This article attempts to identify the key forces driving the successful digitalization of the energy sector, ensuring improvements in the energy triangle including sustainability, stability, and economic performance. The article sheds light on the diverse energy priorities at supra-, national, and managerial levels, and the role of digitalization in achieving these objectives. Catching up economies (such as Poland), being post-socialist EU member states, in order to transform its energetic sector, must overcome a number of infrastructural and social shortcomings retained as a legacy of the socialist economy. As such, sustainability (as the core priority at EU energy agenda) may not be the leading objective at both national and company level in the energy sector transformation. This article presents the results of empirical research carried out through distribution of e-questionnaire addressed to Polish managers from the energy sector. The results were analyzed using the fsQCA method. T... [more]

Data-based decisions have been being made in various fields due to the development of sensors throughout the industries. Likewise, in the power system field, data-based decisions are being made in various tasks, including establishing distribution investment plans. However, in order for it to have validity, it is necessary to get rid of abnormal data or data with low representativeness of a temporary nature. Although in general, such a series of processes are done by preprocessing, the those of power system data should be handled not only noise but also data fluctuations caused by temporary change in operations such as load transfers, as mentioned above. In addition, the characteristics of load data of distribution lines (DLs) can be different depending on the characteristics of the load itself, the characteristics of the connected DLs, and regional characteristics of each DLs, so it is essential to propose and apply the optimized preprocessing method for each DL. In this study, theref... [more]

In the context of an eco-responsible production and distribution of electrical energy at the local scale of an urban territory, we consider a smart grid as a system interconnecting different prosumers, which all retain their decision-making autonomy and defend their own interests in a comprehensive system where the rules, accepted by all, encourage virtuous behavior. In this paper, we present and analyze a model and a management method for smart grids that is shared between different kinds of independent actors, who respect their own interests, and that encourages each actor to behavior that allows, as much as possible, an energy independence of the smart grid from external energy suppliers. We consider here a game theory model, in which each actor of the smart grid is a player, and we investigate distributed machine-learning algorithms to allow decision-making, thus, leading the game to converge to stable situations, in particular to a Nash equilibrium. We propose a Linear Reward Inac... [more]

Emerging wide bandgap (WBG) semiconductors, such as silicon carbide (SiC), will enable chargers to operate at higher switching frequencies, which grants the ability to deliver high power and enhances efficiency. This paper addresses the modeling of a double-sided cooling (DSC) SiC technology-based off-board charger for battery electric buses (BEBs) and the design of its control and real-time (RT) implementation. A three-phase active front-end (AFE) rectifier topology is considered in the modeling and control system design for the active part of the DC off-board charger. The control system consists of a dual-loop voltage−current controller and is used to ensure AC to DC power conversion for charging and to achieve the targeted grid current total harmonic distortion (THD) and unity power factor (PF). Linear and nonlinear simulation models are developed in MATLAB/Simulink for optimum control design and to validate the voltage and current control performances. Four types of controllers (i.... [more]

Transshipment is the process of off-loading an intermodal loading unit (for example, different types of containers, semitrailers, swap-bodies, and so on) from one means of transport (for example, a vessel, a freight railcar, etc.) and loading it onto another. Such a process, as well as other logistics services related to loading units, may take place at a transshipment terminal, which is the intermediate node added to an intermodal transport network when combining two or more liner services that facilitate freight transport. Growing customer requirements affect transshipment terminal operations and contribute to the development of comprehensive logistics services. Terminal clients expect the delivery of complex services that often pose serious challenges to terminals providing these services. The specific decision-making tools are essential for facilitating the shaping of terminals’ complex service offerings. In this study, we investigated the issues connected to the complexity of logi... [more]

The aim of the article is to build a rule-based model (RMFDN) for increasing the energy efficiency of Smart Cities’ digital transformation processes. The problem that arises during the implementation of digital transformation processes concerns the measures that should be assigned to estimate the duration of the digital transformation. Previous studies of digital transformation have been based on the analysis of design processes based on key performance indicators (KPIs), their place and role in the digital transformation processes, and their monitoring with the use of information architecture. The analysis of the digital transformation processes of cities into Smart Cities shows that they seem inappropriate to the complexity and uncertainty of the digital transformation carried out. The new approach presented in the article is based on three key aspects: rule-based description of the state of digital transformation processes enabling their energy assessment, introducing energy maturit... [more]

Globally, around half a million tonnes of spent nuclear fuel (SNF) will be in dry or wet storage by around 2050. Continued storage is not sustainable, and this SNF must eventually either be disposed (the open nuclear fuel cycle) or recycled (the closed fuel cycle). Many international studies have addressed the advantages and disadvantages of these options. To inform this debate, a detailed survey of the available literature related to environmental assessments of closed and open cycles has been undertaken. Environmental impacts are one of the three pillars that, alongside economic and societal impacts, must be considered for sustainable development. The aims are to provide a critical review of the open literature in order to determine what generic conclusions can be drawn from the broad base of international studies. This review covers the results of life cycle assessments and studies on waste arisings, showing how the management of spent fuels in the open and closed cycles impact the... [more]

