A battolyser is a combined battery electrolyser in one unit. It is based on flow battery technology and can be adapted to produce hydrogen at a lower efficiency than an electrolyser but without the need for rare and expensive materials. This paper presents a method of determining if a battolyser connected to a wind farm makes economic sense based on stochastic modelling. A range of cost data and operational scenarios are used to establish the impact on the NPV and LCOE of adding a battolyser to a wind farm. The results are compared to adding a battery or an electrolyser to a wind farm. Indications are that it makes economic sense to add a battolyser or battery to a wind farm to use any curtailed wind with calculated LCOE at £56/MWh to £58/MWh and positive NPV over a range of cost scenarios. However, electrolysers, are still too expensive to make economic sense.

Miscible viscous fingering occurs when a less viscous fluid displaces a more viscous one in porous media or a Hele−Shaw cell. Such flow instabilities are of particular interest in a variety of applications in flows and displacements in subsurface energy and environment systems. In this study, we investigate the miscible viscous fingering dynamics experimentally using water to displace glycerol in a sealed Hele−Shaw cell with two wells located in it instead of at the boundary or corners. We comprehensively examine the spatial and temporal variations of fingering dynamics, different flow regimes, and how they are affected by the water injection rate and control of pressure or rate at the outlet. Alongside the widely recognized diffusion-dominated and convection-dominated flow regimes, we identify three new regimes: a slow expansion regime prior to breakthrough, a rapid shrinkage regime immediately after breakthrough, and a uniform, slow expansion regime without fingering instability. Eac... [more]

Biogas production within cooperatives and energy clusters that include both food businesses and biogas plants seems to be a good way to both improve financial health and increase energy self-sufficiency. The paper assesses the financial health of more than 2100 food businesses operating during the period of 2014−2020; the analysis was based on data from public statistics. The financial analysis carried out using the ROS (Return on Sale) indicator and the SI for the study (saving indicator) showed that the average SI/ROS increased by more than 2.78-fold over the study period. Moreover, for 185 powiats, the observed growth remained above average over a period of one to five years. The application of the Data Envelopment Analysis (DEA) method allowed the relative efficiency of biogas utilization to be calculated at the powiat level (former LAU level 1). It was found that the utilization of biogas potential within cooperatives and energy clusters grouping food businesses is most effective... [more]

Cathode precursors of lithium-NMC 811 were synthesized by the coprecipitation method using two different nickel sources, namely mixed nickel−cobalt hydroxide precipitate (MHP) and nickel sulfate. The characteristics of the synthesized precursors were compared with the characteristics of the commercial NMC 811 cathode precursor obtained from the international market. The XRD analyses identified that the diffraction peaks of the three precursor materials were in close agreement to that of Li0.05Ni0.75Co0.1Mn0.1O2, with the figure(s) of merit (FoM) of 0.81, 0.88, and 0.9, respectively, for the synthesized precursor that used MHP as the source of nickel (SM-LNMCO-811), nickel sulfate as the source of nickel (SX-LNMCO-811), and the commercial precursor (K-NMC-811). The elemental analysis of the synthesized precursors revealed the Ni:Mn:Co mol ratios of 0.8:0.08:0.12 and 0.76:0.11:0.13 for SM-LNMCO-811 and SX-LNMCO-811, respectively. The SEM analysis revealed that SX-LNMCO-811 and K-NMC-811... [more]

The construction of new wastewater treatment plants and the modernization of existing ones lead to the expansion of sewage networks, resulting in a sharp increase in the volume of municipal sewage sludge, which translates into a global problem of sludge management. The solution to this problem could be the recovery of energy from sewage sludge in the cement industry to exploit its energy potential. The aim of the present study was to examine the results of laboratory research on the production of alternative fuels based on municipal sewage sludge, plastic waste from end-of-life vehicles, and wood waste (sawdust) from carpentry enterprises. The tests were carried out for waste mixtures designated as PAZO I, PAZO II, PAZO III, and PAZO IV fuels, differing in the percentage of waste used and the type of plastic waste. The following parameters were evaluated in fuels: water content, ash content, sulfur content, and calorific value. Water content of the obtained fuels ranged from 17.1% to 1... [more]

The study addressed broad aspects related to digital technology platforms and renewable energy sources, including the integration of these systems and concepts. The main objective was to identify the implementation environment for a digital technology platform of renewable energy sources (RES) based on business and consumer feedback. This gives an insight into whether there is a favourable environment for implementing a RES digital technology platform. The study was based on research carried out using computer-assisted telephone interview (CATI) and computer-assisted web interview (CAWI) methods. Additionally, an alternative model of attitudes towards digital technology platforms (DTPs) built using CATREG (categorical regression) analysis was also referred to. The study found that currently, there is a positive attitude among companies, including those which install RES systems, as well as among consumers towards the implementation of DTP-based RES projects. This attitude is driven by... [more]

