It is predicted that, by 2050, about 64% of the developing world and 86% of the developed world will be urbanized [...]

The rapid growth in fossil fuels has resulted in climate change that needs to be controlled in the near future. Several methods have been proposed to control climate change, including the development of efficient energy conversion devices. Fuel cells are environmentally friendly energy conversion devices that can be fuelled by green hydrogen, with only water as a by-product, or by using different biofuels such as biomass in wastewater, urea in wastewater, biogas from municipal and agricultural wastes, syngas from agriculture wastes, and waste carbon. This editorial discusses the fundamentals of the operation of the fuel cell, and their application in various sectors such as residential, transportation, and power generation.

Biomass gasification is a relevant option to produce a gaseous fuel, it faces, however, several barriers regarding its quality for energetic applications. Therefore, in this study, air-steam and O2-enriched air mixtures were used as gasification agents during the gasification of residual biomass from eucalyptus to improve the producer gas quality. The steam addition promoted an increase in CO2 and H2 concentrations, whilst decreasing the CO and CH4 concentrations. The steam addition had no evident impact on the lower heating value of the dry producer gas and a positive effect on gas yield and the H2:CO molar ratio, attaining the later values up to 1.6 molH2∙mol−1CO. The increase in O2 concentration in the gasification agent (φ) promoted an increase in all combustible species and CO2 concentrations. The lower heating value of the dry producer gas underwent an increase of 57%, reaching a value of 7.5 MJ∙Nm−3dry gas, when the φ increased from 20 to 40 %vol.O2, dry GA. The gas yield had a... [more]

Electromobility is generally seen as an efficient means of decarbonizing the transport sector. Ensuring both a broad propagation of electric vehicles and a stable energy system requires intelligent charging strategies in the form of use cases. Most use cases do not combine both the prospect of profit and systemic advantages. This paper analyzes combinations of use cases that merge different use cases to combine profitability and systemic benefits. We present a novel methodological approach for analyzing and comparing the synergies of different use case combinations. The focus is on evaluating the potential for reducing the technical implementation effort resulting from the simultaneous implementation of two to three different use cases. Our findings show that the simultaneous implementation of complex use cases, often involving in-front-of-meter pooling of vehicles, produces the greatest synergies. Combinations that include ancillary services and spot market trading lead to considerabl... [more]

The use of solar photovoltaic (PV) generation and battery energy storage (BES) systems in commercial buildings has been increasing significantly in recent years. Most of these systems, however, are designed to solely minimize the investment and operation costs. With the increasing concerns about high-impact low-probability (HILP) events, such as natural disasters, and their impact on power system resilience, there is a substantial need to integrate outage risks in power system infrastructure planning problems. This paper examines the impact of various electricity rates on the feasibility of PV and BES systems in commercial buildings for financial and resilience purposes. Simulation studies are conducted using the Renewable Energy Integration & Optimization (REopt) decision support software to optimize the size of solar PV and BES systems for both financial and resilience purposes, considering different combinations of geographic locations, load profiles, electricity rates, and outage d... [more]

To reduce greenhouse gas emissions from natural gas use, utilities are investigating the potential of adding hydrogen to their distribution grids. This will reduce the carbon dioxide emissions from grid-connected engines used for stationary power generation, and it may also impact their power output and efficiency. Promisingly, hydrogen and natural gas mixtures have shown encouraging results regarding engine power output, pollutant emissions, and thermal efficiency in well-controlled on-road vehicle applications. This work investigates the effects of adding hydrogen to the natural gas fuel for a lean-burn spark-ignited four-stroke, 8.9 liter eight-cylinder naturally aspirated engine used in a commercial stationary power generation application via an engine model developed in the GT-SUITETM modelling environment. The model was validated for fuel consumption, air flow, and exhaust temperature at two operating modes. The focus of the work was to assess the sensitivity of the engine’s powe... [more]

The automotive sector has been experiencing a rapid development in recent times. Modern trends aim at the progress of so-called sustainable, eco-friendly vehicles, in many cases associated with advanced technologies and assistance systems. It is increasingly common to see cars with electric, hybrid, gas or hydrogen propulsion systems. Such approaches can create a transformation of manufacturing processes towards the growth of new types and fields of technologies and systems in the automotive industry. The manuscript discusses the subject of vehicles with various types of power supply, i.e., propulsion system. The investigation was executed with different respondent groups whereby the analysis was performed predominantly by using two merging criteria such as place of residence and gender of respondents. Following the research conducted, we state that given a variety of variables, the majority of the respondents are convinced that, prospectively, electric and hybrid vehicles in all proba... [more]

