Austria
Characterization of Materials in Pressurized Hydrogen Under Cyclic Loading at Service Conditions in Hydrogen Powered Engines
Sep 2005
Publication
A new testing device for cyclic loading of specimens with a novel shape design is presented. The device was applied for investigations of fatigue of metallic specimens under pressurized hydrogen up to 300 bar at temperatures up to 200 °C. Main advantage of the specimen design is the very small amount of medium here hydrogen used for testing. This allows experiments with hazardous substances at lower safety level. Additionally no gasket for the load transmission is required. Woehler curves which show the influence of hydrogen on the fatigue behaviour of austenitic steel specimens at relevant service conditions in hydrogen powered engines are presented. Material and test conditions are in agreement with the cooperating industry.
Expectations as a Key to Understanding Actor Strategies in the Field of Fuel Cell and Hydrogen Vehicles
Feb 2012
Publication
Due to its environmental impact the mobility system is increasingly under pressure. The challenges to cope with climate change air quality depleting fossil resources imply the need for a transition of the current mobility system towards a more sustainable one. Expectations and visions have been identified as crucial in the guidance of such transitions and more specifically of actor strategies. Still it remained unclear why the actors involved in transition activities appear to change their strategies frequently and suddenly. The empirical analysis of the expectations and strategies of three actors in the field of hydrogen and fuel cell technology indicates that changing actor strategies can be explained by rather volatile expectations related to different levels. Our case studies of the strategies of two large car manufacturers and the German government demonstrate that the car manufacturers refer strongly to expectations about the future regime while expectations related to the socio-technical landscape level appear to be crucial for the strategy of the German government.
Exergy as Criteria for Efficient energy Systems - Maximising Energy Efficiency from Resource to Energy Service, an Austrian Case Study
Sep 2021
Publication
The EU aims for complete decarbonisation. Therefore renewable generation must be massively expanded and the energy and exergy efficiency of the entire system must be significantly increased. To increase exergy efficiency a holistic consideration of the energy system is necessary. This work analyses the optimal technology mix to maximise exergy efficiency in a fully decarbonised energy system. An exergy-based optimisation model is presented and analysed. It considers both the energy supply system and the final energy application. The optimisation is using Austria as a case study with targeted renewable generation capacities of 2030. The results show that despite this massive expansion and the maximum exergy efficiency about half of the primary energy still be imported. Overall exergy efficiency can be raised from today's 34% (Sejkora et al. 2020) to 56%. The major increase in exergy efficiency is achieved in the areas of heat supply (via complete excess heat utilisation and heat pumps) and transport (via electric and fuel cell drives). The investigated exergy optimisation results in an increase of the final electrical energy demand by 44% compared to the current situation. This increase leads to mainly positive residual loads despite a significant expansion of renewable generation. Negative residual loads are used to provide heat and hydrogen.
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.
Achieving Carbon-neutral Iron and Steelmaking in Europe Through the Deployment of Bioenergy with Carbon Capture and Storage
Jan 2019
Publication
The 30 integrated steel plants operating in the European Union (EU) are among the largest single-point CO2 emitters in the region. The deployment of bioenergy with carbon capture and storage (bio-CCS) could significantly reduce their emission intensities. In detail the results demonstrate that CO2 emission reduction targets of up to 20% can be met entirely by biomass deployment. A slow CCS technology introduction on top of biomass deployment is expected as the requirement for emission reduction increases further. Bio-CCS could then be a key technology particularly in terms of meeting targets above 50% with CO2 avoidance costs ranging between €60 and €100 tCO2−1 at full-scale deployment. The future of bio-CCS and its utilisation on a larger scale would therefore only be viable if such CO2 avoidance cost were to become economically appealing. Small and medium plants in particular would economically benefit from sharing CO2 pipeline networks. CO2 transport however makes a relatively small contribution to the total CO2 avoidance cost. In the future the role of bio-CCS in the European iron and steelmaking industry will also be influenced by non-economic conditions such as regulations public acceptance realistic CO2 storage capacity and the progress of other mitigation technologies.
