Showing papers in "Energies in 2021"

Abstract: The paper presents results of tests on the effect of the addition of fly ash (FA) in the amounts of 0%, 20%, and 30% by weight of cement on the interfacial microcracks in concrete composites subjected to dynamic loads. The analyses were carried out based on the results of the microstructural tests using a scanning electron microscope (SEM). The average width of the microcracks (Wc) in the interfacial transition zone (ITZ) of coarse aggregate with cement matrix was evaluated. During the studies beneficial effect of the addition of FA on reduction of the size of Wc in the ITZ of concrete composites under dynamic loading were observed. Based on obtained test results, it was found that using the 20% FA additive causes favorable changes in the microstructure of mature concrete. In this composite, the average value of Wc was lower by more than 40% compared to the result obtained for the reference concrete. In contrast, concrete containing 30% FA additive had greater microcracks in the ITZ area by over 60% compared to the material without additive. In all analyzed composites, an increase in the Wc value by almost 70% to over 110% in the case of occurrence of dynamic loads was also observed. This was the most evident in the case of concrete with a higher content of FA.

Abstract: This paper aims to check the impact of investment and institutional determinants on the energy efficiency gap. The findings of the bibliometric analysis confirmed the growth of research interests in identifying the core determinants of the energy efficiency gap. The central hypothesises are: the increasing quality of the institutions leads to an increase of green investments in the energy sector and the dual relationships between investment and institutional determinants lead to additional synergy effects, which allow boosting the decline of energy efficiency gaps of the national economy. For the analysis, the times series were collected from the World Data Bank, Eurostat, Bloomberg, for Ukraine for the period of 2002–2019. The following methods were used: the unit root test—for checking the stationarity of data—and the Johansen test and VEC-modelling—for the cointegration analysis. The findings prove that to reduce the energy efficiency gaps in Ukraine by 1% next year, it is necessary to increase green energy investments by 1.5% this year, and the political stability and public perception of corruption by 3% and 1%. The increase of the public perception of corruption by 1.47 points and of political stability by 2.38 points leads to maximising the recovery speed of the Ukrainian energy sector. Thus, while developing the policy to decrease the energy efficiency gaps, the Ukrainian government should consider the level of public perception of corruption and political stability.

Abstract: Renewable microgrids are new solutions for enhanced security, improved reliability and boosted power quality and operation in power systems. By deploying different sources of renewables such as solar panels and wind units, renewable microgrids can enhance reducing the greenhouse gasses and improve the efficiency. This paper proposes a machine learning based approach for energy management in renewable microgrids considering a reconfigurable structure based on remote switching of tie and sectionalizing. The suggested method considers the advanced support vector machine for modeling and estimating the charging demand of hybrid electric vehicles (HEVs). In order to mitigate the charging effects of HEVs on the system, two different scenarios are deployed; one coordinated and the other one intelligent charging. Due to the complex structure of the problem formulation, a new modified optimization method based on dragonfly is suggested. Moreover, a self-adaptive modification is suggested, which helps the solutions pick the modification method that best fits their situation. Simulation results on an IEEE microgrid test system show its appropriate and efficient quality in both scenarios. According to the prediction results for the total charging demand of the HEVs, the mean absolute percentage error is 0.978, which is very low. Moreover, the results show a 2.5% reduction in the total operation cost of the microgrid in the intelligent charging compared to the coordinated scheme.

Abstract: Short-term electrical load forecasting plays an important role in the safety, stability, and sustainability of the power production and scheduling process. An accurate prediction of power load can provide a reliable decision for power system management. To solve the limitation of the existing load forecasting methods in dealing with time-series data, causing the poor stability and non-ideal forecasting accuracy, this paper proposed an attention-based encoder-decoder network with Bayesian optimization to do the accurate short-term power load forecasting. Proposed model is based on an encoder-decoder architecture with a gated recurrent units (GRU) recurrent neural network with high robustness on time-series data modeling. The temporal attention layer focuses on the key features of input data that play a vital role in promoting the prediction accuracy for load forecasting. Finally, the Bayesian optimization method is used to confirm the model’s hyperparameters to achieve optimal predictions. The verification experiments of 24 h load forecasting with real power load data from American Electric Power (AEP) show that the proposed model outperforms other models in terms of prediction accuracy and algorithm stability, providing an effective approach for migrating time-serial power load prediction by deep-learning technology.

