Poland

Energy transformation is one of the processes shaping contemporary urban transport systems with public transport being the subject of initiatives designed to enhance its attractiveness and transport utility including electromobility. This article presents a case study for a metropolitan conurbation—the GZM Metropolis in Poland—considering the economic efficiency of implementing buses with conventional diesel engines electric buses (battery electric buses) and hydrogen fuel cell-powered buses. The analysis is based on the cost-benefit analysis (CBA) method using the discounted cash flow (DCF) method.

Hydrogen (H2) production from biomass has emerged as a promising alternative to fossil-based pathways addressing the global demand for low-carbon energy solutions. This study compares the environmental impacts of two biomass-based H2 production processes biogas reforming and agricultural residue gasification through a life cycle assessment (LCA). Using real-world data from the literature the analysis considered key system boundaries for each process including biogas production reforming and infrastructure for the former and biomass cultivation syngas generation and offgas management for the latter. Environmental impacts were evaluated using SimaPro software (Version 9.4) and the ReCiPe midpoint (H) method. The results revealed that biogas reforming emits approximately 5.047 kg CO2-eq per kg of H2 which is 4.89 times higher than the emissions from agricultural residue gasification (1.30 kg CO2-eq/kg H2) demonstrating the latter’s superior environmental performance. Gasification consumes fewer fossil resources (3.20 vs. 10.42 kg oil-eq) and poses significantly lower risks to human health (1.51 vs. 23.28 kg 14-DCB-eq). Gasification water consumption is markedly higher (5.37 compared to biogas reforming (0.041 m3/kg H2)) which is an important factor to consider for sustainability. These findings highlight gasification as a more sustainable H2 production method and emphasize its potential as an eco-friendly solution. To advance sustainability in energy systems integrating socio-economic studies with LCA is recommended alongside prioritizing agricultural residue gasification for hydrogen production.

Alternative fuel opportunities can satisfy energy security and reduce carbon emissions. In this regard the hydrogen fuel is derived from the source of environmental pollutants like sewage and algae wastewater through hydrothermal gasification technique using a KOH catalyst with varied gasification process parameters of duration and temperature of 6–30 min and 500-800 ◦C. The novelty of the work is to identify the optimum gasification process parameter for obtaining the maximum hydrogen yield using a KOH catalyst as an alternative fuel for agricultural engine applications. Influences of gasification processing time and temperature on H2 selectivity Carbon gasification efficiency (CE) Lower heating value (LHV) Hydrogen yield potential (HYP) and gasification efficiency (GE) were studied. Its results showed that the gasifier operated at 800 ◦C for 30 min offering maximum hydrogen yield (26 mol/kg) and gasification efficiency (58 %). The synthesized H2 was an alternative fuel blended with diesel fuel/TiO2 nanoparticles. It was experimentally studied using an internal combustion engine. Influences of H2 on engine perfor mance like brake-specific fuel consumption brake thermal efficiency and emission performances were measured and compared with diesel fuel. The results showed that DH20T has the least (420g/kWh) brake-specific fuel consumption (BSFC) and superior brake thermal efficiency of about 25.2 %. The emission results revealed that the DH20T blend showed the NOX value increased by almost 10.97 % compared to diesel fuel whereas the CO UHC and smoke values reduced by roughly 31.25 28.34 and 42.35 %. The optimum fuel blend (DH20T) result is rec ommended for agricultural engine applications.

This article presents the findings of a bibliometric analysis of scientific publications in journals and materials indexed in the SCOPUS and Web of Science databases covering the broad topic of underground hydrogen storage (UHS). The use of VOSviewer software for keyword analysis enabled the identification of four key research areas related to UHS. These areas include hydrogen and hydrocarbon reservoir engineering; hydrogen economy and energy transformation; processes in hydrogen storage sites including lessons from CO2 sequestration; and the geology engineering and geomechanics of underground gas storage. The interdisciplinary nature of UHS research emphasises the synergy of research across diverse fields. A bibliographic analysis allowed for the identification of areas of intensive research and new directions of work related to UHS key research centres and the dynamics of the development of research topics related to UHS. This study revealed the chronological dispersion of the research results their geographical and institutional variability and the varying contributions of major publishing journals. The research methodology used can serve as an inspiration for the work of other researchers.

Geological storage is an integral element of the green energy transition. Geological formations such as aquifers depleted reservoirs and hard rock caverns are used mainly for the storage of hydrocarbons carbon dioxide and increasingly hydrogen. However potential adverse effects such as ground movements leakage seismic activity and environmental pollution are observed. Existing research focuses on monitoring subsurface elements of the storage while on the surface it is limited to ground movement observations. The review was carried out based on 191 research contributions related to geological storage. It emphasizes the importance of monitoring underground gas storage (UGS) sites and their surroundings to ensure sustainable and safe operation. It details surface monitoring methods distinguishing geodetic surveys and remote sensing techniques. Remote sensing including active methods such as InSAR and LiDAR and passive methods of multispectral and hyperspectral imaging provide valuable spatiotemporal information on UGS sites on a large scale. The review covers modelling and prediction methods used to analyze the environmental impacts of UGS with data-driven models employing geostatistical tools and machine learning algorithms. The limited number of contributions treating geological storage sites holistically opens perspectives for the development of complex approaches capable of monitoring and modelling its environmental impacts.