Despite the many different methods for creating modified heat transfer surfaces to increase critical heat fluxes and heat transfer coefficients at pool boiling of various liquids at given reduced pressures, active research is currently underway to find optimal surface morphology and geometric parameters of structures for practical application. In this work, we used the method of microarc oxidation (MAO) to obtain coatings with different microstructures on the surface of duralumin heaters. In the present work, we studied the effect of MAO coatings on heat transfer, critical heat flux, and evaporation dynamics during liquid nitrogen boiling under conditions of steady-state heat release at pressures of 0.1, 0.05, and 0.017 MPa. It was shown that the modification of heaters led to a 50−60% increase in heat transfer coefficients as compared to the smooth one under the atmospheric pressure. Based on the data of high-speed video filming of boiling, it was shown that the main mechanism of inte... [more]

A distributed propulsion system has the advantage of saving 5−15% fuel burn through ingesting the fuselage boundary layer of an aircraft by fan or compressor. However, due to boundary layer ingestion (BLI), the fan stage will continuously operate under serious inlet distortion. This will lead to a circumferentially non-uniform flow separation distribution on the stator blade suction surface along the annulus, which significantly decreases the fan’s adiabatic efficiency. To solve this problem, a non-uniform stator dihedral design strategy has been developed to explore its potential of improving BLI fan performance. First, the stator full-annulus blade passages were divided into blade dihedral design regions and baseline design regions on the basis of the additional aerodynamic loss distributions caused by BLI inlet distortion. Then, to find the appropriate dihedral design parameters, the full-annulus BLI fan was discretized into several portions according to the rotor blade number and t... [more]

Nuclear energy has played and will continue playing a key role in the fight against climate change due to its extremely low green-house gas emissions, and high energy density and reliability [...]

A giant, ultra-deep (>7000 m) strike-slip fault-related oilfield has been found in the central depression of the Tarim Basin. However, little research has addressed this discovery to understand the fault effects on the oil migration, which constrains the oil exploitation deployment and well optimization. Based on fault modeling and fluid analysis, we present the effects of fault segment on the oil segmentation and migration in the ultra-deep Fuman Oilfield. The results show a distinct fault segmentation and also subsequent variable fault architecture and non-connected fracture network other than a through-going fault zone. There are fault segment-related isolated fractured reservoirs and fluid variation along the fault strike, which indicates that a large oilfield comprises a series of unconnected small oil reservoirs along the fault segments. The fluid segmentation and molecular indicator of dibenzothiophenes reveal that there is a variable petroleum lateral migration along the strike... [more]

Oil shale constitutes an important proportion of unconventional resources, and its efficient exploitation helps alleviate the Chinese oil shortage situation. Nowadays, microwave heating is a promising method for in situ development of oil shale. However, the corresponding numerical simulation lacks in guiding the retorting optimization under microwave heating. A novel pseudo three-dimensional model, considering electromagnetics, temperature field, and chemical reactions coupling was developed and implemented to investigate oil shale reservoirs’ retorting performance under microwave heating based on the finite element method (FEM). The effects of microwave power, antenna number, and antenna position were analyzed creatively to optimize the microwave heating parameters. Numerical results showed high microwave power increased the maximum reservoir temperature quickly near the heating well, but the thermal conductivity of oil shale dominated the temperature of distal formation. For a typic... [more]

Wind turbines (WTs) are exposed to a dynamic/cyclic load environment, and are subjected to 1P/3P loads under operational conditions. Recent studies introduced the Sommerfeld Effect to explain the dynamic response amplification induced by 1P/3P loads. This study establishes a theoretical model to analyze the resonance of WTs under 1P/3P loads. Sensitiveness analysis was conducted for parameters b, c, S, F, and T to explore their influence on the dynamic response. The resonance phenomenon induced by 1P/3P frequency passing the natural frequency is discussed. The results show that there is no Sommerfeld Effect in soft−stiff WTs. Only if the imbalance reaches a much higher value (19200 kg·m in this study) should the Sommerfeld Effect be considered for soft WTs; otherwise, it can be ignored. The 3P resonance appeared when the 3P frequency approached the natural frequency, but it was not the Sommerfeld Effect.

