Natural Gas Research Articles

Estimating Greenhouse Gas Emissions from Hydrogen-Blended Natural Gas Networks

Methane is a significant contributor to anthropogenic greenhouse gas emissions. Blending hydrogen with natural gas in existing networks presents a promising strategy to reduce these emissions and support the transition to a carbon-neutral energy system. However, hydrogen’s potential for atmospheric release raises safety and environmental concerns, necessitating an assessment of its impact on methane emissions and leakage behavior. This study introduces a methodology for estimating how fugitive emissions change when a natural gas network is shifted to a 10% hydrogen blend by combining analytical flowrate models with data from sampled leaks across a natural gas network. The methodology involves developing conversion factors based on existing methane emission rates to predict corresponding hydrogen emissions across different sections of the network, including mainlines, service lines, and facilities. Our findings reveal that while the overall volumetric emission rates increase by 5.67% on the mainlines and 3.04% on the service lines, primarily due to hydrogen’s lower density, methane emissions decrease by 5.95% on the mainlines and 8.28% on the service lines. However, when considering the impact of a 10% hydrogen blend on the Global Warming Potential, the net reduction in greenhouse gas emissions is 5.37% for the mainlines and 7.72% for the service lines. This work bridges the gap between research on hydrogen leakage and network readiness, which traditionally focuses on safety, and environmental sustainability studies on methane emission.

Decarbonization potential of fuel cell technologies in micro-cogeneration applications: spotlight on SOFCs in a Belgian case study

Abstract There is a plethora of fuel cell technologies, many of which hold great promise in terms of their decarbonization potential, which this paper aims to explore. In fact, this paper discusses the only two existing technologies on the market, Polymer Exchange Membrane Fuel Cells (PEMFCs) and Solid Oxide Fuel Cells (SOFCs). Unfortunately, these commercial systems mainly use natural gas as primary fuel due to its cost and practicality (easy transport and storage, existing infrastructures, etc.). Using Belgium as a case study, this paper shows that their GHG mitigation potential remains rather insignificant compared to the average individual carbon footprint if their fuel is not decarbonised. Even so, their mitigation potential would still be far from sufficient, and other measures, including behavioural changes, would still need to be implemented. Nevertheless, some emerging fuel cell technologies, such as Direct Carbon Solid Oxide Fuel Cells (DC-SOFCs) or Direct Formic Acid Fuel Cells (DFAFCs), offer the possibility of facilitating pure CO2 capture at their anode outlet, thus allowing for potential negative emissions. Using a case study of the electricity demand of an average Belgian home (with two adults) supplied by an efficient biomass-fuelled DC-SOFC, this paper shows that these negative emissions could be up to about 4 tCO2eq/year. By comparison, the IPCC's Sixth Assessment Report estimated the emissions footprint that could never be mitigated, even with future net-zero CO2 emissions, to be 1 tCO2eq/year per capita, implying that climate neutrality will require similar levels of carbon sequestration. In populous Western countries, natural carbon sinks are unlikely to be sufficient, and the potential negative emissions of emerging fuel cell technologies will be welcome.

Thermal efficiency dataset around Cuban seas (TEDACS)

Currently, the generation of electrical energy in Cuba is supported by oil and natural gas. These sources, as it is known, are directly linked to large emissions of pollutants that are released into the environment. Therefore, it is necessary to search for new energy options that are directed towards sustainable development, allowing the preservation of natural ecosystems. Owing to the location and geographical characteristics of Cuba, it is necessary to assess the energy possibilities of the seas that surround it and to search for the most feasible areas to obtain energy from the sea temperature. This renewable energy source, in addition to being used to generate electricity, can also be used in derived technologies, such as desalination, refrigeration, and aquaculture. Hence, a dataset is presented with the calculation of the Carnot thermal efficiency for the exploitation of thermal energy from the sea, which is based on the thermal gradient between the sea potential temperatures between the shore and the level of depth being analyzed. Outputs of 27 years of daily data from the Copernicus Marine Environmental Monitoring Service (CMEMS) GLOBAL_MULTIYEAR_PHY_001_030 product with a spatial resolution of 1/12° were used. The calculation was made using a Python script of the daily thermal efficiency at depths of 763, 902, and 1062 m, these depths belong to the depth levels of the model output data used according to the depth ranges that traditionally are studied for the exploitation of sea thermal energy. In this way, 27 files of each level were generated for a total of 81 files in text format separated by commas. Each file is presented with the date, level, coordinates, and thermal efficiency. The dataset is available from the Science Data Bank repository (https://doi.org/10.57760/sciencedb.10037).

