Hungary

The time-range of applicability of various energy-storage technologies are limited by self-discharge and other inevitable losses. While batteries and hydrogen are useful for storage in a time-span ranging from hours to several days or even weeks for seasonal or multi-seasonal storage only some traditional and quite costly methods can be used (like pumped-storage plants Compressed Air Energy Storage or energy tower). In this paper we aim to show that while the efficiency of energy recovery of Power-to-Methane technology is lower than for several other methods due to the low self-discharge and negligible standby losses it can be a suitable and cost-effective solution for seasonal and multi-seasonal energy storage.

Climate change and global warming as well as growing global demand for hydrocarbons in industrial sectors make great incentives to investigate the utilization of CO₂ for hydrocarbons production. Therefore finding an in-depth understanding of the CO₂ hydrogenation reactors along with simulating reactor responses to different operating conditions are of paramount importance. However the reaction mechanisms for CO₂ hydrogenation and their corresponding kinetic parameters have been disputable yet. In this regard considering the previously proposed Langmuir-Hinshelwood-Hougen-Watson (LHHW) mechanism which considered CO₂ hydrogenation as a combination of reverse water gas shift (RWGS) and Fischer-Tropsch (FT) reactions and using a one-dimensional pseudo-homogeneous non-isothermal model kinetic parameters of the rate expressions are estimated via fitting experimental and modelling data through a novel swarm intelligence optimization technique called dragonfly algorithm (DA). The predicted reactants conversion using DA algorithm are closer to the experimental data (with about 4% error) comparing to those obtained by the artificial bee colony (ABC) algorithm and are in significant agreement with available literature data. The proposed model is used to assess the effect of reactor configuration on the performance and temperature fluctuations. Results show that axial flow spherical reactor (AFSR) and radial flow spherical reactor (RFSR) exhibiting the same surface area with that of the cylindrical reactor (CR) i.e. AFSR-2 and RFSR-2-i are the most efficient exhibiting hydrocarbons selectivity of 40.330% and 40.286% at CO₂ conversion of 53.763% and 53.891%. In addition it is revealed that the location of the jacket has an essential role in controlling the reactor temperature.

Hungary’s National Hydrogen Strategy (hereinafter referred to as: Strategy) is ambitious but provides a realistic vision of the future as it opens the way for the establishment of a hydrogen economy therefore contributing to the achievement of decarbonisation goals and providing an opportunity for Hungary to become an active participant of the European hydrogen sector. On the long term the Strategy focuses on “green” hydrogen but in addition to hydrogen based on electricity generated using renewable resources primarily solar energy Hungary does not ignore opportunities for hydrogen production based on carbon-free energy accessed either through a nuclear basis or from the network. Additionally in the short and medium term a rapid reduction in emissions and the establishment of a viable hydrogen market will also require low-carbon hydrogen.

As renewable energy sources are spreading the problems of energy usage transport and storage arise more frequently. In order that the performance of energy producing units from renewable sources which have a relatively low efficiency should not be decreased further and to promote sustainable energy consumption solutions a living lab conception was elaborated in this project. At the pilot site the produced energy (by PV panels gas turbines/engines) is stored in numerous ways including hydrogen production. The following uses of hydrogen are explored: (i) feeding it into the national natural gas network; (ii) selling it at a H-CNG (compressed natural gas) filling station; (iii) using it in fuel cells to produce electricity. This article introduces the overall implementation plan which can serve as a model for the hybrid energy communities to be established in the future.

This study proposes a data-driven methodology for modeling power and hydrogen generation of a sustainable energy converter. The wave and hydrogen production at different wave heights and wind speeds are predicted. Furthermore this research emphasizes and encourages the possibility of extracting hydrogen from ocean waves. By using the extracted data from the FLOW-3D software simulation and the experimental data from the special test in the ocean the comparison analysis of two data-driven learning methods is conducted. The results show that the amount of hydrogen production is proportional to the amount of generated electrical power. The reliability of the proposed renewable energy converter is further discussed as a sustainable smart grid application.

