Publications

This study examines the pricing and assesses resilience methods in hydrogen supply chains by thoroughly analyzing two main disruption scenarios. The model examines a scenario in which a hydrogen production company depends on a Renewable Power plant (RP) for its electricity supply. Ensuring a steady and efficient hydrogen supply chain is crucial but outages at renewable power sources provide substantial obstacles to sustainability and operational continuity. Therefore in the event of disruptions at the RP the company has two options for maintaining resilience: either sourcing electricity from a Fossil fuel Power plant (FP) through a grid network to continue hydrogen production or purchasing hydrogen directly from another company and utilizing third-party transportation for delivery. Using a game theoretic approach we examine how different methods affect demand satisfaction cost implications and environmental sustainability. The study employs sensitivity analysis to evaluate the impact of different disruption probabilities on each scenario. In addition a unique sensitivity analysis is performed to examine the resilience of transmission security to withstand disruptions. This study evaluates how investments in security measures affect the strength and stability of the supply chain in various scenarios of disruption. Our research suggests that the first scenario offers greater reliability and cost-effectiveness along with a higher resilience rate compared to the second scenario. Furthermore the examination of the environmental impact shows that the first scenario has a smaller amount of CO2 emissions per kg of hydrogen. This study offers important insights for supply chain managers to optimize resilience measures hence improving reliability reducing costs and minimizing environmental effects.

This work explores the integration of Proton Exchange Membrane (PEM) electrolysis waste heat with district heating networks (DHN) aiming to enhance the overall energy efficiency and economic viability of hydrogen production systems. PEM electrolysers generate substantial amounts of low-temperature waste heat during operation which is often dissipated and left unutilised. By recovering such thermal energy and selling it to district heating systems a synergistic energy pathway that supports both green hydrogen production and sustainable urban heating can be achieved. The study investigates how the electrolyser’s operating temperature ranging between 50 and 80 ◦C influences both hydrogen production and thermal energy availability exploring trade-offs between electrical efficiency and heat recovery potential. Furthermore the study evaluates the compatibility of the recovered heat with common heat emission systems such as radiators fan coils and radiant floors. Results indicate that valorising waste heat can enhance the overall system performance by reducing the electrolyser’s specific energy consumption and its levelized cost of hydrogen (LCOH) while supplying carbon-free thermal energy for the end users. This integrated approach contributes to the broader goal of sector coupling offering a pathway toward more resilient flexible and resource-efficient energy systems.

With the global energy structure shifting towards clean and efficient hydrogen energy the safety management issues of hydrogen refueling stations are becoming increasingly prominent. To address these issues a hydrogen leak localization algorithm for hydrogen refueling stations based on a combination of reinforcement learning and hidden Markov models is proposed. This method combines hidden Markov model to construct a probability distribution model for hydrogen leakage and diffusion simulates the propagation probability of hydrogen in different grid cells and uses reinforcement learning to achieve fast and accurate localization of hydrogen leakage events. The outcomes denoted that the training accuracy reached 95.2% with an F1 value of 0.961 indicating its high accuracy in hydrogen leak localization. When the wind speed was 0.8 m/s the mean square error of the raised method was 0.03 and when the wind speed was 1.0 m/s the mean square error of the raised method was 0.04 proving its good robustness. After 50 localization experiments the proposed algorithm achieves a localization success rate of 93.7% and an average computation time of 42.8 s further demonstrating its high accuracy and computational efficiency. The proposed hydrogen leakage location algorithm has improved the accuracy and efficiency of hydrogen leakage location providing scientific basis and technical guarantee for the safe operation of future hydrogen refueling stations.

The swift and far-reaching evolution of advanced nanostructures and nanotechnologies has accelerated the research rate and extent which has a huge prospect for the benefit of the practical demands of solid-state hydrogen storage implementation. Carbonaceous materials are of paramount importance capable of forming versatile structures and morphology. This review aims to highlight the influence of the carbon material structure dimension and morphology on the hydrogen storage ability. An extensive range of synthesis routes and methods produces diverse micro/nanostructured materials with superb hydrogen-storing properties. The structures of carbon materials used for hydrogen adsorption from 0 to 3D and fabrication methods and techniques are discussed. Besides highlighting the striking merits of nanostructured materials for hydrogen storage remaining challenges and new research avenues are also considered.