Study on the mechanism and characteristics of pulsed corona discharge in water

Abstract Plasma pulse is a safe and environmentally friendly unconventional technology for enhancing
oil and gas production. However, during the pulsed discharge process, an abnormal discharge
phenomenon often occurs, which severely affects the performance of the equipment and is
referred to as corona discharge. This paper combines laboratory discharge test data to
theoretically analyze and validate through Comsol simulation the mechanism of corona
discharge generation under the same electrode gap distance. A comparative analysis with arc
discharge is also conducted to further examine its characteristics, and nonlinear regression
analysis is used to study the impedance variation of the plasma channel during corona
discharge. Results indicate that the decrease in switch breakdown voltage in the later stages of
continuous discharge leads to the generation of corona discharge. The impedance of the
plasma channel can be characterized by a time-varying resistance model based on a double
exponential function. Finally, validation through theoretical calculations and Simulink
simulations achieves a fitting rate of over 99%. The research provides significant guidance
for further analysis of corona discharge and the development of suppression methods in
plasma pulse technology, contributing to the optimization of the equipment and enhancing its
operational performance.

Digital and technological modernization of the world's largest West Siberian oil and gas production center

The article examines the results of digital and technological modernization of the oil and gas industry within the framework of the state program "Digital Economy 2017-2024" in the implementation of measures proposed by academic institutes of the Russian Academy of Sciences on the basis of a comprehensive scientific and technical program of a full innovation cycle, as well as the potential of exploratory and applied research to prepare a new state program "Data Economy" for the period up to 2030 of the year. The activities are a set of interrelated scientific, technical, digital solutions and innovative technologies that ensure the achievement of goals, developed with the leading participation of the Institute of Oil and Gas Problems of the Russian Academy of Sciences and the Institute of Oil and Gas Geology and Geophysics named after. A. A. Trofimuk SB RAS, program “Digital and technological modernization of the world’s largest West Siberian oil and gas production center.” The main goal of scientific research for the oil and gas economy of big geodata is the creation and implementation of digital modeling technologies, the development of ecosystems, computing platforms and digital twins of oil and gas assets, and the transportation of hydrocarbons to existing and newly created petrochemical clusters in order to develop the domestic market for their complete processing into products with high added value and strengthening the digital leadership of Russian energy companies. The key factor hindering the innovative development of the Russian oil and gas complex is the lack of high-performance computing systems. The main oil and gas tasks that require the involvement of supercomputers with peta- and exascale performance levels (1015 and 1018 floating point operations per second, respectively) include the tasks of managing the “digital ecosystem” of the world’s largest West Siberian oil and gas production center and unique oil and gas fields in the real time. The development of the digital ecosystem is proposed to be formed on the basis of platform solutions and comprehensive scientific and technical programs and projects of a full innovation cycle. The main problems in the sphere of creating a digital energy economy of big data have been identified: an acute shortage of personnel with digital competencies in the field of oil and gas production, specialists in opticalization, multisensorization, supercomputing, cybersecurity and petrorobotics.

A Novel System for Simultaneous Real-Time Determination of 15N-Enriched Ammonia, Hydroxylamine, Nitrite, and Nitrate.

