The article presents problems occurring during remote temperature measurement of lashing clamps of bridge connections on high voltage poles using thermal imaging cameras. The basic metrological parameters of thermal imaging cameras are described. On this basis, typical errors made during the inspection of high voltage lines supplying power substations are presented using infrared cameras. Researching the possible solutions for the problems of remote temperature measurement of small objects of electricity power systems—on the example of lashing clamps of bridge connections on high voltage poles in the proposed paper and showing the basic metrological aspects and parameters of thermal imaging cameras are important because, in this way, it is observed to eliminate costly interruptions in the supply of electricity associated with the breaking of power lines. Small objects are quite difficult to be controlled and monitored on large grids and on large powerline poles; thus, it is very challe... [more]

Dual fuel combustion depicts a possible alternative to reduce emissions from large engines and is characterized by injecting a small amount of diesel fuel into a lean natural gas−air mixture. Thereby, the presence of autoignition, diffusive and premixed combustion determine the high complexity of this process. In this work, an Extended Coherent Flame Model was adapted to consider the effect of natural gas on the ignition delay time. This model was afterward utilized to simulate 25 consecutive engine cycles employing LES. In this framework, the ensemble-average flow field was compared to a RANS solution to assess the advantages of LES in terms of the prediction of the in-cylinder flow field. A detailed investigation of the heat release characteristic showed that natural gas already highly contributes to the heat release at the beginning of combustion. Furthermore, a methodology to investigate the turbulent combustion regimes was utilized. It could be ascertained that the combustion main... [more]

This paper develops new practical rule-based energy management systems (EMSs) for typical grid-connected houses with solar photovoltaic (PV) and battery by considering different rates for purchasing and selling electricity. The EMSs are developed to supply the household’s loads and reduce operating costs of the system based on different options of flat and time-of-use (ToU) rates for buying and selling electricity prices. Four different options are evaluated and compared in this study: (1) Flat-Flat, (2) ToU-Flat, (3) Flat-ToU, and (4) ToU-ToU. The operation cost is calculated based on the electricity exchange with the main grid, the equivalent cost of PV generation, as well as the degradation cost of battery storage. The operation of the grid-connected house with rooftop solar PV and battery is evaluated for a sunny week in summer and a cloudy week in winter to investigate the proper performance for high and low generations of PV. While the developed rule-based EMS are generic and can... [more]

The growing environmental impact and rising emission of greenhouse gases have accelerated the research toward renewable energy sources and electric vehicles since one of the main sources of pollution is the CO2 emissions produced by conventional combustion vehicles. This article presents the analysis of the energy balance between a photovoltaic carport with 4.89 kWp installed capacity and an EV, model Renault Fluence ZE DYN, driven in real conditions. The driving tests were performed during the winter season in the city of Curitiba, the capital of the state of Paraná, Brazil, with approximately 1.7 million inhabitants and 1.1 million vehicles. During the test period, we attempt to reproduce the citizen’s daily routes through the city, presenting an average consumption of 15.75 kWh/100 km. The carport PV module’s energy generation and in-plane incident irradiation were acquired to calculate the performance ratio, making a comparison after cleaning maintenance possible. The solar carport... [more]

With the increasing penetration rate of Power Electronic Converter (PEC) based technologies, the electrical power systems are facing the problem of transient stability since the PEC based technologies do not contribute to the system inertia, and the proportion of synchronous generators (i.e., the source of inertia) is in decreasing rate. In addition, PEC based technologies’ components have poor inherent damping. It is very important to analyze the system characteristics of a power system to minimize the potential instabilities during the contingencies. This paper presents the parametric sensitivity analysis of the rotor angle stability indicators for the 39-bus New England power system. The indicators of rotor angle stability analysis such as critical fault clearing time (CCT), Eigenvalue points, damping ratio, frequency deviation, voltage deviation, and generator’s speed deviation are identified and analyzed for three case scenarios; each scenario has six sub-cases with different iner... [more]

Electrolysis is potentially a valuable tool for cleansing waste water. One might even hope that it is possible to synthesize valuable products in this way. The question is how the reaction conditions can be chosen to obtain desired compounds. In the present study we use Car−Parrinello molecular dynamics to simulate the reaction of nucleobases under electrolytic conditions. We use our own scheme (F. Hofbauer, I. Frank, Chem. Eur. J., 18, 277, 2012) for simulating the conditions after the electron transfer in a self-consistent field calculation. This scheme was employed previously to the electrolysis of pure water and of polluted solutions. On the picosecond timescale, we find a strongly different reaction behavior for each of the four nucleobases contained in DNA.