The aim of this study was the syngas production by the gasification of plastic waste (polyethylene polypropylene and terephthalate polyethylene). Ca Ce La Mg and Mn were used to promote the Ni/ZSM-5 catalyst in order to enhance the production of higher syngas yield. The modified catalysts can enhanced the reaction rate of the pyrolysis process and resulting in high syngas in the product yields. Especially cerium lanthanum promoted catalysts can enhance the yield of syngas. The effect of the reaction temperature and nitrogen/oxygen ratio of the carrier gas was also investigated. The maximum syngas production was obtained with lanthanum catalyst (112.2 mmol/g (95%N2 and 5%O2) and 130.7 mmol/g (90%N2 and 10%O2) at 850 °C. Less carbon depositions was found at 850 °C or even by the using of catalyst and more oxygen in the carrier gas. The oxygen content of the pyrolysis-gasification atmosphere had a key role to the syngas yield and affects significantly the carbon-monoxide/carbon-dioxide ratio. Catalysts can also accelerate the methanization reactions and isomerize the main carbon frame. Increasing in both temperature and oxygen in the atmosphere led to higher n-paraffin/n-olefin ratio and more multi-ring aromatic hydrocarbons in pyrolysis oils. The concentration of hydrocarbons containing oxygen and branched compounds was also significantly affected by catalysts.

Proton Exchange Membrane Fuel Cells (PEMFC) have proven to be a promising energy conversion technology in various power applications and since it was developed it has been a potential alternative over fossil fuel-based engines and power plants all of which produce harmful by-products. The inlet air coolant and reactants have an important effect on the performance degradation of the PEMFC and certain power outputs. In this work a theoretical model of a PEM fuel cell with solar air heating system for the preheating hydrogen of PEM fuel cell to mitigate the performance degradation when the fuel cell operates in cold environment is proposed and evaluated by using energy analysis. Considering these heating and energy losses of heat generation by hydrogen fuel cells the idea of using transpired solar collectors (TSC) for air preheating to increase the inlet air temperature of the low-temperature fuel cell could be a potential development. The aim of the current article is applying solar air preheating for the hydrogen fuel cells system by applying TSC and analyzing system performance. Results aim to attention fellow scholars as well as industrial engineers in the deployment of solar air heating together with hydrogen fuel cell systems that could be useful for coping with fossil fuel-based power supply systems.

In the automotive sector the zero emissions area has been dominated by battery electric vehicles. However prospective users cite charging times large batteries and the deployment of charging stations as a counter-argument. Hydrogen will offer a solution to these areas in the future. This research focuses on the development of a prototype three-wheeled vehicle that is named Neumann H2. It integrates state-of-the-art energy storage systems demonstrating the benefits of solar- battery- and hydrogen-powered drives. Of crucial importance for the R&D platform is the system’s ability to record its internal states in a time-synchronous format providing valuable data for researchers and developers. Given that the platform is equipped with the ROS2 Open-Source interface the data are recorded in a standardized format. Energy management is supported by artificial intelligence of the “Reinforcement Learning” type which selects the optimal energy source for operation based on different layers of high-fidelity maps. In addition to powertrain control the vehicle also uses artificial intelligence to detect the environment. The vehicle’s environment-sensing system is essentially designed to detect distinguish and select environmental elements through image segmentation using camera images and then to provide feedback to the user via displays.

Energy transition will reshape the power sector and hydrogen is a key energy carrier that could contribute to energy security. The inclusion of sustainability criteria is crucial for the adequate design/deployment of resilient hydrogen networks. While cost and environmental metrics are commonly included in hydrogen models social aspects are rarely considered. This paper aims to identify the social criteria related to the hydrogen economy by using a systematic hybrid literature review. The main contribution is the identification of twelve social aspects which are described ranked and discussed. “Accessibility” “Information” “H2 markets” and “Acceptability” are now emerging as the main themes of hydrogen-related social research. Identified gaps are e.g. lack of the definition of the value of H2 for society insufficient research for “socio-political” aspects (e.g. geopolitics wellbeing) scarce application of social lifecycle assessment and the low amount of works with a focus on social practices and cultural issues.

As hydrogen products emerge as a promising energy alternative in multiple sectors low carbon hydrogen supply chains require concerted efforts among a diverse array of stakeholders. Within an evolving energy transition landscape stakeholders’ competition and cooperation play a critical role in expediting the deployment of the hydrogen economy. In this review different strategies referred to as Hydrogen Competition Cooperation and Coopetition (H2CCC) dynamics are analyzed from the lenses of game theory. The study employs hybrid literature review methodology integrating both bibliometric and structured review approaches. The study reveals that competition and cooperation represent a contrasting but interconnected dynamics that drive the energy transition. Coopetition models are less common. Furthermore it is observed that Integrated Energy Systems are mainly used in cooperative and coopetitive approaches while H2 technologies and Hydrogen Supply Chains are more explored in competitive approaches. Industrial and mobility sectors are present in H2CCC dynamics with technological players more present than institutional entities. Maps definitions gaps and perspectives are developed. These insights may be valuable for policymakers industry stakeholders modelers and researchers. There remains a need for further empirical H2CCC case studies and applications of pure coopetitive games.

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.