We have proposed an impact assessment methodology for determining sustainability in energy-intensive industrial production based on a comprehensive combination of economic, environmental, and social indicators for sustainable development. The goal of this study was to disclose this methodology for assessing sustainability in energy-intensive industrial production. We proved that any energy-intensive chemical, metallurgical, and energy generation processes should maximize the material output values and product value addition to ensure innovative sustainable development. We proposed indicators that determine the levels of increasing the sustainability of energy-intensive production as a whole, as well as taking into account individual technological processes. We proposed a procedure for making managerial decisions to increase the sustainability of energy-intensive outputs using the technological renewal of fixed assets and/or technological modernization of production. Our proposed method... [more]

In coal mine goafs, spontaneous combustion of coal can result in methane accumulation, which raises the danger of methane explosion disasters. As an atmospheric control tool, ventilation is applied to ensure air quality for avoiding disasters in underground mines. However, during the process of the spontaneous combustion of coal in coal mine goafs, the impact of ventilation dilution on the possible methane explosions induced by coal combustion has not been well investigated. In this study, a validated gas flow model for the spontaneous coal combustion environment in goafs of coal mines is adopted to investigate the influence of ventilation dilution at the three stages of the spontaneous combustion of coal. The research conclusions suggest that (1) ventilation dilution is a quick measure to dilute methane concentration and intensify heat transfer in the vertical direction in coal mine goafs; (2) ventilation dilution can lessen the danger of methane explosions by diluting methane concent... [more]

Photovoltaic solar cells have been extensively used for various applications and are considered one of the most efficient green energy sources. However, their 2D surface area solar harvesting has limitations, and there is an increasing need to explore the possibility of multiple layer solar harvest for enhanced energy density. To address this, we have developed spectral-selective transparent thin films based on porphyrin and iron oxide compounds that allow solar light to penetrate multiple layers, significantly increasing solar harvesting surface area and energy density. These thin films are designed as photovoltaic (PV) and photothermal (PT) panels that can convert photons into either electricity or thermal energy for various green energy applications, such as smart building skins and solar desalination. The advantages of this 3D solar harvesting system include enlarged solar light collecting surface area and increased energy density. The multilayer system transforms the current 2D to... [more]

Sodium-ion batteries (SIBs) are one of the recent trends in energy storage systems due to their promising properties, the high abundance of sodium in the Earth’s crust, and their low cost. However, the commercialization process of SIBs is in the early stages of development because of some challenges related to electrodes and electrolytes. Electrolytes are vital components of secondary batteries because they determine anode/cathode performance; energy density; operating conditions (electrochemical stability window, open circuit voltage, current rate, etc.); cyclic properties; electrochemical, thermal, mechanical, and dimensional stability; safety level; and the service life of the system. The performance of the battery is based on the structural, morphological, electrical, and electrochemical properties of the electrolytes. In this review, electrolytes used for SIBs are classified according to their state and material, including liquid, quasi-solid, solid, and hybrid, and recent advance... [more]

This article analyzes Green Jobs (GJs) in the energy sector. GJs are naturally created in the processes related to the implementation of the Sustainable Development Goals (SDGs); this is especially visible in the 7th and 8th SDGs. There is currently a green transition from fossil fuels to renewable energy sources in the energy sector, and this mainly technological change also influences GJ creation. Despite this, there is a research gap related to green self-employment and GJ definitions. The goal of this paper is to explore the scientific literature collected from the Scopus database using a qualitative approach to present areas and keywords related to GJs in the energy sector. The adopted method is a Structured Literature Review (SLR), with the original query Q1. The retrieved data results of the SLR method were analyzed in the form of bibliometric maps of co-occurring keywords generated by the VOSviewer software, together with tables showing clusters of keyword features. As a result... [more]

