In northern China, a large volume of coal is consumed for heating in winter, resulting in frequent smog and air pollution, which has a serious effect on people’s health and quality of life. Clean heating is a national important livelihood strategy related to residents’ warmth. Whether haze weather can be effectively reduced and whether the heating energy structure can really be improved needs to be verified. This study takes 115 heating cities in the northern area as the research objects, takes 12 pilot cities implementing clean heating policy as the treatment group, employs the Propensity Score Matching method to match the non-pilot cities to get the reasonable control group city, uses the double-difference method to carry out the quantitative test on the implementation effect of the clean heating policy. The results show that clean heating in northern China reduces the air pollution in winter, and the air pollution level in winter decreases 46.6% after the implementation of the polic... [more]

The accumulation of waste and toxic compounds has become increasingly harmful to the environment and human health. In this context, the use of laccases has become a focus of interest, due to the properties of these versatile enzymes: low substrate specificity, and water formation as a non-toxic end product. Thus, we begin our study with a general overview of the importance of laccase for the environment and industry, starting with the sources of laccases (plant, bacterial and fungal laccases), the structure and mechanism of laccases, microbial biosynthesis, and the immobilization of laccases. Then, we continue with an overview of agro-waste treatment by laccases wherein we observe the importance of laccases for the biodisponibilization of substrates and the biodegradation of agro-industrial byproducts; we then show some aspects regarding the degradation of xenobiotic compounds, dyes, and pharmaceutical products. The objective of this research is to emphasize and fully investigate the e... [more]

This article highlights the need to reduce carbon dioxide emissions by reducing energy consumption. Of course, this can be achieved in various ways, but inter alia, through the practical implementation of the assumptions contained in the CSR programs of individual companies, which include a component on environmental protection and counteracting global warming. The authors also describe a proposal to reduce CO2 emissions by using coke oven gas (if necessary) in exchange for natural gas. Currently, the largest sources of carbon dioxide emissions are the combustion of fossil fuels in power plants, transport—cars and planes, processes related to the production of industrial goods, and deforestation. In the preparation of the article, the analysis of the literature on the subject, analysis of documents, desk research, and two case studies were used. The main goal of the article is to present the possibilities of reducing CO2 emissions by implementing the assumptions of the CSR policy on th... [more]

The smart city (SC) concept is currently one of the leading ideas in the field of management. It has also become important for Polish cities in terms of sustainable development. Therefore, it is important to determine the priority in urban development; and the areas that need investment to make cities smart. Based on the literature review, it can be stated that there are many available concepts of SCs since the level of development of many cities in the world is different and the priorities of the developed areas vary. The identified SC management models present common parts, resulting from the defining basis, as well as additional aspects important for an SC, stemming from their specificity and the approach of their managers. Thus, the aim of the article is to propose the author’s model of resilient smart city development in Poland. To achieve the objective, a systematic literature review was applied, and the analysis of existing SC management models in the world was carried out in or... [more]

Detection of faults and other zones of weakness in shallow permafrost to a few hundreds of meters is extremely important for ensuring the safety during the production and transportation of fuels (oil and gas). The construction of line facilities (power lines and pipelines) should be preceded by detailed surveys in order to localize major areas of potential hazard. Furthermore, reliable geophysical methods are necessary for exploration of gas hydrates. This research aims at proving that induction-based electromagnetic surveys are applicable for permafrost studies and at finding new evidence for the similarity and difference of the permafrost structure in different regions of Northern Siberia. TEM curves are collected in several regions of Northern Siberia with continuous, mostly continuous, and discontinuous permafrost. Transient electromagnetic (TEM) surveys performed in the Russian Arctic image the permafrost structure to a depth of 500 m. The data are acquired with telemetric systems... [more]

A report released by the WHO indicates that aerosols from infected people are one of the major sources of the spread of COVID-19. Therefore, as the COVID-19 infection caused by the SARS-CoV-2 virus spreads, it has become necessary to reconsider the design and operation of buildings. Inside school buildings in cold regions, not only is it not easy to increase ventilation during the winter, but it may also be difficult for students to attend classes while wearing masks during the summer because such buildings are not equipped with air-conditioning systems. In short, school buildings in cold climates have more problems than those in warm climates. We report on the results of indoor environmental measurement using our developed CO2-concentration meters, a questionnaire survey on students’ feeling of being hot or cold (i.e., ‘thermal sensation’), and a comparison of energy consumption before and after the spread of COVID-19 infection in schools in Sapporo, Japan, a cold-climate area. The re... [more]