Abstract: In the 21st century, it is becoming increasingly clear that human activities and the activities of enterprises affect the environment. Therefore, it is important to learn about the methods in which companies minimize the negative effects of their activities. The article presents the steps taken and innovative actions carried out by enterprises in the energy sector. The article analyzes innovative activities undertaken and implemented by enterprises from the energy sector. The relationships between innovative strategies, including, inter alia, digitization, and Industry 4.0 solutions, in the development of companies and the achieved results concerning sustainable development and environmental impact. Digitization has far exceeded traditional productivity improvement ranges of 3–5% per year, with a clear cost improvement potential of well above 25%. Enterprises on a large scale make attempts to increase energy efficiency by implementing the state-of-the-art innovative technical and technological solutions, which increase reliability and durability (material and mechanical engineering). Digitization of energy companies allows them to reduce operating costs and increases efficiency. With digital advances, the useful life of an energy plant can be increased up to 30%. Advanced technologies, blockchain, and the use of intelligent networks enables the activation of prosumers in the electricity market. Reducing energy consumption in industry and at the same time increasing energy efficiency for which the European Union is fighting in the clean air package for all Europeans have a positive impact on environmental protection, sustainable development, and the implementation of the decarbonization program.

Abstract: With the development of technologies in recent decades and the imposition of international standards to reduce greenhouse gas emissions, car manufacturers have turned their attention to new technologies related to electric/hybrid vehicles and electric fuel cell vehicles. This paper focuses on electric fuel cell vehicles, which optimally combine the fuel cell system with hybrid energy storage systems, represented by batteries and ultracapacitors, to meet the dynamic power demand required by the electric motor and auxiliary systems. This paper compares the latest proposed topologies for fuel cell electric vehicles and reveals the new technologies and DC/DC converters involved to generate up-to-date information for researchers and developers interested in this specialized field. From a software point of view, the latest energy management strategies are analyzed and compared with the reference strategies, taking into account performance indicators such as energy efficiency, hydrogen consumption and degradation of the subsystems involved, which is the main challenge for car developers. The advantages and disadvantages of three types of strategies (rule-based strategies, optimization-based strategies and learning-based strategies) are discussed. Thus, future software developers can focus on new control algorithms in the area of artificial intelligence developed to meet the challenges posed by new technologies for autonomous vehicles.

Abstract: The current approaches to estimating the level of energy security are based on applying a comprehensive approach to selecting the factors that affect energy security and the dynamics of processes in this domain. This article reveals the application of the model of energy security estimation and strategizing based on the systemic description of energy security as an object of management: the integral system, elements and connections, functions, processes, and the system’s material. At the same time, this model is able to take into account the dynamics of technological, political, economic, and other factors operating in the country and on the global arena. The energy security estimation model developed uses a modern methodology of integrated estimation: a multiplicative form of the integrated index, a formalized definition of the safe existence limits in order to provide scientific substantiation of the threshold vector, a modified rationing method, the principal components method, and the sliding matrix method to substantiate dynamic weighting coefficients. The paper demonstrates the systemic approach application to shaping strategic goals in the energy security domain in the context of sustainable development; the trajectory of energy security development is calculated by the method of strategizing that applies the principle “future is determined by the trajectory to the future” instead of the classical forecasting “past determines the future”. In general, the article shows the possibility of unifying the process of formalizing energy security (according to the needs of the researcher: country, industry, energy network, supply chain) as an object of management, estimating energy security status, and strategizing the regulatory sphere transformation in accordance with the target values for monitoring the effectiveness of management.

Abstract: The purpose of this study is to examine the relationship between renewable energy sources and economic growth of the South Asian Association for regional cooperation (SAARC) countries. This study uses three main renewable energy sources, namely geothermal, hydro, and wind.This study collects data set from SAARC countries from 1995 to 2018 and applies a fixed effect test and panel vector error correction model (PVECM) for data analysis. The overall results show that all three renewable energy sources have a positive significant impact on economic development among SAARC countries’ economies. Moreover, hydropower renewable energy has more effects and influences on economic growth as compared to the other two individual sources of renewable energy.