Underground hydrogen storage in aquifers is a promising solution to address the imbalance between energy supply and demand yet its practical implementation requires optimized strategies to ensure high efficiency and economic viability. To improve the storage and production efficiency of hydrogen it is essential to select the appropriate cushion gas and to study the influence of reservoir and process parameters. Based on the conceptual model of aquifer with single-well injection and production three potential cushion gas (carbon dioxide nitrogen and methane) were studied and the changes in hydrogen recovery for each cushion gas were compared. The effects of temperature initial pressure porosity horizontal permeability vertical to horizontal permeability ratio permeability gradient hydrogen injection rate and hydrogen production rate on the purity of recovered hydrogen were investigated. Additionally the impact of different well pattern on the purity of recovered hydrogen was studied. The results indicate that methane is the most effective cushion gas for improving hydrogen recovery in UHS. Different well patterns have significant impacts on the purity of recovered hydrogen. The mole fractions of methane in the produced gas for the single-well line-drive pattern and five-spot pattern were 16.8% 5% and 3.05% respectively. Considering the economic constraints the five-spot well pattern is most suitable for hydrogen storage in aquifers. Reverse rhythm reservoirs with smaller permeability differences should be chosen to achieve relatively high hydrogen recovery and purity of recovered hydrogen. An increase in hydrogen production rate leads to a significant decrease in the purity of the recovered hydrogen. In contrast hydrogen injection rate has only a minor effect. These findings provide actionable guidance for the selection of cushion gas site selection and operational design of aquifer-based hydrogen storage systems contributing to the large-scale seasonal storage of hydrogen and the balance of energy supply and demand.

Propulsion systems in aircraft using reciprocating engines often face the challenge of managing thermal loads effectively. This problem is similar to the utilisation of polymer electrolyte membrane fuel cell systems which despite their high efficiency emit a high proportion of heat when converting chemical energy into electrical energy. Transfer of the rejected heat to the air is efficiently performed by heat exchangers. Since convective heat transfer is physically linked to fluid friction at the heat exchanger walls a pressure loss occurs. In a high-speed flow regime of the aircraft during cruise the integration of heat exchangers combined with a fan stage inside a nacelle (thus forming an impeller configuration) represents a promising approach for the dual benefit of dissipating excess heat and harnessing it for additional thrust generation through the ram jet effect. Striving for enhanced thrust performance of hydrogen electric commercial aircraft this paper presents the results of a parameter study based on a 1D-modelling approach. The focus is placed on the influence of design and operating parameters (ambient conditions fan pressure ratio diffusion ratio airside temperature difference) on performance and sizing of the proposed propulsion system. It is shown that the proposed system performs best at an altitude of 11 km and with increasing freestream Mach number. Furthermore the main challenges related to the combination of a thrust generation system with a heat exchanger in terms of sizing in particularly the required heat exchanger dimensions under different operating conditions are discussed.

Hydrogen plays a key role in decarbonising hard-to-abate sectors like aviation steel and shipping. However producing pure hydrogen requires significant energy to break chemical bonds from its sources such as gas and water. Ideally the energy used for this process should match the energy output from hydrogen but in reality energy losses occur at various stages of the hydrogen economy—production packaging delivery and use. This results in needing more energy to operate the hydrogen economy than it can ultimately provide. To address this passive power sources like latent thermal energy storage systems can help reduce costs and improve efficiency. These systems can enable passive cooling or electricity generation from waste heat cutting down on the extra energy needed for compression liquefaction and distribution. This study explores integrating latent thermal energy storage into all stages of the hydrogen economy offering a cost and sizing approach for such systems. The integration could reduce costs close the waste-heat recycling loop and support green hydrogen production for achieving NetZero by 2050.