The utilization of new and renewable energy sources explicitly based on biomass needs to be increased to reduce dependence on fossil fuels. One of the potential biomasses of plantation waste in Indonesia that can be utilized is oil palm plantation waste in the form of fronds and trunks that are converted with multi-stage downdraft gasification technology. This study aimed to conduct a technical analysis, economic analysis, investment risk analysis, social analysis, and an environmental impact assessment of power plants fueled by oil palm plantation waste. The method used was the upscaling of a prototype of a 10 kW power plant to 100 kW. The results showed that it was technically and economically feasible to apply. The economic indicators were a positive NPV of USD 48.846 with an IRR of 9.72% and a B/C ratio of 1.16. The risk analysis predicted a probability of an NPV 49.94% above the base case. The study of the social aspects suggested that the construction of power plants has a positi... [more]

Nowadays, the restructuring of power systems is extremely urgent due to the depletion of fossil fuels on the one hand and the environmental impact on the other. In the restructured environment, the incorporation of renewable energy sources and storage devices is key as they have helped achieve a milestone in the form of microgrid technology. As the restructuring of the power system increases, there are several types of generation sources, and distribution companies express their interest in trading in a deregulated environment to operate economically. When considering the power system deregulation, the contract value deviates in some situations, resulting in an imbalance between the generation and the energy consumption, which can bring the system into a power outage condition. In particular, load frequency control has been a great challenge over the past few decades to ensure the stable operation of power systems. This study considers two generation sources: mini-hydro in GENCO-1 and... [more]

Restrictions on emissions are being imposed by regional and international shipping organisations, which raise the question of which marine fuel and technology can most effectively replace heavy fuel oil and diesel engines. The aim of this study is to find appropriate advanced combined gas and steam turbine cycles for marine propulsion systems in a large container ship with respect to the evolving maritime environmental regulations. The selection criteria are the thermodynamic performance, emissions, size, and weight of advanced combined gas and steam turbine cycles in a large container ship. Two baselines are used: a diesel engine using marine diesel oil and a combined gas and steam turbine system using liquefied natural gas and marine diesel oil. Then, liquefied natural gas cycles are examined based on fuel replacement and enhanced to assess the benefits of liquefied natural gas over marine diesel oil. The results show that the enhanced liquefied natural gas combined gas and steam tur... [more]

This Special Issue of Energies contains the successful invited submissions [...]

The purpose of this article is to investigate whether the wide scope of supply chain collaboration including both customers and suppliers (Upstream−downstream External Collaboration) determines the greening of innovation more significantly than the scope limited only to suppliers (Upstream External Collaboration) or customers (Downstream External Collaboration). This goal was achieved as part of extensive research on the impact of relational capital on the innovativeness of high-tech companies in Poland. The results of the research were analysed using fuzzy conversion scales and descriptive statistics based on triangular fuzzy numbers. The application of the achievements of the fuzzy sets theory made it possible to test the hypotheses presented in the article with the use of fuzzy analysis of variance (fuzzy ANOVA). The findings confirm that the subjective scope of collaboration in the supply chain is important for greening innovation. Companies that cooperate with both suppliers and c... [more]

The heat recovery of hot exhaust air in petroleum refining for energy cogeneration is a circular strategy to reduce costs and environmental impact. Despite several articles on this subject, there is a lack of study on the assessment of the economic and environmental advantages of energy cogeneration in petroleum refining. The objective of this research was to evaluate the economic and environmental gains obtained by energy cogeneration from the heat dissipated in the calcination of green petroleum coke. The research method was a case study in a petrochemical industry in Brazil. From an economic point of view, the cogeneration unit project has shown positive results: a discounted payback period of eight years and nine months, net present value (NPV) over a span of a twenty-year period of US$43,825,592, a return on investment (ROI) estimated to be 14%, and an internal rate of return (IRR) of 12%. From an ecological perspective, the produced energy in the cogeneration process reduced 163,... [more]

Based on new policies of the European Union, green technologies are to be mostly considered for power generation. Hydropower generation is one of the essential elements of sustainable energy production. Therefore, specific attention, both economically and technically, needs to be given to this sector of energy production. The Vistula River in Poland is considered an international waterway. The power production potential of the river has been taken into account over the years. However, further configurations are needed to obtain a more in-depth ecological knowledge-base and economic plans, which are socially approved. In an attempt to make the project environmentally friendly, specific attention was put into sustainable transport. Different methods of transport were researched to find the most renewable transport combination, mainly based on waterways. Having performed a cost−benefit analysis related to the economic aspects of the project, it was found that such an investment is highly... [more]