Ammonium (NH4+), hydroxylamine (NH2OH), nitrite (NO2-), and nitrate (NO3-) account for the most important reactive nitrogen (N) species in the N cycle, playing a key role in N elimination and N retention, as well as the production of nitrogenous trace gases. However, it is still challenging to fulfill simultaneous real-time determination of all four N compounds enriched in 15N. This study successfully established a novel system by coupling an automatic simultaneous sample preparation unit to a membrane inlet mass spectrometer (4n-ASSP-MIMS) for rapid online 15N fraction analysis of all four key compounds in the N cycle. The limit of detection (LOD) was 20.22, 0.38, 0.17, and 0.25 μM for NH4+, NH2OH, NO2-, and NO3-, respectively, and relative error for 15N fraction determination was within 5% when 15N enrichment was higher than 5 atom %. This 4n-ASSP-MIMS system provides a first online analytical tool to capture the real-time isotopic signals during biogeochemical transformations of NH4+, NH2OH, NO2-, and NO3-, using the 15N tracing technique. Application of this system will dramatically advance our understanding of mechanisms involved in the N cycle.

Soil microbiome interventions for carbon sequestration and climate mitigation.

Mitigating climate change in soil ecosystems involves complex plant and microbial processes regulating carbon pools and flows. Here, we advocate for the use of soil microbiome interventions to help increase soil carbon stocks and curb greenhouse gas emissions from managed soils. Direct interventions include the introduction of microbial strains, consortia, phage, and soil transplants, whereas indirect interventions include managing soil conditions or additives to modulate community composition or its activities. Approaches to increase soil carbon stocks using microbially catalyzed processes include increasing carbon inputs from plants, promoting soil organic matter (SOM) formation, and reducing SOM turnover and production of diverse greenhouse gases. Marginal or degraded soils may provide the greatest opportunities for enhancing global soil carbon stocks. Among the many knowledge gaps in this field, crucial gaps include the processes influencing the transformation of plant-derived soil carbon inputs into SOM and the identity of the microbes and microbial activities impacting this transformation. As a critical step forward, we encourage broadening the current widespread screening of potentially beneficial soil microorganisms to encompass functions relevant to stimulating soil carbon stocks. Moreover, in developing these interventions, we must consider the potential ecological ramifications and uncertainties, such as incurred by the widespread introduction of homogenous inoculants and consortia, and the need for site-specificity given the extreme variation among soil habitats. Incentivization and implementation at large spatial scales could effectively harness increases in soil carbon stocks, helping to mitigate the impacts of climate change.

Basic Theory and Applications of Oil and Gas Pipeline Non-Destructive Testing Methods

In recent years, with the increasing construction mileage of oil and gas pipelines (OGPs), the aging problem of OGPs has become increasingly prominent, so, ensuring the safety of OGPs is of great significance. In addition, the safety of OGP transportation is also an important component of pipeline integrity. Therefore, to ensure the safety of OGP transportation, regular OGP inspections should be carried out. During this process, defects in the OGP and measured wall thickness information should be recorded to provide a basis for subsequent pipeline repair or replacement. This study analyzes the literature on pipeline testing and reviews approximately eighty articles. Based on these articles, we summarize the types of common OGP defects and review the basic principles of various non-destructive testing methods for pipelines, including electromagnetic acoustic transducer inspection, magnetic flux leakage testing, ultrasonic testing, and eddy current testing. We also provide a detailed introduction to the applications and innovative testing methods based on the above OGP inspection methods. Finally, an analysis and outlook on the future research focus of OGP inspection technology are presented. This research suggests that different detection methods should be used for different types of defects, such as using the magnetic leakage method for the internal detection of natural gas pipelines.