The search for fossil fuels substitutes forces the use of new propulsion technologies applied to means of transportation. Already widespread, hybrid vehicles are beginning to share the market with hydrogen-powered propulsion systems. These systems are fuel cells or internal combustion engines powered by hydrogen fuel. In this context, road tests of a hydrogen fuel cell drive were conducted under typical traffic conditions according to the requirements of the RDE test. As a result of the carried-out work, energy flow conditions were presented for three driving phases (urban, rural and motorway). The different contributions to the vehicle propulsion of the hydrogen system and the electric system in each phase of the driving route are indicated. The characteristic interaction of power train components during varying driving conditions was presented. A wide variation in the contribution of the fuel cell and the battery to the vehicle’s propulsion was identified. In urban conditions, the sh... [more]

Understanding the residential adoption decision of battery energy storage systems (BESSs) is central to the implementation of successful intervention policies. However, when the residential solar photovoltaics (PV) becomes a widely accepted technology across a society, accurately modelling the behaviour shows a higher degree of complexity. In this vein, the uptake pathway of BESS and PV coupled with BESS (PV−BESS) would predictably exhibit similar attitudinal traits to that of PV consumption. This notion implies that the antecedent PV decision can be regarded as the past behaviour of the BESS adopter by creating attitudinal implications. The PV use status also yields a higher degree of heterogeneity through the emergence of four new household groups and the inherent imbalances in the involvement of the interwoven financial, technical, sociodemographic, and psychological predictors. This perspective employs the Reasoned Action Approach (RAA) to allegorise a decision-making model of BESS... [more]

A building’s energy consumption is assessed considering the energy required for heating, cooling, lighting, and domestic hot water (DHW). Methodologies used to calculate energy certificates in European Union countries consider hot water consumption rates per person or per heated (floor) area, giving wide-ranging values (35−88 dm3/person/day). Using extreme parameters, it is possible to obtain a primary energy index that meets the legal requirements, although unrealistically large proportions of domestic hot water use relative to the total energy balance of the building may marginalize the influence of other components, such as fluctuations in heating, ventilation, or lighting. In the current work, the DHW consumption of three residential buildings was measured to verify the energy consumption for hot water preparation. Investigations were conducted based on the consumption of natural gas for DHW preparation. Experimentally obtained water consumption rates were determined per m2 of a dw... [more]

In many studies, for predicting the remaining capacity of batteries belonging to different electrochemical systems, various analytical models based on the Peukert equation are used. This paper evaluates the advantages and disadvantages of the most famous generalized Peukert equations. For lithium-ion batteries, the Peukert equation cannot be used for estimation of their remaining capacity over the entire range of discharge currents. However, this paper proves that the generalized Peukert equations enable estimation of the capacity released by lithium-ion batteries with high accuracy. Special attention is paid to two generalized Peukert equations: C = Cm/(1 + (i/i0)) and C = Cmerfc((i-i0)/n))/erfc(-i0/n). It is shown that they correspond to the experimental data the best.

Carbon capture and storage (CCS) by geological sequestration comprises a permeable formation (reservoir) for CO2 storage topped by an impermeable formation (caprock). Time-lapse (4D) seismic is used to map CO2 movement in the subsurface: CO2 migration into the caprock might change its properties and thus impact its integrity. Simultaneous forced-oscillation and pulse-transmission measurements are combined to quantify Young’s modulus and Poisson’s ratio as well as P- and S-wave velocity changes in the absence and in the presence of CO2 at constant seismic and ultrasonic frequencies. This combination is the laboratory proxy to 4D seismic because rock properties are monitored over time. It also improves the understanding of frequency-dependent (dispersive) properties needed for comparing in-situ and laboratory measurements. To verify our method, Draupne Shale is monitored during three consecutive fluid exposure phases. This shale appears to be resilient to CO2 exposure as its integrity is... [more]

Developing countries, including Pakistan, need a considerable effort to withstand economic growth; however, these countries have to cope with greenhouse gases emission and other environmental concerns. Financial advancement gives rise to modern, sometimes even innovative and energy-efficient technologies and, thus, contributes to a decline in energy usage among market entities: organizations and households. The current study explores the nonlinear asymmetric relationship between economic growth (Y) and the selected exogenous variables in Pakistan by incorporating time series data spanning from 1971 to 2016. Economic growth was considered as a target variable, while energy consumption (EC), electric power consumption (EPC), financial development (FD), and energy imports (EM) were considered independent variables. To investigate cointegration among the given variables, a nonlinear ARDL bound testing approach was employed. BDS independence test was used to check the nonlinearity, and a st... [more]

Wind turbines can have inertia characteristics similar to synchronous generators through virtual inertia control, which helps to provide the inertia support for the system. However, there is the problem of how to coordinate the allocation of virtual inertia among wind turbines. In response to this problem, this paper first analyzes the inertia response capabilities of wind turbines and puts forward an evaluation index that quantifies the inertia response capability of wind turbines. The inertia response capability of a wind farm is evaluated at the entire system level. Based on the evaluation index, the virtual inertia coordinated allocation method considers the system inertia demand and the inertia response capabilities of the wind turbines. It is proposed to release the inertia response capability of each wind turbine while avoiding an excessive release of kinetic energy and bring a second impact by wind turbines’ exiting operation. Finally, the effectiveness of the proposed method i... [more]

