Unconventional Energy Sources Research Articles

A New Production Data Analysis Method of Shale Gas: Based on Flowing Material Balance Theory and Considering the Complex Flow Mechanisms of Multiple Pressure Systems

Shale gas has become one of the most important unconventional energy sources in ultra-low permeability reservoirs which has unique reservoir properties and exists in the form of free and adsorptive state in the reservoir, forming many kinds of flow mechanism. In this paper, we provide a new method for production data analysis of shale gas well based on the flowing material balance theory. This method can accurately and effectively evaluate the productivity of shale gas wells and the dropdown of formation energy. This new model divides SRV into matrix pressure system and hydraulic fracturing pressure system. Only 5 fitting parameters are needed to complete the productivity evaluation of shale gas well, and the pressure data of matrix system and hydraulic fracturing systems can be calculated by this model. Compared with the Hz Multifrac model in RTA, our model achieves better and more stable evaluation results in the application of typical production wells in many large shale gas fields, such as Fuling, Changning, Eagle Ford and Barnet.

Trend of global carbon emissions with special reference to economy, energy, finance, forest, urbanisation and trade openness: An analysis

Global warming coupled with a staggering level of greenhouse gas (GHG) emissions has pushed our planet to a brink of irreversibility. Concentration of atmospheric carbon dioxide (CO2), one of the major GHGs, today is more than ever seen in 3 million years of human history. An elaborate play of multiple factors has led us to this situation so extreme and hazardous. This paper examines the relationship between CO2 emissions and relevant factors using a multivariate linear and double-log regression model taking economic growth, energy consumption,forestcover, financial development, urbanisation and trade openness as variables across 55 countries with different levels of development. The findings indicate significant causal relationships between the factors, underlining crucial aspects that can majorly benefit climate change research and policymaking. Results emphasize the need to reverse the trend of increasing emissions while moving on to a phase of greener growth and healthier economic practices, based on unconventional energy sources and appropriate policy making.

Use of low potencial wastewater heat

The article points out that exhaustion of fossil stocks of fuel and negative impacts of fuel burning on environment determined a significant interest in technologies of heat utilization of low-potential sources in many developed countries of the world. Therefore the solution of the problem of using heat utilization technologies of low-potential sources will be of great importance for preserving people's habitats. In Russia, the most promising area of using unconventional energy sources is heat supply systems of houses and buildings. The conducted analysis shows that one of the effective directions of energy saving is heat pump systems of heat supply, using the most available low potential heat source of flooded massif of soil. It is noted that a huge energy potential of water pumped from closed mines is practically unused because of considerable distance of heat consumers from water purification complexes.

The Experimental Simulation Technology and System of Solid Fluidization Exploitation of Marine Non-Diagenetic Natural Gas Hydrate

The Experimental Simulation Technology and System of Solid Fluidization Exploitation of Marine Non-Diagenetic Natural Gas Hydrate

Exploitation Technologies of Coalbed Methane in the Qinshui Basin of China

Coalbed methane (CBM) is a new environmentally friendly unconventional energy source of great promise for exploitation. The CBM resources in the Qinshui Basin are as great as 3.97 × 1012 m3, i.e., 10.8% of the total coal gas resources of China. Compared to the main coal basins of the United States, Australia, Canada, and Russia, the Qinshui Basin is characterized by high metamorphism, high gas content, and low values of porosity and permeability, as well as by low formation pressure. The commercial exploitation of productive beds at the Qinshui Basin requires the use of efficient technologies of stimulation. Vertical wells with hydraulic fracturing (HF) predominate at the Qinshui Basin. The CO2 injection, electric pulse, multistage HF, etc. technologies are used as well.

Density functional theory calculation of structure and electronic properties in N-methane hydrate

As a clean and efficient unconventional energy source, natural gas hydrate has been highly valued and vigorously developed by many countries in recent years. In order to solve the problem that the existing hydrate structure symmetry is not high, which leads the theoretical research to be restricted, it is imperative to explore a new type of methane hydrate structure with high symmetry. Using the first-principles method which is based on the density functional theory (DFT), the structure and electronic properties of N-methane hydrate are calculated in the generalized gradient approximation (GGA) for Grimme dispersion correction. The obtained results are shown below. 1) The water cage structure of N-methane hydrate is a truncated octahedron (4<sup>6</sup>6<sup>8</sup>), which is composed of 8 regular hexagons and 6 squares, and the average length of the hexagons and the average length of the squares are both 2.723 Å. The average bond length of water molecules is optimized to be 1.056 Å, and the average bond angle of water molecules is 107.738°. The average bond length of methane molecules is 1.0973 Å. The average distance from methane molecules to water molecules is 4.2831 Å that is longer than the distance in the I- methane hydrate. So N-methane hydrate can accommodate larger volumes of gas molecules. The symmetric group is <inline-formula><tex-math id="M2">\begin{document}${\rm{IM}}\bar 3{\rm{M}}$\end{document}</tex-math><alternatives><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20182230_M2.jpg"/><graphic xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="16-20182230_M2.png"/></alternatives></inline-formula> for N-methane hydrate, which has a simple and strict periodic stable structure. 2) The lattice parameter of N-methane hydrate is 7.70 Å, and the density is 0.903 g/cm<sup>3</sup>, which is greater than I-, II- and H-type hydrate density. 3) The x-ray diffraction(XRD) pattern of N-methane hydrateis calculated and is close to that of of I-methane hydrate, while the water cage of N-methane hydrate is larger. 4) The interaction between methane molecules and the water cage is van der Waals force, and the formation energy of N- methane hydrate is –0.247 eV, which indicates that the N-methane hydrate is easy to form. Both the density of states and partial density of states indicate that the interaction between methane and water cage is weak, and it relies on molecular force. 5) In addition, N-methane hydrate is an insulator material with the energy gap greater than 5 eV.

