The deteriorating condition of the environment and the increasing emission of pollutants into the atmosphere intensify the greenhouse effect. Energy production in power plants results in emissions that affect the increase of global temperatures. According to the Research Institute for Global Climate Change in Berlin there are just over 7 years to cross the critical point, which will start chain reactions associated with irreversible changes in the climate. In order to reduce the climate changes, exhaust emissions must be reduced. One of the steps is to reduce electricity consumption. In the case of roads, electricity is most related to the technical infrastructure. First steps has been taken to reduce the demand for electricity by using lighting systems equipped in the energy saving solutions. The next step should be to use renewable energy sources. There are many solutions to generate electricity that can be used directly on roads or nearby. There are many sides in the area of the roa... [more]

The primary purpose of this research is to assess the long-range energy demand assumption made in relevant Roadmaps for the transformation to a low-carbon energy system. A novel interdisciplinary approach is then implemented: a new model is estimated for the aggregated world primary energy demand with long historical time series for world energy, income, and population for the years 1900−2017. The model is used to forecast energy demand in 2050 and assess the uncertainty-derived risk based on the variances of the series and parameters analysed. The results show that large efficiency savings—up to 50% in some cases and never observed before—are assumed in the main Roadmaps. This discrepancy becomes significantly higher when even moderate uncertainty assumptions are taken into account. A discussion on possible future sources of breaks in current patterns of energy supply and demand is also presented, leading to a new conclusion requiring an active political stance to accelerate efficienc... [more]

Renewable energy (RE) is one of the most popular public policy orientations worldwide. Compared to some other countries and continents, Europe has gained an early awareness of energy and environmental problems in general. At the theoretical level, free-market environmentalism indicates that based on the principle of private property rights, with fewer state interventionist and regulation policies, entrepreneurs, as the driving force of the market economy, can provide better services to meet the necessity of offering RE to protect the environment more effectively. Previous studies have revealed that Germany, Denmark, and the United Kingdom have made some progress in using the market to develop RE. However, this research did not analyze the three countries’ RE conditions from the perspective of free-market environmentalism. Based on our review of the principles of free-market environmentalism, this paper originally provides an empirical study of how Germany, Denmark, and the United Kingd... [more]

Land subsidence caused by groundwater withdrawal induced by mining is a relatively unknown phenomenon. This is primarily due to the small scale of such movements compared to the land subsidence caused by deposit extraction. Nonetheless, the environmental impact of drainage-related land subsidence remains underestimated. The research was carried out in the “Bogdanka” coal mine in Poland. First, the historical impact of mining on land subsidence and groundwater head changes was investigated. The outcomes of these studies were used to construct the influence method model. With field data, our model was successfully calibrated and validated. Finally, it was used for land subsidence estimation for 2030. As per the findings, the field of mining exploitation has the greatest land subsidence. In 2014, the maximum value of the phenomenon was 0.313 cm. However, this value will reach 0.364 m by 2030. The spatial extent of land subsidence caused by mining-induced drainage extends up to 20 km beyon... [more]

Magnetic couplings (MCs) enable contactless speed/torque transmission via interactions between the magnetic fields of permanent magnets (PMs) rather than a physical mechanical connection. The contactless transmission of mechanical power leads to improvements in terms of efficiency and reliability due to the absence of wear between moving parts. One of the most common MC topologies is the coaxial type, also known as the radial configuration. This paper presents an analytical tool for the accurate and fast analysis of coaxial magnetic couplings (CMCs) using a two-dimensional subdomain approach. In particular, the proposed analytical tool resolves Laplace’s and Poisson’s equations for both air-gap and PM regions. The tool can be used to evaluate the impact of several design parameters on the performance of the CMC, enabling quick and accurate sensitivity analyses, which in turn guide the choice of design parameters. After discussing the building procedure of the analytical tool, its appli... [more]

Although battery electric vehicles (BEVs) are locally emission-free and assist automakers in reducing their carbon footprint, two major disadvantages are their shorter range and higher production costs compared to combustion engines. These drawbacks are primarily due to the battery, which is generally the heaviest and most expensive component of a BEV. Lightweight measures (strategies to decrease vehicle mass, e.g., by changing materials or downsizing components) lower energy consumption and reduce the amount of battery energy required (and in turn battery costs). Careful selection of lightweight measures can result in their costs being balanced out by a commensurate reduction in battery costs. This leads to a higher efficiency vehicle, but without affecting its production and development costs. In this paper, we estimate the lightweight potential of BEVs, i.e., the cost limit below which a lightweight measure is fully compensated by the cost savings it generates. We implement a parame... [more]

