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The topic of this paper concerns energy-related carbon dioxide emission factors from the combustion of gaseous methane fuels. It is a very current subject, as methane fuels, mainly of fossil origin, are one of the primary energy carriers used in industrial and municipal applications for energy purposes. Consequently, the emitted carbon dioxide contributes to the intensification of the greenhouse effect in the atmosphere. The problem of the quantities characterising emissions from the combustion of methane fuels is complicated by the diversity of these fuels. This paper presents background information on the gaseous hydrocarbon fuels and the composition of the main types of natural gas. The structure of natural gas consumption in Poland, depending on the sectors of application for particular types of natural gas, is presented. On the basis of the existing data, aggregated energy-related carbon dioxide emission factors were estimated and analysed. The analysis was carried out for high-methane natural gas (HM), colliery gas (CG) and nitrified natural gas (N)—for the years 1988–2021. Trends in fuel consumption and energy-related carbon dioxide emission factors were determined for the years 1988–2021. [ABSTRACT FROM AUTHOR]

The synthesis of methane from hydrogen and carbon dioxide creates an energy resource that is suitable for long-term storage. Once this process is powered by renewable electricity, it produces a clean fuel for producing electricity and heat and supports large-scale renewable energy deployment, energy transition and climate change mitigation. This paper proposes a pragmatic approach to assessing the economic potential of synthetic methane-based power. Today, natural gas plays an important role in the Baltic region due to the existing infrastructure, which includes a transmission and distribution pipeline network, gas power plants and a large underground storage reservoir. Replacing natural gas with synthetic methane would fulfil carbon emission reduction ambitions. In this paper, we simulate electricity producers' actions at market conditions and consider the generation portfolio in the Baltics and the interconnections with Scandinavia and Poland operating in the NORDPOOL electricity market. As a result of these calculations, we obtain the volume of the synthetic gas, the production costs, the volume of gas storage, the installed capacity of the gas power plant, and the investments required to ensure energy transition and system adequacy. These results are essential for the informed decisions made by policymakers, investors and system operators. [ABSTRACT FROM AUTHOR]

The geomechanical modeling turned out to be an essential component of the hydrocarbon exploration assisting reduction of risk of drilling issues and optimization of hydraulic fracturing treatment. This study provides a workflow of critically stressed fracture (CSF) analysis dedicated for coal layers. The main focus of the paper is applying the 1D mechanical models and following modelling of hydraulic fracturing treatment to describe the fracture behavior under the impact of the stresses at the wellbore scale. Another objective of presented study is demonstration of benefits of 1D and 3D CSF analysis to understand fracture contribution to gained volume of hydrocarbon after fracturing of coal seam. Interpretation of fracture orientation and their behavior is vital to effective development of coal bed methane (CBM) resources as the CSF can be responsible for considerable part of CBM production. Natural fractures and faults contribute to fluid flow through rock. It is often noted that natural fractures may not be critically stressed at ambient stress state. However, during stimulation the optimally oriented natural fracture sets have an inclination to become critically stressed. Hence, understanding of the recent stress state and fracture orientations is significant for well planning and fracturing design. The outcome of this study are comprehensive 1D mechanical Earth models (MEMs) for analyzed wells and explanation of behavior of identified CSF under variable stress state as well as understanding of the connectivity of natural fractures within zone subjected to fracturing treatment. [ABSTRACT FROM AUTHOR]

