Hydrogen Storage Sites Research Articles

Hydrogen storage in a novel BCC-structured TiCrW alloys

Body-centered cubic (BCC)-type alloys possess a high theoretical hydrogen storage capacity, yet their high cost, limited effective hydrogen storage capacity, and poor cyclic properties remain challenges. In this work, a novel and cost-effective (Ti0.44Cr0.56)94W6 BCC phase alloy was successful prepared by W doping and heat treatment. The alloy exhibits an effective hydrogen desorption capacity of 2.44 wt% with minimal 9 % degradation over 300 cycles. The microstructural analysis shows that W doping inhibits the formation of Ti-rich phase and Laves phase in the alloy, and makes the alloy form a single BCC phase structure with higher hydrogen storage sites. After heat treatment, the alloy exhibits remarkable hydrogen de-/absorption kinetics and superior plateau characteristics, which reduces the plateau slope factor from 5.32 to 0.18, and increases the effective hydrogen desorption capacity from 1.09 to 2.44 wt%. This alloy’s activation energy and enthalpy change in dehydrogenation process are determined to be 11.64 and 44.31 kJ/mol, respectively. First-principles simulations further illuminated that the incorporation of W doping diminished the migration energy barrier of hydrogen and compromised the structural stability of the hydride. Furthermore, the structural evolution during de-/hydrogenation was analyzed, elucidating the mechanism of the alloy’s cyclic performance decay. These findings offer theoretical insights that guide the development of novel solid state hydrogen storage materials.

Coupled hydro-mechanical model for underground hydrogen storage undergoing cyclic injection and production

ABSTRACT Excess renewable energy can be used to generate and store hydrogen underground, offering a secure and econimical solution to the intermittency challenges of renewable energy sources. The success of underground storage relies on understanding and controlling the geo-mechanical integrity of storage sites during cyclic loadings. While geological deformation during natural gas and carbon dioxide storage is well studied, few have investigated pore pressure and in-situ stress variations during cyclic loading, which is unique to underground hydrogen storage sites. This paper presents a predictive analytical model for the pore pressure and stress changes during cyclic loading. The model was derived based on continuous point source injection, a basic hydro-mechanical model while applying the superposition to consider the cyclic loading. The developed model was evaluated for hydrogen and natural gas subjected to cyclic injection and production. Comparing hydrogen and natural gas storage cases can offer valuable insights into the behavior of hydrogen since the deformation of natural gas storage is more studied. Finally, analytical solutions for both storage cases were validated by numerical models with discrepancies between the models amounting to less than 1%. Comparative analysis of the results from 3 to 99 cycles of injection and production for both hydrogen and methane demonstrates that rise in cycle numbers leads to a corresponding rise in stress accumulation in the system. Neglecting the stress accumulation during these cycles can lead to significant geomechanical issues, potentially compromising the storage system’s safety and integrity.

Introducing Noble Gas as Space Holder under High Pressure to Design Porous Titanium Carbides with Open Metal Sites for Hydrogen Storage at Near-Ambient Conditions.

It has been a long-standing challenge to develop high-performance solid-state hydrogen storage materials operated under near-ambient conditions. In this work, we propose a new strategy of using noble gases for space holding to design porous titanium carbides with abundant open metal sites for hydrogen storage. By using machine learning and graph theory-assisted universal structure searching methods, we obtain 28 porous titanium carbides from three precursors (TiC dimer, C atom, and Kr atom) under 30 GPa of pressure. The stability and hydrogen storage performance of the resulting structures are further assessed and validated through density function theory and grand canonical Monte Carlo simulations with a DFT-fitted force field. Finally, p-TiC2 is identified as a promising quasi-molecular hydrogen storage material with capacity of 4.0 wt % and 106.0 g/L at 230 K and 16 bar.

Molecular Density Fluctuations Control Solubility and Diffusion for Confined Aqueous Hydrogen.