Methodology and uncertainty estimation for measurements of methane leakage in a manufactured house

Abstract. Methane emissions from natural gas appliances and infrastructure within buildings have historically not been captured in greenhouse gas inventories, leading to under-estimates, especially in urban areas. Recent measurements of these post-meter emissions have indicated non-negligible emissions within residences, with impacts on both indoor air quality and climate. As a result, methane losses from residential buildings have been included in the latest US national inventory, with emission factors determined from a single study of homes in California. To facilitate future additional studies investigating building methane emissions, we conducted a controlled experiment to document a methodology for such measurements and estimated associated uncertainties. We determined whole-house methane emission rates with a mass balance approach using near-simultaneous measurements of indoor and outdoor methane mole fractions at a manufactured house. We quantified the uncertainty in whole-house methane emission rates by varying the forced outdoor air ventilation rate of the manufactured house, measuring the outdoor air change rate using both sulfur hexafluoride and carbon dioxide tracers, and performing methane injections at prescribed rates. We found that the whole-house quiescent methane emission rate (i.e., emission rate when all gas appliances were off) in the manufactured house averaged 0.33 g d−1 with methodological errors in the calculated emission rates of approximately 19 % (root-mean-square deviation). We also measured the quiescent leakage from the manufactured house over 3 months to find 26 % (1σ) variability in emissions over two seasons. Our findings can be used to inform plans for future studies quantifying indoor methane losses downstream of residential meters using similar methods. Such quantification studies are sorely needed to better understand building methane emissions and their drivers to inform inventories and plan mitigation strategies.

Improved Method for Methane Pyrolysis Rate Measurement using Molten Metal Catalysts for Turquoise Hydrogen Production

Abstract To develop low-$$\hbox {CO}_2$$ CO 2 emission ferrous metallurgical process, $$\hbox {H}_2$$ H 2 -based ironmaking processes are being actively developed. Several technologies are being developed to provide a sufficient mass of $$\hbox {H}_2$$ H 2 in an environmentally friendly manner. One of such processes is “turquoise” $$\hbox {H}_2$$ H 2 , based on a natural gas pyrolysis such as $$\hbox {CH}_4$$ CH 4 (g) $$\rightarrow $$ → 2$$\hbox {H}_2$$ H 2 (g) + C(s), thereby minimizing $$\hbox {CO}_2$$ CO 2 emission. The reaction could be catalyzed using molten metals in a bubble column reactor. Therefore, the selection of the molten metal catalyst is important for enhancing the reaction efficiency and for minimizing the production cost. In the previous research of the present authors, a new methodology for the pyrolysis rate measurement was introduced by employing an electromagnetic levitation heating of catalytic molten metals followed by quadrupole mass spectrometer (QMS) analysis to assist in the selection of the catalyst metal. However, a potential source of error in this technique was identified. Therefore, two modifications of the methodology are reported in the present study: (1) changing the heating and feed gas supply patterns and (2) gas analysis technique from QMS to Gas Chromatography (GC). Accordingly, the reported pyrolysis rate of pure In, Ga, Bi, Sn, and Cu of the previous study was revised in the present study. It was revealed that Ga and In emitted non-negligible amounts of $$\hbox {H}_2$$ H 2 upon heating, even without the fuel gas ($$\hbox {CH}_4$$ CH 4 ). This was regarded as a noise in the $$\hbox {H}_2$$ H 2 signal measured by GC. On the other hand, Cu, Sn, and Bi did not show the noticeable $$\hbox {H}_2$$ H 2 (noise). The modified method provides $$\hbox {H}_2$$ H 2 production rate by the pyrolysis, by separating the noise in the regime of the chemical reaction control at the surface of the molten metals. $$1^\text {st}$$ 1 st -order reaction was confirmed. Graphical Abstract

Thermodynamic integration in combined fuel and power plants producing low carbon hydrogen and power with CCUS