Accurately obtaining the working status of the sucker rod pumping wells is a challenging problem for oil production. Sensors at the polished rod collect working data to form surface dynamometer cards for fault diagnosis. A prevalent method for recognizing these cards is the convolutional neural network (CNN). However, this approach has two problems: an unbalanced dataset due to varying fault frequencies and similar dynamometer card shapes that complicate recognition. This leads to a low accuracy of fault diagnosis in practice, which is unsatisfactory. Therefore, this paper proposes a hybrid approach of the deep learning method and rule-based method for fault diagnosis of sucker rod pumping wells. Specifically, when the CNN model alone fails to achieve satisfactory accuracy in the working status, historical monitoring data of the relevant wells can be collected, and expert rules can assist CNN to improve diagnostic accuracy. By analyzing time series data of factors such as the maximum a... [more]

Despite global efforts to reduce greenhouse gas emissions, the energy sector remains a major contributor, with hydrocarbon-based resources fulfilling around 80% of energy needs. As such, there is a growing focus on identifying effective and economically feasible policy mechanisms to promote renewable energy adoption. This study focuses on the theoretical problems surrounding the adoption of renewable energy policies. The study aims to highlight the potential for sustainable growth using renewable energy in the UAE and identify the most viable policy mechanisms for enhancing grid-tied solar energy adoption using qualitative and quantitative data collection methods and the HOMER Grid software. Compared to previous research, this study contributes by identifying a unified renewable energy policy mechanism that could significantly enhance the adoption of grid-tied solar energy generation in the UAE. The study’s main findings show that a unified renewable policy mechanism could enhance grid... [more]

A novel linear permanent magnet vernier generator (LPMVG) for small-power off-grid wave power generation systems is proposed in this paper. Firstly, in order to reduce the cogging force and the inherent edge effect of the linear generator, a staggered tooth modular structure is proposed. Secondly, in order to improve the output power and efficiency of the LPMVG and reduce the fluctuation coefficient of electromagnetic force, the relationship between the parameters of the generator is studied, and a method combining multi-objective optimization and single parameter scanning based on the response surface model and particle swarm optimization algorithm is proposed to obtain the optimal structural parameters of the generator. Thirdly, the output power and efficiency of the optimized generator are calculated and analyzed based on the two-dimensional finite element method, and the effectiveness of the multi-objective optimization design method based on the response surface model and particle... [more]

In this study, we investigated the acid (HCl) and alkali (KOH) chemical activation of açaí seeds (Euterpe Oleraceae, Mart.) pre-treatment before pyrolysis at temperatures of 350−450 °C in order to assess how reactions proceed when affected by temperature. Chemical composition of bio-oil and aqueous phase were determined by GC-MS and FT-IR. The bio-char is characterized by XRD. For the activation with KOH, the XRD analysis identified the presence of Kalicinite (KHCO3), the dominant crystalline phase in bio-char, while an amorphous phase was identified in bio-chars for the activation with HCl. The experiments have shown that bio-oil yield increases with temperature for the KOH activated biomass and decreases for the acid activated one. The KOH bio-oil is primarily composed of alcohols and ketones, showing the lowest acid values when compared with the HCl one, which is composed mainly of carboxylic acids and phenols. An increase in alcohol content and a decrease in ketones in the KOH bio-... [more]

Harvested wood products (HWPs) are a class of products that are recognized for their potential to mitigate climate warming: the absorption of CO2, which is necessary to the growth of their biomass feedstock, temporarily reduces the amount of CO2 present in the Earth’s atmosphere, effectively mitigating global warming. This study decided to look into the effect of changing two important parameters associated with HWPs: the rotation period of the biomass used for their raw material (effectively, the rate of CO2 absorption), and the length of their lifetime (effectively, the amount of time the captured carbon is stored within them in the form of embodied carbon). For this purpose, a carbon accounting calculator, Quantis’ Biogenic Carbon Footprint Calculator for Harvested Wood Products (BCFC-HWP), was employed. The Biogenic Global Warming Potential (GWPbio) metric, which was used by the BCFC-HWP to describe the climate impact of a wooden product’s embodied carbon, was analyzed for its evol... [more]