World wind energy output is steadily increasing in both production scale and capacity of harvesting wind. Hydrostatic transmission systems (HTSs) have been used mostly in offshore wind turbine applications. However, their potential has not been fully utilized in onshore wind turbines, partially due to concerns related to hydraulic losses. In our prior work, it was shown that the annual energy production from a hydrostatic wind turbine can match or exceed that of a mechanical drive wind turbine with appropriate optimal control techniques. In this paper, we present an optimal control technique that can further improve energy production of a hydrostatic wind turbine, particularly in low speed regions. Here, the overall loss equation of the HTS is developed and used as a cost function to be minimized with respect to system model dynamics. The overall loss function includes the losses due to both the aerodynamic efficiencies and the hydrostatic efficiencies of the motor and pump. A nonlinea... [more]

Accurately estimating the state of health (SOH) of a lithium-ion battery is significant for electronic devices. To solve the nonlinear degradation problem of lithium-ion batteries (LIB) caused by capacity regeneration, this paper proposes a new LIB degradation model and improved particle filter algorithm for LIB SOH estimation. Firstly, the degradation process of LIB is divided into the normal degradation stage and the capacity regeneration stage. A multi-stage prediction model (MPM) based on the calendar time of the LIB is proposed. Furthermore, the genetic algorithm is embedded into the standard particle filter to increase the diversity of particles and improve prediction accuracy. Finally, the method is verified with the LIB dataset provided by the NASA Ames Prognostics Center of Excellence. The experimental results show that the method proposed in this paper can effectively improve the accuracy of capacity prediction.

Wind power penetration into existing electrical power systems continues to experience year-on-year growth. Consequently, modern wind turbine systems (WTS) are required to comply with relevant grid codes and provide ancillary grid services to assist with overall grid stability. Adhering to these grid codes and services can cause additional mechanical loading on WTS, which can result in a reduction in service life of some of the drivetrain components, and instability if a sufficient means of damping is not present in the drivetrain. In this paper, a dynamic simulation model of a Type 1, direct grid-connected, fixed-speed (FS) slip-synchronous wind turbine system (SS-WTS) is developed to investigate its dynamic stability in response to the additional mechanical loads imparted onto it during transient events on the grid. The SS-WTS is not equipped with a power converter and, consequently, an understanding of its dynamic stability is critical to evaluate its ability to assist with grid serv... [more]

The optimization of the steam parameters of the heat recovery steam generators (HRSG) of Combined Cycle Gas Turbines (CCGT) has become one of the important means to reduce the power generation cost of combined cycle units. Based on the structural theory of thermoeconomics, a thermoeconomic optimization model for a triple pressure reheat HRSG is established. Taking the minimization of the power generation cost of the combined cycle system as the optimization objective, an optimization algorithm based on three factors and six levels of orthogonal experimental samples to determine the optimal solution for the high, intermediate and low pressure steam pressures under different gas turbine (GT) operation strategies. The variation law and influencing factors of the system power generation cost with the steam pressure level under all operation strategies are analyzed. The research results show that the system power generation cost decreases as the GT load rate increases, T4 plays a dominant r... [more]

This article presents the analysis of the performance of a flexible wind turbine blade. The simulation analysis is based on a 3 m span blade prototype. The blade has a flexible surface and a cam mechanism that modifies the aerodynamic profile and adapts the surface to different configurations. The blade surface was built with a flexible fiberglass composite, and the internal mechanism consists of a flexible structure actuated with an eccentric cam. The cam mechanism deforms five sections of the blade, and the airfoil geometry for each section was measured from zero cam displacement to full cam displacement. The measured data were interpolated to obtain the aerodynamic profiles of the five sections to model the flexible blade in the simulation process. The simulation analysis consisted of determining the different aerodynamic coefficients for different deformed surfaces and a range of wind speeds. The aerodynamic coefficients were calculated with the BEM method (QBlade®); as a result, t... [more]

The infrastructure required for international natural gas trade is considerable, which often leads to hold-up problems and supply disruptions. This study discusses disruptions of gas supply from Algeria, Indonesia, Russia, and Turkmenistan since the early 1980s. The novelty of this study is its focus on the issues related to transit countries, which are rarely considered in the literature. The results of the study classify supply disruptions into six types, show the evolution of supply disruptions over time, and discuss mitigation strategies. The six types of disruptions include political change, price demands, debts, technical issues, transit fees, theft of gas. The evolution of the disruptions shows that the issues related to transit countries have become more frequent in the last two decades. Mitigation strategies tailored to transit countries include using an international organisation, designing contracts with price mechanisms that might reduce the possibility of disputes and redu... [more]