Measurements of medium and high voltages in a power grid are normally performed with large and bulky voltage transformers or capacitive dividers. Besides installation problems, these devices operate in a relatively narrow frequency band, which limits their usability in modern systems that are saturated with power electronic devices. A sensor that can be installed directly on a wire and can operate without a galvanic connection to the ground may be used as an alternative voltage measurement device. This type of voltage sensor can complement current sensors installed on a wire, forming a complete power acquisition system. This paper presents such a sensor. Our sensor is built using two dielectric elements with different permeability coefficients. A finite element method simulation is used to estimate the parameters of a constructed sensor. Besides simulations, a laboratory model of a sensor was built and tested in a medium-voltage substation. Our results provide a proof of concept for th... [more]

This review paper provides a critical interpretation and analysis of almost 150 dedicated optimization research papers in the field of droop-controlled islanded microgrids. The significance of optimal microgrid allocation and operation studies comes from their importance for further deployment of renewable energy, reliable and stable autonomous operation on a larger scale, and the electrification of rural and isolated communities. Additionally, a comprehensive overview of islanded microgrids in terms of structure, type, and hierarchical control strategy was presented. Furthermore, a larger emphasis was given to the main optimization problems faced by droop-controlled islanded microgrids such as allocation, scheduling and dispatch, reconfiguration, control, and energy management systems. The main outcome of this review in relation to optimization problem components is the classification of objective functions, constraints, and decision variables into 10, 9 and 6 distinctive categories,... [more]

The reliability and security of power systems may be jeopardized by the increase in the amounts of renewable generation and the uncertainties produced by these devices. In particular, the protection schemes of traditional power systems have been challenged by the integration of distributed generation (DG) resources. Distance relays (DRs), which have been mainly employed to protect transmission systems, are increasingly proposed as one of the solutions to protect distribution systems with a heavy penetration of DGs. However, conventional distance protection faces several drawbacks that might lead to maloperation. One of those challenges is the “infeed effect”, which causes the impedance seen by the distance relay to be larger than the actual positive-sequence line impedance between the fault and relay location. This paper proposes three new methods to estimate the distance to the fault in the presence of infeeds, whether in a radial distribution feeder or the transmission line. Unlike o... [more]

Basic knowledge about the factors and mechanisms affecting the performance of solar cells and their identification is essential when thinking of future improvements to the device. Within this paper, we investigated the current transport mechanism in GaAsN p-i-n solar cells grown with atmospheric pressure metal organic vapour phase epitaxy (AP-MOVPE). We examined the electro-optical and structural properties of a GaAsN solar cell epitaxial structure and correlated the results with temperature-dependent current-voltage measurements and deep level transient spectroscopy findings. The analysis of J-V-T measurements carried out in a wide temperature range allows for the determination of the dominant current transport mechanism in a GaAsN-based solar cell device and assign it a nitrogen interstitial defect, the presence of which was confirmed by DLTFS investigation.

This work refines and updates estimates of the fuel-cycle greenhouse-gas (GHG) emission impacts of electric vehicles (EVs) rebated in California. Emissions are estimated using disaggregated data from the start of the rebate program through August 2018 (N = 269,902 participants) and factors that characterize fuel use and fuel life-cycle carbon intensity. GHG reductions are calculated for the first year of vehicle operation and subsequently scaled to reflect various operational timeframes. GHG reduction estimates over the first year of vehicle ownership total approximately 855 thousand metric tons of CO2-equivalent emissions, or 3.2 tons per vehicle. For nonfleet individuals, 54% of reductions are associated with “Rebate-Essential” participants who were most highly influenced by the rebate to purchase/lease. Comparing the estimated warranty-life benefit of 7.9 million tons of GHG reductions to USD 603 million in corresponding rebates results in USD 76 of state incentives per metric ton r... [more]

The massive integration of variable renewable energy (VRE) in modern power systems is imposing several challenges; one of them is the increased need for balancing services. Coping with the high variability of the future generation mix with incredible high shares of VER, the power system requires developing and enabling sources of flexibility. This paper proposes and demonstrates a single layer control system for coordinating the steady-state operation of battery energy storage system (BESS) and wind power plants via multi-terminal high voltage direct current (HVDC). The proposed coordinated controller is a single layer controller on the top of the power converter-based technologies. Specifically, the coordinated controller uses the capabilities of the distributed battery energy storage systems (BESS) to store electricity when a logic function is fulfilled. The proposed approach has been implemented considering a control logic based on the power flow in the DC undersea cables and coordi... [more]

