Publications

This study investigates the combustion process in a marine spark-ignition engine fueled with an ammonia–hydrogen blend (15% hydrogen by volume) using a passive pre-chamber. A 3D-CFD model supported by a 1D engine model was employed to analyze equivalence ratios between 0.7 and 0.9 and pre-chamber nozzle diameters from 7 to 3 mm. Results indicate that combustion is consistently initiated by turbulent jets but at an equivalence ratio of 0.7 the charge combustion is incomplete. For lean mixtures reducing nozzle size improves flame propagation although not sufficiently to ensure stable operation. At an equivalence ratio of 0.8 reducing the nozzle diameter from 7 to 5 mm advances CA50 by about 6 CAD while further reduction causes minor variations. At richer conditions nozzle diameter plays a negligible role. Optimal performance was achieved with a 7 mm nozzle at equivalence ratio 0.8 delivering about 43% efficiency and 1.17 MW per cylinder.

The hydrogen energy industry is rapidly developing positioning hydrogen refueling stations (HRSs) as critical infrastructure for hydrogen fuel cell vehicles. Within these stations hydrogen compressors serve as the core equipment whose performance and reliability directly determine the overall system’s economy and safety. This article systematically reviews the working principles structural features and application status of mechanical hydrogen compressors with a focus on three prominent types based on reciprocating motion principles: the diaphragm compressor the hydraulically driven piston compressor and the ionic liquid compressor. The study provides a detailed analysis of performance bottlenecks material challenges thermal management issues and volumetric efficiency loss mechanisms for each compressor type. Furthermore it summarizes recent technical optimizations and innovations. Finally the paper identifies current research gaps particularly in reliability hydrogen embrittlement and intelligent control under high-temperature and high-pressure conditions. It also proposes future technology development pathways and standardization recommendations aiming to serve as a reference for further R&D and the industrialization of hydrogen compression technology.

The gradual exhaustion of fossil fuel reserves along with the adverse effects of their consumption on global climate drives the need for research into alternative energy sources that can meet the growing demand in a sustainable and eco-friendly way. Among these hydrogen stands out as one of the most promising options for the automotive sector being the cleanest available fuel and capable of being produced from renewable resources. This paper reviews the existing literature on compression ignition engines operating in a dualfuel configuration where diesel serves as the ignition source and hydrogen is used to enhance the combustion process. The reviewed studies focus on engine systems with hydrogen injection into the intake manifold. The investigations analyzed the influence of hydrogen energy fraction on combustion characteristics engine performance combustion stability and exhaust emissions in diesel/hydrogen dual-fuel engines operating under full or near-full-load conditions. The paper identifies the main challenges hindering the widespread and commercial application of hydrogen in diesel/hydrogen dual-fuel engines and discusses potential methods to overcome the existing barriers in this area.

Fuel cells are highly efficient electrochemical devices that convert the chemical energy of fuel directly into electrical energy while generating minimal pollutant emissions. In recent decades they have established themselves as a key technology for sustainable energy supply in the transport sector stationary systems and portable applications. In order to assess their real contribution to environmental protection and energy efficiency a comprehensive analysis of their life cycle Life Cycle Assessment (LCA) is necessary covering all stages from the extraction of raw materials and the production of components through operation and maintenance to decommissioning and recycling. Particular attention is paid to the environmental challenges associated with the extraction of platinum catalysts the production of membranes and waste management. Economic aspects such as capital costs the price of hydrogen and maintenance costs also have a significant impact on their widespread implementation. This manuscript presents detailed mathematical models that describe the electrochemical characteristics energy and mass balances degradation dynamics and cost structures over the life cycle of fuel cells. The models focus on proton exchange membrane fuel cells (PEMFCs) with possible extensions to other types. LCA is applied to quantify environmental impacts such as global warming potential (GWP) while the levelized cost of electricity (LCOE) is used to assess economic viability. Particular attention is paid to the sustainability challenges of platinum catalyst extraction membrane production and end-of-life material recovery. By integrating technical environmental and economic modeling the paper provides a systematic perspective for optimizing fuel cell deployment within a circular economy.