Abstract: The present study is in line with the United Nations Sustainable Development Goals (UN-SDGs) that address pertinent global issues. This study focuses on the need for access to clean and affordable energy consumption, responsible energy consumption, sustainable economic growth, and climate change mitigation. To this end, this paper evaluates the relevance of the renewable energy sector on the environmental Kuznets curve (EKC) framework in Portugal, Italy, Greece, and Spain for the period 1995–2015. As an econometric strategy, we adopt the use of panel data over the highlighted countries. In the first step, we apply the unit root test recommended by Levin, Lin, and Chu in conjunction with ADF-Fisher, and Phillips-Perron for robustness and consistency. We found that the variables used in this study are integrated I (1) in the first difference. In the second step, we apply the Pedroni cointegration test, and Kao Residual cointegration test, and we observe that the variables are cointegrated in the long run. The generalized least squares (GLS), the panel fully modified least squares (FMOLS), ordinary least squares robust (OLS), and panel quantile regression are considered in this research. The econometric results validate the assumption of the environmental Kuznets curve, i.e., and there is a positive correlation between income per capita and a negative effect of squared income per capita on carbon dioxide emissions. In contrast, we observe that renewable energy reduces CO2 emissions. Finally, we also find a direct connection between the urban population and the environmental degradation in the examined blocs. These results show that in Portugal, Italy, Greece, and Spain, more is required to achieve environmental sustainability in the respective countries growth trajectory. Further policy prescriptions are appended in the concluding section of this study.

Abstract: There are a lot of studies that show the legitimacy of subsidizing renewable energy; however, some mechanisms are defective, and there are problems with the appropriate allocation of funds. Therefore, this paper aims to look at the situation of allocating funds to photovoltaics (PV) micro-installations in Poland through the “My Electricity” program. The article presents the results of analyses aimed at identifying inequalities between provinces in the use of funds available under the “My Electricity” program and verifying whether these inequalities are getting worse and whether the intensity of support should not be territorially conditioned in terms of maximization an electricity production. As part of two editions of the “My Electricity” program (until 1 August 2020), over 64,000 PV micro-installations were created with an average power of approximately 5.7 kWp. The total installed PV capacity was 367.1 MWp (1st edition: 159.3 MWp, 2nd edition: 207.8 MWp). Financial resources (as a whole), in the second edition of “My Electricity” program, were distributed better than in the first edition. In the first edition, as much as 7.60% of funds were allocated inefficiently; in the second edition, it was only 3.88%. Allocation surpluses occur in provinces where the average disposable income is low and where there are a small number of households. There is a potential to introduce a territorial project selection criteria. The analysis shows that the criteria should promote provinces with higher disposable income and a larger number of households.

Abstract: Every year the interest in biofuels, including biomethane, grows in Poland. Biomethane, obtained from biogas, is widely used in the Polish economy; the most important two applications are as gas injected into the gas grid and as automotive fuel. The aim of this work is to determine the potential for the development of the biomethane sector in Poland. The following article presents the technological stages of biomethane extraction and purification. The investment process for biogas/biomethane installation is presented in the form of a Gannt chart; this process is extremely long in Poland, with a duration of three years. In the coming months, the Polish Oil Mining and Gas Extraction will begin to invest in biomethane, which will be connected to the gas grid, while the Polish oil refiner and petrol retailer, Orlen, will invest in biomethane to be used as automotive fuel. This article includes a SWOT (Strengths, Weaknesses, Opportunities, Threats) and PEST (Political, Economic, Social, Technological) analysis of the biogas/biomethane sector in Poland. The main barriers to the development of the biogas/biomethane sector in Poland are high investment costs, long lead times and a strong conventional energy lobby. The most important advantages of biogas/biomethane technology in Poland include environmental aspects, high biomethane potential and well-developed agriculture. The development of biogas/biomethane technology in Poland will slowly reduce environmental pollution, reduce carbon dioxide emissions and allow for partial independence from the importing of natural gas.