Hydropower plants cover almost 70% of the Colombian electrical demand, were built several decades ago, and present low levels of digitisation compared to other modern power-generation technologies, e.g., wind turbines, solar PV plants, and recently buil hydroelectric plants t. Renovating power plant equipment and investing in modernisation and digitisation can significantly increase the plant flexibility. Those actions will increase a plant’s operational safety and contribute to the solution of environmental and social problems. This work presents the actions followed to extend the lifetime of a 1000 MW hydropower plant operating for more than 40 years. Activities included a residual life status evaluation of generators and component upgrades, among others. The rehabilitation and digitalisation of the generation units allow their integration and remote monitoring so that diagnostic actions can be carried out during a continuous and economically sustainable operation. These activities c... [more]

Using direct numerical simulation (DNS) in combination with the volume of fluid method (VoF), we investigate the influence of the density ratio between the carrier and dispersed phase on emulsions, where the baseline simulation approximately corresponds to the ratio of water-in-gasoline emulsions. For this purpose, homogeneous isotropic turbulence (HIT) is generated using a linear forcing method, enhanced by a proportional−integral−derivative (PID) controller, ensuring a constant turbulent kinetic energy (TKE) for two-phase flows, where the TKE balance equation contains an additional term due to surface tension. Then, the forcing is stopped, and gravitational acceleration is activated. The proposed computational setup represents a unique and well-controlled configuration to study emulsification and segregation. We consider four different density ratios, which are applied in industrial processes, to investigate the influence of the density ratio on the statistically steady state of the... [more]

The most common fuel used for powering compression ignition engines is diesel, whose main components are petroleum products. The constantly growing energy demand involves the implementation of new technical solutions and applying alternative fuels, including renewable ones, such as rapeseed oil, sunflower oil, peanut oil, and animal fats. The most commonly used biofuels are those obtained from chemically processed rapeseeds (transesterification) to provide them with physical−chemical properties similar to diesel fuel. The study presents the results of tests of a power unit fueled with different mixtures of diesel oil and fatty acid methyl esters. The experiment was carried out for a compression ignition engine of 81 kW power with direct fuel injection. Performance parameters of the vehicle power unit and its computer software were modified for the needs of the tests. Those modifications involved increasing the fuel dose and the fuel injection pressure. The test results were statistical... [more]

In ship systems, diesel power generators are used in various systems of autonomous power plants to ensure power supply security. This article presents an autonomous hybrid system of a ship power plant with a diesel generator with a permanent magnet synchronous generator and electricity storage in parallel topology (the permanent magnet synchronous generator is connected directly to the receiving network). The electricity storage through the active converter is connected to the receiving network in parallel with the permanent magnet synchronous generator. The decoupled control of the reactive and active power in the active converter enables stabilization of the voltage in the ship’s electrical power grid while ensuring the possibility of obtaining different operating regimes of the power plant at various stages of the ship’s operation. The innovative method of voltage stabilization presented in this article is based on the compensation of the unfavorable reaction of the permanent magnet... [more]

The employment of microgrids and distributed power generation have exponentially increased over recent decades, due in part to the increased inclusion of renewable energies as these technologies become cheaper to install. However, microgrids are highly sensitive to power variation, leading to distortion of the grid voltage (amplitude and frequency changes) which could destabilize the entire microgrid under variation of loads and/or other power sources. In this context, a new control strategy is proposed for a photovoltaic grid connected system, operating under voltage variations typical of a low inertial electric power network. The main problem related to voltage fluctuation is that the variables may take the power converter out of the operating region, and therefore, all controllers, including the maximum power point tracking, will not work as designed. The analysis, based on the mathematical operating region, demonstrates that the control strategy can include overmodulation compensat... [more]

