New methods for the use of waste products as input for other technologies are a constant subject of research efforts. One such product is waste engine oil. Due to the constantly increasing number of motor vehicles in the world, the recycling or application of engine oils for energy production purposes is currently of considerable importance. This paper contains research regarding the analysis of the electro-oxidation potential of waste engine oil, and thus the possibility of using such oil as a material in fuel cells. The research demonstrates the basic possibility of the electro-oxidation of this oil emulsion on a platinum electrode in an acid electrolyte (aqueous solution of H2SO4). It was shown that in the temperature range of 20−80 °C, the electro-oxidation of the waste engine oil emulsion occurred for all emulsion concentrations (0.005%, 0.010%, 0.030%, and 0.060% of the reactor volume). The maximum current density obtained in the measurements was 21 mA·cm−2 at the temperature of... [more]

This paper presents a mathematical approach for determining the reliability of solar tracking systems based on three fault coverage-aware metrics which use system error data from hardware, software as well as in-circuit testing (ICT) techniques, to calculate a solar test factor (STF). Using Euler’s named constant, the solar reliability factor (SRF) is computed to define the robustness and availability of modern, high-performance solar tracking systems. The experimental cases which were run in the Mathcad software suite and the Python programming environment show that the fault coverage-aware metrics greatly change the test and reliability factor curve of solar tracking systems, achieving significantly reduced calculation steps and computation time.

Environmental problems such as air pollution and greenhouse gas emissions are caused by almost all transport modes. A potential solution to these problems could be electric mobility. Currently, efforts to increase the use of various types of electric vehicles are under way virtually worldwide. While in recent years a major focus was put on the electrification of passenger cars, electricity has already, for more than hundred years, been successfully used in some public transport modes such as tramways and metros. The core objective of this paper is to analyze the historical developments and the prospects of electric mobility in different transport modes and their potential contribution to the solution of the current environmental problems. With respect to the latter, we analyze the effect of the electricity generation mix on the environmental performance of electric vehicles. In addition, we document major policies implemented to promote various types of e-mobility. Our major conclusion... [more]

Ester liquids are environmentally friendly insulating oils, and they can be used as an alternative to mineral oil in transformers, even though in most countries spills of ester oils must be treated like spills of mineral oil. Furthermore, the breakdown characteristics of ester liquids are worse than those of mineral oils in heterogeneous electric fields. In this paper, we present a comprehensive experimental research on both positive and negative lightning impulse breakdown properties in point-plane geometries with gaps varying from 1 mm to 50 mm. The breakdown voltages and streamer velocities of five kinds of ester liquids, including natural ester, synthetic ester, and three kinds of single component esters have been measured. The results show that the double bonds have no effect on the breakdown voltage of ester liquids. The average streamer velocities of mono-esters are faster than that of other esters under positive polarity, and the breakdown voltages of all esters are close.

The scientific community is active in developing new models and methods to help reach the ambitious target set by UN SDGs7: universal access to electricity by 2030. Efficient planning of distribution networks is a complex and multivariate task, which is usually split into multiple subproblems to reduce the number of variables. The present work addresses the problem of optimal secondary substation siting, by means of different clustering techniques. In contrast with the majority of approaches found in the literature, which are devoted to the planning of MV grids in already electrified urban areas, this work focuses on greenfield planning in rural areas. K-means algorithm, hierarchical agglomerative clustering, and a method based on optimal weighted tree partitioning are adapted to the problem and run on two real case studies, with different population densities. The algorithms are compared in terms of different indicators useful to assess the feasibility of the solutions found. The algo... [more]

Waste incineration air pollution control (APC) residues require pretreatment before landfilling because these types of residues encompass pollutants from an incineration gas stream. The environmental concerns of APC residues consist of a risk of leaching and subsequent release of potentially harmful substances that occur under environmental exposure. The stabilization/solidification (S/S) method of incineration residues is one of the most applied technologies for hazardous incineration residues. Portland cement is commonly used as a binder material in S/S for pollutant encapsulation, in order to change the hydrological characteristics of the landfilled material. Based on previous research, an innovative S/S method for APC residues is investigated, meant to replace Portland cement with cement-like material made from lignite fly ash (FA). To do this, a lab-scale landfill was created through the promoted S/S method and exposed to the environment for 12 months. Thus, this article assesses... [more]