Demand for low-carbon sources of hydrogen and power is expected to rise dramatically in the coming years. Individually, steam methane reformers (SMRs) and combined cycle gas power plants (CCGTs), when combined with carbon capture utilisation and storage (CCUS), can produce large quantities of on-demand decarbonised hydrogen and power respectively. The ongoing trend towards the development of CCUS clusters means that both processes may operate in close proximity, taking advantage of a common infrastructure for natural gas supply, electricity grid connection and the CO2 transport and storage network. This work improves on a previously described novel integration process, which utilizes flue gas sequential combustion to incorporate the SMR process into the CCGT cycle in a single “combined fuel and power” (CFP) plant, by increasing the level of thermodynamic integration through the merger of the steam cycles and a redesign of the heat recovery system. This increases the 2nd law thermal efficiency by 2.6% points over un-integrated processes and 1.9% points the previous integration design. Using a conventional 35% wt. monoethanolamine (MEA) CO2 capture process designed to achieve two distinct and previously unexplored CO2 capture fractions; 95% gross and, 100% fossil (CO2 generated is equal to the quantity of CO2 captured). The CFP configuration reduces the overall quantity of flue gas to be processed by 36%–37% and increases the average CO2 concentration of the flue gas to be treated from 9.9% to 14.4% (wet). This decreases the absorber packing volume requirements by 41%–56% and decreases the specific reboiler duty by 5.5% from 3.46–3.67 GJ/tCO2 to 3.27–3.46 GJ/tCO2, further increasing the 2nd law thermal efficiency gains to 3.8%–4.4% points over the un-integrated case. A first of a kind techno economic analysis concludes that the improvements present in a CO2 abated CFP plant results in a 15.1%–17.3% and 7.6%–8.0% decrease in capital and operational expenditure respectively for the CO2 capture cases. This translates to an increase in the internal rate of return over the base hurdle rate of 7.5%–7.8%, highlighting the potential for substantial cost reductions presented by the CFP configuration.

Sijunzi San alleviates the negative energy balance in postpartum dairy cows by regulating rumen fermentation capacity

IntroductionPostpartum dairy cows are susceptible to negative energy balance caused by decreased feed intake and the initiation of lactation. Sijunzi San, a famous Chinese traditional herbal formulation, can promote gastrointestinal digestion and absorption and improve disorders of intestinal microbiota. Therefore, we hypothesized that Sijunzi San might alleviate negative energy balance in postpartum dairy cows by modulating the structure of the rumen microbiota and enhancing its fermentation capacity.MethodsLiquid chromatography-mass spectrometry (LC–MS/MS) was utilized in vitro to identify the main active ingredients in the Sijunzi San. Techniques including in vitro ruminal fermentation, gas chromatography, and 16S rRNA high-throughput sequencing were employed to evaluate their effects on the structure of the rumen microbiota. To test their in vivo effects, sixteen postpartum Holstein dairy cows, with similar body condition and parity, were randomly assigned to two groups, with 8 cows per group. The CONT group was fed a basic diet, while the SJZS group received an additional 300 g/d of Sijunzi San along with the basic diet, continuously for 7 days. ELISA and untargeted metabolomics using ultra-high-performance liquid chromatography-tandem mass (UHPLC–MS/MS) were employed to assess the impacts on immunoglobulin levels, fat mobilization, and the blood metabolome in postpartum dairy cows.ResultsDoses of 100 to 500 mg of the Sijunzi San significantly enhanced gas production, microbial protein (MCP), and short-chain fatty acid (SCFA) levels, while notably reducing pH and NH3-N content (p < 0.05), exhibiting a significant dose-dependent relationship. The results revealed that 500 mg of the prescription significantly increased the abundances of the Succiniclasticum and Prevotella genera and notably decreased the abundances of the Christensenellaceae_R-7_group, Muribaculaceae, UCG-005, Comamonas, and F082 genera (p < 0.05). Succiniclasticum and Prevotella showed a significant positive correlation with ruminal SCFAs, whereas UCG-005 exhibited a significant negative correlation with them (p < 0.05). Additionally, Luteolin and Glycitein were significantly positively correlated with Prevotella, while Licochalcone B and Liquoric acid were significantly negatively correlated with Comamonas (p < 0.05). Subsequently, the prescription significantly increased the concentrations of IgA, IgM, and microsomal triglyceride transfer protein (MTTP) in the blood (p < 0.01), while reducing the levels of ketones (KET) (p < 0.05), non-esterified fatty acids (NEFA), and triglycerides (TG) (p < 0.01). Notable alterations were observed in 21 metabolites in the blood metabolome (p < 0.05). Additionally, metabolic pathways associated with linoleic acid metabolism and steroid hormone biosynthesis were significantly affected.DiscussionThe findings suggest that administering Sijunzi San to dairy cows during the postpartum period can ameliorate negative energy balance by stimulating rumen fermentation and modifying the composition and abundance of the rumen microbiota.