This work aims to propose a method enabling the evaluation of wind turbine blade damage and fatigue related to a 1 Hz wind speed signal applied to a large period and based on standard 10-min SCADA data. Previous studies emphasize the need for sampling with a 1 Hz frequency when carrying out blade damage computation. However, such methods cannot be applied to evaluate the damage for a long period of time due to the complexity of computation and data availability. Moreover, 1 Hz SCADA data are not commonly used in the wind farm industry because they require a large data storage capacity. Applying such an approach, which is based on a 1 Hz wind speed signal, to current wind farms is not a trivial pursuit. The present work investigates the possibility of overcoming the preceding issues by estimating the equivalent 1 Hz wind speed damage over a 10-min period characterized by SCADA data in terms of measured mean wind speed and turbulence intensity. Then, a discussion is carried out regarding... [more]

The application of voltage reduction in medium and low voltage grids to reduce peak power demand or energy consumption has been implemented since the 1980s using several approaches. Conservation Voltage Reduction (CVR), as one such approach, uses a voltage control device to reduce or increase the voltage setpoint on a busbar, thereby reducing or increasing the amount of active and reactive power supply in the network. Voltage regulation for CVR is always implemented according to established network planning standards in each country. Research in this field has proven that a CVR factor (CVRf) of 0.7−1.5 for peak demand reduction can be achieved. This is an evaluation metric of CVR. The aim of this research is to determine and validate CVRf for peak demand reduction by comparing actual results obtained during regular tap changes with other randomly distributed periods outside tap change operations, using a set of measurement data. It is important to understand CVR deployment capability b... [more]

The development of AC distribution systems provides for the seamless integration of low-voltage microgrids with distributed energy resources (DERs). This poses new challenges for the control of normal, emergency, and post-emergency states of microgrids, calling for the creation and development of information and communications technology infrastructure. Power converters/inverters that are used to integrate renewable DERs lack inertia. Along with them, fossil fuel-fired generation units are also being integrated into microgrids. These include gas generator sets, diesel generator sets, and microturbines, having small (up to 1−2 s) values of mechanical inertia constants—Tj. This leads to an increase in the rate of transients by a factor of 5−10. Under these conditions, the technical requirements for the speed of automatic power flow control systems, as well as the methods they rely on, have to be reconsidered. Microgrids include DC microgrids, AC microgrids, and hybrid (AC-DC) microgrids.... [more]

The negative socio-economic consequences of the COVID-19 pandemic are widely discussed. However, relatively less attention is paid to its impact on the world commodity price formation including energy and food prices. The aim of this paper is to examine the impact of the COVID-19 pandemic on world energy commodity prices and their interactions with world food commodity prices. Using the World Bank data on commodity prices we look for evidence of changes in energy and food prices caused by occurrence of the COVID-19 pandemic, which was assumed to be a negative shock to the global economy in terms of both supply and demand. Based on data series analysis of indices of world energy and food commodity prices, it is evident that after the outbreak of the COVID-19 pandemic the energy prices, especially oil prices, plummeted. Food prices followed the same direction; however, their plunge was much less extreme. In general, it can be concluded that the pandemic caused a severe energy price shock... [more]

In 2021, there was a global energy crisis that affected different parts of the world. In most countries, energy heavily relies on natural gas, including Nigeria, India, and Bangladesh. Several studies have explored the differences in the energy of crude oil and natural gas. Nonetheless, little effort has been made toward exploring the exportation of energy for exchange markets in Nigeria, India, and Bangladesh. This paper primarily aims at comparatively exploring the energy of crude oil and natural gas for exchange markets in the aforementioned countries. The methodology used in this paper is qualitative content analysis (QCA) and a systematical literature review (SLR) which includes various sources such as journals, the core collection of the Web of Science (WOS), oil peer review resources, and library sources. The study systematically mapped out different bibliographic materials whereby the visualization of similarities (VOS) was used to explore exchange markets for energy, crude oil... [more]

