A new way is proposed to thermodynamically gauge the evolving complexity of nation-states and their growing cities. Energy rate density is a useful metric to track the evolution of energy budgets, which help facilitate how well or badly human society trends toward winning or losing. The fates of nations and their cities are unknown, their success is not assured. Those nations and cities with rising per-capita energy usage while developing and those that are nearly flat while already developed seem destined to endure; those with falling energy usage seem likely to fail. Globally, more energy, not less, and more energy rate density, too, will be needed in the 21st century. Conserving energy and efficiently using it are welcome since energy costs less when used less, but neither will likely help much to mitigate increasing energy demands. To survive, humanity nationally and internationally needs to culturally adapt to using more, clean, safe energy by embracing the Sun in an evolving Univ... [more]

A case study of solar collector outdoor test of the experimental technique conducted at Avadi, Chennai. To lower the temperature of solar PV panels, water, and water-based nanofluids were utilized concurrently. Higher cell temperatures restrict the effectiveness of solar PV systems since only a minor amount of power from the sun is gathered as electricity from the energy conversion, and the remaining energy is squandered as heat. The study aimed to develop and build a hybrid collector while also analyzing its electrical and thermal energy performance. The effort was invested in improving the system’s performance; the PVT collector was tested at volume concentrations of two, such as 0.5 and 1.0 L per minute (LPM). The PV/T collector determined thermal efficiency as highest was 48.38 percent and 54.03 percent, respectively, at 0.5 LPM and 1.0 LPM of volume flow rates. The PV/T collector’s highest electrical efficiency was 18.32 percent and 19.35 percent, respectively, for 0.5 LPM and 1.0... [more]

Perception towards nuclear energy is a vital factor determining the success or failure of nuclear projects. An online survey obtained attitudes toward nuclear energy, opinions on whether benefits of nuclear energy outweigh the risks, and views of using nuclear energy as an energy source. A total of 4318 participants from across the U.S. completed the survey. Logistic regression was used to predict perceptions of nuclear energy by participant demographics and geographical location. Participants living closest to Idaho National Laboratory (INL) were more likely to have positive attitudes towards nuclear energy (aOR: 7.18, p < 0.001), believe the benefits were greater than the risks (aOR: 4.90, p < 0.001), and have positive attitudes toward using nuclear energy as an electricity source (aOR: 5.70, p < 0.001), compared to people living farther from INL. Males and non-Hispanic white participants were more likely to have positive perceptions of nuclear energy. Developing and impleme... [more]

One of the most advanced systems of microbial fuel cells is the benthic microbial fuel cell (BMFC). Despite several developments, this strategy still has a number of significant flaws, such as instable organic substrate. Waste material (sugarcane) is used as a substrate in this work to address the organic substrate instability. The process was operated continuously for 70 days. A level of 300 mV was achieved after 33 days of operation, while the degradation efficiencies of Pb (II), Cd (II), and Cr (III) were more than 90%. More than 90% of the removed chemical oxygen demand (COD) was also recorded. The measured power density was 3.571 mW/m2 at 1000 external resistance with 458 internal resistance. This demonstrates that electrons are effectively transported throughout the operation. The Bacillus strains are the most dominant bacterial community on the surface of the anode. This research’s mechanism, which involves metal ion degradation, is also explained. Finally, parameter optimizatio... [more]

Auditing activity, in the last decade, is one of the most dynamically changing types of economic activity, on the one hand, due to an increase in the number of state projects implemented by many countries, and on the other hand, due to technological innovations and digitalization. Russian auditing practices are also being actively reformed. For example, the Ministry of Energy is updating their audit methodology. The subject of this study is to ensure the efficiency of spending public funds for the implementation of strategic projects. The object of this study is the methodology of a state audit. An analysis of the currently used Russian and international standards for public audits shows that there are many opportunities to improve the methodology for conducting financial, strategic and performance audits. First of all, there is a need to solve methodological problems in monitoring the efficiency of investment developments, since partnerships between private investors and government bo... [more]

The aim of this review was to analyze to what extent the relationship between corporate social responsibility (CSR), environment and energy has been addressed in the specialized literature and which are the deficient segments in this regard. VOSviewer was used for data extraction, mapping and grouping the articles from journals that have been indexed in Web of Science (WOS). A total of 102 papers were found approaching the topic of corporate social responsibility, environment and energy policy, 5192 research papers for CSR and the environment and 320 on CSR and energy policy. Following the bibliometric analysis, we can conclude that we are facing a shortage of works that analyze the relationship between the three fields together. The number of published articles was reduced to establish the direction of influence between the three variables, as well as the impact between them. However, the advantage that emerges from this lack of works is that there are many opportunities to find news... [more]