Integrated Energy Systems (IESs) which leverage the synergistic coordination of electricity heat and gas networks serve as crucial enablers for a low-carbon transition. Current research predominantly treats energy storage as a subordinate resource in dispatch schemes failing to simultaneously optimise IES economic efficiency and storage operators’ profit maximisation thereby overlooking their potential value as independent market entities. To address these limitations this study establishes an operator-autonomous management framework incorporating electrical thermal and hydrogen storage in IESs. We propose a joint optimal dispatch model for hybrid energy storage systems in low-carbon IES operation. The upper-level model minimises total system operation costs for IES operators while the lower-level model maximises net profits for independent storage operators managing various storage assets. These two levels are interconnected through power price and carbon signals. The effectiveness of the proposed model is verified by setting up multiple scenarios for example analysis.

The effect of tempering temperature and tempering time on the density of hydrogen traps hydrogen diffusivity and microhardness in a vanadium-modified AISI 4140 martensitic steel was determined. Tempering parameters were selected to activate the second third and fourth tempering stages. These conditions were intended to promote specific microstructural transformations. Permeability tests were performed using the electrochemical method developed by Devanathan and Stachurski and microhardness was measured before and after these tests. It was observed that hydrogen diffusivity is inversely proportional to microhardness while the density of hydrogen traps is directly proportional to microhardness. The lowest hydrogen diffusivity the highest trap density and the highest microhardness were obtained in the as-quenched condition and the tempering at 286 ◦C for 0.25 h. In contrast tempering at a temperature corresponding to the fourth tempering stage increases hydrogen diffusivity and decreases the density of hydrogen traps and microhardness. However as the tempering time or temperature increases the opposite occurs which is attributed to the formation of alloy carbides. Finally hydrogen has a softening effect for tempering temperatures corresponding to the fourth tempering stage tempering times of 0.25 h and in the as-quenched condition. However with increasing tempering time hydrogen has a hardening effect.

This review explores the evolving role of hydrogen in global decarbonization analysing national hydrogen strategies value chain developments and future market potential. Through a comprehensive review of policy frameworks market trends and technology pathways the paper evaluates hydrogen’s role in decarbonising sectors such as steel ammonia methanol refining transport and power generation. The study highlights the expected growth in global hydrogen demand projected cost reductions and advancements in production technologies including electrolysis and carbon capture-integrated hydrogen production. While green hydrogen offers a sustainable pathway challenges remain in infrastructure development energy efficiency and the integration of hydrogen into existing energy networks. The paper considers the economic and technological factors affecting international hydrogen trade. Despite more than 30 national hydrogen strategies being in place significant challenges remain particularly in scaling renewable electricity and infrastructure to meet growing hydrogen demand projected to reach up to 600 Mt by 2050. Key players such as Australia Norway and the Middle East are positioning themselves as major hydrogen exporters by leveraging their abundant natural resources and strategic infrastructure. On the demand side countries like Japan South Korea Germany and the Netherlands are emerging as leading importers investing heavily in hydrogen hubs and import terminals to secure future energy supplies. The expansion of hydrogen storage and transportation alongside investments in large-scale hydrogen hubs will be critical for market growth. Additionally the study emphasize the need for policy alignment strategic investments and cross-border cooperation to accelerate hydrogen adoption. Hydrogen can become a key element of the global clean energy transition by addressing optimal energy consumption and by leveraging renewable resources.

Fuel cell electric vehicles (FCEVs) are zero-emission but face cost and power density challenges. To mitigate these limitations a novel 3D-ordered nano-structured self-supporting membrane electrode assembly (MEA) has been developed. This paper investigates the optimal component sizing of the battery and fuel cell in FCEVs equipped with 3D-ordered MEAs integrating the energy management. To explore the trade-offs between component cost operational cost and fuel cell degradation the sizing and energy management problem is formulated into a multi-objective optimisation problem. A Pareto frontier (PF) study is conducted using the decomposed multi-objective evolutionary algorithm (MOEA/D) for a more diverse distribution of feasible solutions. The modular design of fuel cells is derived from a scaled and stressed experiment. After executing MOEA/D across the three aggressive driving cycles power source configurations are selected from the corresponding PFs based on objective trade-offs ensuring robustness of the overall system. The optimisation performance of the MOEA/D is compared with that of the multi-objective Particle Swarm Optimisation. In addition the selected powertrain configurations are evaluated and compared through standard and realworld driving cycles in a simulation environment. This paper also performs a sensitivity analysis to reveal the influence of diverse component unit costs and hydrogen price. The results indicate that the mediumsized configuration consisting of a 63.31 kW fuel cell stack and a 52.15 kWh battery pack delivers the best overall performance. It achieves a 26.71% reduction in component cost and up to 12.76% savings in hydrogen consumption across various driving conditions. These findings provide valuable insights into the design and optimisation of fuel cell systems for FCEVs.