In Spain the winery industry exerts a great influence on the national economy. Proportional to the scale of production a significant volume of waste is generated estimated at 2 million tons per year. In this work a laboratory-scale reactor was used to study the feasibility of the energetic valorization of winery effluents into hydrogen by means of dark fermentation and its subsequent conversion into electrical energy using fuel cells. First winery wastewater was characterized identifying and determining the concentration of the main organic substrates contained within it. To achieve this a synthetic winery effluent was prepared according to the composition of the winery wastewater studied. This effluent was fermented anaerobically at 26 ◦C and pH = 5.0 to produce hydrogen. The acidogenic fermentation generated a gas effluent composed of CO2 and H2 with the percentage of hydrogen being about 55% and the hydrogen yield being about 1.5 L of hydrogen at standard conditions per liter of wastewater fermented. A gas effluent with the same composition was fed into a fuel cell and the electrical current generated was monitored obtaining a power generation of 1 W·h L−1 of winery wastewater. These results indicate that it is feasible to transform winery wastewater into electricity by means of acidogenic fermentation and the subsequent oxidation of the bio-hydrogen generated in a fuel cell.

Issues related to the components of modern fuel equipment wear processes have been discussed. The fuel injector is one of the key elements of the fuel equipment system because it is a device responsible for distributing and spraying hydrogen-containing fuel in the engine combustion chamber. It is mounted in the modern engine head directly in the combustion chamber. If the fuel injector is faulty it affects the operating parameters and in particular the ecological parameters of the modern engine such as the emission of toxic substances into the environment. Additionally a hydrogen reactor has been installed in the Common Rail (CR) system the task of which is to produce hydrogen. As a result of the temperature prevailing in the operating environment of the injection equipment various types of wear occur inside the system including hydrogen degradation. The types of degradation processes of precision pairs of modern fuel injectors have been analyzed and classified. Microscopic tests were performed to analyze the contamination in the fuel system and to compare the ecological parameters of the engine operating on efficient and worn fuel injectors. The emission of nitrogen oxides carbon monoxide and soot has been analyzed as a key ecological parameter. It has been established that the loss of precision of pairs of elements of a damaged fuel injector significantly affects the size of the injection doses of the fuel mixture containing hydrogen.

This paper presents a novel literature survey on leveraging electrolysis for grid frequency stabilization in power systems with high penetration of renewable energy sources (RESs) uniquely integrating global research findings with specific insights into the Polish energy context—a region facing acute grid challenges due to rapid RES growth and infrastructure limitations. The intermittent nature of wind and solar power exacerbates frequency fluctuations necessitating dynamic demand-side management solutions like hydrogen production via electrolysis. By synthesizing over 30 studies the survey reveals key results: electrolysis systems particularly PEM and alkaline electrolyzers can reduce frequency deviations by up to 50% through fast frequency response (FFR) and primary reserve provision as demonstrated in simulations and real-world pilots (e.g. in France and the Netherlands); however economic viability requires enhanced compensation schemes with current models showing unprofitability without subsidies. Technological advancements such as transistor-based rectifiers improve efficiency under partial loads while integration with RES farms mitigates overproduction issues as evidenced by Polish cases where 44 GWh of solar energy was curtailed in March 2024. The survey contributes actionable insights for policymakers and engineers including recommendations for deploying electrolyzers to enhance grid resilience support hydrogen-based transportation and facilitate Poland’s target of 50.1% RESs by 2030 thereby advancing the green energy transition amid rising instability risks like blackouts in RES-heavy systems.

According to the European Hydrogen Strategy hydrogen will solve many of the problems with energy storage for balancing variable renewable energy sources (RES) supply and demand. At the same time we can see increasing popularity of the so-called energy communities (e.g. cooperatives) which (i) enable groups of entities to invest in manage and benefit from shared RES energy infrastructure; (ii) are expected to increase the energy independence of local communities from large energy corporations and increase the share of RES. Analyses were conducted on 2000 randomly selected energy cooperatives and four energy cooperatives formed on the basis of actual data. The hypotheses assumed in the research and positively verified in this paper are as follows: (i) there is a relationship between hydrogen storage capacity and the power of RES which allows an energy community to build energy independence; (ii) the type of RES generating source is meaningful when optimizing hydrogen storage capacity. The paper proves it is possible to build “island energy independence” at the local level using hydrogen storage and the efficiency of the power-to-power chain. The results presented are based on simulations carried out using a dedicated optimization model implemented by mixed integer programming. The authors’ next research projects will focus on optimizing capital expenditures and operating costs using the Levelized Cost of Electricity and Levelized Cost of Hydrogen methodologies.

Adverse climate change has forced a deeper reflection on the scale of pollution related to human activity including in the aviation industry. As a result fundamental questions have arisen about the characteristics of these pollutants the mechanisms of their formation and potential strategies for reducing them. This paper provides a comprehensive overview of key technical solutions to minimize the environmental impact of aircraft engines. The solutions presented range from fuel innovations to advanced design changes and drive concepts. Particular attention was paid to sustainable aviation fuels (SAFs) which are currently an important element of the environmental strategy regulated by the European Union. It also discusses the potential use of hydrogen as a potential alternative fuel to replace traditional aviation fuels in the long term. The analysis in the article made it possible to characterize in detail possible modifications in the functioning of aircraft engines based both on the current state of technical knowledge and on the anticipated directions of its development which has not been a frequent issue in comprehensive research so far. The analysis shows that the type of raw material used to create SAF has a strong impact on its physical and chemical parameters and the degree of greenhouse gas emissions. This necessitates a broader analysis of the legitimacy of using a given type of fuel from the SAF group in the direction of selected air operations and areas with a higher risk of severe atmospheric pollution. These results provide the basis for further research into sustainable solutions in the aviation sector that can contribute to significantly reducing its impact on climate change.