The Future Potential Hydrogen Demand in Energy-intensive Industries - A Site-specific Approach Applied to Germany
Dec 2021
Publication
Hydrogen when based on renewable electricity can play a key role in the transition towards CO2-neutral industrial production since its use as an energy carrier as well as a feedstock in various industrial process routes is promising. At the same time a large-scale roll-out of hydrogen for industrial use would entail substantial impacts on the energy system which can only be assessed if the regional distribution of future hydrogen demand is considered. Here we assess the technical potential of hydrogen-based technologies for energy-intensive industries in Germany. The site-specific and process-specific bottom-up calculation considers 615 individual plants at 367 sites and results in a total potential hydrogen demand of 326 TWh/a. The results are available as an open dataset. Using hydrogen for non-energy-intensive sectors as well increases the potential hydrogen demand to between 482 and 534 TWh/a for Germany - based on today’s industrial structure and production output. This assumes that fossil fuels are almost completely replaced by hydrogen for process heating and feedstocks. The resulting hydrogen demand is very unevenly distributed: a few sites account for the majority of the overall potential and similarly the bulk of demand is concentrated in a few regions with steel and chemical clusters.
Magnesium Gasar as a Potential Monolithic Hydrogen Absorbent
Feb 2021
Publication
The study focuses on the aspect of using the structure of gasars i.e. materials with directed open porosity as a potential hydrogen storage. The structure of the tested gasar is composed of a large number of thin open tubular pores running through the entire longitudinal section of the sample. This allows hydrogen to easily penetrate into the entire sample volume. The analysis of pore distribution showed that the longest diffusion path needed for full penetration of the metal structure with hydrogen is about L = 50–70 μm regardless of the external dimensions of the sample. Attempts to hydrogenate the magnesium gasar structure have shown its ability to accumulate hydrogen at a level of 1 wt%. The obtained results were compared with the best result was obtained for the ZK60 alloy after equal channel angular pressing (ECAP) and crushed to a powder form. The result obtained exceeded 4 wt% of hydrogen accumulated in the metal structure at theoretical 6.9 wt% maximum capacity. A model analysis of the theoretic absorption capacity of pure magnesium was also carried out based on the concentration of vacancies in the metal structure. The theoretical results obtained correlate well with experimental data.
Hydrocarbon Production by Continuous Hydrodeoxygenation of Liquid Phase Pyrolysis Oil with Biogenous Hydrogen Rich Synthesis Gas
Feb 2019
Publication
This paper presents a beneficial combination of biomass gasification and pyrolysis oil hydrodeoxygenation for advanced biofuel production. Hydrogen for hydrodeoxygenation (HDO) of liquid phase pyrolysis oil (LPP oil) was generated by gasification of softwood. The process merges dual fluidized bed (DFB) steam gasification which produces a hydrogen rich product gas and the HDO of LPP oil. Synthesis gas was used directly without further cleaning and upgrading by making use of the water gas-shift (WGS) reaction. The water needed for the water gas-shift reaction was provided by LPP oil. HDO was successfully performed in a lab scale over 36 h time on stream (TOS). Competing reactions like the Boudouard reaction and Sabatier reaction were not observed. Product quality was close to Diesel fuel specification according to EN 590 with a carbon content of 85.4 w% and a residual water content of 0.28 w%. The water-gas shift reaction was confirmed by CO/CO2-balance high water consumption and 28% less hydrogen consumption during HDO.
Data-driven Parameterization of Polymer Electrolyte Membrane fuel Cell Models Via Simultaneous Local Linear Structured State Space Identification
Feb 2021
Publication
In order to mitigate the degradation and prolong the lifetime of polymer electrolyte membrane fuel cells advanced model-based control strategies are becoming indispensable. Thereby the availability of accurate yet computationally efficient fuel cell models is of crucial importance. Associated with this is the need to efficiently parameterize a given model to a concise and cost-effective experimental data set. A challenging task due to the large number of unknown parameters and the resulting complex optimization problem. In this work a parameterization scheme based on the simultaneous estimation of multiple structured state space models obtained by analytic linearization of a candidate fuel cell stack model is proposed. These local linear models have the advantage of high computational efficiency regaining the desired flexibility required for the typically iterative task of model parameterization. Due to the analytic derivation of the local linear models the relation to the original parameters of the non-linear model is retained. Furthermore the local linear models enable a straight-forward parameter significance and identifiability analysis with respect to experimental data. The proposed method is demonstrated using experimental data from a 30 kW commercial polymer electrolyte membrane fuel cell stack.
Methodology for Efficient Parametrisation of Electrochemical PEMFC Model for Virtual Observers: Model Based Optimal Design of Experiments Supported by Parameter Sensitivity Analysis
Nov 2020
Publication
Determination of the optimal design of experiments that enables efficient parametrisation of fuel cell (FC) model with a minimum parametrisation data-set is one of the key prerequisites for minimizing costs and effort of the parametrisation procedure. To efficiently tackle this challenge the paper present an innovative methodology based on the electrochemical FC model parameter sensitivity analysis and application of D-optimal design plan. Relying on this consistent methodological basis the paper answers fundamental questions: a) on a minimum required data-set to optimally parametrise the FC model and b) on the impact of reduced space of operational points on identifiability of individual calibration parameters. Results reveal that application of D-optimal DoE enables enhancement of calibration parameters information resulting in up to order of magnitude lower relative standard errors on smaller data-sets. In addition it was shown that increased information and thus identifiability inherently leads to improved robustness of the FC electrochemical model.
