Hungary

Nickel-based catalysts recognized for their cost-efficiency and availability play a critical role in advancing hydrogen production technologies. This study evaluates their optimization in water electrolysis to improve efficiency and system stability. Key findings highlight the enhancement of these catalysts with nickel-iron oxyhydroxide and nickel-molybdenum co-catalysts. Technological innovations such as Perovskite Solar Cells integration for solar-to-hydrogen conversion are explored. The use of nickel foam enhances electrode durability offering valuable insights into designing sustainable and efficient hydrogen production systems.

Biogas is a renewable fuel source that helps the circular economy by turning organic waste into energy. This study tackles existing research gaps by exploring the use of biogas as a hydrogen carrier in dual-fuel engine systems. It additionally employs explainable machine learning techniques for predictive modelling and interpretive analysis. The dual-fuel engine was powered with biogas as main fuel while biodiesel-diesel blend was used as pilot fuel. The engine was tested at different Compression Ratios (CR) and Brake Powers (BP). The generated data from testing was used to develop the mathematical models and parametric optimization of engine performance and emissions using Response Surface Methodology (RSM). Desirability-based optimization identified optimal results: a Peak Cylinder Pressure (Pmax) of 54.97 bar and a brake thermal efficiency (BTE) of 24.35 % achieved at a CR of 18.3 and a BP of 3.3 kW. The predictive machine learning approach Extreme Gradient Boosting (XGBoost) was employed to develop predictive models. XGBoost precisely forecasted engine performance and emissions with Coefficient of Determination (R2 ) values (up to 0.9960) and minimal Mean Absolute Percentage Error (MAPE) values (1.47–4.89 %) for all parameters. SHapley Additive exPlanations (SHAP) based analysis identified BP as the predominant feature with a normalized importance score reaching up to 0.9 surpassing that of CR. These findings underscore the potential of biogas as a viable sustainable fuel and highlight the role of explainable prediction–optimization frameworks can play in achieving optimal engine performance and emission control.

Low-carbon hydrogen is a promising option for energy security and decarbonization. Cooperation is needed to ensure the widespread use of low-carbon energy. Cooperation among hydrogen supply chain (HSC) agents is essential to overcome the high costs the lack of infrastructure that needs heavy financial support and the environmental failure risk. But how can cooperation be operationalized and its potential benefits be measured to evaluate the impact of different allocation schemes in low-carbon HSCs? This research works around this question and aims to analyze the potential of cooperation in a generalized low-carbon HSC with limited and critical resources using systems and cooperative game theory. This work is original in several aspects. It evaluates cooperation effects under different benefit allocation schemes while considering infrastructure agents’ dependencies (production transportation and storage) and specific traits. Additionally it provides a transparent replicable methodology adaptable to various case studies. It is highlighted that HSC coalitions form hierarchies with veto power pursuing common goals like maximizing decarbonization and demand fulfillment. A cooperative game theory toolbox is developed to evaluate display and compare the results of six allocation solutions. The toolbox does not aim to determine the best allocation scheme but rather to support smart decision-making in the bargaining process facilitating debate and agreement on a trade-off solution that ensures the viability and achievement of long-term coalition goals. It is built on three naïve and three game-theoretical allocation rules (Gately Nucleolus and Shapley value) applicable to peer group games with transferable utility. Results are presented for an 8-agent low-carbon HSC along with the total environmental benefit the allocated individual shares and numerical indicators (stability satisfaction propensity to disrupt) reflecting the acceptability of allocations. Numerical results show that the Nucleolus achieves the highest satisfaction among stable allocations while the Gately allocation minimizes disruption propensity. Naïve rules yield different outcomes: “equal distribution for producers” carries the highest risk whereas “equal shares for all agents” and “proportional to individual benefits” rules are stable but perform poorly on other criteria.

Hydrogen is a carbon-neutral fuel so in theory it holds enormous potential. The use of hydrogen as a fuel for traditional internal combustion engines is becoming increasingly prominent. The authors now have the opportunity to retrofit a single-cylinder diesel research engine to an engine with hydrogen operation. For this reason before that conversion they prepared a comprehensive review study regarding hydrogen. Firstly the study analyzes the most essential properties of hydrogen in terms of mixture formation and combustion compared to diesel. After that it deals with indirect and direct injection and what kind of combustion processes can occur. Since there is a possibility of preignition backfire and knocking the process can be dangerous in the case of indirect mixture formation and so a short subsection is devoted to these uncontrolled combustion phenomena. The next subsection shows how important in many ways a special spark plug and ignition system are for hydrogen operation. The next part of the study provides a detailed presentation of the possible combustion chamber design for operation with hydrogen fuel. The last section reveals how many parameters can be focused on analyzing the hydrogen’s combustion process. The authors conclude that intake manifold injection and a Heron-like combustion chamber design with a special spark plug with an ignition system would be an appropriate solution.

The increasing global demand for sustainable energy solutions has intensified the need to replace fossil fuels in gas turbines particularly in aviation and power generation where alternatives to gas turbines are currently limited. This review explores the feasibility of utilizing sustainable liquid and gaseous fuels in gas turbines by evaluating their environmental impacts performance characteristics and technical integration potential. The study examines a broad range of alternatives including biofuels hydrogen alcohols ethers synthetic fuels and biogas focusing on their production methods combustion behavior and compatibility with existing turbine technology. Key findings indicate that several bioderived and synthetic fuels can serve as viable drop-in replacements for conventional jet fuels especially under ASTM D7566 standards. Hydrogen and other gaseous alternatives show promise for industrial applications but require significant combustion system adaptations. The study concludes that a transition to sustainable fuels in gas turbines is achievable through coordinated advancements in combustion technology fuel infrastructure and regulatory support thus enabling meaningful reductions in greenhouse gas emissions and advancing global decarbonization efforts.