Full-electric boats are an expression of recent advancements in the area of vessel electrification. The installed batteries can suffer from poor cold-start performance, especially in the frigid season and at higher latitudes, leading to driving power limitations immediately after startup. At state, the leading solution is to adopt a dedicated heater placed on the common cooling/heating circuit; this implies poor volume, weight, and cost figures, given the very limited duty cycle of such a part. The Heater-in-Converter (HiC) technology allows removing this specialized component, exploiting the power electronics converters already available on board: HiC modulates their efficiency to produce valuable heat (pseudo-cogeneration). In this work, we use the model-based approach to design this system, which requires heating power minimization to fulfill power electronics limitations, while guaranteeing the user-expected startup time to full power. A multistage model is used to get the yearly v... [more]

The new generation of capsules that circulate through vacuum tubes at speeds up to 1200 km/h, which is being developed, demands communication systems that can operate at these speeds with high capacity and quality of service. Currently, the two technologies available are the new generation of 802.11ax networks and 5G NR. Using these technologies at such high speeds in a confined environment requires a careful study and design of the configuration of the network and optimization of the physical interface. This paper describes the requirements for critical and business communications, proposing a WLAN and 5G network design based on the analysis of the propagation characteristics and constraints of vacuum tubes and using propagation measurements and simulations made in similar environments at frequencies of 2.5/5.7/24 GHz. These measurements and simulations show that propagation losses in this environment are low (4−5 dB/100 m), as a consequence of the guided propagation, so that the use... [more]

Among the variety of problems encountered in transmission lines, the outer jacket degradation-derived faults of communication cables in railway applications have a significant impact on the transmission line parameters, especially if the cables are exposed to extremely varying environmental conditions, such as temperature deviation and humidity changes. In this paper, an advanced model of a twisted pair communication cable is proposed, together with approximated degradation functions for distributed parameters of the model, such as the shielding inductance, resistance, and capacitance per meter of cable length. This allows for gathering the distributed parameters for the proposed model under specific environmental conditions. The degradation functions for the parameters have been identified and compared with simulation results, including the communication speed and frequency band, and it has been confirmed that the transmission reliability depends on the cable condition. The authors di... [more]

The importance and awareness of accurate online water quality measurements increase every year in the oil and gas sector, whether it is for reducing oil discharge, preparing produced water for reinjection, or improving operational performance. For online measurement techniques to yield valuable analytical information, an understanding of their outputs must be established. Produced water reinjection has gained increasing attention in the last decade, as it can minimize negative environmental impacts by reducing oil discharge and has the potential to extend the economic life of reservoirs. To increase the amount of produced water that can be reinjected, the water must be maintained at a sufficient quality to prevent unintended formation damage. This review paper thoroughly describes different water quality issues related to suspended solids that can occur in an injection water treatment system and how the issues are often interlinked. A case study of measuring the total suspended solids... [more]

The cost of solar-generated electricity and battery costs have been decreasing significantly. These developments can be combined to introduce solar-powered charging networks with demand management prices (DMP) to enable electric vehicle (EV) customers to help utilities to manage renewable energy. As solar-generated electricity becomes the cheapest source of power, the need to increase demand for electricity during the day can be met by charging EVs at an attractive DMP in parking lots with solar panels and charging stations that are connected to the electrical grid. The demand for electricity can be managed and controlled by the utility with the goal of increasing demand for power as needed so that all electricity that is generated can be sold. The proposal is to introduce a new DMP rate that is only implemented when the utility wants to increase demand and sell power at this low rate in order to make full use of the supply. As utilities strive to reach 100% renewable electrical power... [more]

The growing production of coke and, consequently, coke wastewater is a significant problem for the environment. Coke wastewater, because it contains high amounts of toxic substances, is classified as an extremely hazardous industrial wastewater. The treatment of such wastewater requires a combination of advanced physicochemical and biological methods. The aim of the research was to investigate the effectiveness of the application of the ultrasonic disintegration of coke wastewater in a sequencing batch reactor (SBR). The tests were conducted in two stages, wherein the first stage involved determining the most favorable sonication conditions, that is, time and amplitude. The authors used the following amplitudes: 31 µm; 61.5 µm; 92 µm; 123 µm and times: 120 s; 240 s; 480 s; 960 s. The second stage focused on treating coke wastewater in SBRs (Reactor A—a proportion of coke wastewater in the mixture: 5%, 10%, and 20%; reactor B—sonicated coke wastewater, proportion in mixture: 5%, 10%, 20... [more]