Hydrogen's contribution to a sustainable energy transformation requires intermittent storage technologies, e.g., underground hydrogen storage (UHS). Toward designing UHS sites, atomistic molecular dynamics (MD) simulations are used here to quantify thermodynamic and transport properties for confined aqueous H2. Slit-shaped pores of width 10 and 20 Å are carved out of kaolinite. Within these pores, water yields pronounced hydration layers. Molecular H2 distributes along these hydration layers, yielding solubilities up to ∼25 times those in the bulk. Hydrogen accumulates near the siloxane surface, where water density fluctuates significantly. On the contrary, a dense hydration layer forms on the gibbsite surface, which is, for the most part, depleted of H2. Although confinement reduces water mobility, the diffusion of aqueous H2 increases as the kaolinite pore width decreases, also a consequence of water density fluctuations. These results relate to H2 permeability in underground hydrogen storage sites.

Artificial intelligence-driven assessment of salt caverns for underground hydrogen storage in Poland

This study explores the feasibility of utilizing bedded salt deposits as sites for underground hydrogen storage. We introduce an innovative artificial intelligence framework that applies multi-criteria decision-making and spatial data analysis to identify the most suitable locations for storing hydrogen in salt caverns. Our approach integrates a unified platform with eight distinct machine-learning algorithms—KNN, SVM, LightGBM, XGBoost, MLP, CatBoost, GBR, and MLR—creating rock salt deposit suitability maps for hydrogen storage. The performance of these algorithms was evaluated using various metrics, including Mean Squared Error (MSE), Mean Absolute Error (MAE), Mean Absolute Percentage Error (MAPE), Root Mean Square Error (RMSE), and Correlation Coefficient (R2), compared against an actual dataset. The CatBoost model demonstrated exceptional performance, achieving an R2 of 0.88, MSE of 0.0816, MAE of 0.1994, RMSE of 0.2833, and MAPE of 0.0163. The novel methodology, leveraging advanced machine learning techniques, offers a unique perspective in assessing the potential of underground hydrogen storage. This approach is a valuable asset for various stakeholders, including government bodies, geological services, renewable energy facilities, and the chemical/petrochemical industry, aiding them in identifying optimal locations for hydrogen storage.

Underground Hydrogen Storage in Porous Media: The Potential Role of Petrophysics

The objective of this study is to showcase the key geological and reservoir engineering parameters that influence underground hydrogen storage, demonstrate the value of some petrophysical data, and show how hydrogen storage differs between depleted gas fields and saline aquifers for reservoir and geomechanical modeling. We utilized numerical simulation modeling to create a base-case model of a synthetic reservoir that accurately represented the hydrodynamic conditions relevant to underground hydrogen storage in porous media. A two-step sensitivity analysis was then conducted. Firstly, we identified the critical parameters that significantly influence the storage and flow of hydrogen in porous media. Subsequently, we analyzed the geomechanical impact of underground hydrogen storage. In addition, we compared the behavior of hydrogen storage to natural gas storage. The study showed that the reservoir depth or current pressure, the reservoir dip, and the flow capacity were the top three factors impacting the optimal withdrawal of hydrogen. The study also revealed that rock displacement and stress changes were important to be monitored, while changes in strain were not significant. If it is assumed that injection occurs in a critically stressed rock, hydrogen injection and withdrawal in saline aquifers could result in more incidence of microseismicity compared to hydrogen storage in depleted fields or even gas storage in depleted fields. This study quantifies uncertainties in data and pinpoints areas where petrophysical measurements could minimize the uncertainty associated with critical parameters relevant to underground hydrogen storage. It also identifies gaps in measurements for hydrogen storage in porous media. These parameters with large uncertainty are crucial for selecting optimal sites for hydrogen storage and detecting subsurface integrity issues when monitoring for underground hydrogen storage in porous media.