As an emerging foundation structure for offshore wind turbines, bucket foundations with superior bearing capacities and efficient construction procedures have attracted significant attention in China. Thick-walled bucket foundations with concrete skirts can effectively reduce the cost and prevent the buckling problem of steel skirts during construction, transportation, and installation. However, great challenges are encountered during the sinking process, and the accurate calculation of sinking resistance is a critical process. Static-pressure tests of thin-walled and thick-walled models in sand were performed to measure the penetration resistance and soil pressure at the sidewalls and ends. The horizontal-soil-pressure coefficients of different models were calculated, and the end and skin-friction coefficients in the cone-penetration test method are recommended. The drag-reduction effects of the anti-drag ring and pressure-pull-out loading method were examined, and the drag-reduction... [more]

Converting municipal solid waste (MSW) into valuable feedstocks, such as refuse-derived fuel (RDF), is a sustainable method according to the concept of waste management hierarchy. A heterogeneous composition with a good calorific value and lower emissions allows RDF to be used for energy recovery purposes. We have earlier analyzed the generation and thermochemical characteristics of the MSW produced in Kazakhstan. This work aims to study the combustion characteristics in terms of emissions and ash composition to evaluate the possibility of RDF co-firing with Ekibastuz coal. In particular, RDF is blended with high ash bituminous coal (Ekibastuz coal) and co-fired in the laboratory scale bubbling fluidized bed reactor (BFB) at a bed temperature of 850 °C. The co-firing tests of RDF to coal samples were conducted under various proportions to analyze flue gas compositions. Experiments were carried in the presence of bed material (sand), and the fuel particles were fed in batch mode into th... [more]

Pineapple production around the world creates large amounts of wasted organic residue, mainly in the form of pineapple leaves. Current management practices consist of in situ decomposition or in situ burning, both of which cause the proliferation of flies and air pollution, respectively. The research conducted aims to develop a utilization process for this residue. Considering that pineapple leaves are rich in carbohydrates and other nutrients, a simple biological process involving a two-step procedure for juice production and ethanol fermentation has been developed to convert the leaves into renewable fuel and spent yeasts for animal feed. The liquid fraction extracted from the leaves is used as the nutrients to culture yeast, Kluyveromyces marxianus, for ethanol and yeast protein production. In Costa Rica, one of the major pineapple-producing countries in the world, the studied process can produce 92,708 and 64,859 tons of bioethanol and spent yeast per year, respectively, from its 4... [more]

This paper presents the experimental research conducted for the Biomimetic Unmanned Underwater Vehicle (BUUV). The study’s major goal is to create a single, flexible side fin with adequate proportions and stiffness for an energy-efficient propulsion system. The experiments were carried out in a laboratory water tunnel equipped with a sensor for direct thrust measurement for various fin dimensions. Further, the particle image velocimetry (PIV) approach was used for a more in-depth examination of fluid−structure interaction (FSI) phenomena. The given experiments indicate the region of superior propulsion system performance and explain the main aspects that have influenced thrust generation using image processing and the PIV approach.

In this article, a switched reluctance machine (SRM) with six phases and a misaligned segmental rotor is proposed. The segmental rotor has an internal 15-degree misalignment, allowing the SRM structure to be a one-layer 2D structure with a short flux path structure. The proposed SRM produces a relatively low torque ripple by exciting two phases simultaneously. Additionally, an optimization method is applied, allowing for the maximum torque position of one phase to be aligned with the zero-torque position of the adjacent phase. The finite element method (FEM) is used to analyze and design the proposed SRM and to simulate the proposed liquid cooling system. The static torque waveforms are analyzed, and the dynamic torque waveforms are simulated with a drive using SiC MOSFETs. Finally, a prototype is manufactured, and the experiment is performed to validate the design and simulation results.

This paper studies the speed control strategy of a switched reluctance motor based on angle-position control (APC). The switched reluctance motor has three control parameters: turn-on angle, turn-off angle and voltage PWM duty cycle. This paper studies the function of the three parameters and designs the control algorithms of the parameters, respectively, which can reduce the coupling degree, simplify the control process, and realize the optimal control of the switched reluctance motor. By studying the nonlinear characteristics of the switched reluctance motor, the optimal current waveform in the effective working range of the inductor is obtained, and then a control strategy of the turn-on angle is designed to realize the ideal winding current waveform. According to the torque characteristics of the motor, taking the coincidence of the freewheeling zero point and the position angle at the end of the maximum inductance interval as the control target, a control strategy for the turn-off... [more]

This paper explores the current attitudes of managers and executives working in the energy sector towards the Data-Driven Organizational Model implied by Big Data. The aim is to explore and understand the current mindset of senior decision makers, since their success depends as much on cognitive and behavioral processes as on their technical competences. We adopt a grounded-theory approach, developing models of understanding and belief abductively, driven by the data obtained from participants through a reflection guide. We find that managers differ significantly in their understanding and engagement with their challenges; they display interest but differ in their commitment and enthusiasm; they identify a lack of strategy and skills as current barriers; and they are currently unwilling to trust data, treating evidence according to their own prior commitments. This is a significant barrier to establishing the Data-Driven Organizational Model. These findings raise concerns, and the pape... [more]