The article presents an extended computer model of a HTS (high temperature superconducting) 21 MVA 70/10.5 kV transformer with severalfold compound windings, based on a verified PSpice model of 10 kVA transformer with single windings. Two superconducting tapes: SCS12050 (with a copper stabiliser layer) and SF12050 (without a stabiliser) were used in the windings. The circuit model of the transformer developed in the PSpice environment considers Rhyner’s power law and the Jiles−Atherton description of the magnetic hysteresis loop. Two types of transient states were analysed: switching on a superconducting transformer to the network and an emergency short-circuit of the secondary winding. For the first five unidirectional current pulses generated when connecting an unloaded transformer to the network, the values of the pulse duration (γ angle), the temperature increase in the primary winding as well as the mean and effective values of the switch-on current were calculated. The waveforms... [more]

Intense economic, social and environmental changes are creating new challenges for both consumers and businesses. Today’s consumer is becoming increasingly conscious of the importance of living in harmony with both ethical standards and the environment. Access to global resources, including utilities such as water, sewage collection, electricity or gas, is so ubiquitous that modern man cannot imagine functioning without them. The aim of this article is to show how the statistical Polish consumer has, or wants to have, an impact on improving the quality of the natural environment by using available resources and technological solutions. The novelty here is the use of the structural equation model (SEM) to build a model of pro-environmental behaviors in relation to the motivating and limiting factors for undertaking such behaviors in Poland. The hypothesis that the statistical Polish consumer undertakes pro-environmental behaviors because of their positive impact on the natural environme... [more]

Global CO2 concentration level in the air is unprecedently high and should be rapidly and significantly reduced to avoid a global climate catastrophe. The work indicates the possibility of quickly lowering the impact of changes that have already happened and those we know will happen, especially in terms of the CO2 emitted and stored in the atmosphere, by implanting a virgin ivy plant on the available area of walls and roofs of the houses. The proposed concept of reducing CO2 from the atmosphere is one of the technologies with significant potential for implementation entirely and successfully. For the first time, we showed that the proposed concept allows over 3.5 billion tons of CO2 to be captured annually directly from the atmosphere, which makes even up 6.9% of global greenhouse gas emissions. The value constitutes enough high CO2 reduction to consider the concept as one of the applicable technologies allowing to decelerate global warming. Additional advantages of the presented conc... [more]

To date, hydropower dams raise numerous interpretations about their impact on the Lancang-Mekong River. While most research studies analyze the negative aspects of hydropower development on people’s livelihoods and local environments, the hydropower sector was historically one of the most iconic economic segments facilitating transboundary water cooperation for decades. By using the constructive discourse analysis and critical political ecology approach, the presented text (1) outlines the current environmental narratives over the Lancang-Mekong hydropower development and (2) explores the politicization of the Chinese mainstream dams. The data were collected upon the multi-level content analysis of relevant sources and double-checked with the Lancang-Mekong Cooperation and Conflict Database (LMCCD) monitoring over 4000 water-related events among six riparian countries between 1990 and 2021. Our data show that (i) there is a stark contrast in positive and negative narratives over the ra... [more]

The paper presents a design and operation analysis of an Integrated Collector Storage (ICS) solar water heater, which consists of an asymmetric Compound Parabolic Concentrating (CPC) reflector trough, while the water tank comprises two concentric cylinders. The annulus between these vessels is partially depressurized and contains a small amount of water in the bottom of the outer vessel which dominantly contributes to the heat transfer from the outer to the inner cylinder. A multi-criteria optimization algorithm is applied to re-evaluate the design specifications of the parabolic surface, thus modifying the design of the entire ICS system and predict the necessary number of units for achieving the highest possible effectiveness with minimized fabrication costs and environmental impacts. The environmental footprint of the device is assessed through Life Cycle Assessment (LCA). The produced thermal energy in conjunction with the environmental and economic results are evaluated as a funct... [more]

Enterprises’ green technology innovation is critical to achieving the “win-win” of enterprise competitiveness and environmental protection. The impact of environmental regulation on green technology innovation by enterprises has been widely considered, but the conclusion has not yet been determined, and needs to be studied in detail. To this end, we studied the impact of pollution charge policy on different types of green technology innovation by industrial enterprises in China. We found that (1) the impact of pollution charges on most types of green technology innovation by enterprises has increased significantly over time; (2) the pollution charge policy has a certain inhibition effect on the end-of-pipe technology innovation, but can promote the process improvement of reducing industrial wastewater emissions; (3) there is a U-shaped relationship between the pollution charges and some green technological innovation (e.g., emission intensity of SO2, industrial wastewater emission inte... [more]