Reserve Estimation Technique for Low Permeability Shale Gas Formations of Lower Indus Basin, Using Simulation Approach

Produced Natural Gas from the low permeability tight shale reservoirs are called as Shale Gas, has a great importance in economic terms of supply and demand because of natural gas prices. Shale is composed of a rock having sedimentary of clastic nature that contains mudstone and siltstone under the specific reservoir conditions of pressure and temperature are called Shale gas. Shales are of the soft nature formation that formed due to pre-existing rocks which have been elated, worn out and transported into a new form of rock. Shale is found in reservoir rock where organic material migrated upward and in areas where conventional clays are normally present. Shale is known as unconventional energy source. Due to high demand in population rate and increasing consumption of natural gas in transportation sector it is challenging for Pakistan to meet the energy requirements and needs in utilizing both conventional and unconventional energy resources. In this research study, the set of data, tools and methodology applied to estimate initial gas in place (IGIP), recoverable reserves, recovery factor, and risk analysis of shale gas reservoirs. The study reveals potential and characteristics of shale reservoir to grade the areas in term of shale thickness, its hydrocarbon generation potential, current depth and maturity for shale gas exploitation.

Reserve Estimation Technique for Low Permeability Shale Gas Formations of Lower Indus Basin, Using Simulation Approach

Produced Natural Gas from the low permeability tight shale reservoirs are called as Shale Gas, has a great importance in economic terms of supply and demand because of natural gas prices. Shale is composed of a rock having sedimentary of clastic nature that contains mudstone and siltstone under the specific reservoir conditions of pressure and temperature are called Shale gas. Shales are of the soft nature formation that formed due to pre-existing rocks which have been elated, worn out and transported into a new form of rock. Shale is found in reservoir rock where organic material migrated upward and in areas where conventional clays are normally present. Shale is known as unconventional energy source. Due to high demand in population rate and increasing consumption of natural gas in transportation sector it is challenging for Pakistan to meet the energy requirements and needs in utilizing both conventional and unconventional energy resources. In this research study, the set of data, tools and methodology applied to estimate initial gas in place (IGIP), recoverable reserves, recovery factor, and risk analysis of shale gas reservoirs. The study reveals potential and characteristics of shale reservoir to grade the areas in term of shale thickness, its hydrocarbon generation potential, current depth and maturity for shale gas exploitation.

Interconexión de mercados transfronterizos de electricidad y la necesidad de políticas de coordinación

La interconexión de dos mercados eléctricos necesita nuevas políticas de regulación que la rijan, porque hay diversos factores que se involucran cuando se interconectan dos mercados, ya que las políticas del mercado de electricidad de cada país están diseñadas para su mercado interno, por lo que existe la necesidad de determinar cuál es el mejor mecanismo para la interconexión de ambos mercados, tratando que ambos países compartan los beneficios y los costos. Estudiar el impacto de la participación de grandes centrales hidroeléctricas con embalse y el efecto que tendrán en la complementariedad de los mercados eléctricos transfronterizos; la implementación de RER no convencionales y como afectaran en la integración de los mercados eléctricos transfronterizos, son problemas que no tienen soluciones generales y que deben tratarse para cada caso específico.

Optimization Algorithms to Solve Problems of Comprehensive Electrification Based on Renewable Energy Sources

The article shows the possibilities of optimal use of unconventional and renewable energy sources for agricultural consumers and presents methods of creation of optimization algorithms allowing solving the problems of comprehensive electrification of agroindustrial areas with many factors taken into account.