Assessment of hydrogen storage potential in depleted gas fields and power-to-hydrogen conversion efficiency: A northern California case study

This study assessed the potential for storing hydrogen underground in depleted gas fields using Northern California as a case study. We examined how much hydrogen California could produce from the electrolysis of curtailed solar and wind energy. Afterward, we assessed the geological and reservoir properties of fields that could potentially support safe and secure underground hydrogen storage. We applied two stages of a three-stage process to select prospective hydrogen storage sites in depleted gas fields. The first stage of the screening process involved integrating geoscience and environmental factors in order to identify the fields that will not be considered suitable for hydrogen storage. Among 182 depleted and underground gas storage fields in Northern California, 147 were disqualified in the first stage of the assessment. The remaining 35 fields were scored and ranked in stage two based on their potential to maximize hydrogen storage and withdrawal. High-scoring sites for underground hydrogen storage and production included reservoirs with dips between 5° and 15°, reservoir porosity above 20%, reservoir flow capacity above 5000 mDm, and reservoir depths between 430 m and 2400 m. We determined that a total of 203.5 million tonnes of hydrogen could be stored at the ten high-scoring sites. We estimated the potential hydrogen recovery from a hypothetical depleted field in California and evaluated the efficiency of converting the curtailed renewable electricity to hydrogen via electrolysis, storing it in the subsurface, and converting produced hydrogen back to electricity. Based on the results, we determined that depleted gas fields have sufficient underground storage capacity to store hydrogen produced from Northern California's curtailed renewable energy sources. Hydrogen recovery efficiency was estimated to be larger than 75% and was limited by the bottom hole pressure of the withdrawal well, hydrogen mixing with in-situ gas, and hydrogen spreading laterally. This study found that power-to-hydrogen-to-power round-trip efficiency maxed out at 36%. Improvements in hydrogen recovery could increase the round-trip efficiency by 8%, while improvements in electrolyzer efficiency could increase the round-trip efficiency by 33%.

A one-dimensional diffusive transport model to evaluate H2S generation in salt caverns hydrogen storage sites

Salt caverns are considered a potential hydrogen storage site given the ductility, tightness, and chemical inertness of halite. In addition, unlike porous media, salt caverns require less cushion gas and allow more cycles of injection and production within a year. However, hydrogen is an electron donor for many hydrogenotrophic microorganisms including halophilic sulfate-reducing microbes (SRM) and hydrogen sulfide (H2S) can be generated in a cavern once sulfate and hydrogen become available in the aqueous phase. As salt deposits are often associated with large amounts of impurities such as anhydrite and gypsum, their dissolution during the leaching phase can release the required sulfate ions for SRMs to produce H2S once hydrogen diffuses and dissolves in the brine at the bottom of the cavern. In this study, a one-dimensional diffusive transport model was developed using PHREEQC to simulate sulfate reduction and H2S generation in a cavern at the gas-brine interface. The solution of Fick's diffusion equation was used to calculate the hydrogen concentration at each level of the 1D model while the kinetic rates of reactions were derived from reported experimental and field site observations of brine samples taken from salt caverns. The results obtained indicated that hydrogen consumption at the gas-brine interface can trigger H2S and methane formations. This is followed by a reduction in sulfate and carbonate concentration and a slight increase in pH due to the reduction of protons in the solution. It was also observed that the presence of Fe2+ ions can reduce the amount of the hydrogen sulfide production while Ca2+ ions slightly favour sulfate reduction due to the production of methane. Although the kinetic reaction rate of the reactions in the model is subject to a certain degree of uncertainty, the workflow and results this study can serve as a guide for the future storage of hydrogen in salt caverns.

Assessment of the in situ biomethanation potential of a deep aquifer used for natural gas storage.

