Jacek Misiak

Large-scale underground hydrogen storage (UHS) in saline aquifers requires preliminary screening methods that consider both subsurface suitability and the spatial context of the energy system. This study develops an integrated geographic information system with multi-criteria decision analysis (GIS–MCDA) framework for the regional assessment of candidate UHS sites under conditions of limited data availability. Eleven geological and operational criteria were grouped into reservoir quality (RQ), seal integrity (SI), and operational conditions (OC) and weighted using the Best–Worst Method (BWM), resulting in component weights of 0.520, 0.296, and 0.184, respectively. The normalised criteria were aggregated into a Geological Hydrogen Suitability Index (GHSI), which was subsequently combined with the spatial distribution of installed renewable energy (RE) capacity and proximity to high-voltage power infrastructure (DI) to derive a Total Suitability Index (TSI). Three weighting scenarios representing geological, balanced, and energy–infrastructure priorities were analysed. The framework was applied to five candidate structures in north-western Poland: structure S4 achieved the highest GHSI (0.757), followed by structure S1 (0.699); structures S2 and S5 obtained very similar intermediate values (0.579 and 0.578, respectively); and structure S3 received the lowest score (0.505). The contrasting component profiles demonstrate that high performance in a single criterion group does not necessarily result in high overall geological suitability. The scenario analysis also showed that increasing the weights of the components relating to installed renewable energy (RE) capacity and distance from power transmission infrastructure (DI) can significantly alter the assessment, which is based primarily on geological suitability; these changes are particularly pronounced in the case of structures S4 and S5. The proposed framework provides a transparent spatial decision-support approach for preliminary regional UHS screening. Its results should be interpreted as relative suitability assessments rather than direct estimates of storage safety, capacity, injectivity, or commercial feasibility.

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.

Coal is a cheap and accessible source of energy. However, the environmental costs associated with its exploitation and combustion are increasing. Burning coal generates large amounts of carbon dioxide. A gas that is a major contributor to global climate change. Coal is a raw material used in various technologies (from energy to medicine) and is also the subject of scientific research. The directions for its use change over time. By tracing research trends related to coal, new research directions can be identified. Bibliometric analysis is used for this purpose, using a variety of data pertaining to scientific publications observed with the development of science. This method makes it possible to analyse networks of research, national and international, and to identify the internal logic of scientific development. This article aims to analyse research topics related to the word “coal” in the period covering 1950–2023. The article presents an analysis of publications indexed in the SCOPUS database. Publications that contained phrases related to search phrases containing the word “COAL” in the title, abstract, or keywords were included in the analysis. The dynamics of changes in the interest of coal researchers in subject areas, research areas, and countries were presented. On this basis, an attempt was made to identify future leading research topics related to coal and to identify limitations and barriers to the development of this research topic.

Energy, gases, and solids in underground sites are stored in mining excavations, natural caverns, salt caverns, and in the pore spaces of rock formations. Aquifer formations are mainly isolated aquifers with significant spreading, permeability, and thickness, possessing highly mineralized non-potable waters. This study discusses the most important aspects that determine the storage of natural gas, hydrogen, or carbon dioxide in deep aquifers. In particular, the selection and characterization of the structure chosen for underground storage, the storage capacity, and the safety of the process are considered. The choice of underground sites is made on the basis of the following factors and criteria: geological, technical, economic, environmental, social, political, or administrative–legal. The geological and dynamic model of the storage site is then drawn based on the characteristics of the structure. Another important factor in choosing a structure for the storage of natural gas, hydrogen, or carbon dioxide is its capacity. In addition to the type and dimensions of the structure and the petrophysical parameters of the reservoir rock, the storage capacity is influenced by the properties of the stored gases and the operating parameters of the storage facility. Underground gas storage is a process fraught with natural and technical hazards. Therefore, the geological integrity of the structure under consideration should be documented and verified. This article also presents an analysis of the location and the basic parameters of gas storage and carbon dioxide storage facilities currently operating in underground aquifers. To date, there have been no successful attempts to store hydrogen under analogous conditions. This is mainly due to the parameters of this gas, which are associated with high requirements for its storage.