Green Hydrogen Blending into the Tunisian Natural Gas Distributing System

It is likely that blending hydrogen into natural gas grids could contribute to economy-wide decarbonization while retaining some of the benefits that natural gas networks offer energy systems. Hydrogen injection into existing natural gas infrastructure is recognised as a key solution for energy storage during periods of low electricity demand or high variable renewable energy penetration. In this scenario, natural gas networks provide an energy vector parallel to the electricity grid, offering additional energy transmission capacity and inherent storage capabilities. By incorporating green hydrogen into the NG network, it becomes feasible to (i) address the current energy crisis, (ii) reduce the carbon intensity of the gas grid, and (iii) promote sector coupling through the utilisation of various renewable energy sources. This study gives an overview of various interchangeability indicators and investigates the permissible ratios for hydrogen blending with two types of natural gas distributed in Tunisia (ANG and MNG). Additionally, it examines the impact of hydrogen injection on energy content variation and various combustion parameters. It is confirmed by the data that ANG and MNG can withstand a maximum hydrogen blend of up to 20%. The article’s conclusion emphasises the significance of evaluating infrastructure and safety standards related to Tunisia’s natural gas network and suggests more experimental testing of the findings. This research marks a critical step towards unlocking the potential of green hydrogen in Tunisia.

Green villages by Wind + Solar + Hydrogen

This paper describes 5 steps on the move to cost-effective green villages, powered mainly by Solar, Wind and Hydrogen. In Britain, there are around 6000 villages comprising almost half the total population. These village dwellers wish to reduce their expensive energy bills, achievable by profitably going green with local Wind and Solar generation of electricity plus Hydrogen energy storage. The first step is to measure the total energy usage in the village. This defines the size of the required renewable private wire energy installations. The second step calculates savings on grid bills for electricity, natural gas and petroleum transport products, to ensure rapid payback for the renewables to be installed. A third concern is the planning permission for Wind/Solar installations that may take months to approve. Perhaps the most important requirement is to attract investment in the fourth step. Finally, the fifth step is to procure and commission the equipment needed in the village to prove that local energy can beat the present centralized grid energy systems, using Hydrogen as the vital energy storage molecule to fill gaps in Wind/Solar supply.

Assessing the Environmental Impacts of the Valorization of Creole-Antillean Avocado via an Extractive-Based Biorefinery in the Montes de María Region

In recent years, the environmental evaluation of biorefineries has become critical for ensuring sustainable practices in bio-based production systems. This study focuses on the application of the Waste Reduction (WAR) Algorithm to assess the environmental impacts of an Extractive-based Creole-Antillean Avocado Biorefinery located in Northern Colombia, aimed at producing bio-oil, chlorophyll, and biopesticide from avocado pulp, peel, and seed, respectively. The environmental impacts were evaluated using the WAR algorithm, which quantifies the potential environmental impacts (PEI) of different process streams. The following four scenarios were developed: (1) considering only waste, (2) including waste and products, (3) including waste and energy sources, and (4) incorporating waste, products, and energy consumption. This study analyzed global impacts focusing on atmospheric and toxicological categories, with a detailed assessment of the most critical scenario. The results indicated that Scenario 4 had the highest PEI, particularly in the atmospheric and toxicological categories, driven by emissions of volatile organic compounds (VOCs), greenhouse gases (GHGs), and the presence of heavy metals. However, the avocado biorefinery process demonstrated a net reduction in overall environmental impacts, with negative PEI generation rates across all scenarios, suggesting that the biorefinery transforms high-impact substances into products with lower global impact potential. Energy consumption emerged as a significant contributor to environmental impacts, particularly in acidification potential (AP) and Atmospheric Toxicity Potential (ATP). Using natural gas as an energy source had a relatively lower environmental impact compared to coal and liquid fuels, emphasizing the need to optimize energy use in biorefinery design to improve environmental performance.