Propuesta para disminuir el alto consumo energético en las industrias dependientes de combustible fósiles

El presente trabajo tuvo como objetivo ofrecer una panorámica para valorar la mejora de la eficiencia de los sistemas de suministro de energía en industrias con la utilización de fuentes no convencionales de energía que proporcionen beneficios económicos y ambientales para el desarrollo sostenible de la sociedad en general. En la búsqueda de fuentes de energía para disminuir este alto costo, se presentó una propuesta metodológica para impulsar a corto y largo plazo la eficiencia energética con el empleo de biogás en la producción de electricidad. Incentivados como parte del proyecto de investigación científica de eficiencia energética: Introducción de fuentes renovables de energía en el territorio holguinero, del departamento de Ingeniería Mecánica de la Universidad de Holguín.

Finite element model of nail penetration into lithium ion battery

Abstract Numerical modelling is the method by virtually testing and verifying the functionality of a specific product or component. The primary goal is to get approximate results of how the system behaves in a given time and environment. This paper deals with a possibility of the use the numerical simulation for system simulation in the unconventional power sources of electrical energy. This method is useful in application where the complex environment is necessary to use, e.g. electro-mobility, solar power station, etc. It is possible to simulate electro-chemical reactions, current fields, temperature fields, electric potentials, concentrations, charging and discharging cycle, electromagnetism, etc. In this case, it will be presented the multiphysical approach of system simulation of short circuit in the lithium ion battery.

Optimal control of single stage LiBr/water absorption chiller

Low-capacity refrigeration and space conditioning systems have increased significantly in the last years, increasing primary energy demand. For this reason, it is important to start implementing refrigeration and space conditioning system that can be driven by unconventional energy sources, such as a single stage lithium bromide absorption refrigeration chiller since it can be powered by a low grade heat source. Therefore, we establish an optimal control strategy to operate these systems. For the implementation of the optimum control a dynamic model to evaluate the system is developed and discretized and solved using the interior point optimization (IPOPT) solver. The cases studied where a step and a sinusoidal perturbation on the hot water inlet temperature. The results obtained are promising because, through the implementation of the optimal control strategy, the coefficient of performance (COP) of the refrigeration system was significantly improved, reducing operational cost and all this without affecting the cold water outlet temperature.

Combustion Characteristics of Tight Sandstone

As a promising unconventional energy source, tight sandstone gas has attracted increasing attention. Because of the extremely low porosity/permeability of tight sandstone, large scale exploration and development are still challenging. Recently, high-temperature combustion or pyrolysis has been employed to increase sandstone porosity/permeability. In this study, the sandstone samples obtained from Xinjiang Province in China were heated for 30 min in air atmosphere at temperatures of 350, 500, 700, 800, and 900 °C respectively. The combustion characteristics and property changes of sandstone were investigated. In the beginning, thermal decomposition process of sandstone and gas emission were tested using thermogravimetry combined with Fourier transform infrared spectroscopy. Then, the mineral composition and pore structure of different combusted sandstones were tested and analyzed. Moreover, the effects of combustion temperature on particle size of sandstone were also investigated. Finally, scanning electron microscopy (SEM) technology was performed to study the surface appearance change of sandstone. According to the experiment results, organic matters started releasing at 350–500 °C, and most of the minerals such as carbonate decomposed at 600–870 °C. During the combustion process, carbon dioxide and water vapor were the main product gases. With the increase of combustion temperature, the mean pore diameter increased from 8.0 to 22.6 nm, while the particles size remained almost constant. In addition to the increase of pore size, it can be found from SEM photos that the compact surface of sandstone became smooth and some new pores and small cracks appeared on the surface of sandstone after high-temperature combustion, especially at 900 °C. As a result, high-temperature combustion is one of the feasible methods to improve the porosity/permeability of sandstone.

New lipopeptide produced by Corynebacterium aquaticum from a low-cost substrate.

Conventional biosurfactants have high production costs. Therefore, the use of low-cost carbon sources for their production is attractive for industry. The ability to remain stable under various environmental conditions further extends industrial application. Here we aimed to evaluate the stability of a new lipopeptide produced by Corynebacterium aquaticum using fish residue as an unconventional energy source. The biosurfactant was produced using 3% fish residue, 2% of the microorganism, and mineral medium. Biosurfactant characterization was performed by thin layer chromatography (TLC), as well as by testing its infrared, surface tension, emulsifying activity, and ionic character. The stability of the biosurfactant was evaluated by testing its surface tension at a range of temperatures, pH, and saline concentrations, as well as after 6 months of storage. The biosurfactant was characterized as a lipopeptide due to its retention time, which was coincident with the amino acid and lipid chains obtained in the TLC analysis, being confirmed by some regions of absorption verified in the infrared analysis. The surface tension and emulsifying activity of the biosurfactant were 27.8 mN/m and 87.6%, respectively, and showed anionic character. The biosurfactant was stable at temperatures of 20 to 121°C, in saline concentrations of 1 to 7%, and at pH close to neutrality. Based on our findings, it is possible to use unconventional sources of energy to produce a lipopeptide biosurfactant that can act under various environments.

