Applications & Pathways

As hydrogen fuel cell vehicles gain momentum as crucial zero-emission transportation solutions the urgency to address hydrogen permeability through the polymer liner becomes paramount for ensuring the safety efficiency and longevity of Type IV hydrogen storage tanks. This paper synthesizes existing research findings analyzes the influence of different materials and structures on gas permeability elucidates the dissolution and diffusion mechanisms of hydrogen in plastic liners and discusses their engineering applications. We focus on measurement methods influencing factors and improvement strategies for liner gas permeability. Additionally we explore the prospects of Type IV hydrogen storage tanks in fields such as automotive aerospace and energy storage industries. Through this comprehensive review of liner gas permeability critical insights are provided to guide the development of efficient and safe hydrogen storage and transportation systems. These insights are vital for advancing the widespread application of hydrogen energy technology and fostering sustainable energy development significantly contributing to efforts aimed at enhancing the performance and safety of Type IV hydrogen storage tanks.

The transportation sector is a significant contributor to global carbon emissions thus necessitating a transition toward renewable energy sources (RESs) and electric vehicles (EVs). Among EV technologies fuel-cell EVs (FCEVs) offer distinct advantages in terms of refueling time and operational efficiency thus rendering them a promising solution for sustainable transportation. Nevertheless the integration of FCEVs in rural areas poses challenges due to the limited availability of refueling infrastructure and constraints in energy access. In order to address these challenges this study proposes a multi-objective energy management model for a hydrogen refueling station (HRS) integrated with RESs a battery storage system an electrolyzer (EL) a fuel cell (FC) and a hydrogen tank serving diverse FCEVs in rural areas. The model formulated using mixed-integer linear programming (MILP) optimizes station operations to maximize both cost and load factor performance. Additionally bi-directional trading with the power grid and hydrogen network enhances energy flexibility and grid stability enabling a more resilient and self-sufficient energy system. To the best of the authors’ knowledge this study is the first in the literature to present a multi-objective optimal management approach for grid-interactive renewablesupported HRSs serving hydrogen-powered vehicles in rural areas. The simulation results demonstrate that RES integration improves economic feasibility by reducing costs and increasing financial gains while maximizing the load factor enhances efficiency cost-driven strategies that may impact stability. The impact of the EL on cost is more significant while RES capacity has a relatively smaller effect on cost. However its influence on the load factor is substantial. The optimization of RES-supported hydrogen production has been demonstrated to reduce external dependency thereby enabling surplus trading and increasing financial gains to the tune of USD 587.83. Furthermore the system enhances sustainability by eliminating gasoline consumption and significantly reducing carbon emissions thus supporting the transition to a cleaner and more efficient transportation ecosystem.

Virtual power plants (VPPs) are gaining significance in the energy sector due to their capacity to aggregate distributed energy resources (DERs) and optimize energy trading. However their effectiveness largely depends on accurately modeling the uncertain parameters influencing optimal bidding strategies. This paper proposes a deep learning-based forecasting method to predict these uncertain parameters including solar irradiation temperature wind speed market prices and load demand. A stochastic programming approach is introduced to mitigate forecasting errors and enhance accuracy. Additionally this research assesses the flexibility of VPPs by mapping the flexible regions to determine their operational capabilities in response to market dynamics. The study also incorporates power-to‑hydrogen (P2H) and hydrogen-to-power (H2P) conversion processes to facilitate the integration of hydrogen fuel cell vehicles (HFCVs) into VPPs enhancing both technical and economic aspects. A network-aware VPP connected to generation resources storage facilities demand response programming (DRP) vehicle-to-grid technology (V2G) P2H and H2P is used to evaluate the proposed method. The problem is formulated as a convex model and solved using the GUROBI optimizer. Results indicate that a hydrogen refueling station can increase profits by approximately 49 % compared to the base case of directly selling surplus generation from renewable energy sources (RESs) to the market and profits can further increase to roughly 86 % when other DERs are incorporated alongside the hydrogen refueling station.