Improving energy efficiency and increasing the level of intelligence are two main factors determining the current development trends for new and modernized buildings. They are especially important in the perspective of development of prosumer installations and local microgrids. A key tool to achieve these goals is a well-designed and implemented Building Automation and Control System (BACS). This paper presents a new hybrid approach to the design and technical organization of BACS based on the provisions of the EN 15232 standard and the guidelines of the Smart Readiness Indicator (SRI) defined in the Energy Performance of Buildings Directive 2018 (EPBD 2018). The main assumptions of this hybrid approach along with examples of functional BACS designs for small prosumer installations organized according to them are provided. Potential impact on building energy performance is discussed as well. Finally, a SWOT analysis of the possibility of merging the EN 15232 standard guidelines and the... [more]

The paper presents the results of analytical and experimental studies of the hydrodynamics of the translational−rotational motion of incompressible gas flow within a working space of a variable-geometry vortex heat generator. The terminal velocity and pressure have been identified analytically. The effect of vortex generation on the ratio of the parameters has been analyzed. A mathematical model has been developed with a simplified design scheme that simulates the movement inside a vortex channel with fixed elements. On the basis of mathematical modelling, the influence of the apparatus-constructive (AC) design of the working space of a vortex heat generator on the generation of vortices inside the apparatus has been analyzed. The influence of the main geometric and hydrodynamic parameters of the device on the indicators of its energy efficiency has been investigated. The obtained models show the critical regions where the most intense cavitation zones are possible. An analysis of the... [more]

This article presents the possibility of evaluating the efficiency of the heat exchange element with a special stamping plate, which is based on the results of computer simulation. The method is based on a comparative analysis of convective heat transfer models implemented in ANSYS using a k-ε turbulence model. To conduct the study, 3D models of three different types of cavity geometry formed between two heat exchange plates (flat plate, chevron plate, and plate with conical stampings) were built. Simulation was performed by finite element analysis in ANSYS for channels formed by the three types of plates, one of which is a new configuration. The results of hydrodynamic and heat exchange parameters allowed for establishing the efficiency of convective heat exchange for plates of known structures and to compare them with the proposed one. It was found that the plates with conical stamping form the smallest channels through which the fluid moves. The velocity of the coolant is uniform th... [more]

The study about the low-temperature performance of lithium-ion batteries (LIB) is of great significance at extreme temperatures, such as polar scientific research, space exploration, deep-sea exploration, military fields, and so on. In this study, normal devices and symmetrical devices were fabricated by ternary Li(Ni0.5Mn0.3Co0.2)O2 as cathode and graphite as anode at 25 and −20 °C. The results show that the specific discharge capacity of normal device is up to 120 mAh g−1 at 1 C and 25 °C. The specific capacity and energy density at 0.2 C and −20 °C are 106.05 mAh g−1 and 376.53 mWh g−1, respectively, which can reach 92.82% of that at 1 C and 25 °C. The value of activation energy Ea of the interface reaction of the LIB is calculated to be 63.72 kJ/mol by the Arrhenius equation. When the temperature dropped from 25 to −20 °C, the lattice spacing of Li1−x(Ni0.5Mn0.3Co0.2)O2 hardly changed, while the lattice spacing (002) of graphite reduces 0.00248 Å. In addition, some cracks were obse... [more]

In a modern smart energy system, the amount of available data from various sources is growing significantly. Other sectors such as medical or social sectors exhibit the same phenomenon. Due to the amount, complexity and heterogeneity of data, a complex algorithm is required for the integration and analysis of heterogeneous data sources. The Web of Things and semantic-based approaches address the fragmentation of standards, platforms, services and technologies in smart energy and non-energy sectors, and enable heterogeneous data integration and interoperability. This paper presents SiSEG, a semantic annotation service that is developed to automate the process of annotating data and address the problem of heterogeneous data integration in a reusable and extensible way by using the fuzzy method. Moreover, the accuracy of SiGEG has been evaluated.