Energy security, as one of the most important components of state security, is a permanent element of academic debates and political discussions. Owing to the multidimensional and multifaceted nature of energy security, defining it is a complex process, requiring the consideration of a wide range of factors straddling economics, geology, ecology and geopolitics which decide whether we are dealing with the state of energy security or the lack of it. Energy security is usually equated with the security of supply. Another group of definitions of energy security focuses on the concept of security of services. A different approach to energy security issues is presented by energy exporting countries, whose objective is to ensure sufficiently high and stable income from sales of energy resource exports (security of demand). The subject of this paper is an analysis of the energy security of hydropower-producing countries—Tajikistan and Kyrgyzstan. Energy security has been analyzed in the conte... [more]

The development of emerging technologies not only has recently affected current industrial production but also has generated promising manufacturing opportunities that impact significantly on social and economic factors. Exploring upcoming renovation tendencies of technologies prematurely is essential for governments, research and development institutes, and industrial companies in managing strategies to achieve dominant advantages in business competitiveness. Additionally, the prospective changes, the scientific research directions, and the focus of technologies are crucial factors in predicting promising technologies. On the other hand, Industry 4.0 revolutionizes standards and models by accompanying significant technology developments in numerous sectors, including the sector of Smart energy. Moreover, asset performance management is always a prominent topic that has attained prevalence over the last decade because numerous challenges force all industrial companies to optimize their... [more]

This paper examines 16 years (2004−2019) of research on energy in eleven Central and Eastern European countries. The findings are based on an analysis of 3534 academic articles indexed in the Web of Knowledge database. The paper presents a systematic overview of the authorship, journal of publication, countries covered, and article content. The main conclusion is that the discussion is fragmented, because most of the journals (800 were identified) published only one paper on energy in the region. About one-fourth of the research was published in a handful of major journals. Male researchers dominated our dataset and there has been a visible increase in the average number of authors per article. The country most often covered by the research was Poland and energy efficiency was the most-discussed issue and renewables the most-frequently researched energy source. Surprisingly, nuclear energy and energy security, considered to be the dominant features of the CEE region energy picture, wer... [more]

Commercial buildings consume approximately 1.9 EJ of energy in the United States, 50% of which is for heating, cooling, and lighting applications. It is estimated that windows contribute up to 34% of the energy used for heating and cooling. However, window retrofits are not often undertaken to increase energy efficiency because of the high cost and disruptive nature of window installation. Highly efficient window technologies would also need shading devices for glare prevention and visual comfort. An automated window shading system with an appropriate control strategy is a technology that can reduce energy demand, maintain occupant comfort, and enhance the aesthetics and privacy of the built environment. However, the benefits of the automated shades currently used by the shading industry are not well studied. The topic merits an analysis that will help building owners, designers and engineers, and utilities make informed decisions using knowledge of the impact of this technology on ene... [more]

This paper explores current approaches and future directions for energy efficiency education and training in the tertiary sector. Energy efficiency is a significant element in many jobs across the economy, with potential for substantial growth. It crosses disciplinary boundaries, as the range of skills and knowledge required by practitioners is broad, reflecting the diversity and expanding range of work roles that require energy efficiency skills and knowledge. Limitations of education and training contribute to a situation where business and consumer decision-making often involves little or no consideration of energy, so outcomes are often sub-optimal. This increases costs, environmental and social impacts and undermines productivity improvement. As the significance of energy efficiency skills and knowledge in workplaces increases, more flexible and varied education and training models are needed to allow workers to upskill, gain new skills and integrate energy efficiency into busines... [more]

This editorial note is dedicated to the 1st International Conference on Nanofluids (ICNf19), which was organized under the auspices of Nanouptake COST Action in June 2019, in Castelló (Spain). After a brief report about the conference issues, the successful selected contributions to this Special Issue of Energies about the ICNf19 are introduced.