The dihydrogen (H2) sector is undergoing development and will require massive storage solutions. To minimize costs, the conversion of underground geological storage sites, such as deep aquifers, used for natural gas storage into future underground hydrogen storage sites is the favored scenario. However, these sites contain microorganisms capable of consuming H2, mainly sulfate reducers and methanogens. Methanogenesis is, therefore expected but its intensity must be evaluated. Here, in a deep aquifer used for underground geological storage, 17 sites were sampled, with low sulfate concentrations ranging from 21.9 to 197.8µM and a slow renewal of formation water. H2-selected communities mainly were composed of the families Methanobacteriaceae and Methanothermobacteriaceae and the genera Desulfovibrio, Thermodesulfovibrio, and Desulforamulus. Experiments were done under different conditions, and sulfate reduction, as well as methanogenesis, were demonstrated in the presence of a H2 or H2/CO2 (80/20) gas phase, with or without calcite/site rock. These metabolisms led to an increase in pH up to 10.2 under certain conditions (without CO2). The results suggest competition for CO2 between lithoautotrophs and carbonate mineral precipitation, which could limit microbial H2 consumption.

Fine-tuned MOF-74 type variants with open metal sites for high volumetric hydrogen storage at near-ambient temperature

Adsorbent-based hydrogen storage systems offer a potential solution to current challenges in hydrogen storage, particularly those requiring high pressures or cryogenic temperatures. Specifically, the use of metal–organic frameworks (MOFs) featuring open metal sites that strongly adsorb hydrogen represents a promising strategy for near-ambient-temperature hydrogen storage. This study investigates the hydrogen storage properties of M2(dondc) (M = Mg2+, Co2+, and Ni2+), an extended version of MOF-74. Among this series, Ni2(dondc) exhibits the second-highest volumetric hydrogen capacity of 10.74 g L−1 at 298 K under pressure swing adsorption conditions (100 to 5 bar) at ambient temperatures. The superior hydrogen storage performance of Ni2(dondc) is attributed to its highly polarizable Ni open metal sites and a significant heat of adsorption of 12.2 kJ mol−1. These findings are corroborated by temperature-programmed desorption spectroscopy and van der Waals-corrected density functional theory calculations. In addition to its exceptional hydrogen capacity, Ni2(dondc) exhibits robust structural stability and long-term durability, positioning it as a promising candidate for near-ambient-temperature hydrogen storage applications.

The ranking of geological structures in deep aquifers of the Polish Lowlands for underground hydrogen storage

Selection of the proper underground hydrogen storage (UHS) site is an essential issue for zero-emission systems based on renewables. The article presents the method for assessing storage traps in saline aquifers and the ranking of storage traps in saline aquifers from the Polish Lowlands for UHS. The ranking was based on the multi-criteria approach of the hierarchical analysis of the decision-making process. The best UHS site was determined based on geological and reservoir criteria. The criteria weights were evaluated using two methods for comparative purposes. The parameters of individual storage traps came from the database developed in the Hystories project. The highest positions in the ranking were obtained by storage traps characterized by the best sealing parameters of caprock, lack of faults within the traps, and good permeability of the reservoir layers. The presented ranking approach can support the decision-making process for selecting UHS sites in other countries.

Multi-criteria site selection workflow for geological storage of hydrogen in depleted gas fields: A case for the UK

Underground hydrogen storage (UHS) plays a critical role in ensuring the stability and security of the future clean energy supply. However, the efficiency and reliability of UHS technology depend heavily on the careful and criteria-driven selection of suitable storage sites. This study presents a hybrid multi-criteria decision-making framework integrating the Analytical Hierarchy Process (AHP) and Preference Ranking Organisation Method for Enrichment of Evaluations (PROMETHEE) to identify and select the best hydrogen storage sites among depleted gas reservoirs in the UK. To achieve this, a new set of site selection criteria is proposed in light of the technical and economic aspects of UHS, including location, reservoir rock quality and tectonic characteristics, maximum achievable hydrogen well deliverability rate, working gas capacity, cushion gas volume requirement, distance to future potential hydrogen clusters, and access to intermittent renewable energy sources (RESs). The framework is implemented to rank 71 reservoirs based on their potential and suitability for UHS. Firstly, the reservoirs are thoroughly evaluated for each proposed criterion and then the AHP-PROMETHEE technique is employed to prioritise the criteria and rank the storage sites. The study reveals that the total calculated working gas capacity based on single-well plateau withdrawal rates is around 881 TWh across all evaluated reservoirs. The maximum well deliverability rates for hydrogen withdrawal are found to vary considerably among the sites; however, 22 % are estimated to have deliverability rates exceeding 100 sm3/d, and 63 % are located within a distance of 100 km from a major hydrogen cluster. Moreover, 70 % have access to nearby RESs developments, with an estimated cumulative RESs capacity of approximately 181 GW. The results highlight the efficacy of the proposed multi-criteria site selection framework. The top five highest-ranked sites for UHS based on the evaluated criteria are the Cygnus, Hamilton, Saltfleetby, Corvette, and Hatfield Moors gas fields. The insights provided by this study can contribute to informed decision-making, sustainable development, and the overall progress of future UHS projects within the UK and globally.