One of the aspects to consider during high-voltage (HV) equipment design is the reduction in the probability of corona effect onset. Indeed, the corona effect is related to high electric field values beyond the equipment’s insulation levels and insulation strength, among other factors. This issue can be addressed during the design step, either by modifying the geometry of the electrical device or by including additional elements in the equipment structure to smooth out the voltage gradient along critical regions, such as anti-corona devices. The study of anti-corona devices for HV insulators is well documented, in contrast to substation connectors. Therefore, the present study proposed the design of a novel anti-corona device for HV substation connectors, including a method for the selection of its dimensions. This study shows that the relationship between the dimensional design variables and the critical electrical field on the connector is described by linear and rational functions.... [more]

The maritime silk road policy of China brings opportunities to companies relating to overseas investment. Despite the investment potentials, the risks cannot be ignored and have still not been well assessed. Considering the fact that ICRG comprehensive risk has certain subjectivity, it is not completely applicable to China’s overseas investment. Therefore, based on the data of the China Statistical Yearbook and International Statistical Yearbook, a new indictor is adopted to better capture the Chinese investment risk and to make our prediction more objective. In order to acquire the ability to predict the investment risk in the future which is essential to stakeholders, machine learning techniques are applied by training the ICRG data of the previous year and Outward Foreign Direct Investment (OFDI) data of the next year together. Finally, a relative reliable link has been built between the OFDI indicator in the next year and the left ICRG indicators in the last year with both the best... [more]

Alkali pretreatment is one of the chemical pretreatment technologies that has been examined on various types of lignocellulosic biomass. To gain a better insight into the effects of a potassium-based catalyst on pyrolysis behavior with different materials, potassium bicarbonate (KHCO3) and potassium nitrate (KNO3) were used as additives in this study. The experimental parameters which included particle size, heating rate, and additive loading were investigated. The results showed that adding potassium for both KHCO3 and KNO3 to feedstocks led to increase in biochar. A model-free method, Flynn−Wall−Ozawa (FWO), was implemented in this study to determine the activation energy values for untreated and potassium-treated feedstocks. A reduction in apparent activation energy values of treated biomass was observed. This indicates that adding potassium salt to biomass influenced the structures of the main components and promoted the catalytic effect of pyrolysis. Activation energies of treated... [more]

The importance of the quality and continuity of electricity supply is increasingly evident given the dependence of the world economy on its daily and instantaneous operation. In turn, the network is made up of power transmission lines. This study has been carried out based on the Scopus database, where all the publications, over 5000 documents, related to the topic of the power transmission lines have been analyzed up to the year 2022. This manuscript aims to highlight the main global research trends in power transmission lines and to detect which are the emerging areas. This manuscript cover three main aspects: First, the main scientific categories of these publications and their temporal trends. Second, the countries and affiliations that contribute to the research and their main research topics. Third, identification of the main trends in the field using the detection of scientific communities by means of the clustering method. The three main scientific categories found were Enginee... [more]

Recently, there was a great focus on integrating renewable energy sources (RESs) into electrical power systems (hybrid systems) due to their many environmental and economic advantages. The output of most of these RESs is DC; some power electronic devices, including inverters, must be used to integrate these RESs into the electrical grid. Any maloperation, faults, or improper control in these power electronic devices will enormously affect these hybrid systems’ performance. This paper aims to mitigate the misfire and fire-through faults that occur at the switching of the inverter that connects three renewable sources: PV, wind, and the fuel cell to the grid. This mitigation of such inverter faults (misfire and fire-through) is performed through optimal tuning of the PI controller driving a dynamic voltage restorer (DVR) connected at the system’s AC side. The optimization technique used is particle swarm optimization (PSO). While mitigating these two inverter faults using the PI-PSO cont... [more]

Well construction operations require continuous complex decision-making and multi-step action planning. Action selection at every step demands a careful evaluation of the vast action space, while guided by long-term objectives and desired outcomes. Current human-centric decision-making introduces a degree of bias, which can result in reactive rather than proactive decisions. This can lead from minor operational inefficiencies all the way to catastrophic health and safety issues. This paper details the steps in structuring unbiased purpose-built sequential decision-making systems. Setting up such systems entails representing the operation as a Markov decision process (MDP). This requires explicitly defining states and action values, defining goal states, building a digital twin to model the process, and appropriately shaping reward functions to measure feedback. The digital twin, in conjunction with the reward function, is utilized for simulating and quantifying the different action seq... [more]