Austria

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.

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 (H_D) in arc weld metal is determined. Based on the implant test results lower critical stress (LCS) for complete fracture critical implant stress (σ_krit) 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 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

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.

This contribution places emphasis on tuning pore architecture and film thickness of mesoporous Pd–Cu–Si thin films sputtered on Si/SiO2 substrates for enhanced electrocatalytic and hydrogen sorption/desorption activity and their comparison with the state-of-the-art thin film electrocatalysts. Small Tafel slope of 43 mV dec–1 for 1250 nm thick coatings with 2 µm diameter pores with 4.2 µm interspacing (H2) electrocatalyst with comparable hydrogen overpotentials to the literature suggests its use for standard fuel cells. The largest hydrogen sorption has been attained for the 250 nm thick electrocatalyst on 5 µm pore diameter and 12 µm interspacing (2189 µC cm–2 per CV cycle) making it possible for rapid storage systems. Moreover the charge transfer resistance described by an equivalent circuit model has an excellent correlation with Tafel slopes. Along with its very low Tafel slope of 42 mV dec–1 10 nm thick H2 pore design electrocatalyst has the highest capacitive response of ∼0.001 S sn cm–2 and is promising to be used as a nano-charger and hydrogen sensor.

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.

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.

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.

Energy management is a critical issue for the advancement of fuel cell vehicles because it significantly influences their hydrogen economy and lifetime. This paper offers a comprehensive investigation of the energy management of heavy-duty fuel cell vehicles for road freight transportation. An important and unique contribution of this study is the development of an extensive and realistic representation of the vehicle operation which includes 1750 hours of real-world driving data and variable truck loading conditions. This framework is used to analyze the potential benefits and drawbacks of heuristic optimal and predictive energy management strategies to maximize the hydrogen economy and system lifetime of fuel cell vehicles for road freight transportation. In particular the statistical evaluation of the effectiveness and robustness of the simulation results proves that it is necessary to consider numerous and realistic driving scenarios to validate energy management strategies and obtain a robust design. This paper shows that the hydrogen economy can be maximized as an individual target using the available driving information achieving a negligible deviation from the theoretical limit. Furthermore this study establishes that heuristic and optimal strategies can significantly reduce fuel cell transients to improve the system lifetime while retaining high hydrogen economies. Finally this investigation reveals the potential benefits of predictive energy management strategies for the multi-objective optimization of the hydrogen economy and system lifetime.

A polyethylene (PE) liner is the basic element in high-pressure type 4 composite vessels designed for hydrogen or compressed natural gas (CNG) storage systems. Liner defects may result in the elimination of the whole vessel from use which is very expensive both at the manufacturing and exploitation stage. The goal is therefore the development of efficient non-destructive testing (NDT) methods to test a liner immediately after its manufacturing before applying a composite reinforcement. It should be noted that the current regulations codes and standards (RC&S) do not specify liner testing methods after manufacturing. It was considered especially important to find a way of locating and assessing the size of air bubbles and inclusions and the field of deformations in liner walls. It was also expected that these methods would be easily applicable to mass-produced liners. The paper proposes the use of three optical methods namely visual inspection digital image correlation (DIC) and optical fiber sensing based on Bragg gratings (FBG). Deformation measurements are validated with finite element analysis (FEA). The tested object was a prototype of a hydrogen liner for high-pressure storage (700 bar). The mentioned optical methods were used to identify defects and measure deformations.