Given the significance of energy conservation as a prime objective of environmental sustainability, countries all around the world are keen to identify significant factors that lead to the augmentation of energy utilization. Considering the rising emphasis of economies in utilizing natural resources to attain higher levels of globalization, the current research was aimed at investigating how the returns of natural resources and globalization affect energy consumption in top Asian economies. In doing so, the study emphasized the nonlinear relationship among the variables and applied the novel nonparametric method of causality in quantile to identify the quantile-based causal connection of natural resources and globalization on the returns and volatility of energy utilization in selected Asian countries. Moreover, the presence of nonlinearity in the variables was tested by the Brock- Dechert-Scheinkman test (BDS test), which confirmed that all variables showed nonlinear behavior. Further... [more]

The global climate crisis forces the search for new ecological sources of energy and mining methods. Space mining can solve those problems, but, first, wide geological surveying space missions using drilling methods are necessary. Additionally, drilling methods will be important in geological, life searching, geoengineering, and many other studies of extraterrestrial objects. Space is becoming a new area of possible drilling applications. Designing future space drilling missions requires adapting drilling technologies, not only to the conditions of the space environment, but also to the economic and technological realities of the space industry. The possibility of constructing low mass coring devices with energy consumption below 100 W was investigated in this paper. Minimization of energy consumption and mass of a coring is essential for the device to be used in space missions, when lander instruments supplied by low power electric battery are expected to work reliably and the launch... [more]

Energy and exergy (EnE) efficiencies are considered the most important parameters to compare the performance of various thermal systems. In this paper, an analysis was carried out for EnE efficiencies of a flat plate solar collector (FPSC) using four different kinds of nanofluids as flowing mediums, namely, Al2O3/water, MgO/water, TiO2/water, and CuO/water, and compared with water as a flowing medium (traditional base fluid). The analysis considered nanofluids made of nanomaterials’ volume fractions of 1−4% with water. The volume flow rates of nanofluids and water were 1 to 4 L/min. The solar collector′s highest EnE efficiency values were obtained for CuO/water nanofluid among the four types of nanofluids mentioned above. The EnE efficiencies of the CuO nanofluid-operated solar collector were 38.21% and 34.06%, respectively, which is significantly higher than that of water-operated solar collectors. For the same volume flow rate, the mass flow rate was found to be 15.95% higher than wa... [more]

Direct steam generation is a promising alternative to conventional heat transfer fluids for solar thermal power plants using linear concentrators because water and steam do not have thermal and chemical stability problems. The novelty of this study, an energy and exergy (2E) analysis, was that it was performed on several configurations of a conceptual direct steam generation solar power plant with optimized Fresnel reflectors in Agua Prieta, Mexico coupled with a regenerative steam Rankine power cycle to quantify their efficiency and establish a reference for future implementation of this technology in concentrated solar power plants in Mexico. The thermal model was assumed to be a 1D steady-state flow and validated against results in the literature. It was then applied directly to a case study to determine the size of the solar field. The design point was the lowest solar irradiance day, and evaluating the solar multiple with the highest solar irradiance, taking care not to oversize t... [more]

In Poland, the development of photovoltaic (PV) installations is an important element in the development of the Renewable Energy Sources (RES) sector and supports the prosumer power industry. The purpose of the article is to present a case study of the PROSUMENT program. It analyzes the data available to date on the development of the PV market in Poland. Apart from the costs of installing the PV systems, the article analyzes the profitability of investment for different micro-power installation capacities. A calculation for micro-power installations subsidized under the PROSUMENT program for various PV capacities is presented, along with the actual amount of the subsidy. The adopted calculation methodology is a comparative verification analysis of the investment cost estimate for a for the two studied PV facilities, i.e., Micro-power installation 1 and Micro-power installation 2. The building’s annual energy demand was adopted at the same level for both examples, with fixed active ene... [more]

The role of the energy industry has always been central for one reason or another, being environmentalism the main motive in the last two decades. Therefore, attention and research have been directed in this sense. However, human resources—or human capital—have remained understudied, especially concerning the salaries received. Thus, this study is disruptive as it explored the factors that influence employee remuneration in the energy subsector, using Spain as a case study. For this, the PLS-SEM (Partial Least Squares Structural Equation Modelling) path modelling methodology was used, executing a traditional PLS analysis, bootstrapping and, finally, IPMA (Importance-Performance Analysis). Solid and significant relationships were found among labour conditions, human capital, market and wages, with the relationships between human capital and wages and between human capital and labour conditions being especially relevant. Besides, through IPMA, a series of considerations was made regardin... [more]

The growth in global electricity demand has expanded the search for new energy resources. Renewable sources such as photovoltaic (PV) systems have proven to be major alternatives. PV generators connected to distribution grids have exhibited significant growth in the last decade, so it is essential to analyse the impacts resulting from this increase. This work investigated the influence of high PV system penetration in distribution grids in terms of harmonic levels. In particular, this study addressed the distortions in voltage and current waveforms in the presence and absence of PV generators connected to a distribution grid. Additionally, the total harmonic content and the individual harmonic frequencies of voltage and current were analysed. This study was performed with an IEEE 37 bus distribution system and the Open Distribution System Simulator software (OpenDSS). The results show that the voltage limits of some phases far away from a substation can exceed the limits. Furthermore,... [more]

