrometallurgical-type Process Streams
Aug 2018
Publication
Solutions that simulate hydrometallurgical base metal process streams with high nickel (Ni) and minor platinum (Pt) concentrations were used to create Pt/Ni nanoparticles on TiO2 nanotube surfaces. For this electrochemical deposition – redox replacement (EDRR) was used that also allowed to control the nanoparticle size density and Pt/Ni content of the deposited nanoparticles. The Pt/Ni nanoparticle decorated titanium dioxide nanotubes (TiO2 nanotubes) become strongly activated for photocatalytic hydrogen (H2) evolution. Moreover EDRR facilitates nanoparticle formation without the need for any additional chemicals and is more effective than electrodeposition alone. Actually a 10000-time enrichment level of Pt took place on the TiO2 surface when compared to Pt content in the solution with the EDRR method. The results show that hydrometallurgical streams offer great potential as an alternative raw material source for industrial catalyst production when coupled with redox replacement electrochemistry.
Results of the Pre-normative Research Project PRESLHY for the Safe Use of Liquid Hydrogen
Sep 2021
Publication
Liquid hydrogen (LH2) compared to compressed gaseous hydrogen offers advantages for large-scale transport and storage of hydrogen with higher densities. Although the gas industry has good experience with LH2 only little experience is available for the new applications of LH2 as an energy carrier. Therefore the European FCH JU funded project PRESLHY conducted pre-normative research for the safe use of cryogenic LH2 in non-industrial settings. The central research consisted of a broad experimental program combined with analytical work modelling and simulations belonging to the three key phenomena of the accident chain: release and mixing ignition and combustion. The presented results improve the general understanding of the behavior of LH2 in accidents and provide some design guidelines and engineering tools for safer use of LH2. Recommendations for improvement of current international standards are derived.
Expected Impacts on Greenhouse Gas and Air Pollutant Emissions Due to a Possible Transition Towards a Hydrogen Economy in German Road Transport
Nov 2020
Publication
Transitioning German road transport partially to hydrogen energy is among the possibilities being discussed to help meet national climate targets. This study investigates impacts of a hypothetical complete transition from conventionally-fuelled to hydrogen-powered German transport through representative scenarios. Our results show that German emissions change between −179 and +95 MtCO2eq annually depending on the scenario with renewable-powered electrolysis leading to the greatest emissions reduction while electrolysis using the fossil-intense current electricity mix leads to the greatest increase. German energy emissions of regulated pollutants decrease significantly indicating the potential for simultaneous air quality improvements. Vehicular hydrogen demand is 1000 PJ annually requiring 446–525 TWh for electrolysis hydrogen transport and storage which could be supplied by future German renewable generation supporting the potential for CO2-free hydrogen traffic and increased energy security. Thus hydrogen-powered transport could contribute significantly to climate and air quality goals warranting further research and political discussion about this possibility.
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.
Origin of the Catalytic Activity at Graphite Electrodes in Vanadium Flow Batteries
Jun 2021
Publication
For many electrochemical devices that use carbon-based materials such as electrolyzers supercapacitors and batteries oxygen functional groups (OFGs) are considered essential to facilitate electron transfer. Researchers implement surface-active OFGs to improve the electrocatalytic properties of graphite felt electrodes in vanadium flow batteries. Herein we show that graphitic defects and not OFGs are responsible for lowering the activation energy barrier and thus enhance the charge transfer properties. This is proven by a thermal deoxygenation procedure in which specific OFGs are removed before electrochemical cycling. The electronic and microstructural changes associated with deoxygenation are studied by quasi in situ X-ray photoelectron and Raman spectroscopy. The removal of oxygen groups at basal and edge planes improves the activity by introducing new active edge sites and carbon vacancies. OFGs hinder the charge transfer at the graphite–electrolyte interface. This is further proven by modifying the sp2 plane of graphite felt electrodes with oxygen-containing pyrene derivatives. The electrochemical evolution of OFGs and graphitic defects are studied during polarization and long-term cycling conditions. The hypothesis of increased activity caused by OFGs was refuted and hydrogenated graphitic edge sites were identified as the true reason for this increase.
The New Oil? The Geopolitics and International Governance of Hydrogen
Jun 2020
Publication
While most hydrogen research focuses on the technical and cost hurdles to a full-scale hydrogen economy little consideration has been given to the geopolitical drivers and consequences of hydrogen developments. The technologies and infrastructures underpinning a hydrogen economy can take markedly different forms and the choice over which pathway to take is the object of competition between different stakeholders and countries. Over time cross-border maritime trade in hydrogen has the potential to fundamentally redraw the geography of global energy trade create a new class of energy exporters and reshape geopolitical relations and alliances between countries. International governance and investments to scale up hydrogen value chains could reduce the risk of market fragmentation carbon lock-in and intensified geo-economic rivalry.