A Comparative Analysis of Collaborative Models between Government and Business Entity in National Asset Management: Case Study of the Cisem-1 Gas Transmission Pipelines

Developing infrastructure for natural gas transportation requires substantial investment. The high standards of safety in its equipment material, workmanship, design, and construction methods are the reason for this. Consequently, investment in natural gas infrastructure entails significant risk when supply and demand situations are variable and immature. The Cirebon-Semarang Gas Transmission Pipeline project, awarded to Rekind in 2006, has had delays from the beginning. Following Rekind’s resignation, the Government continues the project to regard the Cisem Pipeline as strategic, capable of fostering economic and industrial growth in Java, especially in Central Java. The government utilized the APBN to assume control of the Cisem project, initiating the first phase, designated as Cisem-1, in 2022. Following the completion of the Cisem-1 project in 2023, Lemigas, as the designated asset manager and user, is required to seek a partnership with a business entity that possesses the requisite capabilities and adheres to regulations governing gas transportation operations. This study proposes alternative partnership models between the government, represented by Lemigas, and the business entity, PT Pertamina Gas (Pertagas). This study evaluates and analyzes the most suitable partnership model between Lemigas and Pertagas, taking into account operational costs to maintain affordable gas prices for customers, as well as processing time for partner selection and operatorship alignment with project timelines to ensure the MEMR that the asset is utilized and not abandoned. The KSP (Kerja Sama Pemanfaatan) of BMN (Barang Milik Negara) scheme has been identified as the most suitable option.

The Role of Hydrogen in the Energy Mix: A Scenario Analysis for Turkey Using OSeMOSYS

The urgent need to tackle climate change drives the research on new technologies to help the transition of energy systems. Hydrogen is under significant consideration by many countries as a means to reach zero-carbon goals. Turkey has also started to develop hydrogen projects. In this study, the role of hydrogen in Turkey’s energy system is assessed through energy modeling using the cost optimization analytical tool, Open Source Energy Modelling System (OSeMOSYS). The potential effects of hydrogen blending into the natural gas network in the Turkish energy system have been displayed by scenario development. The hydrogen is produced via electrolysis using renewable electricity. As a result, by using hydrogen, a significant reduction in carbon dioxide emissions was observed; however, the accumulated capital investment value increased. Furthermore, it was shown that hydrogen has the potential to reduce Turkey’s energy import dependency by decreasing natural gas demand.

Silage Quality, Aerobic Stability, Gas Production and in vitro Digestibility of Pumpkin Waste Silages

This experiment was carried out to determine the silage quality of pumpkin waste with wheat straw (S) and alfalfa hay (A). The treatment groups as follows: 1) 100% pumpkin waste (PR), 2) 80%PR and 20% A (PW80+A20), 3) 80%PW and 20%S (PW80+S20), 4) 60%PW and 40%A (PW60+A40), 5) 60%PW and 40%S (PW60+S40), 6) 80%PW+10%A+10%S (PW80+A10+S10) and 7) 60%PW + 20%A + 20%S (PW40+A20+S20). The lowest dry matter content was observed in PW group (39.0 g/kg). The crude protein ratio in the alfalfa groups were higher than those of S and PW groups. The crude cellulose was lower and NDF higher in the PW group than those of other groups and ADF was highest in the 40%S group. Water soluble carbohydrate ratio in PW and PW60+A20+S20 groups were higher than those of other groups. In the PW group, the lactic acid ratio was higher than PW80+S10+A10 group. In the PW80+S20 group the highest gas production was observed at 48th, 72nd and 96th hours. The energy values of PW group were higher than those of other groups. The aerobic stability of pumpkin silage was improved with hay addition especially alfalfa addition in 400 g/kg concentration.