Reducing CO2 emissions is an increasingly important goal in general aviation. The dual-fuel hydrogen–kerosene combustion process has proven to be a suitable technology for use in small aircraft. This robust and reliable technology significantly reduces CO2 emissions due to the carbon-free combustion of hydrogen during operation while pure kerosene or sustainable aviation fuel (SAF) can be used in safety-critical situations or in the event of fuel supply issues. Previous studies have demonstrated the potential of this technology in terms of emissions performance and efficiency while also highlighting challenges related to abnormal combustion phenomena such as knocking and pre-ignition which limit the maximum achievable hydrogen energy share. However the causes of such phenomena—especially regarding the role of lubricating oils—have not yet been sufficiently investigated in hydrogen engines making this a crucial area for further development. In this paper investigations at the TU Wien Institute of Powertrain and Automotive Technology concerning the role of different engine oils in influencing pre-ignition tendencies in a hydrogen–kerosene dual-fuel engine are described. A specialized test procedure was developed to account for the unique combustion characteristics of the dual-fuel process along with a detailed purge procedure to minimize oil carryover. Multiple engine oils with varying compositions were tested to evaluate their influence on pre-ignition tendencies with a particular focus on additives containing calcium magnesium and molybdenum known for their roles in detergent and anti-wear properties. Additionally the study addressed the contribution of particles to pre-ignition occurrences. The results indicate that calcium and magnesium exhibit no notable impact on pre-ignition behavior; however the addition of molybdenum results in a pronounced reduction in pre-ignition events which could enable a higher hydrogen energy share and thus decrease CO2 emissions in the context of hydrogen dual-fuel aviation applications.

This study explores a multi-faceted approach to improving the combustion performance and emission characteristics of a single-cylinder four-stroke direct injection (DI) compression ignition engine through the combined effects of butanol enrichment green-synthesized copper oxide (CuO) nanoparticles and hydrogen supplementation. The baseline fuel was a B20 biodiesel blend further enriched with 10 % butanol to enhance oxygen availability and atomization. CuO nanoparticles were synthesized via an eco-friendly aloe vera extractmediated method and dispersed into the fuel to promote oxidation kinetics and stabilize combustion. Experimental results revealed that the B20+But10 %+CuO100 blend achieved the highest brake thermal efficiency (BTE) of 33.6 % at full load alongside notable reductions in carbon monoxide (CO) unburned hydrocarbons (HC) nitrogen oxides (NOx) and smoke opacity compared to neat B20. Reactivity controlled compression ignition (RCCI) trials further demonstrated that hydrogen enrichment at 5 LPM and 10 LPM improved flame propagation Brake thermal efficiency (33.89 % & 35.43 %) and reduced brake-specific fuel consumption of nearly 10 % (0.26 Kg/KWh) & 0.25 Kg/KWh). While excessive hydrogen supply (10 LPM) marginally increased HC emissions (110 PPM) at higher loads due to localized incomplete oxidation overall results confirm significant emission mitigation. The findings highlight that the synergistic integration of butanol oxygenation catalytically active CuO nanoparticles and optimized hydrogen enrichment offers a viable pathway toward cleaner combustion improved energy efficiency and reduced pollutant emissions in biodiesel-fueled CI engines.

This study develops and applies a life cycle assessment (LCA) framework combined with predictive market models to evaluate the environmental impacts of electricity and hydrogen for transport in the EU27+UK from 2020 to 2050. By linking evolving power sector scenarios with hydrogen supply models we assess the wellto-wheels (WTW) performance of battery electric vehicles (BEVs) and fuel cell electric vehicles (FCEVs) under consistent energy assumptions. Results show that electricity decarbonization can reduce GWP by up to 80% by 2050 but increases land use and mineral/metal demand due to renewable infrastructure expansion. The environmental impacts of hydrogen production are strongly influenced by the electricity mix especially in high electrolysis scenarios. WTW analysis indicates that while BEVs consistently achieve lower WTW GWP than FCEVs across all scenarios both drivetrains exhibit notable trade-offs in other impact categories. Scenarios dominated by blue hydrogen although not optimal in terms of GWP present a more balanced environmental profile making them a viable transitional pathway in contexts that prioritize minimizing other environmental impacts.

The thermal management system and the balance-of-plant (BoP) in fuel cell electric vehicles (FCEV) are characterized by a particularly high level of complexity and a number of interfaces. Optimizing the efficiency of the overall vehicle is of special importance to maximize the range and increase the attractiveness of this technology to customers. This paper focuses on the optimization potential of the air supply system in the BoP whereby the charging concepts of the electric supercharger (ESC) and the electrically assisted turbocharger (EAT) as well as the integration of water spray injection (WSI) at the compressor inlet are investigated in the framework of an FCEV complete vehicle co-simulation. As a benchmark for the integration of these optimization measures the complete vehicle co-simulation is designed for a fuel cell electric passenger car of the current generation. Here thermo-hydraulic fluid circuits in the thermal management software KULI are coupled with mathematical-physical models in MATLAB/Simulink. Applying advanced simulation methodologies for the components of fuel cell powertrain and vehicle cabin enables the mapping of the effects of realistic operating conditions on the FCEV characteristics. The EAT offers the advantage over the ESC that due to the arrangement of an exhaust gas turbine a part of the exhaust gas enthalpy flow downstream of the fuel cell stack can be recovered which reduces the electrical compressor drive power. Moreover an additional reduction of this power consumption can be achieved by WSI as the effect of evaporative cooling lowers the initial compression temperature. For analysis and comparison these concepts are again modeled with high degree of detail and integrated into the benchmark overall vehicle simulation. The results indicate considerable reductions in the electric compressor drive power of the EAT compared to the ESC with noteworthy potential for reducing the vehicle’s hydrogen consumption. At an operating point in Worldwide harmonized Light Duty Test Cycle (WLTC) under 35 ◦ C ambient temperature and 25 % relative humidity the electrical compressor drive power shows a reduction potential of −40 % which corresponds to a vehicle-level hydrogen consumption reduction of up to −3 %. In addition the results also highlight the effect of the WSI in both charging concepts whereby its potential to reduce the hydrogen consumption on the overall vehicle level is relatively small. In WLTC at 35 ◦C ambient temperature and 25 % relative humidity the compressor drive power reduction potential for ESC and EAT averages −5 % while the effect on hydrogen consumption is only around −0.25 %.