The Ukrainian renewable energy sector has demonstrated a significant increase in its renewable power capacity, especially for solar and wind power plants. Decommissioning the end-of-life equipment in Ukraine has not yet taken place, but it is only a matter of time. With this in mind, this paper assesses the quantities and the market values of the materials that could potentially be recovered from used solar and wind power plants, and it estimates the impact of their decommissioning on employment in Ukraine. It has been estimated that approximately 8.9 GW of solar power plants, and 3.6 GW of wind power plants, will be decommissioned from 2044 to 2059, and that the cost of the raw materials recovered could reach EUR 421.4 million and EUR 124.6 million in 2021 prices, respectively, compared to the decommissioning costs of EUR 240.1 million and EUR 49.1 million, respectively. Decommissioning renewable power plants will require the creation of new jobs, including 11.6 thousand in the solar... [more]

The reconstruction of ageing thermal power plants with the possibility of their increased efficiency, prolonged service and decreased environmental impact is an intensely debated and researched topic nowadays. Among various concepts, the replacement of the steam cycle by a supercritical CO2 cycle is proposed with the prospect of reaching higher efficiencies at the same working fluid inlet parameters as the ultra-supercritical steam cycles. A paper published previously by Rogalev et al. (2021) analyzed the variants of supercritical coal power plant reconstruction to a supercritical CO2 cycle and ranked them according to the cycle efficiency. This contribution comments on the scope and applied method in that paper aiming to provide additional input relevant to the decision-making process on thermal power plant reconstruction to such a cycle.

In this study, confluent jets ventilation (CJV) supply devices with three different nozzle arrays (1 × 19, 2 × 19, 3 × 19) were investigated both numerically and experimentally at two different airflow and supply air temperature set-ups. The performance of the CJV supply devices was investigated concerning thermal comfort, indoor air quality (IAQ), and heat removal effectiveness in a conference room environment. A comparison between the experimental and numerical results showed that the  ϑ2¯−f model had the best agreement out of the investigated turbulence models. The numerical results showed that the size of the array had a great impact both on near-field development and on the conditions in the occupied zone. A larger array with multiple rows and a lower momentum conserved the inlet temperature and the mean age of the air better than a single-row array with a higher momentum. A larger array with multiple rows had a higher IAQ and a greater heat removal effectiveness in the occup... [more]

Synthetic Natural Gas (SNG) is the most researched option for a Power-to-Fuel pathway in Germany after hydrogen, having the advantage of being compatible with the existing infrastructure. However, it is not clear under which conditions SNG is economically and environmentally advantageous compared to natural gas usage, since this is determined by a complex interplay of many factors. This study analyzes the technical, economic and environmental aspects of a pilot SNG plant to determine the key parameters for profitable and sustainable operation. The SNG plant was simulated in Aspen Plus® with CO2 from biogas production as a feedstock and with hydrogen provided by a 1 MWel electrolyzer unit. A life cycle analysis (LCA) was undertaken considering several impact categories with a special focus on global warming potential (GWP). An SNG cost of 0.33−4.22 €/kWhth was calculated, depending on factors such as operational hours, electricity price and type of electrolyzer. It was found that the CO... [more]

The paper presents the experimental measurements of thermal efficiency of a tubular direct absorption solar collector (DASC) with a hybrid nanofluid based on magnetite (Fe3O4) and multi-walled carbon nanotubes (MWCNT). The volumetric concentration of Fe3O4 and MWCNT was 0.0053% and 0.0045%, respectively. The experiments were carried out for the flow rates of 2−10 L/min and a temperature difference up to 20 ∘C between the environment and the DASC. The performance of the DASC with a hybrid nanofluid was in the range of 52.3−69.4%, which was just beyond the performance of the collector with surface absorption. It was also found that using a MWCNT-based nanofluid with an equivalent total volumetric concentration of particles (0.0091%), the efficiency was 8.3−31.5% higher than for the cases with the hybrid nanofluid.

The Saudi Arabian climate, generally speaking, is known to be hot and arid. Even with its extensive energy resources, Saudi Arabia is not immune to the demands of climate change. Over 50% of the country’s electricity is consumed by residential buildings. For economic, fiscal, and environmental reasons, government policy is to stem the profligate use of finite energy resources. It is incumbent on the Saudi building industry to adapt to changing conditions by re-assessing the choice of materials and the design and lay-out of new buildings to help quell demands for air-conditioning during the hotter parts of the year. Throughout the country, electricity consumption doubles in the summer months. Given this situation, this study explores the indoor thermal environment typical of residential buildings. The study selected one house located in a hot dry climatic region as a case study. The features of the house were assessed to determine the permeable features that require improvement. Two mai... [more]