Background: Increasing the efficiency of the biogas production process is possible by modifying the technological installations of the biogas plant. In this study, specific solutions based on a mathematical model that lead to favorable results were proposed. Three configurations were considered: classical anaerobic digestion (AD) and its two modifications, two-phase AD (TPAD) and autogenerative high-pressure digestion (AHPD). The model has been validated based on measurements from a biogas plant located in Poland. Afterward, the TPAD and AHPD concepts were numerically tested for the same volume and feeding conditions. Results: The TPAD system increased the overall biogas production from 9.06 to 9.59%, depending on the feedstock composition, while the content of methane was slightly lower in the whole production chain. On the other hand, the AHPD provided the best purity of the produced fuel, in which a methane content value of 82.13% was reached. At the same time, the overpressure leads to a decrease of around 7.5% in the volumetric production efficiency. The study indicated that the dilution of maize silage with pig manure, instead of water, can have significant benefits in the selected configurations. The content of pig slurry strengthens the impact of the selected process modifications—in the first case, by increasing the production efficiency, and in the second, by improving the methane content in the biogas. Conclusions: The proposed mathematical model of the AD process proved to be a valuable tool for the description and design of biogas plant. The analysis shows that the overall impact of the presented process modifications is mutually opposite. The feedstock composition has a moderate and unsteady impact on the production profile, in the tested modifications. The dilution with pig manure, instead of water, leads to a slightly better efficiency in the classical configuration. For the TPAD process, the trend is very similar, but the AHPD biogas plant indicates a reverse tendency. Overall, the recommendation from this article is to use the AHPD concept if the composition of the biogas is the most important. In the case in which the performance is the most important factor, it is favorable to use the TPAD configuration. [ABSTRACT FROM AUTHOR]

Increasing emissions from mining areas and a high global warming potential of methane have caused gas management to become a vital challenge. At the same time, it provides the opportunity to obtain economic benefits. In addition, the use of combined heat and power (CHP) in the case of coalbed methane combustion enables much more efficient use of this fuel. The article analyses the possibility of electricity production using gas engines fueled with methane captured from the Budryk coal mine in Poland. The basic issue concerning the energy production from coalbed methane is the continuity of supply, which is to ensure the required amount and concentration of the gas mixture for combustion. Hence, the reliability of supply for electricity production is of key importance. The analysis included the basic characterization of both the daily and annual methane capture by the mine's methane drainage system, as well as the development of predictive models to determine electricity production based on hourly capture and time parameters. To forecast electricity production, predictive models that are based on five parameters have been adopted. Models were prepared based on three time variables, i.e., month, day, hour, and two values from the gas drainage system-capture and concentration of the methane. For this purpose, artificial neural networks with different properties were tested. The developed models have a high value of correlation coefficient. but showed deviations concerning the very low values persisting for a short time. The study shows that electricity production forecasting is possible, but it requires data on many variables that directly affect the production capacity of the system. [ABSTRACT FROM AUTHOR]

Every year the interest in biofuels, including biomethane, grows in Poland. Biomethane, obtained from biogas, is widely used in the Polish economy; the most important two applications are as gas injected into the gas grid and as automotive fuel. The aim of this work is to determine the potential for the development of the biomethane sector in Poland. The following article presents the technological stages of biomethane extraction and purification. The investment process for biogas/biomethane installation is presented in the form of a Gannt chart; this process is extremely long in Poland, with a duration of three years. In the coming months, the Polish Oil Mining and Gas Extraction will begin to invest in biomethane, which will be connected to the gas grid, while the Polish oil refiner and petrol retailer, Orlen, will invest in biomethane to be used as automotive fuel. This article includes a SWOT (Strengths, Weaknesses, Opportunities, Threats) and PEST (Political, Economic, Social, Technological) analysis of the biogas/biomethane sector in Poland. The main barriers to the development of the biogas/biomethane sector in Poland are high investment costs, long lead times and a strong conventional energy lobby. The most important advantages of biogas/biomethane technology in Poland include environmental aspects, high biomethane potential and well-developed agriculture. The development of biogas/biomethane technology in Poland will slowly reduce environmental pollution, reduce carbon dioxide emissions and allow for partial independence from the importing of natural gas. [ABSTRACT FROM AUTHOR]

