Austria

Fuel storage systems for vehicles require a fail-safe design strategy. In case of system failures or accidents the control electronics have to switch the system into a safe operation mode. Failure Mode and Effect Analysis (FMEA) or Failure Tree Analysis (FTA) are performed already in the early design phase in order to minimize the risk of design failures in the fuel storage system. Currently the specifications of requirements for pressurized and liquid hydrogen fuel tanks are based on draft UN-ECE Regulations developed by the European Integrated Hydrogen Project (EIHP). Used materials and accessories shall be compatible with hydrogen. A selection of metallic and non-metallic materials will be presented. Complex components have to be optimised by FEM simulations in order to determine weak spots in the design which will be overstressed in case of pressure thermal expansion or dynamic vibrations. According to automotive standards the performance of liquid hydrogen fuel tank systems has to be verified in various destructive and non-destructive tests.

Solid oxide electrolysis cells (SOECs) are an efficient technology for the production of green hydrogen that has great potential to contribute to the energy transition and decarbonization of industry. To date however time- and resource-intensive experimental campaigns slow down the development and market penetration of the technology. In order to speed-up the evaluation of SOEC performance and durability accelerated testing protocols are required. This work provides the results of experimental studies on the performance of a SOEC stack operated under accelerated degradation conditions. In order to initiate and accelerate degradation experiments were performed with high steam partial pressures at the gas inlet higher voltages and lower temperatures and high steam conversion rates. Thereby different types and degrees of impact on performance were observed which were analyzed in detail and linked to the underlying processes and degradation mechanisms. In this context significantly higher degradation rates were found compared to operation under moderate operating conditions with the different operating strategies varying in their degradation acceleration potential. The results also suggest that a few hundred hours of operation may be sufficient to predict long-term performance with the proposed operating strategies providing a solid basis for accelerated assessment of SOEC performance evolution and lifetime.

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.

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.

Fundamental understanding of H localization in steel is an important step towards theoretical descriptions of hydrogen embrittlement mechanisms at the atomic level. In this paper we investigate the interaction between atomic H and defects in ferromagnetic body-centered cubic (bcc) iron using density functional theory (DFT) calculations. Hydrogen trapping profiles in the bulk lattice at vacancies dislocations and grain boundaries (GBs) are calculated and used to evaluate the concentrations of H at these defects as a function of temperature. The results on H-trapping at GBs enable further investigating H-enhanced decohesion at GBs in Fe. A hierarchy map of trapping energies associated with the most common crystal lattice defects is presented and the most attractive H-trapping sites are identified.

Chemical looping water splitting or chemical looping hydrogen is a very promising technology for the production of hydrogen. In recent years extensive research has enabled remarkable leaps towards a successful integration of the chemical looping technology into a future hydrogen infrastructure. Progress has been reported with iron based oxygen carriers for stable hydrogen production capacity over consecutive cycles without significant signs of degradation. The high stability improvements were achieved by adding alien metal oxides or by integrating the active component into a mineral structure which offers excellent resistance towards thermal stress. Prototype systems from small μ-systems up to 50 kW have been operated with promising results. The chemical looping water splitting process was broadened in terms of its application area and utilization of feedstocks using a variety of renewable and fossil resources. The three-reactor system was clearly advantageous due to its flexibility heat integration capabilities and possibility to produce separate pure streams of hydrogen CO₂ and N₂. However two-reactor and single fixed-bed reactor systems were successfully operated as well. This review aims to survey the recently presented literature in detail and systematically summarize the gathered data.

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.

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.

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.

To reduce loss of hydrogen in storage vessels with high energy-to-weight-ratio new materials especially polymers have to be developed as barrier materials. Very established methods for characterization of barrier materials with permeation measurements are the time-lag and flow rate method along with the differential pressure method which resembles the nature of hydrogen vessel systems very well. Long measurement durations are necessary to gain suitable measurement data for these evaluation methods and often restrictive conditions have to be fulfilled. For these reasons common models for hydrogen permeation through single-layer and multi-layer membranes as well as models for hydrogen gas properties were collected and reviewed. Using current computer power together with these models can reduce measurement time for characterization of the barrier properties of materials while additional information about the quality of the measurement results is obtained.