One of the basic conditions for the successful implementation of energy demand-side management (EDM) in smart grids is the monitoring of different loads with an electrical load monitoring system. Energy and sustainability concerns present a multitude of issues that can be addressed using approaches of data mining and machine learning. However, resolving such problems due to the lack of publicly available datasets is cumbersome. In this study, we first designed an efficient energy disaggregation (ED) model and evaluated it on the basis of publicly available benchmark data from the Residential Energy Disaggregation Dataset (REDD), and then we aimed to advance ED research in smart grids using the Turkey Electrical Appliances Dataset (TEAD) containing household electricity usage data. In addition, the TEAD was evaluated using the proposed ED model tested with benchmark REDD data. The Internet of things (IoT) architecture with sensors and Node-Red software installations were established to... [more]

The carbon intensity of China’s resource-based cities (RBCs) is much higher than the national average due to their relatively intensive mode of development. Low carbon transformation of RBCs is an important way to achieve the goal of reaching the carbon emissions peak in 2030. Based on the panel data from 116 RBCs in China from 2003 to 2018, this study takes the opening of high-speed railway (HSR) lines as a quasi-experiment, using a time-varying difference-in-difference (DID) model to empirically evaluate the impact of an HSR line on reducing the carbon intensity of RBCs. The results show that the opening of an HSR line can reduce the carbon intensity of RBCs, and this was still true after considering the possibility of problems with endogenous selection bias and after applying the relevant robustness tests. The opening of an HSR line is found to have a significant reducing effect on the carbon intensity of different types of RBC, and the decline in the carbon intensity of coal-based... [more]

A model has been developed for the optimization of the share structure of an investment portfolio in high-tech projects supported by the leaders of the leading industry companies in Russia. Several indicators (financial leverage, integrated rating of companies, industry rating) were applied in the decision support system for the shared distribution of investments. High-tech production is based on innovative technologies for saving resources, the resiliency of systems for transporting and transferring raw materials and finished products within Russia, so the main income will remain within the country. It is possible to export high-tech products, rather than raw materials, which will increase export revenues. Investors will invest in high-tech projects of Russian companies, taking into account the targeting of investment development. The guarantee is the stable financial position of the companies and the competitiveness rating. Methods: The authors propose a new approach that does not co... [more]

Currently, built LED luminaires are usually multi-source. This causes a large number of photometric and simulation problems connected with computer lighting visualization. This paper highlights three key issues with these luminaires: a change in the traditional understanding of the coordinate system for these luminaires, the photometric test distance of these luminaires and the need for the photometric separation of a single LED in the computer lighting simulation process. An optical model of a linear LED luminaire used in floodlighting was formulated on this basis. The presented conclusions refer to practical applications. Thus, it is necessary to address the crucial points that specify the coordinate system for the multi-source LED luminaire by its designer and present the information in a datasheet. The other important points concern determining the appropriate photometric test distance for the multi-source LED luminaires of a given type and creating photometric files for the differ... [more]

In order to improve the thermal conductivity and the insulation properties of polyethylene (PE) used as cable insulation under DC stress, hexagonal boron nitride (h-BN) and inorganic particles have been considered as micro-filler and nano-filler, respectively. As a 2D material, the orientation of h-BN possibly affects the insulation properties of the polymer. It is important to understand the influence of the filler orientation on the insulation performance of the polymer. In this work, a numerical simulation has been performed to investigate the effect of orientation of micro-h-BN on charge transport and DC breakdown of PE-based micro/nano-composites and a comparison between the simulation result and previous literature data has been conducted. The h-BN was designated to be parallel, perpendicular to the normal sample surface vector (the direction of electric field in this work) or randomly distributed in the matrix, and the charge transport behavior and DC breakdown strength in the s... [more]

The power system network topology influences the system frequency response to power imbalance disturbances. Here, the objective is to find the network metric(s) contributing to frequency transient stability. The graph Laplacians of six 4-node network topologies are analysed using Spectral Graph Theory. For homogeneous network connections, we show that the node degree measure indicates node robustness. Based on these analytical results, the investigation expands to a 10-node network topology consisting of two clusters, which provide further insight into the spectral results. The research then involves a simulation of a power imbalance disturbance on three 20-node networks with different topologies based on node degree, where we link the node degree measure to imbalance disturbance propagation through Wave Theory. The results provide an intuitive understanding of the impact of network topology on power system frequency stability. The analytical and simulation results indicate that a node... [more]

The improvement of the supercapacitor model redundancy is a significant method to guarantee the reliability of the power system in electric vehicle application. In order to enhance the accuracy of the supercapacitor model, eight conventional supercapacitor models were selected for parameter identification by genetic algorithm, and the model accuracies based on standard diving cycle are further discussed. Then, three fusion modeling approaches including Bayesian fusion, residual normalization fusion, and state of charge (SOC) fragment fusion are presented and compared. In order to further improve the accuracy of these models, a two-layer fusion model based on SOC fragments is proposed in this paper. Compared with other fusion models, the root mean square error (RMSE), maximum error, and mean error of the two-layer fusion model can be reduced by at least 23.04%, 8.70%, and 30.13%, respectively. Moreover, the two-layer fusion model is further verified at 10, 25, and 40 °C, and the RMSE ca... [more]