Hydrogen Storage Performance of the Multi-principal-component CoFeMnTiVZr Alloy in Electrochemical and Gas–solid Reactions
Jun 2020
Publication
The single-phase multi-principal-component CoFeMnTiVZr alloy was obtained by rapid solidification and examined by a combination of electrochemical methods and gas–solid reactions. X-ray diffraction and high-resolution transmission electron microscopy analyses reveal a hexagonal Laves-phase structure (type C14). Cyclic voltammetry and electrochemical impedance spectroscopy investigations in the hydrogen absorption/desorption region give insight into the absorption/desorption kinetics and the change in the desorption charge in terms of the applied potential. The thickness of the hydrogen absorption layer obtained by the electrochemical reaction is estimated by high-resolution transmission electron microscopy. The electrochemical hydrogen storage capacity for a given applied voltage is calculated from a series of chronoamperometry and cyclic voltammetry measurements. The selected alloy exhibits good stability for reversible hydrogen absorption and demonstrates a maximum hydrogen capacity of ∼1.9 wt% at room temperature. The amount of hydrogen absorbed in the gas–solid reaction reaches 1.7 wt% at 298 K and 5 MPa evidencing a good correlation with the electrochemical results.
Hydrogen in Grid Balancing: The European Market Potential for Pressurized Alkaline Electrolyzers
Jan 2022
Publication
To limit the global temperature change to no more than 2 ◦C by reducing global emissions the European Union (EU) set up a goal of a 20% improvement on energy efficiency a 20% cut of greenhouse gas emissions and a 20% share of energy from renewable sources by 2020 (10% share of renewable energy (RE) specifically in the transport sector). By 2030 the goal is a 27% improvement in energy efficiency a 40% cut of greenhouse gas emissions and a 27% share of RE. However the integration of RE in energy system faces multiple challenges. The geographical distribution of energy supply changes significantly the availability of the primary energy source (wind solar water) and is the determining factor rather than where the consumers are. This leads to an increasing demand to match supply and demand for power. Especially intermittent RE like wind and solar power face the issue of energy production unrelated to demand (issue of excess energy production beyond demand and/or grid capacity) and forecast errors leading to an increasing demand for grid services like balancing power. Megawatt electrolyzer units (beyond 3 MW) can provide a technical solution to convert large amounts of excess electricity into hydrogen for industrial applications substitute for natural gas or the decarbonization of the mobility sector. The demonstration of successful MW electrolyzer operation providing grid services under dynamic conditions as request by the grid can broaden the opportunities of new business models that demonstrate the profitability of an electrolyzer in these market conditions. The aim of this work is the demonstration of a technical solution utilizing Pressurized Alkaline Electrolyzer (PAE) technology for providing grid balancing services and harvesting Renewable Energy Sources (RES) under realistic circumstances. In order to identify any differences between local market and grid requirements the work focused on a demonstration site located in Austria deemed as a viable business case for the operation of a largescale electrolyzer. The site is adapted to specific local conditions commonly found throughout Europe. To achieve this this study uses a market-based solution that aims at providing value-adding services and cash inflows stemming from the grid balancing services it provides. Moreover the work assesses the viability of various business cases by analyzing (qualitatively and quantitatively) additional business models (in terms of business opportunities/energy source potential grid service provision and hydrogen demand) and analyzing the value and size of the markets developing recommendations for relevant stakeholder to decrease market barriers.