Coastal regions in Cameroon including Douala Kribi Campo Dibamba and Limbe faced persistent electricity challenges driven by grid instability growing demand and dependence on fossil fuels. Solar resource availability was high but intermittent whereas tidal energy was predictable and energy-dense yet underused. This pilot delivers the first Cameroonian assessment of an off-grid tidal/PV/electrolyzer/hydrogen-storage/fuel-cell architecture explicitly co-optimizing electricity service and green hydrogen production and evaluating performance with a tri-metric economic lens (net present cost levelized cost of electricity and the levelized cost of hydrogen). The system was optimized to minimize net present cost (NPC) levelized cost of electricity (LCOE) levelized cost of hydrogen (LCOH) and three tidal-flow scenarios were analyzed to represent hydrokinetic variability. The design served households small businesses fishing activities schools and health facilities with a baseline demand of 389.50 kWh/day; surplus renewable power drove the electrolyzer to produce hydrogen for later reconversion in the fuel cell. Under the first scenario (1.25 m/s average speed) the optimal mix comprised 137 PV modules (600 W each) a 100 kW fuel cell six 40 kW tidal turbines six 10 kW electrolyzers a 19.5 kW converter and 41 hydrogen tanks (40 L each) yielding an NPC of US$ 2.16 million an LCOE of US$ 0.782/kWh and a LCOH of US$ 19.2/kg of hydrogen. The second scenario (1.47 m/s) required only 12 PV modules one electrolyzer and an 11.3 kW converter lowering costs to an NPC of US$ 1.52 million an LCOE of US$ 0.553/ kWh and a LCOH of US$ 15.4/kg of hydrogen. In the third scenario (1.61 m/s) the configuration shifted to 298 PV modules three tidal turbines eight electrolyzers and a 39.6 kW converter resulting in the highest NPC (US$ 2.47 million) and LCOE (US$ 0.901/kWh) with a LCOH of US$ 18.8/kg of hydrogen. The study also contributes a transparent component-wise employment indicator linking installed capacities/energies to jobs; deployment is expected to create about seven local jobs during installation and early operation tidal turbines (3) solar panels (1) electrolyzers (1) hydrogen tanks (1) and fuel cell (1) with additional minor operation and maintenance positions thereafter. Social analysis indicated improved energy access support for local livelihoods and job creation; environmental results confirmed clean operation with limited marine disturbance. A sensitivity study varying capital and replacement-cost multipliers showed robust performance across economic conditions. Taken together these contributions provide a decision-ready blueprint for coastal communities: a first-of-its-kind Cameroonian hybrid that quantifies both electricity and hydrogen costs (including feasible LCOH) and demonstrates socio-economic co-benefits offering a cost-effective pathway to strengthen energy security foster local development and reduce environmental impact.

The adoption of clean hydrogen is expected to transform the global energy landscape reducing greenhouse gas emissions bridging gaps in renewable energy integration and driving innovation across multiple sectors. In the medical and pharmaceutical industries hydrogen offers unique opportunities for transformative progress. This review critically examines recent advances in three domains: hydrogen fuel cells as reliable scalable and sustainable energy solutions for hospitals; molecular hydrogen as a therapeutic and preventive medical gas particularly for brain disorders; and hydrogenation technologies for the efficient and sustainable pharmaceutical production. Despite encouraging advancements widespread adoption remains limited by economic constraints regulatory gaps and limited clinical evidence. Addressing these barriers through technological innovation largescale studies and life-cycle sustainability assessments is essential to translate hydrogen’s full potential into clinical and industrial practice. Responsible adoption of green hydrogen is poised to reshape the clinical approach to global health and enhance the quality of life for people worldwide.