China’s Role in the Transition to a New International Energy Order

With the shift of energy production centres and oil consumption markets the international energy order has been changing, indicating four trends: the Arctic region and the international seabed area will become new energy sources; the exploitation of unconventional energy sources - a new focus; and the rulemaking right in the energy market - a new battlefield. Contemporary international law promotes, regulates, and safeguards the transition to a new international energy order, in which China should make efforts to shift its role from a passive recipient to an active innovator of international energy rules; from an onlooker to an active participant in international energy affairs; and from a receiver to a contributor of international energy public goods.

Coal-derived compounds and their potential impact on groundwater quality during coalbed methane production.

Coalbed methane (CBM) is an important unconventional energy source and accounts for a substantial portion of the overall natural gas production in the USA. The extraction of CBM generates significant amounts of produced water, where the withdrawal of groundwater may disturb the subsurface environment and aquifers. The release of toxic recalcitrant compounds from the coal seam is of great concern for those who use groundwater for irrigation and potable water sources. Experiments were conducted that determined a small fraction of coal carbon can be extracted and solubilized in water during the CBM formation and production. These soluble components included long-chain alkanes, aromatic hydrocarbons, and humic compounds. Biometer flask assays demonstrated that these compounds are bioamenable and can be potentially degraded by microorganisms to produce methane and carbon dioxide, where these biodegradation processes may further impact groundwater quality in the coal seam.

Illustration of Hydrate-Based Methane Gas Separation in Coal Bed Methane Type Gas Composition at Lower Pressures

Coal bed methane is an emerging and prosperous unconventional energy source, encompassing highly variable (10–70%) mole fractions of methane gas along with other higher hydrocarbon and nonhydrocarbon gases. The gas pressure at the source is typically low, posing technical constraints in the gas separation process. In particular, separation of methane gas from this source is a topic of wider scientific interest. The present study demonstrates the ability of hydrate-based technology in trapping methane gas, in nitrogen (N 2 ) + methane (CH 4 ) gas mixture, using tetrahydrofuran (THF)-based hydrate-forming system at lower operating pressures (1.0 MPa). It is observed that the gas trapping is efficient and rapid. All the experiments were conducted at non-stirred condition, which is technically easy to achieve. Mole fraction of CH 4 was increased in proportion with N 2 , and it was found that methane gas uptake capacity in hydrate cages, increased progressively with increasing CH 4 concentration. Gas uptake kinetics was also found to be extremely fast and 90% of the gas consumed in hydrates within 50–60 min from hydrate nucleation.

Analysis of the incremental cost method and the net present value method applied in the energy sector

The study characterizes hybrid sources applied in the power industry, created with the use of unconventional energy sources. An example of cooperation of heat pumps and conventional sources was used. The article notes the technological progress also concerning heat exchangers. To calculate economic efficiency, the MKN Incremental Cost Method and the NPV Net Present Value method were used. The article refers to the calculation of investment outlays and operating costs and repayment of a bank loan for individual heat sources. The possibility of assuming separate values of discount rates for the installation of heat pumps and hybrid boilers as well as the comparative installation were shown. Also included is the possibility of adopting a separate discount rate for income derived from savings associated with the purchase of fuel and energy and the sale of heat to a third party consumer. The analysis covered the MKN Incremental Cost Method and the NPV Net Present Value method. The computational algorithm contains costs of hybrid installation with heat pumps and costs of a comparative conventional installation in a version without revenues and with revenues from the sale of heat. Presented is the method of calculating the net present value in the next year of operation, discounting to the zero year and observing in which year the positive value will be obtained. Economic calculations, according to popular views, are the basis for choosing the optimal heating variant. Ecological effects and social demand may provide additional separate criteria in the selection of the heating system.

Melting of bulk non-ferrous metallic materials by microwave hybrid heating (MHH) and conventional heating: a comparative study on energy consumption

Foundry industries aim at reducing energy consumption in processing of materials. Continuous efforts are ongoing to exploit unconventional energy sources such as microwave energy to overcome drawbacks of conventional sources. In the present work, a comparative study of electrical energy consumption during melting of known quantity of metallic material in microwave oven and in conventional muffle electric furnace is carried out. The non-ferrous bulk metallic materials such as tin, zinc, aluminum and brass are used as candidate materials. A 900-W modified domestic microwave oven, operating at 2.45 GHz and a conventional muffle furnace are used for the study. The electrical energy consumed for melting of known quantity of metallic materials is presented along with the observed material wastage during melting process. The study shows that microwave oven consumes significantly lesser time than the conventional muffle electric furnace for the melting of known quantity of candidate materials. It is found that melting bulk metallic materials by microwave irradiation reduces electrical energy consumption than that of conventional melting process. In addition, material wastage is around twofold lesser by microwave melting process than the conventional melting process for the known quantity of candidate materials.