Achieving Net zero emissions is a common challenge facing all mankind. Low-carbon electricity has always been the main research field of global GHG emission control. The current article aims to use the bibliometric analysis to describe the characteristics and trends of low-carbon electricity publications from 1983 to 2021. We found that: (1) the number of publications in this area has shown an overall increase in the past 33 years. (2) the United States is the most powerful country in this field of research. Moreover, with the exception of major developed countries, more and more emerging economies have also joined the research on low-carbon power systems. (3) co-citation analysis and literature clustering characteristics show that the knowledge base in this field is focused on the decomposition of driving factors for carbon dioxide emissions and the optimization of the operation of renewable energy (RE) in low-carbon power systems. (4) the utilization of RE is a hot topic in low-carbo... [more]

The development of electric vehicles (EVs) is an important step towards clean and green cities. An electric powertrain provides power to the vehicle and consists of a charger, a battery, an inverter, and a motor as the main components. Supplied by a battery pack, the automotive inverter manages the power of the motor. EVs require a highly efficient inverter, which satisfies low cost, size, and weight requirements. One approach to meeting these requirements is to use the new wide-bandgap (WBG) semiconductors, which are being widely investigated in the industry as an alternative to silicon switches. WBG devices have superior intrinsic properties, such as high thermal flux, of up to 120 W/cm2 (on average); junction temperature of 175−200 °C; blocking voltage limit of about 6.5 kV; switching frequency about 20-fold higher than that of Si; and up to 73% lower switching losses with a lower conduction voltage drop. This study presents a review of WBG-based inverter cooling systems to investig... [more]

One organizational innovation introduced by the clean energy for all Europeans package (CEP) is that of the energy community (EC), including the renewable energy community (REC) and citizen energy community (CEC). The translation of related directives into national legislation is underway in Sweden, and the Swedish Energy Market Inspectorate (Ei) has proposed a new law on ECs, which has been sent for consultation. This article analyzes the Ei proposal and the responses from the 27 referral bodies commenting on the new EC regulations. Positive aspects of the proposal were that it would be a law on ECs and that it would be easy to start and run an EC. Critics were concerned that the law was too vague, the relationship between existing cooperatives and the new ECs was not clear, both CEC and REC are used instead of only using one term, there is a lack of suggestions on supportive measures for ECs, ECs will have less favorable conditions than other micro-producers of electricity, there is... [more]

Fuel cell technologies have several applications in stationary power production, such as units for primary power generation, grid stabilization, systems adopted to generate backup power, and combined-heat-and-power configurations (CHP). The main sectors where stationary fuel cells have been employed are (a) micro-CHP, (b) large stationary applications, (c) UPS, and IPS. The fuel cell size for stationary applications is strongly related to the power needed from the load. Since this sector ranges from simple backup systems to large facilities, the stationary fuel cell market includes few kWs and less (micro-generation) to larger sizes of MWs. The design parameters for the stationary fuel cell system differ for fuel cell technology (PEM, AFC, PAFC, MCFC, and SOFC), as well as the fuel type and supply. This paper aims to present a comprehensive review of two main trends of research on fuel-cell-based poly-generation systems: tracking the market trends and performance analysis. In deeper de... [more]

To achieve carbon neutrality by 2050, Korea has been expanding its investment in renewal energy distribution and technology development. However, with this rapid expansion of renewable energy, public concern about it has grown. This study developed and used a big data analysis-based procedure to analyze the questions registered on Naver, the largest portal site in Korea, from 2008 to 2020 to identify public concern over renewable energy. The big data analysis-based procedure consisted of two steps. The first was a frequency analysis to identify the most frequently registered words. The second was to classify questions using term frequency-inverse document frequency (TF-IDF) weight and cosine similarity based on word2vec. The analysis revealed the most frequently registered words related to renewable energy, such as “solar power,” “power generation,” “energy,” and “wind power.” It also revealed the most frequently registered questions, such as those related to solar panel installation,... [more]

The amount of CO2 released in the atmosphere has been at a continuous surge in the last decade, and in order to protect the environment from global warming, it is necessary to employ techniques like carbon capture. Developing technologies like Carbon Capture Utilization and Storage aims at mitigating the CO2 content from the air we breathe and has garnered immense research attention. In this review, the authors have aimed to discuss the various technologies that are being used to capture the CO2 from the atmosphere, store it and further utilize it. For utilization, researchers have developed alternatives to make profits from CO2 by converting it into an asset. The development of newer fuel cells that consume CO2 in exchange for electrical power to drive the industries and produce valuable hydrocarbons in the form of fuel has paved the path for more research in the field of carbon utilization. The primary focus on the article is to inspect the environmental and economic feasibility of n... [more]