In recent years, the investment in the wind energy sector has increased in the context of producing green electricity and saving the environment. The installation of small wind turbines (SWTs) represents an actual strategy for meeting energy needs for off-grid systems and certain specialized applications. SWTs are more expensive per kilowatt installed as compared to large-scale wind turbines. Therefore, the main objective of this study is to produce an economical technology for the wind power market offering low-cost SWTs. The idea consists of considering a simple structure of the wind turbine using direct-drive permanent magnet synchronous generator (DDPMSG). DDPMSGs are the most useful machines in the wind energy field thanks to several advantages, such as elimination of noise and maintenance cost due to suppression of the gearbox and absence of the rotor circuit excitation barriers by the presence of the permanent magnets (PMs). Their major downside is the high cost of active materi... [more]

The need for accurate measurements and for estimating the uncertainties associated with measures are two pillars for researchers and metrologists. This is particularly true in distribution networks due to a mass deployment of new intelligent electronic devices. Among such devices, phasor measurement units are key enablers for obtaining the full observability of the grid. The phasor measurement unit performance is mostly evaluated by means of the total vector error, which combines the error on amplitude, phase, and time. However, the total vector error is typically provided merely as a number, that could vary within an unknown interval. This may result into the phasor measurement unit incompliance with the final user expectancies. To this purpose, and with the aim of answering practical needs from the industrial world, this paper presents a closed-form expression that allows us to quantify, in a simple way, the confidence interval associated with the total vector error. The input requir... [more]

This article presents the research results related to the methodology of threat analysis to implement in energy security. In the conducted studies, the world’s output in scenario planning and the most famous cases of global security and technology scenarios were analysed. These projects were the Lisbon Group analysis, Shell’s scenario planning concepts, and the US National Intelligence Council’s long-term analysis. In this way, I demonstrated the limitations of a scenario-based view of the issues under study, resulting mainly from considering only one type of environment. The formulated conclusions made it possible to build the author’s model of the strategic analysis process for the energy security sector. It goes beyond scenario analysis, complementing it with the sector, portfolio, and integrated analysis methods. The strategic analysis built in this way takes into account the achievements of many scientific disciplines, namely, technology, security, strategic management, foresight,... [more]

A revolution of the global energy industry is without an alternative to solving the climate crisis. However, renewable energy sources typically show significant seasonal and daily fluctuations. This paper provides a system concept model of a decentralized power-to-green methanol plant consisting of a biomass heating plant with a thermal input of 20 MWth. (oxyfuel or air mode), a CO2 processing unit (DeOxo reactor or MEA absorption), an alkaline electrolyzer, a methanol synthesis unit, an air separation unit and a wind park. Applying oxyfuel combustion has the potential to directly utilize O2 generated by the electrolyzer, which was analyzed by varying critical model parameters. A major objective was to determine whether applying oxyfuel combustion has a positive impact on the plant’s power-to-liquid (PtL) efficiency rate. For cases utilizing more than 70% of CO2 generated by the combustion, the oxyfuel’s O2 demand is fully covered by the electrolyzer, making oxyfuel a viable option for... [more]

The importance of corporate social responsibility, especially in the environmental domain, continues to grow in an era of mounting climate urgency. This study is based on original, empirical, survey-based research in two post-communist European countries and seeks to add a geographical viewpoint and to investigate the influence of innovative constructs (environmental reporting, environmental strategy, environmental management control system) on environmental and economic performance. Data are analysed through partial least squares structural equation modelling, which enables the use of a complex model with several links between constructs. Findings reveal that environmental strategy has a positive impact on the use of an environmental management control system and an indirect positive impact on environmental performance. The environmental management control system has been shown to have a positive influence on environmental performance and, ultimately, on economic performance.

Aiming at the problem of end structure heating caused by the excessive eddy current loss of large synchronous condensers used in ultra-high voltage (UHV) power transmission, combined with the actual operation characteristics of the synchronous condenser, a three-dimensional transient electromagnetic field physical model is established, and three schemes for adjusting the end structure of the condenser under rated condition are researched. The original structure has a copper shield and a steel clamping plate. Scheme 1 has no copper shield but has a steel clamping plate. Scheme 2 has no copper shield but has an aluminum clamping plate. By constructing a three-dimensional fluid−solid coupling heat transfer model in the end of the synchronous condenser, and giving the basic assumptions and boundary conditions, the eddy current loss of the structure calculated by the three schemes is applied to the end region of the synchronous condenser as the heat source, and the velocity distribution of... [more]