The combined microwave-assisted sorting and microwave-assisted comminution of minerals has been proposed to reduce the huge grinding energy consumption in mineral processing. However, gangue minerals would be discarded after the sorting process despite the microwave energy absorbed during their treatment. Therefore, this paper investigates the effect of microwave pretreatment on the Bond work index (BWI) of quartz and calcite samples, as they represent the dominant gangues in many ores and are key inputs in the cement industry, which requires intensive grinding. The samples were characterized using a scanning electron microscope coupled with energy dispersive X-ray (SEM-EDX), and Fourier transform infrared (FTIR) and X-ray diffraction (XRD) methods. The BWIs of the two samples were determined before and after the microwave treatment (2.45 GHz, 1.7 kW) at 2, 4 and 6 minutes. SEM image analyses of the untreated and microwave-treated samples were performed using ImageJ software. The resul... [more]

Low-carbon development is one of the more significant problems of the Visegrad Group countries (Czech Republic, Poland, Slovakia, and Hungary). It is related, among others, to the improvement of life quality in economic terms while taking into account activities for environmental protection. The aim of the article is to identify and explain the problems connected with low-carbon development. The purpose of the analyses is also to prove the negative impact of the emission of greenhouse gas emission (GHG) and other harmful substances into the air on the quality of human life and the natural environment. During the research, an assessment of the eco-efficiency of the used energy resources and technologies that negatively affect the environment was carried out. Moreover, the paper also presents methods to use greener energy sources and analyses the potential of implementing solutions supporting low-carbon development. The study recommends actions that may contribute to the reduction of gre... [more]

This article presents a proposal for a wireless diagnostic system for checking the air tightness of the ventilation network. The solution is designed to increase crew safety in underground mining plants and increase the energy efficiency of the ventube ventilation system. The system is based on sensors measuring the pressure inside the ventilation duct in relation to the barometric pressure in the immediate vicinity of the duct. The flow of diagnostic data is based on a cascade transfer. The data from the first sensor are transferred successively to the last one. Based on the prior calibration of alarm thresholds in each device, the leakage or factor influencing the increase of air flow resistance is located. The article presents the genesis of the creation and discusses the principle and purpose of the system. In the following chapters, the progress of work related to testing the system in laboratory, industrial, and underground conditions at the Velenje Premogovnik mine (Slovenia) is... [more]

The constant problems evidenced in the Brazilian hydrological scenario, where the source of hydraulic potential corresponds to about 63.9% of the energy matrix, coupled with the exponential growth in the supply of renewable energy, corroborates the importance of thermal power generation as the basis of Brazilian’s energy matrix. With the operation of thermal power plants, which characteristically involve a large number of systems, subsystems, and auxiliary equipment, there is a high demand for the use of methodologies for monitoring and controlling processes, analyzing failures, and implementing improvements and actions that increase the reliability and, consequently, reduce the failure rate. In this context, decision-making about prioritizing criticality for operational monitoring of an asset’s components, from the perspective of operation and maintenance planning and based on reliability-centered maintenance (RCM) concepts, can be considered a complex task. Given this, the research s... [more]

The refurbishment of the building stock is a key strategy towards the achievement of the climate and energy goals of the European Union. This study aims at evaluating the energy and environmental impacts associated with retrofitting a residential apartment to improve its vertical envelope thermal insulation. Two insulation materials, stone wool and cellulose fibers, are compared. The life cycle assessment methodology is applied assuming 1 m2 of retrofitted vertical envelope as functional unit. Moreover, to estimate the net energy and environmental benefits achievable in the retrofitted scenario compared with the non-retrofitted one, a second analysis is performed in which the system boundaries are expanded to include the building operational phase, and 1 m2 of walkable floor per year is assumed as reference. The results show that the use of cellulose fibers involve lower impacts in most of the assessed categories compared to stone wool, except for abiotic resource depletion. In detail,... [more]

This paper quantifies the long-term impact of wind energy development on electricity prices across the residential, commercial, and industrial sectors in the United States. Our data set is made up of state level panel data from 2000 through 2018. This time period covers the vast majority of total wind energy capacity installed in the history of the USA. Our econometric model accounts for the primary factors that influence electricity prices, incorporating both fixed effects and general method of moments in order to more precisely isolate the effect of wind energy. The empirical results conclude that wind energy is positively and significantly related to electricity prices across all sectors, as indicated by the higher average electricity prices in states with higher percentages of wind energy. The price increase is largest in the industrial sector, followed by commercial, then residential. Wind turbine technology has become significantly more efficient, but the technical gains have bee... [more]