This paper presents QDQN-ThermoNet a novel Quantum-Driven Dual Deep Q-Network framework for intelligent thermal regulation in next-generation electric vehicles with hybrid energy systems. Our approach introduces a dual-agent architecture where a classical DQN governs solid-state battery thermal management while a quantumenhanced DQN regulates proton exchange membrane fuel cell dynamics both sharing a unified quantumenhanced experience replay buffer to facilitate cross-system information transfer. Hardware-in-the-Loop validation across diverse operational scenarios demonstrates significant performance improvements compared to classical methods including enhanced thermal stability (95.1 % vs. 82.3 %) faster thermal response (2.1 s vs. 4.7 s) reduced overheating events (0.3 vs. 3.2) and superior energy efficiency (22.4 % energy savings). The quantum-enhanced components deliver 38.7 % greater sample efficiency and maintain robust performance under sparse data conditions (33.9 % improvement) while material-adaptive control strategies leveraging MXeneenhanced phase change materials achieve a 50.3 % reduction in peak temperature rise during transients. Component lifetime analysis reveals a 33.2 % extension in battery service life through optimized thermal management. These results establish QDQN-ThermoNet as a significant advancement in AI-driven thermal management for future electric vehicle platforms effectively addressing the complex challenges of coordinating thermal regulation across divergent energy sources with different optimal operating temperatures.

This study investigates numerically combustion attributes and NOx formation of premixed ammonia-hydrogen/air flames within a swirl burner of a gas turbine considering various conditions of hydrogen fraction (HF: 0 % 5 % 30 % 40 % and 50 %) equivalence ratio (φ: 0.85 1.0 and 1.2) and mixture inlet temperature (Tin: 400–600 K). The results illustrate that flame temperature increases with hydrogen addition from 1958 K for pure ammonia to 2253 K at 50 % HF. Raising the inlet temperature from 400 K to 600 K markedly enhances combustion intensity resulting in an increase of the Damköhler number (Da) from 117 to 287. NOx levels rise from ∼1800 ppm (0 % HF) to ∼7500 ppm (50 % HF) and peak at 8243 ppm under lean conditions (φ = 0.85). Individual NO N2O and NO2 emissions also reach maxima at φ = 0.85 with values of 5870 ppm 2364 ppm and 10 ppm respectively decreasing significantly under richer conditions (2547 ppm 1245 ppm and 5 ppm at φ = 1.2). These results contribute to advancing low-carbon fuel technologies and highlight the viability of ammonia-hydrogen co-firing as a pathway toward sustainable gas turbine operation.

The transport sector is the largest source of greenhouse gases in the EU after the energy supply one contributing approximately 27% of total emissions. Although decarbonization pathways for light-duty transport are relatively well established heavy-duty transport shipping and aviation emissions are difficult to eliminate through electrification. In particular the aviation sector is strongly dependent on liquid hydrocarbons making the development of sustainable aviation fuels (SAFs) a critical priority for achieving long-term climate targets. This study evaluates four biomass-to-liquid pathways for producing jet-like SAF from lignocellulosic biomass: (1) triacylglycerides (TAGs) production from syngas fermentation (2) TAGs production from sugar fermentation (3) ethanol production from syngas fermentation and (4) ethanol production from sugar fermentation. These pathways are simulated using Aspen Plus™ and the mass and heat balances obtained are used to assess their technical performance (e.g. carbon utilization energetic fuel efficiency) and techno-economic viability (e.g. production cost capital investment). Pathway (4) demonstrated the highest jet fuel selectivity (63%) and total carbon utilization (32.5%) but at higher power demands. Pathway (1) was self-sufficient in energy due to internal syngas utilization but exhibited lower carbon efficiencies. Cost analysis revealed that microbial oil-based pathways were restrained by higher hydrogen demands and lower product selectivity compared to ethanol-based routes. However with advancements in microbial oil production efficiency and reduced water usage these pathways could become competitive.