The use of a gravity-assisted-storage-extraction protocol for hydrogen storage in saline aquifers

The hydrogen gas produced through the electrolysis of water using excess energy could serve as a prospective source to meet peak energy demand during certain seasons. Because of the large storage capacity and ease of accessibility, saline aquifers are a highly desirable geological storage option for hydrogen. Common challenges encountered in aquifer-based hydrogen storage systems during production include the notable lateral migration of the hydrogen plume caused by the high mobility of hydrogen, as well as the occurrence of gravity override due to the low density of hydrogen and the subsequent production of significant amounts of water during withdrawal. The proposed approach for mitigating water coning and increasing hydrogen production is a gravity-assisted-storage-extraction (GASE) protocol. This involves injecting the working hydrogen gas from the lower region of the formation and extracting it from the top region using a horizontal well. The proposed process capitalizes on the gravitational effects that facilitate the vertical migration of hydrogen, creating a gas-enriched zone within the aquifer. This results in improved hydrogen production as the lateral flow of water and hydrogen is restricted. The implementation of GASE protocol is demonstrated by numerical simulation experiment based on an actual hydrogen storage site at San Pedro belt. The results of simulations conducted on the numerical model indicate that if the GASE protocol is implemented, it has the potential to recover over 93% of the working gas, which is a 20–30% improvement compared to the data that has been previously published. The major limitation of the GASE protocol is the potential capital cost increments due to the drilling and completion of the horizontal wells, which makes it more suitable for a hydrogen storage project with long-term and sustainable hydrogen supplies.

An Insight into Underground Hydrogen Storage in Italy

Hydrogen is a key energy carrier that could play a crucial role in the transition to a low-carbon economy. Hydrogen-related technologies are considered flexible solutions to support the large-scale implementation of intermittent energy supply from renewable sources by using renewable energy to generate green hydrogen during periods of low demand. Therefore, a short-term increase in demand for hydrogen as an energy carrier and an increase in hydrogen production are expected to drive demand for large-scale storage facilities to ensure continuous availability. Owing to the large potential available storage space, underground hydrogen storage offers a viable solution for the long-term storage of large amounts of energy. This study presents the results of a survey of potential underground hydrogen storage sites in Italy, carried out within the H2020 EU Hystories “Hydrogen Storage In European Subsurface” project. The objective of this work was to clarify the feasibility of the implementation of large-scale storage of green hydrogen in depleted hydrocarbon fields and saline aquifers. By analysing publicly available data, mainly well stratigraphy and logs, we were able to identify onshore and offshore storage sites in Italy. The hydrogen storage capacity in depleted gas fields currently used for natural gas storage was estimated to be around 69.2 TWh.