Displacement ventilation is a proven method of providing conditioned air to enclosed spaces with the aim to deliver good air quality and thermal comfort while reducing the amount of energy required to operate the system. Until now, the practical applications of displacement ventilation have been exclusive to providing ventilation and cooling to large open spaces with high ceilings. The provision of heating through displacement ventilation has traditionally been discouraged, out of concern that warm air supplied at the floor level would rise straight to the ceiling level without providing heat to the occupied space. Hence, a separate heating system is regularly integrated with the displacement ventilation in cold climates, increasing the cost and energy use of the system. This paper goes beyond the common industry practice and explores the possibility of using displacement ventilation to provide heating without any additional heating system. It reports on experimental investigations con... [more]

In this study we aimed to determine the extent to which changes in the share of renewable energy sources, their structural complex, and the level of energy security in Eastern Europe, Caucasus and Central Asia (EECCA) countries in the medium- and long-term are interconnected. The study was performed through modeling and determination of the structural characteristics of energy security in the countries. The methodology of the approach to modeling was based on solving the problem of nonlinear optimization by selecting a certain scenario. For the study, the data of EECCA countries were used. The ability of EECCA countries to benefit from long-term indirect and induced advantages of the transformation period depends on the extent to which their domestic supply chains facilitate the deployment of energy transformation and induced economic activity. This study provides an opportunity to assess the degree of influence of renewable energy sources on the level of energy security of countries i... [more]

Bioenergy, along with other renewables, has always played its part in the world’s energy transition. Tracking the progress to meet specific goals has long been tackled and led to performance evaluation in the field. The present study aims to contribute to this area with a performance assessment framework in the bioenergy field. It comprises 16 European countries and 30 indicators assigned to three dimensions: innovation, efficiency, and sustainability and it follows a well-established methodology. For enabling country-to-country comparison, five maps are designed for better illustration. The country performance ranking is one of the main outputs of the analysis, revealing the outperformers and the weakest countries from its bottom half, as well as the particularities of countries scoring on each of the three dimensions. The policy recommendations and study limitations represent the most relevant part of the conclusions.

This research tackles effective and functional management practices in energy consumption using advanced technological solutions to mitigate unexpected events. This study specifically focuses on the recent COVID-19 pandemic that led to a reduction in energy consumption and therefore meddled with the project management’s status quo for the energy sources. Moreover, this research analyzes the role of information and communication technology (ICT) solutions in energy management before and after the recent coronavirus pandemic turmoil. This study also examined the role and place of sustainable energy resources in the effective management of energy consumption during the COVID-19 pandemic. The main purpose of this research is to demonstrate how the recent coronavirus pandemic affected energy consumption and energy prices in many countries and how it paved the way for the new ICT in managing energy consumption. This study elaborated a model to show how these changes evolved in selected Europ... [more]

In the conditions of climate change and the scarcity of natural resources, the future of energy is increasingly associated with the development of the so-called green energy. Its development is reflected in the European Commission strategic vision to transition to a climate-neutral economy. This is a challenge that the Central and Eastern European (CEE) countries, members of the EU, are also trying to meet. In recent years, these countries have seen an increase in the share of renewable energy and a reduction in greenhouse gas emissions (GGE). On the other hand, basing the energy sector on unstable energy sources (photovoltaics and wind technologies) may imply new challenges on the way to sustainable development. These are old problems in a new version (ecology, diversification of supplies) and new ones related to the features of renewable energy sources (RES; instability, dispersion). The aim of the article was to classify, on the basis of taxonomic methods, the CEE countries from the... [more]

The urban context is an experimentation space to accelerate the transition to a circular economy [...]

Modern buildings with new heating, ventilation and air conditioning (HVAC) systems offer possibility to fit parameters of the indoor environment to the occupants’ requirements. The present paper describes the results of measurements performed in an office room in the first Polish passive commercial office building during four months of normal operation. They were used to calculate parameters describing thermal comfort: vertical air temperature profile, floor surface temperature, predicted mean vote (PMV) and predicted percent of dissatisfied (PPD). Obtained results confirmed good thermal conditions in the analysed room. The average temperature of the floor’s surface varied from 20.6 °C to 26.2 °C. The average vertical air temperature, calculated for working days, was from 22.5 °C to 23.1 °C. The temperature difference between the floor and 5 cm below the ceiling was from −0.9 °C to 6.3 °C. The PMV index varied from 0.52 to 1.50 indicating ‘slightly warm’ sensation, in spite of ‘neutral... [more]