Macroeconomic Implications of Switching to process-emission-free Iron and Steel Production in Europe
Nov 2018
Publication
Climate change is one of the most serious threats to the human habitat. The required structural change to limit anthropogenic forcing is expected to fundamentally change daily social and economic life. The production of iron and steel is a special case of economic activities since it is not only associated with combustion but particularly with process emissions of greenhouse gases which have to be dealt with likewise. Traditional mitigation options of the sector like efficiency measures substitution with less emission-intensive materials or scrap-based production are bounded and thus insufficient for rapid decarbonization necessary for complying with long-term climate policy targets. Iron and steel products are basic materials at the core of modern socio-economic systems additionally being essential also for other mitigation options like hydro and wind power. Therefore a system-wide assessment of recent technological developments enabling almost complete decarbonization of the sector is substantially relevant. Deploying a recursive-dynamic multi-region multi-sector computable general equilibrium approach we investigate switches from coke-to hydrogen-based iron and steel technologies in a scenario framework where industry decisions (technological choice and timing) and climate policies are mis-aligned. Overall we find that the costs of industry transition are moderate but still ones that may represent a barrier for implementation because the generation deciding on low-carbon technologies and bearing (macro)economic costs might not be the generation benefitting from it. Our macroeconomic assessment further indicates that anticipated bottom-up estimates of required additional domestic renewable electricity tend to be overestimated. Relative price changes in the economy induce electricity substitution effects and trigger increased electricity imports. Sectoral carbon leakage is an imminent risk and calls for aligned course of action of private and public actors.
Characterization of the Inducible and Slow-Releasing Hydrogen Sulfide and Persulfide Donor P*: Insights into Hydrogen Sulfide Signaling
Jun 2021
Publication
Hydrogen sulfide (H2S) is an important mediator of inflammatory processes. However controversial findings also exist and its underlying molecular mechanisms are largely unknown. Recently the byproducts of H2S per-/polysulfides emerged as biological mediators themselves highlighting the complex chemistry of H2S. In this study we characterized the biological effects of P* a slow-releasing H2S and persulfide donor. To differentiate between H2S and polysulfide-derived effects we decomposed P* into polysulfides. P* was further compared to the commonly used fast-releasing H2S donor sodium hydrogen sulfide (NaHS). The effects on oxidative stress and interleukin-6 (IL-6) expression were assessed in ATDC5 cells using superoxide measurement qPCR ELISA and Western blotting. The findings on IL-6 expression were corroborated in primary chondrocytes from osteoarthritis patients. In ATDC5 cells P* not only induced the expression of the antioxidant enzyme heme oxygenase-1 via per-/polysulfides but also induced activation of Akt and p38 MAPK. NaHS and P* significantly impaired menadione-induced superoxide production. P* reduced IL-6 levels in both ATDC5 cells and primary chondrocytes dependent on H2Srelease. Taken together P* provides a valuable research tool for the investigation of H2S and per-/polysulfide signalling. These data demonstrate the importance of not only H2S but also per-/polysulfides as bioactive signaling molecules with potent anti-inflammatory and in particular antioxidant properties.
Beyond Traditional Energy Sector Coupling: Conserving and Efficient Use of Local Resources
Jun 2022
Publication
Decentralisation and sector coupling are becoming increasingly crucial for the decarbonisation of the energy system. Resources such as waste and water have high energy recovery potential and are required as inputs for various conversion technologies; however waste and water have not yet been considered in sector coupling approaches but only in separate examinations. In this work an open-source sector coupling optimisation model considering all of these resources and their utilisation is developed and applied in a test-bed in an Israeli city. Our investigations include an impact assessment of energy recovery and resource utilisation in the transition to a hydrogen economy with regard to the inclusion of greywater and consideration of emissions. Additionally sensitivity analyses are performed in order to assess the complexity level of energy recovery. The results demonstrate that waste and water energy recovery can provide high contributions to energy generation. Furthermore greywater use can be vital to cover the water demands in scarcity periods thus saving potable water and enabling the use of technology. Regarding the transition to hydrogen technologies resource energy recovery and management have an even higher effect than in the original setup. However without appropriate resource management a reduction in emissions cannot be achieved. Furthermore the sensitivity analyses indicate the existence of complex relationships between energy recovery technologies and other energy system operations.
State-of-the-art Expansion Planning of Integrated Power, Natural Gas, and Hydrogen Systems
Apr 2022
Publication
Renewable hydrogen is considered key in the transition towards a carbon-neutral future. This is due to its spatio-temporal storage and sector coupling potential which has seen it referred to as energy vector. However many unresolved issues remain regarding hydrogen's large-scale deployment e.g. least-cost production optimal facility siting and overall implications on power and energy systems. Expansion planning provides an option to study these issues in the holistic context of energy systems. To this end this article presents a comprehensive review on state-of-the-art expansion planning models that consider integrated power natural gas and hydrogen systems. We cluster the existing literature in terms of modelling themes and scope study the applied systematic modelling characteristics and conduct an in-depth analysis of the technical model features regarding hydrogen technologies and natural gas infrastructure. Finally we identify and discuss research gaps in the existing literature.