Currently, there is an increasing number of research studies on underground storage of hydrogen in porous rocks (aquifers and depleted hydrocarbon fields). An important aspect of this process is the efficiency of hydrogen storage, which is defined as the correct operation of a storage facility (the ability to inject and withdraw an appropriate quantity of gas) and the safety of storage, which is influenced by numerous factors, including geological factors. With an increasing number of publications, gathering knowledge and keeping track of scientific progress is becoming increasingly complex. In addition to the technical interdependence of the parameters analysed, there are also interrelationships between scientific publications addressing issues related to underground hydrogen storage in porous rocks. The aim of this paper is to analyse the literature on hydrogen storage efficiency in porous rocks and, on the basis of the analysis, to identify the most important research trends and issues relevant to their implementation. This article presents an analysis of publications indexed in the SCOPUS database. The analysis included publications that contained expressions related to the relevant search phrases in their title, abstract or keywords. The dynamics of changes in the interest of researchers on the problem of hydrogen storage in porous rocks and the distribution of studies by geographical location (countries) are presented. Based on an analysis of the number of citations, the most influential publications were identified. Using the VOSviewer version 1.6.19 software, clusters reflecting research sub-areas were identified based on co-occurrence analysis, such as geological and reservoir aspects, reservoir engineering aspects, hydrogeological aspects and petrophysical aspects. Bibliometric methods have great potential for performing quantitative confirmation of subjectively delineated research fields and/or examining unexplored areas. The literature on underground hydrogen storage in porous rocks has been growing rapidly since at least 2018, with researchers conducting their studies in four major research streams: geological and reservoir aspects, reservoir engineering aspects, hydrogeological aspects and petrophysical aspects.

Przedmiotem badań był pokład węgla 116/2 należący do krakowskiej serii piaskowcowej Górnośląskiego Zagłębia Węglowego. Reflektogramy próbek uwzględniające wszystkie występujące w węglu macerały grupy witrynitu, zarejestrowano w postaci reflektogramów przy stadium Δ Ro zbliżonego do odchylenia standardowego oraz w zakresie standardowym. Reflektogramy witrynitu dokładniej rejestrowane ujawniają obecność 3 lub 4 wyraźnie wyodrębnionych pików. Znaczenie w ocenie stopnia uwęglenia badanego węgla przypisano wyłącznie głównemu maksimum – pik nr 4. Wykonano także pomiary średniej refleksyjności kolotelinitu wyłącznie na powierzchniach warstewek witrynu o grubości większej od 1 mm. Na szczegółowych reflektogramach ujawniły się jedynie 2 maksima. Maksima te korelują z pikami oznaczonymi jako nr 3 i 4 w reflektogramach próbek uwzględniający wszystkie macerały grupy witrynitu. Zawartość pierwiastka Cdaf w badanym węglu z KWK Janina zmienia się w przedziale od 75,9 do 77,5 %wt, natomiast w witrynie od 71,1 do 75,5 %wt. Zależność ta ma charakter regresji o charakterze wykładniczym o współczynniku korelacji r = 0,95, która może być przybliżona korelacją liniową o r = 0,94. Zbadano również siłę korelacyjną między zawartością części lotnych a współczynnikiem średniej refleksyjności w witrynitu badanego węgla. Statystycznie istotna korelacja jest silna, co wyraża współczynnik korelacji wykładniczej „r” bliski wartości 0,99 i liniowe jej przybliżenie o wartości współczynnika korelacji r = 0,98. Nie stwierdzono natomiast korelacji pomiędzy pomierzonymi wartościami refleksyjności a współczynnikiem GI obliczonym dla badanych próbek.