The contribution of the energy sector to human development (HD) is one of the aspects that requires measuring growth of the overall sustainability of HD. The UN program, Agenda 2030, has defined the vision of advanced development by introducing a sustainable HD paradigm, the balanced integrated development paradigm, in three dimensions: economic, social and environmental. The overall performance of countries is not currently assessed; there are several proposals for measuring sustainable HD level, but none have become widely accepted due to their weaknesses. The selected indirect measurement method reflects the interlinkage of development dimensions in real cases of low data availability. By combining the strengths of existing proposals and eliminating their weaknesses, the measuring methodology has been created and an appropriate tool—the Advanced Human Development Index (AHDI)—has been designed, which ensures unity and concordance of all included comprehensive dimension indices. The... [more]

Dundee City has been successful in installing green infrastructure for charging electric vehicles (EVs). This intervention matches the Sustainable Development Goals (SDGs) of affordable clean energy (SDG 7), sustainable cities and communities (SDG 11) and climate action (SDG 13) of the United Nations General Assembly Agenda 2030 (Transforming our World: the 2030 Agenda for Sustainable Development). Local authorities can align interventions with SDGs according to needs. The purpose of this paper is to consider whether Dundee’s EV strategy represents the most viable and equitable intervention that could be adopted given the city’s context. We adopt a positive review and value argumentation approach to determine the extent to which the strategy satisfies the criteria of “level of urgency”, “systemic impact” and “policy gaps”, which have been employed in the extant literature as the basis for a multi-criteria analysis (MCA). We eclectically review elements of the strategy against the city’... [more]

Solar photovoltaic (PV) technology is now a profitable method to decarbonize the grid, but if catastrophic climate change is to be avoided, emissions from transportation and heating must also decarbonize. One approach to renewable heating is leveraging improvements in PV with heat pumps (HPs). To determine the potential for PV+HP systems in northern areas of North America, this study performs numerical simulations and economic analysis using the same loads and climate, but with local electricity and natural gas rates for Sault Ste. Marie, in both Canada and U.S. Ground-mounted, fixed-tilt, grid-tied PV systems are sized to match 100% of electric loads considering cases both with and without air source HPs for residences with natural gas-based heating. For the first time the results show North American residents can profitably install residential PV+HP systems, earning up to 1.9% return in the U.S. and 2.7% in Canada, to provide for all of their electric and heating needs. Returns on PV... [more]

Partial shading is widely considered to be a limiting factor in the performance of photovoltaic (PV) systems applied in urban environments. Modern system architectures, combined with per module deployment of power electronics, have been used to improve performance, especially at heterogeneous irradiance conditions, but they come with a high investment cost. In this paper, another approach is used to evaluate the selective deployment of power optimizers (SDPO), which can operate with a variety of string inverters and can be retrofitted in PV systems suffering from high shading losses. A combination of modelling and outdoor field testing showed the benefits and drawbacks of SDPOs in a variety of shading scenarios. Results suggest that there is an energy yield increase of 1−2% on an annual basis compared to that of a reference system. The exact level of increase depends on the shading patterns and combination scenarios used in this paper.

Decarbonising heavy-duty trucks is challenging due to high journey power and energy requirements. With a growing fleet of commercial vehicles in the UK, biomethane can provide significant reductions in greenhouse gas (GHG) emissions compared to fossil diesel. Methane is a potent GHG with a global warming potential (GWP) of 23−36, therefore reducing levels in the atmosphere can have a significant impact on climate change. There are a range of anthropogenic sources of methane that could be collected and processed to provide sustainable energy (upcycled), e.g., agricultural waste and the waste water system. This paper explores the impact of using upcycled methane in transport in South East England, evaluating local sources of anthropogenic methane and the environmental and economic impact of its use for a heavy-duty truck compared to fossil and battery electric alternatives. Analysis concludes that the use of upcycled methane in transport can provide significant reductions in lifecycle GH... [more]

It is very challenging to capture the drag effects for the computational fluid dynamics numerical simulations of the urban canopy wind environment. This study proposed a novel canopy drag coefficient model for accurate analysis of the urban wind environment based on a large eddy simulation, where the drag coefficients varied with quantitatively identified canopy parameters along with the height. Four computational parameters, namely the average kinetic energy, turbulent kinetic energy, sub-grid scale turbulent kinetic energy, and sub-grid scale dissipation, were incorporated into the conventional drag coefficient. The Meixi Lake International Community in Changsha, China, was considered as a case study. The inlet boundary conditions were provided by the Weather Research and Forecasting model, and the proposed drag coefficient model was utilized to simulate the wind field characteristics. The results showed that the drag coefficient was relatively large near the ground, and it decreased... [more]