This article deals with a thermal energy storage system in the form of a water tank with a thermocline. The well-known thermocline phenomenon is modeled using computational fluid dynamics (CFD). However, the reservoir model proposed in this article is zero-dimensional. This is due to the fact that the aim of this article is to build a mathematical model that will be more useful in mathematical models of complex energy systems in which a hot water tank is one of many elements of the system. In such a zero-dimensional mathematical model, the hot water tank will be modeled using equations describing heat transfer, and the thermocline itself will be treated as a heat transfer surface with known dimensions and heat transfer coefficient. A novelty of this paper is that it addresses heat loss across the thermocline as defined in this manner. A CFD model of a thermal storage tank is created, validated with available experimental data, and used to obtain the heat transfer coefficient U. The res... [more]

A future nuclear fusion plant DEMO needs neutral beam injection (NBI) systems requiring a vacuum pumping system with a very high pumping speed, in the order of several 1000 m3/s. Large customized cryopumps are actually used to meet the requirements. A promising concept for future NBI systems is based on high capacity getter materials. The ZAO® alloy, developed by SAES Getters, Italy, provides a drastically improved performance for the pumping of hydrogen compared to conventional getter materials. This paper describes the experimental characterization of a large pump of scalable size with 15 kg of ZAO® and the achieved results, in particular the systematic investigation of sorption characteristics and regeneration behaviors. Major findings include a very good repeatability of the sorption performance, a reduced pumping speed at higher pressures only above the NBI relevant level, an improved performance (+20%) with elevated getter temperature and an isotope independent sticking coefficie... [more]

Oil (and natural gas) field brines can be considered promising sources of lithium for the sustainable supply of a growing market. To date, many materials have been developed for direct lithium recovery from brines, but most often these materials have been tested under various conditions, what makes it impossible to compare them. The aim of this research is to provide knowledge that would enable the comparison and selection of effective sorbents for different types of brines. For this purpose, an eight-step experimental protocol was employed. The recovery tests started with a pure lithium solution (300 mg/kg), and then other salts were gradually added, resulting in a brine containing Li+ (220 mg/kg), Na+ (7.21 wt%), Ca2+ (3.0 wt%) and Mg2+ (1000 mg/kg). For selected cases, the effect of pH was also investigated. Fifty materials (including ion exchange resins, organophosphate extractants, mineral adsorbents) were examined, for which the distribution coefficient and lithium recovery were... [more]

With the proposal of China’s “carbon peak, carbon neutral” strategy, the increasing awareness of low carbon production among consumers, and the government’s introduction of carbon trading mechanism and low carbon consumption subsidy policies, enterprises are facing good opportunities for development. However, how the government can reasonably formulate low carbon policies and how enterprises can implement optimal low-carbon production decisions are still key issues in China’s low-carbon transition development. In this context, this paper is based on the carbon trading mechanism and carbon consumption subsidies. In this context, based on the carbon trading mechanism, this paper focuses on green production and green consumption, considers the impact of low-carbon consumer preferences and government subsidies on enterprises’ low-carbon production decisions, and uses the optimal theory to study the optimal pricing strategy and the optimal carbon reduction strategy. The study shows that the... [more]

Plug-in electric vehicles (PEVs) and distributed generation (DG) can positively and negatively impact the distribution system. Therefore, this paper presents the modeling and analysis of DG and PEVs’ penetration levels of the three-phase unbalanced radial distribution system. The study aims to optimize the distribution system’s DG sizing and PEV charging to minimize total power loss. The test system is the 4th circuit of the Nonsung service station along Thaharn Road, Muang District, Udon Thani, Thailand. According to objective function and constraints, such control variables as installation buses and rated outputs of DG and the penetration levels of PEVs were obtained to evaluate the total power loss. Significantly, the charging demand of PEVs is an uncertain load estimated by queuing theory integration with the minimization tool called the differential evaluation (DE) method. According to the result comparison of a four case simulation, the total power losses of queuing theory and DE... [more]