Using the Jet Stream for Sustainable Airship and Balloon Transportation of Cargo and Hydrogen
Jul 2019
Publication
The maritime shipping sector is a major contributor to CO2 emissions and this figure is expected to rise in coming decades. With the intent of reducing emissions from this sector this research proposes the utilization of the jet stream to transport a combination of cargo and hydrogen using airships or balloons at altitudes of 10–20 km. The jet streams flow in the mid-latitudes predominantly in a west–east direction reaching an average wind speed of 165 km/h. Using this combination of high wind speeds and reliable direction hydrogen-filled airships or balloons could carry hydrogen with a lower fuel requirement and shorter travel time compared to conventional shipping. Jet streams at different altitudes in the atmosphere were used to identify the most appropriate circular routes for global airship travel. Round-the-world trips would take 16 days in the Northern Hemisphere and 14 in the Southern Hemisphere. Hydrogen transport via the jet stream due to its lower energy consumption and shorter cargo delivery time access to cities far from the coast could be a competitive alternative to maritime shipping and liquefied hydrogen tankers in the development of a sustainable future hydrogen economy.
Renewable Power and Heat for the Decarbonisation of Energy-Intensive Industries
Dec 2022
Publication
The present review provides a catalogue of relevant renewable energy (RE) technologies currently available (regarding the 2030 scope) and to be available in the transition towards 2050 for the decarbonisation of Energy Intensive Industries (EIIs). RE solutions have been classified into technologies based on the use of renewable electricity and those used to produce heat for multiple industrial processes. Electrification will be key thanks to the gradual decrease in renewable power prices and the conversion of natural-gas-dependent processes. Industrial processes that are not eligible for electrification will still need a form of renewable heat. Among them the following have been identified: concentrating solar power heat pumps and geothermal energy. These can supply a broad range of needed temperatures. Biomass will be a key element not only in the decarbonisation of conventional combustion systems but also as a biofuel feedstock. Biomethane and green hydrogen are considered essential. Biomethane can allow a straightforward transition from fossil-based natural gas to renewable gas. Green hydrogen production technologies will be required to increase their maturity and availability in Europe (EU). EIIs’ decarbonisation will occur through the progressive use of an energy mix that allows EU industrial sectors to remain competitive on a global scale. Each industrial sector will require specific renewable energy solutions especially the top greenhouse gas-emitting industries. This analysis has also been conceived as a starting point for discussions with potential decision makers to facilitate a more rapid transition of EIIs to full decarbonisation.
The Merit and the Context of Hydrogen Production from Water and Its Effect on Global CO2 Emission
Feb 2022
Publication
For a green economy to be possible in the near future hydrogen production from water is a sought-after alternative to fossil fuels. It is however important to put things into context with respect to global CO2 emission and the role of hydrogen in curbing it. The present world annual production of hydrogen is about 70 million metric tons of which almost 50% is used to make ammonia NH3 (that is mostly used for fertilizers) and about 15% is used for other chemicals [1]. The hydrogen produced worldwide is largely made by steam CH4 reforming (SMR) which is one of the most energy-intensive processes in the chemical industry [2]. It releases based on reaction stoichiometry 5.5 kg of CO2 per 1 kg of H2 (CH4+ 2 H2O → CO2 + 4 H2). When the process itself is taken into account in addition the production [3] becomes about 9 kg of CO2 per kg of H2 and this ratio can be as high as 12 [4]. This results in the production of about one billion tons/year of CO2. The world annual CO2 emission from fossil fuels is however much larger: it is about 36 billion tons of which roughly 25% is emitted while generating electricity and heat 20% due to transport activity and 20% from other industrial processes. Because of the link between global warming and CO2 emissions there is an increasing move towards finding alternative approaches for energy vectors and their applications.