This work uses the outcome of a computational tool that performs Energy Performance Certification (EPC) data processing and transforms raw data into comparable data. Multi-correlation among variables results in probability distributions for the most relevant form and fabric building parameters. The model consistently predicts the distributions for heating and cooling energy needs for the Lisbon Metropolitan Area, with an error below 7% for the first, second and third quartiles. Differences in the energy needs estimation are below 6% when comparing the seasonal steady-state with the resistance-capacitance (RC) model, which proved to be a robust alternative algorithm capable of modeling hourly user profiles. The RC model calculates electricity consumption for actual, adequate, and minimum thermal comfort scenarios corresponding to different user profiles. The actual scenario, built from statistics and a previous survey, defines a reference to evaluate other scenarios for the mean electri... [more]

Friction and heat generated in conventional bearings impose a limit on maximum design speed in electrical machines. Superconducting bearings offer the potential for low loss, simplified, and passively stable bearings that can overcome the speed limit and operate at high loads. Although such bearings are contactless and seem to be loss free, AC loss mainly caused by magnetic field inhomogeneity gradually slows down the rotating body. This loss, whose mechanism has not been fully explored, is measured through spin-down tests where the rotational speed of the spinning rotor is measured as a function of time. However, there are some challenges in performing a reliable spin-down test. In this paper, we discuss these challenges as well as the engineering of an experimental test rig that enables us to spin-up, release, and recapture the levitated permanent magnet. We also discuss the specifications of the driving mechanism including the self-aligning coupling, which accommodates permanent mag... [more]

Reducing green-house gases emission from light-duty vehicles is compulsory in order to slow down the climate change. The application of High Frequency Ignition systems based on the Corona discharge effect has shown the potential to extend the dilution limit of engine operating conditions promoting lower temperatures and faster combustion events, thus, higher thermal and indicating efficiency. Furthermore, predicting the behavior of Corona ignition devices against new sustainable fuel blends, including renewable hydrogen and biogas, is crucial in order to deal with the short-intermediate term fleet electric transition. The numerical evaluation of Corona-induced discharge radius and radical species under those conditions can be helpful in order to capture local effects that could be reached only with complex and expensive optical investigations. Using an extended version of the Corona one-dimensional code previously published by the present authors, the simulation of pure methane and dif... [more]

In the last years, the fact of anthropogenic impact on climate change taking place in the world has become indisputable. Both countries and international organizations have taken steps to reduce GHG emissions, move to a low-carbon economy and implement solutions that reduce human impact on the environment. The EU, by intensifying its activities, has also prepared a strategy known as the European Green Deal. In implementing the EGD, it is important to analyze the impact of energy development in energy-intensive sectors of the economy (industry, transport, agriculture, services and other cores) on atmospheric pollution. Energy development is understood as the energy consumption percentage from all its consumption. In the article, complex correlation−regression analysis was implemented, which included not only energy development impact on the CO2 emissions level (i.e., production-based CO2 efficiency), but also its impact on economic growth. The research was conducted for the EU euro area... [more]

In this study, an online cell screening algorithm is proposed to estimate the maximum peak current considering the cell inconsistencies in battery packs for electric vehicles. Based on the equivalent circuit model, the maximum peak current is mathematically defined, and the inconsistency parameters affecting the maximum peak current are analyzed. The proposed algorithm compares the inconsistency parameters of each cell and subsequently selects a cell or a group of cells whose voltage can exceed the allowable voltage range. The maximum peak current is determined based on the selected cells, while ensuring that all the cells are charged and discharged within the allowable voltage range. The feasibility and superiority of the proposed algorithm are verified through an experiment conducted on a commercially manufactured battery pack for electric vehicles.

Battery Electric Buses (BEBs) are considerably integrated into cities worldwide. These buses have a strict schedule; thus, they could be charged in a very short time with a power level up to 600 kW. The high-power systems and short charging times imply special grid operation conditions that should be taken into account. Therefore, it is necessary to consider the influence of their charging infrastructure on the distribution system operation, especially near the charging point. This work presents two Use Cases (UCs) from two demos (Germany and the Netherlands) to investigate the impact of the slow and fast-chargers’ integrations on the power grid and environment. Fast-chargers up to 350 kW based on pantograph technology and slow-chargers up to 50 kW based on Combined Charging System Type 2 (CCS2) are used on the BEB line route and in the depot, respectively. The charging of BEBs with these solutions is studied here to investigate their impact on the grid in terms of power quality. It wa... [more]

The growth in the number of vehicles circulating has led to a proportional increase in polluting gas emissions. Bioenergy can be used to help meet these increasing energy demands and mitigate environmental impacts. This work verified the effect of the content of ethanol on the exergy and exergoenvironmental analyses of a spark-ignition engine. Different gasoline−ethanol mixtures were tested along with hydrous ethanol (4.6% water by volume). The thermodynamic data refer to wide-open throttle conditions and variable engine speeds. The life cycle assessment methodology quantified the environmental impacts associated with equipment and fuel using the Eco-indicator 99 method. Pollutants emitted during combustion were measured and included in the environmental assessment (nitrogen oxides, carbon monoxide, and dioxide). Hydrous ethanol at 1500 rpm presented the highest energy efficiency. The effects of the environmental impact rate of pollutant formation and exergy efficiency were significant... [more]