Abstract: To ensure optimum working conditions for lithium-ion batteries, a numerical study is carried out for three-dimensional temperature distribution of a battery liquid cooling system in this work. The effect of channel size and inlet boundary conditions are evaluated on the temperature field of the battery modules. Based on the thermal behavior of discharging battery obtained experimental measurements, two temperature control strategies are proposed and studied. The results show that the channel width of the cooling plates has a great influence on the maximum temperature in the battery module. It is also revealed that increasing inlet water flow rate can significantly improve the heat transfer capacity of the battery thermal management system, while the relationship between them is not proportional. Lowering the inlet temperature can reduce the maximum temperature predicted in the battery module significantly. However, this will also lead to additional energy consumed by the cooling system. It is also found that the Scheme 5 among various temperature control strategies can ensure the battery pack working in the best temperature range in different depths of discharge. Compared with the traditional one with a given flow rate, the parasitic energy consumption in Scheme 5 can be reduced by around 80%.

Abstract: The topic of the article considers the functioning of the renewable energy (RE) sector in Poland. This is really important in the context of the energy transition of the national economy because it influences the creation of modern technologies and increases the competitiveness and innovation of the country. Poland is in a process of energy transition where the RE sector has been developing for two decades. The authors aimed to research the RE sector improvement possibilities in Poland, including the influence of this sector on chosen social and economic aspects. Because of this research’s aim a critical situation assessment of RE in Poland was conducted and a survey of a group of experts in this field was also involved. Legal, physical and mental determinants and their influence on RE sector were looked into. In the legal determinant context a necessity to simplify relevant legislation acts in Poland was found. Undoubtedly there is a need to improve several legal acts, including the Distance Act. In physical determinants it was found that solar, wind and biomass energy have the biggest chances for development. In the case of mental determinants the authors paid attention to the need of educating the public about using and obtaining energy. It is also important to make people aware how the RE sector influences the low emission economy positively. This will improve the creation of new jobs and reduce the emissions of harmful substances to the environment.

Abstract: The article aims to enhance understanding of how relations, behavior and attitude of the executives and contractors to achieving the objectives by energy supplying companies affect the efficiency of the latter’s overall development. There is offered a factor-reflexive approach to diagnosing the executives’ and contractors’ attitude to realizing the tasks of developing the energy supplying companies. This approach includes models to identify and analyze the factors that influenced the change in contractors’ behavior based on the combination of expert techniques, correlation and regression analysis and evaluation of the personnel response to organizational, resource and staffing projects development, through accumulating sufficient statistical information based on the enterprise’s features, relations and environment. This approach to diagnosing executives’ and contractors’ response to the implementation of tasks and the resulting changes takes into account the subjective component of their response. Practical implementation of this approach in monitoring the conformity of the development tasks has proven the ability to identify problems from the viewpoint of the task executives.

Abstract: With the growing application of green energy, the importance of effectively handling the volatile nature of these energy sources is also growing in order to ensure economic and operational viability. Accordingly, the main contribution of this work is to evaluate the revenue potential for wind parks with integrated storage systems in the day-ahead electricity markets using genetic algorithm. It is achieved by the concept of flexible charging–discharging of the Energy Storage System (ESS), taking advantage of the widespread electricity prices that are predicted using a feedforward-neural-network-based forecasting algorithm. In addition, the reactive power restrictions posed by grid code that are to be followed by the wind park are also considered as one of the constraints. Moreover, the profit obtained with a Battery Energy Storage System (BESS) is compared with that of a Thermal Energy Storage System (TESS). The proposed method gave more profitable results when utilizing BESS for energy arbitrage in day-ahead electricity markets than with TESS. Moreover, the availability of ESS at wind park has reduced the wind power curtailment.