The use of rare earth elements in hydrogen storage processes offers significant advantages in terms of increasing technological efficiency and ensuring system security. However this process also creates some serious problems in terms of environmental and economic sustainability. It is necessary to determine the most critical indicators affecting the sustainable use of these elements. Studies on this subject in the literature are quite limited and this may lead to wrong investment decisions. The main purpose of this study is to determine the most important indicators to increase the sustainable use of rare earth elements in hydrogen storage processes. An original decision-making model in which Siamese network logarithmic percentage-change driven objective weighting (LOPCOW) fractal fuzzy numbers and weighted influence super matrix with precedence (WISP) approaches are integrated in the study. This study provides an original contribution to the literature by identifying the most critical indicators affecting the sustainable use of rare earths in hydrogen storage processes by presenting an innovative model. Fractal structures such as Koch Snowflake Cantor Dust and Sierpinski Triangle can model complex uncertainties more successfully. Fractal structures are particularly effective in modeling linguistic fuzziness because their recursive nature closely mirrors the layered and imprecise way humans often express subjective judgments. Unlike linear fuzzy sets fractals can capture the patterns of ambiguity found in expert evaluations. Hydrogen storage capacity and government supports are determined as the most vital criteria affecting sustainability in rare earth use.

Hydrogen energy is key for the global green energy transition and biomass thermochemical has become an important option for green hydrogen production due to its carbon neutrality advantage. Pyrolysis is the initial step of thermochemical technologies. A systematic analysis of the mechanism of H2 production from biomass pyrolysis is significant for the subsequent optimal design of efficient biomass thermochemical H2 production technologies. Biomass is mainly composed of cellulose hemicellulose and lignin and differences in their physicochemical properties and structures directly affect the pyrolysis hydrogen production process. In this study thermogravimetry-mass spectrometry-Fourier transform infrared spectroscopy (TG-MS-FTIR) was employed and fixed-bed pyrolysis experiments were conducted to systematically investigate the pyrolysis of biomass component with focusing on hydrogen production. According to the results of TG-MS-FTIR experiments hemicellulose produced hydrogen through the breaking of C-H bonds in short chains and acetyl groups as well as secondary cracking of volatiles and condensation of aromatic rings at high temperatures. Cellulose produced hydrogen through the breaking of C-H bonds in volatiles generated from sugar ring cleavage along with char gasification and condensation of aromatic rings at high temperatures. Lignin produced hydrogen through ether bond cleavage breaking of methoxy groups as well as cleavage of phenylpropane side chains and condensation of aromatic rings at high temperatures. Results from fixed-bed pyrolysis experiments further showed that hemicellulose exhibited the strongest hydrogen production capacity with the maximum H2 production efficiency of 6.09 mmol/g the maximum H2 selectivity of 17.79% and the maximum H2 effectiveness of 59% at 800°C.

The global climate crisis necessitates the urgent implementation of sustainable practices and carbon emission reduction strategies across all sectors. Transport as a major contributor to greenhouse gas emissions requires transitional technologies to bridge the gap between fossil fuel dependency and renewable energy systems. Natural gas recognised as the cleanest fossil-derived fuel with approximately half the CO2 emissions of coal and 75% of oil presents a potential transitional solution through Natural Gas Vehicles (NGVs). This manuscript presents several distinctive contributions that advance the understanding of Natural Gas Vehicles within the contemporary energy transition landscape while synthesising updated emission performance data. Specifically the feasibility and sustainability of NGVs are investigated within the energy transition framework by systematically incorporating recent technological developments and environmental economic and infrastructure considerations in comparison to conventional vehicles (diesel and petrol) and unconventional alternatives (electric and hydrogen-fuelled). The analysis reveals that NGVs can reduce CO2 emissions by approximately 25% compared to petrol vehicles on a well-to-wheel basis with significant reductions in NOx and particulate matter. However these environmental benefits depend heavily on the source and type of natural gas used (CNG or LNG) while economic viability hinges largely on governmental policies and infrastructure development. The findings suggest that NGVs can serve as an effective transitional technology in the transport sector’s sustainability pathway particularly in regions with established natural gas infrastructure but require supportive policy frameworks to overcome implementation barriers.