International Association for Hydrogen Safety ‘Research Priorities Workshop’, September 2018, Buxton, UK
Sep 2018
Publication
Hydrogen has the potential to be used by many countries as part of decarbonising the future energy system. Hydrogen can be used as a fuel ‘vector’ to store and transport energy produced in low-carbon ways. This could be particularly important in applications such as heating and transport where other solutions for low and zero carbon emission are difficult. To enable the safe uptake of hydrogen technologies it is important to develop the international scientific evidence base on the potential risks to safety and how to control them effectively. The International Association for Hydrogen Safety (known as IA HySAFE) is leading global efforts to ensure this. HSE hosted the 2018 IA HySAFE Biennial Research Priorities Workshop. A panel of international experts presented during nine key topic sessions: (1) Industrial and National Programmes; (2) Applications; (3) Storage; (4) Accident Physics – Gas Phase; (5) Accident Physics – Liquid/ Cryogenic Behaviour; (6) Materials; (7) Mitigation Sensors Hazard Prevention and Risk Reduction; (8) Integrated Tools for Hazard and Risk Assessment; (9) General Aspects of Safety.<br/>This report gives an overview of each topic made by the session chairperson. It also gives further analysis of the totality of the evidence presented. The workshop outputs are shaping international activities on hydrogen safety. They are helping key stakeholders to identify gaps in knowledge and expertise and to understand and plan for potential safety challenges associated with the global expansion of hydrogen in the energy system.
Review of Power-to-Gas Projects in Europe
Nov 2018
Publication
Core of the Power-to-Gas (PtG) concept is the utilization of renewable electricity to produce hydrogen via water electrolysis. This hydrogen can be used directly as final energy carrier or can be converted to e.g. methane synthesis gas liquid fuels electricity or chemicals. To integrate PtG into energy systems technical demonstration and systems integration is of mayor importance. In total 128 PtG research and demonstration projects are realized or already finished in Europe to analyze these issues by May 2018. Key of the review is the identification and assessment of relevant projects regarding their field of application applied processes and technologies for electrolysis type of methanation capacity location and year of commissioning. So far main application for PtX is the injection of hydrogen or methane into the natural gas grid for storing electricity from variable renewable energy sources. Producing fuels for transport is another important application of PtX. In future PtX gets more important for refineries to lower the carbon food print of the products.
Hybrid Hydrogen Home Storage for Decentralized Energy Autonomy
May 2021
Publication
As the share of distributed renewable power generation increases high electricity prices and low feed-in tariff rates encourage the generation of electricity for personal use. In the building sector this has led to growing interest in energy self-sufficient buildings that feature battery and hydrogen storage capacities. In this study we compare potential technology pathways for residential energy storage in terms of their economic performance by means of a temporal optimization model of the fully self-sufficient energy system of a single-family building taking into account its residential occupancy patterns and thermal equipment. We show for the first time how heat integration with reversible solid oxide cells (rSOCs) and liquid organic hydrogen carriers (LOHCs) in high-efficiency single-family buildings could by 2030 enable the self-sufficient supply of electricity and heat at a yearly premium of 52% against electricity supplied by the grid. Compared to lithium-ion battery systems the total annualized cost of a self-sufficient energy supply can be reduced by 80% through the thermal integration of LOHC reactors and rSOC systems.
Improving the Efficiency of PEM Electrolyzers through Membrane-Specific Pressure Optimization
Feb 2020
Publication
Hydrogen produced in a polymer electrolyte membrane (PEM) electrolyzer must be stored under high pressure. It is discussed whether the gas should be compressed in subsequent gas compressors or by the electrolyzer. While gas compressor stages can be reduced in the case of electrochemical compression safety problems arise for thin membranes due to the undesired permeation of hydrogen across the membrane to the oxygen side forming an explosive gas. In this study a PEM system is modeled to evaluate the membrane-specific total system efficiency. The optimum efficiency is given depending on the external heat requirement permeation cell pressure current density and membrane thickness. It shows that the heat requirement and hydrogen permeation dominate the maximum efficiency below 1.6 V while above the cell polarization is decisive. In addition a pressure-optimized cell operation is introduced by which the optimum cathode pressure is set as a function of current density and membrane thickness. This approach indicates that thin membranes do not provide increased safety issues compared to thick membranes. However operating an N212-based system instead of an N117-based one can generate twice the amount of hydrogen at the same system efficiency while only one compressor stage must be added.
A Review of Recent Developments in Molecular Dynamics Simulations of the Photoelectrochemical Water Splitting Process
Jun 2021
Publication
In this review we provide a short overview of the Molecular Dynamics (MD) method and how it can be used to model the water splitting process in photoelectrochemical hydrogen production. We cover classical non-reactive and reactive MD techniques as well as multiscale extensions combining classical MD with quantum chemical and continuum methods. Selected examples of MD investigations of various aqueous semiconductor interfaces with a special focus on TiO2 are discussed. Finally we identify gaps in the current state-of-the-art where further developments will be needed for better utilization of MD techniques in the field of water splitting.
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