Abstract: The solar irradiation at the gulf Arabia is considered one of the highest in the world. However, this region is classified as a desert with high dust accumulation. Thus, the objective of this study is to analyze the effect of soiling and the photovoltaic (PV) tilt angle on the performance of 2.0 MWp of car park PV plant in Oman. Experimental measurements were taken and a model was developed for simulation. The power generation by the cleaned PV system was measured as 1460 kW around noon. After one week of operation, the power production (at the same irradiance level) reduced to 1390 kW due to soiling. It further reduced to 1196 kW and 904 kW after three and five weeks of operation, respectively. The results also show that a soiling-percentage of 7.5% reduced the monthly electricity generation (307 MWh) by 5.6% and a soiling-percentage of 12.5% reduced the generation by 10.8%. Furthermore, the increase in tilt is not recommended due to the duo-pitch canopy effect of the car park where the panels with 180° azimuth generate lower electricity than the panels with 0° azimuth. In addition, the part of the car park with 180° azimuth caused shading to the other part for high tilt angles.

Abstract: The main purpose of the paper was to present the energy balance in the EU countries. The specific objectives were to show the concentration and directions of changes in the demand, production, import, and export of energy in the EU countries, to determine the degree of variability (or stability) of these energy balance parameters, and to establish the correlation between the energy balance parameters and economic parameters. All members of the European Union were determinedly selected for research on 31 December 2018 (28 countries). The research period embraced the years 2004–2018. The sources of materials were the literature on the topic and data from Eurostat. Descriptive, tabular, and graphical methods, Gini coefficient, Lorenz curve, coefficient of variation, Pearson’s linear correlation coefficient, and constant-based dynamics indicators were used in the analysis and presentation of materials. It was determined that only the demand for energy and its import in EU countries were nearly related to the economic situation. In turn, exports and production were medium and weakly correlated. In these parameters, economic factors had a smaller impact than other factors, such as political development or the level of energy development in the country. It was also found that the EU countries’ energy imports were characterized by lower volatility than its exports. As a rule, the most significant stabilization in the given parameters occurred in countries with a stable economy, the so-called developed economies, while the most significant volatility was in developing countries. Energy security is of great importance in all EU countries.

Abstract: This paper aims to identify the determinants of the decarbonisation processes in Poland within the scope of energy transformation. The purpose of the study is to identify how the public perceives decarbonisation determinants in order to develop a sustainable energy strategy for Poland. The transition of the energy market to low-carbon technology is a policy challenge. Governments must implement policies that are environmentally friendly, cost-effective, but, most of all, socially acceptable. Social acceptance risk plays a significant role in Poland, influencing the decarbonisation process. In Poland’s case, the coal share is decreasing, but it is still the most important fuel for electricity production. This process of decarbonisation is a fundamental influence on the transformation of the energy sector in Poland. The social perception of solutions that can be applied was examined. The Polish natural environment is poisoned. Poles suffer from diseases related to the burning of coal for energy production. Societal awareness, how people perceive the government’s actions, and what they expect in this regard is crucial.

Abstract: Electromobility is a growing technology for land transport, constituting an important element of the concept of sustainable economic development. The article presents selected research results concerning one of the segments of this market-vehicles powered by hydrogen fuel cells. The subject of the research was to gain extensive knowledge on the economic factors influencing the future purchasing decisions of the demand side in relation to this category of vehicles. The research was based on a numerical experiment. For this purpose, a comparative analysis of purchase prices in relation to the TCO of the vehicle after 3–5 years of use was performed. The research included selected models that are powered by both conventional and alternative fuels. The use of this method will allow to assess the real costs associated with the hydrogen vehicle. The authors emphasize the important role of economic factors in the form of the TCO index for the development of this market. The experimental approach may be helpful in understanding the essence of economic relations that affect the development of the electro-mobility market and the market demand for hydrogen fuel cell-powered vehicles in Poland.