The earliest studies of the Moon consisted of observations from Earth and meteorites containing lunar material. As technology progressed, the observations were made using remote sensing techniques. The next stage of the Moon reconnaissance consisted of unmanned flights, and later manned flights, with the help of which, in-situ tests were performed. The obtained materials enable the formulation of conclusions both about the geological structure and the mineral resources of the moon. The latest maps provided by the United States Geological Survey (USGS) and NASA Planetary Data System (PDS) enable a detailed analysis of the geological structure of the moon. Since they are available in shapefile format for QGIS and ArcGIS software, they can be freely modified and processed. On the basis of these, it is possible to analyze the complexity of the geological structure of the moon, especially with regard to the structure of its substrate and the surface covered with craters. Data obtained from the observation of the Moon with the use of research satellites and research carried out during landings related to the collection of samples enabled the formulation of conclusions about the raw materials present there. These raw materials are related to the surface layer of the so-called regolith, the recognition of which is relatively good because it is based not only on remote studies but also on the basis of collected samples. Additionally, there are indications of the possible presence of mineral resources related to the substrate, but its recognition is relatively poor because it is based on remote and geophysical surveys. The presented analysis shows that the Moon has such minerals as rare earth elements (REE) and Th and U found in the KREEP area. Fe and Ti are found to be in basaltic lava flows occurring in the mares and aluminum, silicon and Helium-3 occur in the regolith.

In coal seams, depending on the composition of coal macerals, rank of coal, burial history, and migration of thermogenic and/or biogenic gas. In one ton of coal 1 to 25 m³ of methane can be accumulated. Accumulation of this gas is included in unconventional deposits. Exploitation of methane from coal seams is carried out with wells from mining excavations (during mining operations), wells drilled to abandoned coal mines, and wells from the surface to unexploited coal seams. Due to the low permeability of the coal matrix, hydraulic fracturing is also commonly used. Operations related to exploration (drilling works) and exploitation of methane from coal seams were analyzed. The preliminary analysis of the environmental threats associated with the exploration and exploitation of coalbed methane has made it possible to identify types of risks that affect the environment in various ways. The environmental risks were estimated as the product of the probability weightings of adverse events occurring and weightings of consequences. Drilling operations and coalbed methane (CBM) exploitation leads to environmental risks, for which the risk category falls within the controlled and accepted range.

In this paper, we discuss the impact of the rank of coal, petrographic composition, and physico-chemical coal properties on the release and composition of syngas during coal gasification in a CO₂ atmosphere. This study used humic coals (parabituminous to anthracite) and lithotypes (bright coal and dull coal). Gasification was performed at temperatures between 600 and 1100 °C. It was found that the gas release depends on the temperature and rank of coal, and the reactivity increases with the increasing rank of coal. It was shown that the coal lithotype does not affect the gas composition or the process. Until 900 °C, the most intense processes were observed for higher rank coals. Above 1000 °C, the most reactive coals had a vitrinite reflectance of 0.5–0.6%. It was confirmed that the gasification of low-rank coal should be performed at temperatures above 1000 °C, and the reactivity of coal depends on the petrographic composition and physico-chemical features. It was shown that inertinite has a negative impact on the H₂ content; at 950 °C, the increase in H₂ depends on the rank of coal and vitrinite content. The physicochemical properties of coal rely on the content of maceral groups and the rank of coal. An improved understanding these relationships will allow the optimal selection of coal for gasification.

The new boreholes drilled between 2009 and 2012 enabled a detailed exploration of the profile of the Kraków sandstone series in the Dąb area between the “Sobieski” and “Janina” mining plants, USCB (Upper Silesian Coal Basin). The core from the No. 111. bituminous coal seam was selected for further analysis. 30 intervals corresponding to the defined lithotypes were separated in the seam with a thickness of 116.8 cm. The thickness of lithotypes ranges from 10 mm to 89 mm. A microprofile of the examined seam was made using the modified method of determining microlithotypes. A quantitative determination of the maceral composition was performed for each interval corresponding to the separated lithotypes. This allowed petrographic and facies characteristics of the seam to be determined. Its lower part is dominated by lithotypes with a large share of bright coal – vitrain coal. This section of the profile was formed under conditions of a strongly flooded wet forest swamp. In the upper section of the seam, a higher macroscopic share of dull coal – durain was observed. The microscopic analysis has shown that the conditions dominant during the formation of this section were typical for swamp forest peats. New technologies also require expanding knowledge about the structure of coal seams. This is only possible with a detailed profiling of the coal seam on a macro scale combined with micro-profiling and a detailed petrographic description of the isolated lithotypes. This methodology is also useful in the facies analysis of bituminous coal seams.