CHANGES IN THE GLOBAL ENERGY SECTOR CAUSED BY RUSSIA'S WAR AGAINST UKRAINE

Problems. The Russian invasion of Ukraine, Russia's refusal to accept the planned volumes of natural gas to the countries of the European Union caused a global energy and financial crisis, and changed the movement towards the development of renewable energy. the transition to sustainable and clean energy sources has become problematic for many countries. Objective. General review and analytical analysis of trends in the development of energy consumption and the introduction of renewable sources in electric power systems in 2017-2023 using the results of research International Energy Agency (IEA), listed in World Energy Outlook (WEO) [1-6]. Methodology of implementation Trends in the development of the world system of renewable power plants to ensure climate neutrality, zero emissions, and a clean ecological environment have been analyzed for the study of the topic article. The study of changes and ways to limit the negative consequences of hostilities in Europe and the Middle East was carried out according to the long-term plans of the IEA. Results. An overview of changes in the structure of energy resources in the world energy balance is presented. It is shown that the energy crisis has led to a sharp increase in the production of fossil fuels, primarily coal and oil. The construction of new capacities for the production of 250 billion tons of liquefied gas has begun. in order to stabilize fuel prices and reduce the price of electricity. Statistical and forecast information on the structure of the world energy balance and annual electricity production by types of generation is provided. The environmental negative consequences registered for the last three years are considered: increased CO2 emissions; air pollution with fine dust; pollution of soils and water horizons; changes in climatic indicators. The problems that have arisen for the implementation of new projects for the construction of renewable sources, the development of electric power infrastructure, security and reliability of power supply are analyzed. An analysis of the proposed measures under several scenarios to increase the production and use of solar, wind and nuclear energy, reduce dependence on traditional energy sources and the prospect of zero carbon dioxide emissions by 2030 is carried out. Conclusions. Actions aimed at reducing energy consumption, projected reduction in fuel prices, planned restarts of nuclear power and further implementation of renewable power plants – these are the proposed measures that make it possible to solve the problems that have arisen around the world. Confidence in meeting the tasks is confirmed by 83 countries and the European Union to meet their commitments to achieve zero carbon dioxide emissions on time and in full. Learning from the experience and directions of development of the world energy sector will create an opportunity for the rapid restoration of the energy structure in Ukraine in the post-war period.

An Interpretation Method of Gas–Water Two-Phase Production Profile in High-Temperature and High-Pressure Vertical Wells Based on Drift-Flux Model

With the increasing demand for oil and gas, the depth of some vertical gas wells can reach 6000 m. At this time, the downhole fluid is in a state of high temperature and pressure, and interpretation of the production logging output profile faces the problem of inaccurate production calculations and difficulty judging the water-producing layer. The drift-flux model is usually used to calculate the gas–water two-phase flow. The drift-flux model is widely used to describe the two-phase flow in pipelines and wells because of its accuracy and simplicity. The constitutive correlations used in drift-flux models, which specify the relative motion between phases, have been extensively studied. However, most of the correlations are only extended by laboratory data of small pipe diameters at standard temperature and pressure and do not apply to high-temperature and high-pressure large-diameter gas wells. Therefore, we improved the distribution coefficient and drift velocity of drift-flux correlations in this study for high-temperature and high-pressure gas wells with large pipe diameters. Therefore, this study improved the distribution coefficient and drift velocity of the drift-flux correlations for high-temperature and high-pressure gas wells with large pipe diameters. In practical application, the coincidence rates of gas production and water production calculated by the new drift-flux model were 12.68% and 19.39%, respectively. For high-temperature and high-pressure deep wells, the measurement errors of production logging instruments are significant, and surface laboratory pipelines are challenging to configure and equip with actual high-temperature and high-pressure conditions. Therefore, this study used the method of numerical simulation to study the flow characteristics of the two phases of high-temperature and high-pressure gas and water to provide a basis for identifying the water layer. Combined with the proposed drift-flux correlations and the new method of determining the water-producing layer, a new method of production profile interpretation of high-temperature and high-pressure gas wells is obtained.