Abstract: According to the United Nations (UN), although cities occupy only 3% of Earth’s surface, they host more than half of the global population, are responsible for 70% of energy consumption, and 75% of carbon emissions. All this is a consequence of the massive urbanization verified since the 1950s and which is expected to continue in the coming decades. A crucial issue will therefore concern the management of existing cities and the planning of future ones, and this was also emphasized by the UN Sustainable Development Goals (SDGs), especially in Goal 11 (Sustainable Cities and communities). Smart Cities are often seen as ideal urban environments in which the different dimensions of a city (economy, education, energy, environment, etc.) are managed successfully and proactively. So, one of the most important challenges cities will have to face, is to guide citizens towards a form of “clean” energy consumption, and the dimension on which decision-makers will be able to work is the decarbonization of transport. To achieve this, electric mobility could help reduce polluting emissions on the road. Within this research, the strategies that six Smart Cities (London, Hamburg, Oslo, Milan, Florence, and Bologna) have implemented to encourage the transition to this form of mobility have been studied. Through a systematic review of the literature (Scopus, Google Scholar, and Web of Science) and through the study of the main political/energy documents of the cities, their policies on electric mobility have been evaluated. Then, for each city, SDG 11.6.2 was analyzed to assess the air quality in the last four years (2016–2019) and, therefore, the effectiveness of the policies. The analysis showed, in general, that the policies have worked, inducing reductions in the pollutants of PM2.5, PM10, NO2. In particular, the cities showed the most significant reduction in pollutant (above 20%) were Hamburg (−28% PM2.5 and −2%6 NO2), Milan (−25% PM2.5 and −52% NO2), and London (−26% NO2).

Abstract: Seismic data and nuclear magnetic resonance (NMR) data are two of the highly trustable kinds of information in hydrocarbon reservoir engineering. Reservoir fluids influence the elastic wave velocity and also determine the NMR response of the reservoir. The current study investigates different pore types, i.e., micro, meso, and macropores’ contribution to the elastic wave velocity using the laboratory NMR and elastic experiments on coal core samples under different fluid saturations. Once a meaningful relationship was observed in the lab, the idea was applied in the field scale and the NMR transverse relaxation time (T2) curves were synthesized artificially. This task was done by dividing the area under the T2 curve into eight porosity bins and estimating each bin’s value from the seismic attributes using neural networks (NN). Moreover, the functionality of two statistical ensembles, i.e., Bag and LSBoost, was investigated as an alternative tool to conventional estimation techniques of the petrophysical characteristics; and the results were compared with those from a deep learning network. Herein, NMR permeability was used as the estimation target and porosity was used as a benchmark to assess the reliability of the models. The final results indicated that by using the incremental porosity under the T2 curve, this curve could be synthesized using the seismic attributes. The results also proved the functionality of the selected statistical ensembles as reliable tools in the petrophysical characterization of the hydrocarbon reservoirs.

Abstract: This review presents a detailed summary of the latest technologies used in flywheel energy storage systems (FESS). This paper covers the types of technologies and systems employed within FESS, the range of materials used in the production of FESS, and the reasons for the use of these materials. Furthermore, this paper provides an overview of the types of uses of FESS, covering vehicles and the transport industry, grid leveling and power storage for domestic and industrial electricity providers, their use in motorsport, and applications for space, satellites, and spacecraft. Different types of machines for flywheel energy storage systems are also discussed. This serves to analyse which implementations reduce the cost of permanent magnet synchronous machines. As well as this, further investigations need to be carried out to determine the ideal temperature range of operation. Induction machines are currently stoutly designed with lower manufacturing cost, making them unsuitable for high-speed operations. Brushless direct current machines, the Homolar machines, and permanent magnet synchronous machines should also be considered for future research activities to improve their performance in a flywheel energy storage system. An active magnetic bearing can also be used alongside mechanical bearings to reduce the control systems’ complications, thereby making the entire system cost-effective.

Abstract: This paper presents an empirical study on the impact of maintenance function on more sustainable manufacturing processes. The work methodology comprises four stages. At first, ten factors of maintenance activities from a sustainable manufacturing point of view were identified. Then, in the second stage, the matrix of crossed impact multiplications applied to a classification (MICMAC) was carried out to categorize these factors based on their influence and dependence values. In the third stage, the criteria for evaluation of maintenance factors were defined, then the fuzzy analytic hierarchy process (F-AHP) was applied to determine their relative weights. In the last stage, the results of MICMAC and F-AHP analyses were used as inputs for the fuzzy technique for order preference by similarity to ideal solution (F-TOPIS) to generate aggregate scores and selection of the most important maintenance factors that have an impact on sustainable manufacturing processes. A numerical example is provided to demonstrate the applicability of the approach. It was observed that factors “Implementation of preventive and prognostic service strategies”, “The usage of M&O data collection and processing systems”, and “Modernization of machines and devices” are the major factors that support the realization of sustainable manufacturing process challenges.