In order to avoid high-temperature and large rate discharge impact on the performance of battery modules, a microchannel liquid cooling battery thermal management system (BTMS) and BTMS virtual model of the microchannel structure based on digital twin (DT) is proposed. On the basis of accurate virtual simulation model, the computational fluid dynamics (CFD) model and the Gaussian process regression algorithm were combined to drive the optimization process in order to improve the cooling capacity of the system. The results show that the microchannel plates can greatly enhance the cooling capacity of the direct cooling system and effectively improve the uniformity of the coolant. The width of the microchannel plates and the side spacing actually represent the amount of coolant flowing through the inside and outside of the battery module, which significantly impacts the maximum temperature and maximum temperature difference. Increasing the coolant flow can only effectively improve the coo... [more]

This study aims to improve the electrochemical properties of lithium metal for application as a negative electrode in high-energy-density batteries. Lithium metal was heat-treated at varying temperatures to modify the native and solid electrolyte interphase (SEI) films, which decreased the interfacial resistance between the lithium electrode and electrolyte, thereby improving the cycling performance. Moreover, the influence of the native and SEI films on lithium metals depended on the heat-treatment temperature. Accordingly, X-ray photoelectron spectroscopy (XPS) was performed to investigate the chemical composition of the native and SEI films on the heat-treated lithium metals before and after immersion in an organic electrolyte solution. The XPS results revealed the high dependence of the chemical composition of the outer layer of the native and SEI films on the heat-treatment temperature, implying that the native and SEI films can be effectively modified by heat treatment.

The main aim of the research is to evaluate the innovativeness of Polish municipalities in the field of energy. The study was carried out as a part of the First National Competition for the Most Innovative Local Government in Poland, taking into account the original method of assessing the innovativeness of local governments. From all over Poland, 30 communes participated in the research: 14 urban communes, 8 rural communes, and 8 urban−rural communes. The study analyzes the activities of municipalities in the field of energy-related construction and transport innovations and inventories innovative social campaigns in the area of climate and energy policy implementation. The second part of the article presents a case study of innovations recognized as exemplary. As a result of the conducted research, it was found that 50% of the surveyed local governments are innovative and the remaining are moderately innovative. No commune has been assigned to the non-innovative category. In terms of... [more]

Local area energy networks (E-LANs) are cyber-physical systems whose physical layer is a meshed low-voltage microgrid fed by a multiplicity of sources, i.e., utilities, energy storage systems, and distributed power sources. The cyber layer includes distributed measurement, control, and communication units, located at end-user premises, as well as centralized supervision and dispatchment control. As compared with standard microgrid, the E-LAN encompasses the ability for end-users to actively contribute to the operation of the microgrid while acting as independent energy traders in the electrical market. Operational goals include active contribution of end-users to power sharing, loss reduction, voltage stability, demand response, fault identification and clearing, isolation of sub-grids for maintenance, islanding, and black start. Economic goals include the possibility, for each end-user, to decide in every moment, based on convenience, how his energy and power capacity is shared with o... [more]

Hydrothermal carbonisation (HTC) can be integrated with anaerobic digestion (AD) for the treatment of digestate, resulting in a solid hydrochar or bio-coal and a process water, which can be recirculated back into AD to produce biogas. The properties of digestate-derived hydrochars do not lend themselves to producing high quality bio-coal and blending with lignocellulosic feedstocks can improve its properties. This study investigates the co-processing of sewage sludge (SS) digestate with three lignocellulosic biomass (grass, privet hedge, and woodchip). The calorific value of the resulting bio-coal is increased following co-processing, although feedstock interactions result in non-additive behaviour. The largest increase in calorific value was observed for co-processing with woodchip. There is evidence for non-additive partitioning of metals during co-processing resulting in only moderate improvements in ash chemistry during combustion. Co-processing also effects the composition of proc... [more]

This article presents an overview of the graphical user interfaces (GUIs) developed at CEA/SERMA (Service d’Études des Réacteurs et de Mathématiques Appliquées) in Saclay, France, which have been used for over forty years by engineers and scientists to build geometries and meshes for general-purpose lattice transport calculations (neutrons and photons). Several applications make use of these calculations, from fuel assembly to full core design, criticality and safety, needing consistency check of the geometry and input properties before starting any lattice calculation. The software pattern design of the GUIs is briefly discussed, showing also the rationale behind the two interfaces for the construction of the geometries for simple fuel assemblies and complex motifs including the reflector (colorsets). The new GUI, ALAMOS, specifically developed for APOLLO3® with a Python Application Programming Interface (API), is here presented as the successor of Silène, which was the first GUI rele... [more]