• The ratio of the CH 4 production paths in freshwater sediments changes with depth. • The quality of organic matter is main controlling factor of the CH 4 production pathways. • The incompletely degraded organic matter favours hydrogenotrophic methanogenesis. • Higher contents of labile organic matter favours acetoclastic methanogenesis. The paper presents the research results on methane production (CH 4) pathways in freshwater sediments of the Nielisz Reservoir located in south-eastern Poland. The research was performed in spring, summer and autumn 2018 at four research stations located along the reservoir and in three sediments layers: 0–5 cm, 5–10 cm and 10–15 cm. The values of δ13C-CH 4 in pore water, the fractionation coefficient α CH4-CO2 , and the δ13C isotope mass balance of pore water CH 4 and CO 2 were used to determine the temporal and spatial changes of CH 4 production pathways. The obtained values of δ13C-CH 4 in the pore water of the Nielisz Reservoir ranged from −68.40‰ to −50.87‰, the α CH4-CO2 values varied from 1.04 to 1.07, and the calculated contributions of hydrogenotrophic methanogenesis in the total production of CH 4 (f CH4,h) ranged from 7% to 85%. These values varied depending on the research station and the sediment layer studied. During the entire study period, both acetate and hydrogenotrophic methanogenesis participated in CH 4 and the contribution of hydrogenotrophic methanogenesis increases in the deeper layers of sediment and in the autumn season. The main controlling factor of CH 4 production pathways in sediments is the qualitative composition of organic matter (content of labile organic matter and humic substances). [ABSTRACT FROM AUTHOR]

An attempt was made to estimate the annual production of CH4 at a municipal waste landfill site in Poland. As a matter of fact, the extent of the unorganized emission of CH4 from the landfill surface was approached based on the adopted mathematical model. The Ward agglomeration method for cluster analysis and the Pearson coefficient were employed to evaluate the distance-based similarity measure and to optimize methods for estimating methane emissions from a landfill as well as to verify the input parameters for the model. In order to calculate the content of biodegradable organic parts in the waste, morphological tests of the landfilled waste were performed. Physical quantities, measurements and the actual amount of the landfilled waste as well as the volume of CH4 neutralized in a collective flare were implemented in the model, respectively. The model-based findings and experimental outcome demonstrated stable gas production in the landfill with a high CH4 content. On the other hand, a rather low efficiency of the landfill passive degassing installation indicated the necessity to design and develop its active counterpart with the prospective application of the generated biogas for energy production in a cogeneration system. [ABSTRACT FROM AUTHOR]

During the extraction of hard coal in Polish conditions, methane is emitted, which is referred to as 'mine gas'. As a result of the desorption of methane, a greenhouse gas is released from coal seams. In order to reduce atmospheric emissions, methane from coal seams is captured by a methane drainage system. On the other hand, methane, which has been separated into underground mining excavations, is discharged into the atmosphere with a stream of ventilation air. For many years, Polish hard coal mines have been capturing methane to ensure the safety of the crew and the continuity of mining operations. As a greenhouse gas, methane has a significant potential, as it is more effective at absorbing and re-emitting radiation than carbon dioxide. The increase in the amount of methane in the atmosphere is a significant factor influencing global warming, however, it is not as strong as the increase in carbon dioxide. Therefore, in Polish mines, the methane–air mixture captured in the methane drainage system is not emitted to the atmosphere, but burned as fuel in systems, including cogeneration systems, to generate electricity, heat and cold. However, in order for such use to be possible, the methane–air mixture must meet appropriate quality and quantity requirements. The article presents an analysis of changes in selected parameters of the captured methane–air mixture from one of the hard coal mines in the Upper Silesian Coal Basin in Poland. The paper analyses the changes in concentration and size of the captured methane stream through the methane capturing system. The gas captured by the methane drainage system, as an energy source, can be used in cogeneration, when the methane concentration is greater than 40%. Considering the variability of CH4 concentration in the captured mixture, it was also indicated which pure methane stream must be added to the gas mixture in order for this gas to be used as a fuel for gas engines. The balance of power of produced electric energy in gas engines is presented. Possible solutions ensuring constant concentration of the captured methane–air mixture are also presented. [ABSTRACT FROM AUTHOR]