Abstract: Attaining sustainable development and cleaner production is a major challenge both for developed and developing economies; income, institutional regulations, institutional quality and international trade are the key determinants of environmental externalities The current work attempts to study the role of environmental taxes and regulations on renewable energy generation for developed economies For that, the authors have used the annual dataset for the period 1994 to 2018 More specifically, the study investigates the impacts of environmental taxes, environment-related technologies and the environmental policy stringency index on renewable electricity generation in 29 developed countries Given the short available data of these countries, the authors have developed panel cointegration and panel regressions models (fully modified ordinary least square (FMOLS), quantile regressions) The heterogeneous panel empirics stated that environmental regulations and income level support renewable electricity generation The conclusions further mention that bureaucratic qualities such as decision making and trade openness tend to reduce renewable energy generation The empirical findings allowed us to draw new narrative and implications Overall, the conclusions argue that innovative regulations and policies can be useful for attaining specific sustainable development goals (eg, SDG-7: cleaner and cheap energy)

Abstract: This paper focuses on effects of implementing zero-emission buses in public transport fleets in urban areas in the context of electromobility assumptions It fills the literature gap in the area of research on the impact of the energy mix of a given country on the issues raised in this article The main purpose of this paper is to identify and analyse economic effects of implementing zero-emission buses in public transport in cities The research area was the city of Szczecin, Poland The research study was completed using the following research methods: literature review, document analysis (legal acts and internal documents), case study, ratio analysis, and comparative analysis of selected variants (investment variant and base variant) The conducted research study has shown that economic benefits resulting from implementing zero-emission buses in an urban transport fleet are limited by the current energy mix structure of the given country An unfavourable energy mix may lead to increased emissions of SO2 and CO2 resulting from operation of this kind of vehicle Therefore, achieving full effects in the field of electromobility in the given country depends on taking concurrent actions in order to diversify the power generation sources, and in particular on increasing the share of Renewable Energy Sources (RES)

Abstract: The COVID-19 pandemic represents not just a global health crisis, but may signal the beginning of a new era of economic activity, the potential consequences of which we currently do not fully understand. In this context, the mid-to-long-range impacts of the pandemic on the energy sector have been studied extensively in the last few months. Despite these efforts, the pandemic still raises many open questions concerning the long-term operation and planning of power systems. For instance, how will the pandemic affect the integration of renewable energy sources? Should current power system expansion plans change in light of the COVID-19 pandemic? What new tools should be provided to support system operators during global health crises? It is the purpose of this paper to better understand the many aspects of these open questions by reviewing the relevant recent literature and by analyzing measured data. We point out the main challenges that the pandemic introduced by presenting patterns of electricity generation and demand, frequency deviations, and load forecasting. Moreover, we suggest directions for future research that may assist in coping with the mentioned challenges. We hope that this paper will trigger fruitful discussions and encourage further research on these important emerging topics.

Abstract: Urban agglomerations close to road infrastructure are particularly exposed to harmful exhaust emissions from motor vehicles and this problem is exacerbated at road intersections. Roundabouts are one of the most popular intersection designs in recent years, making traffic flow smoother and safer, but especially at peak times they are subject to numerous stop-and-go operations by vehicles, which increase the dispersion of emissions with high particulate matter rates. The study focused on a specific area of the city of Rzeszow in Poland. This country is characterized by the current composition of vehicle fleets connected to combustion engine vehicles. The measurement of the concentration of particulate matter (PM2.5 and PM10) by means of a preliminary survey campaign in the vicinity of the intersection made it possible to assess the impact of vehicle traffic on the dispersion of pollutants in the air. The present report presents some strategies to be implemented in the examined area considering a comparison of current and project scenarios characterized both by a modification of the road geometry (through the introduction of a turbo roundabout) and the composition of the vehicular flow with the forthcoming diffusion of electric vehicles. The study presents an exemplified methodology for comparing scenarios aimed at optimizing strategic choices for the local administration and also shows the benefits of an increased electric fleet. By processing the data with specific tools and comparing the scenarios, it was found that a conversion of 25% of the motor vehicles to electric vehicles in the current fleet has reduced the concentration of PM10 by about 30% along the ring road, has led to a significant reduction in the length of particulate concentration of the motorway, and it has also led to a significant reduction in the length of the particulate concentration for the access roads to the intersection.