Role of Grain Boundaries in Hydrogen Embrittlement of Alloy 725: Single and Bi-crystal Microcantilever Bending Study
Jan 2022
Publication
In situ electrochemical microcantilever bending tests were conducted in this study to investigate the role of grain boundaries (GBs) in hydrogen embrittlement (HE) of Alloy 725. Specimens were prepared under three different heat treatment conditions and denoted as solution-annealed (SA) aged (AG) and over-aged (OA) samples. For single-crystal beams in an H-containing environment all three heat-treated samples exhibited crack formation and propagation; however crack propagation was more severe in the OA sample. The anodic extraction of H presented similar results as those under the H-free condition indicating the reversibility of the H effect under the tested conditions. Bi-crystal micro-cantilevers bent under H-free and H-charged conditions revealed the significant role of the GB in the HE of the beams. The results indicated that the GB in the SA sample facilitated dislocation dissipation whereas for the OA sample it caused the retardation of crack propagation. For the AG sample testing in an H-containing environment led to the formation of a sharp severe crack along the GB path.
Interlinking the Renewable Electricity and Gas Sectors: A Techno-Economic Case Study for Austria
Oct 2021
Publication
Achieving climate neutrality requires a massive transformation of current energy systems. Fossil energy sources must be replaced with renewable ones. Renewable energy sources with reasonable potential such as photovoltaics or wind power provide electricity. However since chemical energy carriers are essential for various sectors and applications the need for renewable gases comes more and more into focus. This paper determines the Austrian green hydrogen potential produced exclusively from electricity surpluses. In combination with assumed sustainable methane production the resulting renewable gas import demand is identified based on two fully decarbonised scenarios for the investigated years 2030 2040 and 2050. While in one scenario energy efficiency is maximised in the other scenario significant behavioural changes are considered to reduce the total energy consumption. A techno-economic analysis is used to identify the economically reasonable national green hydrogen potential and to calculate the averaged levelised cost of hydrogen (LCOH2) for each scenario and considered year. Furthermore roll-out curves for the necessary expansion of national electrolysis plants are presented. The results show that in 2050 about 43% of the national gas demand can be produced nationally and economically (34 TWh green hydrogen 16 TWh sustainable methane). The resulting national hydrogen production costs are comparable to the expected import costs (including transport costs). The most important actions are the quick and extensive expansion of renewables and electrolysis plants both nationally and internationally
Role of Hydrogen-based Energy Carriers as an Alternative Option to Reduce Residual Emissions Associated with Mid-century Decarbonization Goals
Mar 2022
Publication
Hydrogen-based energy carriers including hydrogen ammonia and synthetic hydrocarbons are expected to help reduce residual carbon dioxide emissions in the context of the Paris Agreement goals although their potential has not yet been fully clarified in light of their competitiveness and complementarity with other mitigation options such as electricity biofuels and carbon capture and storage (CCS). This study aimed to explore the role of hydrogen in the global energy system under various mitigation scenarios and technology portfolios using a detailed energy system model that considers various energy technologies including the conversion and use of hydrogen-based energy carriers. The results indicate that the share of hydrogen-based energy carriers generally remains less than 5% of global final energy demand by 2050 in the 2 ◦C scenarios. Nevertheless such carriers contribute to removal of residual emissions from the industry and transport sectors under specific conditions. Their share increases to 10–15% under stringent mitigation scenarios corresponding to 1.5 ◦C warming and scenarios without CCS. The transport sector is the largest consumer accounting for half or more of hydrogen production followed by the industry and power sectors. In addition to direct usage of hydrogen and ammonia synthetic hydrocarbons converted from hydrogen and carbon captured from biomass or direct air capture are attractive transport fuels growing to half of all hydrogen-based energy carriers. Upscaling of electrification and biofuels is another common cost-effective strategy revealing the importance of holistic policy design rather than heavy reliance on hydrogen.
Simulation-Assisted Determination of the Start-Up Time of a Polymer Electrolyte Fuel Cell
Nov 2021
Publication
Fuel starvation is a major cause of anode corrosion in low temperature polymer electrolyte fuel cells. The fuel cell start-up is a critical step as hydrogen may not yet be evenly distributed in the active area leading to local starvation. The present work investigates the hydrogen distribution and risk for starvation during start-up and after nitrogen purge by extending an existing computational fluid dynamic model to capture transient behavior. The results of the numerical model are compared with detailed experimental analysis on a 25 cm2 triple serpentine flow field with good agreement in all aspects and a required time step size of 1 s. This is two to three orders of magnitude larger than the time steps used by other works resulting in reasonably quick calculation times (e.g. 3 min calculation time for 1 s of experimental testing time using a 2 million element mesh).
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