Quantifying onshore salt deposits and their potential for hydrogen energy storage in Australia

Hydrogen energy will remarkably aid the global energy transition from fossil fuels to renewables. Hydrogen is the lightest molecule. It requires large volume storage facilities only found in geological formations. Salt caverns are a potential geo-storage medium that has been used in practice at a commercial scale. In Australia, several basins, i.e., Advalae, Carnarvon, Amadeus, Officer, and Canning, have been identified with notable salt deposits. The feasibility and potential of storing hydrogen in these salts have yet to be determined by geology, salt thickness, or salt type data. Here, we identified potential hydrogen storage sites. Additionally, hydrogen storage volume was estimated in Mallowa and Minjoo salts (Carribuddy salts: ~95 % halite and ~1 % anhydrite) in Willara Sub-basin, Canning Basin, Western Australia (WA). The results show a high potential for constructing salt caverns for hydrogen storage in these areas. The geochemical data suggest the presence of Bromine (90 to 670 ppm and <150 ppm in some wells), which are favorable for the solution mining process for the development of salt caverns. Our study demonstrates that approximately 28,282 onshore salt caverns (500,000 m3 each) could be constructed in the Willara Sub-basin salt in WA. The estimated number of caverns can store 14,697 PJ of hydrogen energy. The proposed site would be in the Northwest of WA, ~70 to 80 km from the Indian Ocean, with access to the shore and transportation. The estimated H2 storage capacity in the salt caverns satisfies Australia's energy consumption (5790 PJ in 2020–21), providing 8900 PJ of H2 energy for export to ensure a sustainable hydrogen value chain.

Enhanced hydrogen storage properties of Ti–Cr–Nb alloys by melt-spin and Mo-doping

Ti–Cr–Nb hydrogen storage alloys with a body centered cubic (BCC) structure have been successfully prepared by melt-spin and Mo-doping. The crystalline structure, solidification microstructural evolution, and hydrogen storage properties of the corresponding alloys were characterized in details. The results showed that the hydrogen storage capacity of Ti–Cr–Nb ingot alloys increased from 2.2 wt% up to around 3.5 wt% under the treatment of melt-spin and Mo-doping. It is ascribed that the single BCC phase of Ti–Cr–Nb alloys was stabilized after melt-spin and Mo-doping, which has a higher theoretical hydrogen storage site than the Laves phase. Furthermore, the melt-spin alloy after Mo doping can further effectively increase the de-/absorption plateau pressure. The hydrogen desorption enthalpy change ΔH of the melt-spin alloy decreased from 48.94 kJ/mol to 43.93 kJ/mol after Mo-doping. The short terms cycling test also manifests that Mo-doping was effective in improving the cycle durability of the Ti–Cr–Nb alloys. And the BCC phase of the Ti–Cr–Nb alloys could form body centered tetragonal (BCT) or face center cubic (FCC) hydride phase after hydrogen absorption and transform to the original BCC phase after desorption process. This study might provide reference for developing reversible metal hydrides with favorable cost and acceptable hydrogen storage characteristics.

Salt reconstruction in full-waveform inversion using topology optimization techniques

SUMMARY With the increasing advances in the oil and gas industry, seismic imaging near or under salt structures has become an important point in deep-water exploration. Detailed velocity models of these areas are particularly interesting not only to characterize hydrocarbon reservoirs but also to identify potential sites for hydrogen and carbon dioxide storage in offshore salt caverns. Thus, we study the full-waveform inversion for the salt reconstruction in acoustic media with constant density considering the time-harmonic wave propagation in a finite element formulation using the topology optimization (TO) method. This problem is challenging due to the strong velocity contrast between salt bodies and the sedimentary background, in addition to the lack of low-frequency data and the inherent ill-posedness of the inverse problem. In this context, we incorporate techniques from the TO field, usually used in design applications, to overcome or reduce these known problems. We initially defined the squared slowness as a combination of two fields, one related to the salt shape and the other to the background. An interpolation rule based on the solid isotropic material with penalization method, combined with filtering and projection schemes, is used to find the shape of the salt bodies with increased sharpness interfaces. A Helmholtz-type filter is applied to modify the gradient aimed to regularize the problem and provide a more stable way for the salt shape to evolve during the inversion process. In particular, we demonstrate that the proposed approach may be relevant for reconstructing media with salt bodies when a suitable starting model is unavailable, and sharp interfaces are required. In addition, we present inversion results from synthetic data generated by a variable density model to demonstrate the approach capability when subjected to a reconstruction application.