Abstract: The article presents the methodology of isolating aperiodic phenomena constituting the basis of the energy balance of vehicles for the analysis of electromobility system indicators. The symptom observation matrix (SOM) and experimental input data are used to analyze periodic phenomena symptoms. The multidimensional nature of the engine efficiency shortage has been well defined and analyzed in terms of errors in the general model using neural networks, singular value decomposition, and principal component analysis. A more difficult task is the analysis of a multidimensional decision-making process. The research used a data fusion method and the concept of symptom reliability, which is applied to the generalized failure symptom obtained by applying the singular value decomposition (SVD). The model research has been based on the gray system theory (GST) and GM forecasting models (1,1). Input data were obtained from the assessment of driving cycles and analysis of the failure frequency for 1200 vehicles and mileage of 150,000 km. Based on this analysis, it can be concluded that with the current infrastructure and operating costs and the frequency of failure of PHEV and BEV drives, ICEV vehicles are unrivaled in terms of their operating costs.

Abstract: Banks Strait, Tasmania, Australia, has been identified as a potential site for the deployment of tidal turbines. In this study, the characterization of sediment transport and large sand waves for this site is performed. Observations of bed level change collected from surveys in 2018 showed a migration of large sand waves over a period of nine months. Migration rates in an excess of one hundred meters for nine months were found, which are large compared to the rate reported at other coastal sites, by several meters per year. A validated hydrodynamic model is coupled with a morphodynamic model to perform sensitivity tests and identify what parameters influence migration to better understand sediment dynamic in the Banks Strait. Numerical analysis showed a constant shift of the sand waves profile in an eastward direction, consistent with the observations. This migration was strongly linked with tidal asymmetry, with a residual current flowing towards the east. The principal parameters driving the migration of sand waves in the Banks Strait were found to be sediment sorting, bed friction and residual current. This study gives new insights for the seabed of Banks Strait and provides an assessment of the natural variability of sediment for futures tidal farms deployments.

Abstract: The longitudinal vibration of the drill pipe contains considerable energy which can be used to improve the rock-breaking efficiency during drilling. It is very important to the development of drilling speed-up tools to have a comprehensive understanding of the energy conversion efficiency of downhole drill string vibration. In this paper, the characteristics of downhole bit load and longitudinal vibration of drill string under different conditions were studied in the experiment, and the analysis method of energy conversion efficiency from drill string vibration to spring potential energy was proposed. The experimental analysis showed that the fluctuation of the downhole bit load was reduced by 10%–90% after the spring was installed in the bottom hole assembly. The rotation rate and the spring elastic stiffness had a significant and positive influence on the fluctuation amplitude of the downhole bit load. Meanwhile, the longitudinal vibration amplitude and acceleration of the drill string peaked at the elastic stiffness of 1 kN/mm. The closer the spring position to the drill bit was, the more severe the longitudinal vibration of the drill string above the spring component was. The bit load and the rotation rate had a positive influence on the severity of longitudinal vibration. The analysis of energy conversion efficiency showed that the available mechanical energy range of the longitudinal vibration of the drill pipe was about 200–420 kW. The work power of the drill string vibration to the spring component increased sharply and then decreased with the increasing of elastic stiffness. The energy conversion efficiency came to the optimal value when the elastic stiffness was between 1 kN/mm and 2 kN/mm. Increasing the rotation rate, keeping the bit load below 134.5 kN and installing the spring component near the drill bit are beneficial for improving the energy conversion efficiency of drill string vibration. This paper reveals the main factors affecting the energy conversion efficiency of drill string vibration and their influencing laws, and determines the range of WOB, rotation speed, spring position and stiffness to obtain the best energy conversion efficiency.