Effect of hydrogen on calcite reactivity in sandstone reservoirs: Experimental results compared to geochemical modeling predictions

Geologic reservoirs including calcite bearing sandstones are among the highest potential structures that can serve as sites for underground hydrogen storage (UHS). However, to confirm the viability of sandstone reservoirs, better knowledge about rock–porewater–hydrogen gas (H2) systems is needed. Previous geochemical modeling studies predicted significant H2 loss induced by the reaction of carbonate minerals with H2. Our recent combined experimental-modeling study investigated the geochemical impact of H2 on calcite (CaCO3), a characteristic rock forming mineral in potential hydrogen storage reservoirs. Static batch reactor experiments were conducted in the pressure and temperature range (100 bar, 105 °C) of UHS to track the effect of H2 on calcite. The experiments demonstrated the non-reactive behavior of calcite as there were no signs (chemical and morphological) of increased calcite dissolution in H2 atmosphere compared to results with inert gas (N2). On the contrary, the kinetic PHREEQC model, using a non-modified thermodynamic database, predicts intensive reactions between calcite and H2, resulting in extensive calcite dissolution and methane formation. Our conclusion, therefore, is that the thermodynamic databases of geochemical modeling must be reviewed for UHS and modified for such projects to provide reliable results. This study gives practical insight into the potential path forward to correct this problem.

Performance simulation of hydrogen-electric transit bus running in a mountain environment

As is well known, the transport sector accounts for a third of all final energy consumption in the EU and is responsible for more than a quarter of total greenhouse gas emissions, making it one of the main contributors to climate change. Reducing the negative effects of transport is a strategic objective of the EU, which has put in place a series of actions to promote cleaner and more efficient transport modes, using more sustainable technologies, fuels, and infrastructure. The development of more sustainable and zero-emission collective transport solutions implies the use of novel propulsion systems capable of using energy carriers produced from renewable energy sources. This article deals with the preliminary design and performance analysis of a hydrogen hybrid passenger bus to be used in a mountainous area characterized by mainly curvilinear routes with high gradients both uphill and downhill, within an experimental context of technological-energy innovation. The study is part of a wider project (LIFE3H) co-funded by the European Union, which, among other objectives, intends to lay the bases for the development of a Hydrogen Valley (integrated hydrogen production, storage, and use site), through public hydrogen transport and refuelling stations in the mountain area of “Altopiano delle Rocche” in Abruzzo (Italy). The studied vehicle power-train configuration is based on an electric motor fed by a hybrid power unit consisting of a hydrogen fuel cell functionally coupled with an electrochemical battery. A minibus configuration run over a round trip path according to the real traffic conditions is simulated and main vehicle powertrain components are sized. Finally, hydrogen consumption for traction is estimated.

Kinetics and mechanism effects of 2D carbon supports in hydrogen spillover composites.

Extensive research has been performed using two-dimensional (2D) carbon materials as catalyst supports to achieve high-performance hydrogen storage composites through the hydrogen spillover phenomenon. However, the kinetics and mechanism effects of different support materials still need to be investigated. This study employed high-energy ball milling to fabricate Co1-xS/C60 and C1-xS/rGO composites with stable structures and abundant hydrogen storage sites. We explored the mechanism of hydrogen adsorption behavior through electrode kinetic studies and density functional theory calculations, revealing the intrinsic relationship between material composition, structure, and hydrogen diffusion kinetics. The 2D flakes of C60 and rGO support and connect C1-xS nanoparticles, providing electron transport pathways for the composites. Theoretically, the spherical C60 support with less steric hindrance showed a more vital ability to increase the hydrogen adsorption capacity, while kinetically, thin film rGO offers fast channels for hydrogen diffusion. These findings contribute to our understanding of hydrogen spillover and present opportunities to investigate the synergistic effects in 2D carbon-based composites.