This article presents the results of a study on metallurgical slag reduction using biomass such as Spent Coffee Grounds (SCGs). The proposed solution is a new aspect of searching for alternatives to standard reducers used in pyrometallurgical processes of metal production. Its gasification yields significant amounts of hydrocarbons, which are excellent reducing agents in such processes. The research results of copper slag reduction with the use of SCG biomass indicate this process is characterised by lower carbon dioxide emissions compared with the process using solid fuels such as coke and coke breeze. The addition of SCG as the reducer ensures the decrease in copper content in the slag to 0.32 wt.%, which corresponds to the increase of so-called relative decopperisation degree even up to 96.9%. As the decopperisation degree of slag increases, significantly more intense reduction in lead oxides during the reduction process is observed. The smallest lead content in waste slag of 0.91 w... [more]

During the trial production of marine gas hydrate in the former Soviet Union, Canada, North Slope of Alaska, South Sea Trough of Japan and Shenhu Sea of South China Sea, the problem of sand and water production cannot be avoided. The problems of sand production and water production in the process of natural gas hydrate depressurization exploitation have seriously restricted the exploitation efficiency and production of natural gas hydrate. The problems of sand production and water production are some of the main factors that prevent natural gas hydrate being commercially exploited. Therefore, it is urgent to carry out useful, relevant and cutting-edge research on the efficient drainage of sand and water from the wellbore in the process of natural gas hydrate mining. This paper innovatively proposes liquid-carrying and solid-carrying technology under foam circulation purging to address the existing problems of sand removal and drainage technology in hydrate mining. At present, no schola... [more]

A single sensible thermal storage system has the disadvantage of poor system efficiency, and a sensible-latent graded thermal storage system can effectively solve this problem. Moreover, the graded thermal storage system has the virtue of being adjustable, which can be adapted to many power generation systems. Therefore, this paper first analyzes the influence factors of the graded thermal storage system’s exergy and thermal efficiency. Subsequently, each factor’s significance was analyzed using the response surface method, and the prediction model for system exergy efficiency and cost was established using the support vector machine method. Finally, the second-generation nondominated sorting genetic algorithm (NSGA-II) was used to globally optimize the graded thermal storage system’s exergy efficiency and cost by Matlab software. As a result, the exergy efficiency was increased by 11.01%, and the cost was reduced by RMB 5.85 million. In general, the effect of multi-objective optimizat... [more]

Widely employed in hydrate exploitation, the single well method is utilized to broaden the scope of hydrate decomposition. Optimizing the well structure and production strategy is necessary to enhance gas recovery efficiency. Complex wells represented by the multilateral wells have great application potential in hydrate mining. This study focused on the impact of multilateral well production methods on productivity, taking the Nankai Trough in Japan as the study area. The spatial distribution of physical parameters such as porosity, permeability, and hydrate saturation in the Nankai Trough has significant heterogeneity. For model accuracy, the Sklearn machine learning and Kriging interpolation methods were used to construct a three-dimensional heterogeneous geological model to describe the structure and physical property parameters in the study area of the hydrate reservoir. The numerical simulation model was solved using the TOUGH + Hydrate program and fitted with the measured data of... [more]

The search for charging electric vehicles using renewable energy sources and ensuring the stability of the electrical system has been growing. This has led to the development of charging stations that integrate photovoltaic systems, energy storage systems in batteries, and charging stations. The storage system allows for applications that increase the reliability of the electrical network. The objective of this work is to study, based on real operational scenarios, the impacts, and criteria of energy quality of a charging solution containing a photovoltaic system, a storage system, and a charging station. In the solution, the batteries are lead-carbon type and photovoltaics have priority in energy supply, using excess generation to charge the batteries. In this aspect, the work presents relevant contributions to the study of energy quality. An improvement in energy quality is pointed out with the use of batteries, proving that even in the most diverse operating situations, such as part... [more]

In recent years, photovoltaic energy has become a popular alternative to traditional fossil fuels due to its renewable and sustainable nature, and the incentives provided by countries to encourage research and development in this field have accelerated the implementation of photovoltaic roofs. One important factor in maximizing the efficiency of solar panels is their orientation to harness maximum irradiation with minimum roof area. In this article, an optimizer-supported east−west-oriented solar power plant installation is experimentally presented to utilize more solar energy with less area compared to wide-area south orientation. Furthermore, an analysis of different angle placements is simulated by PVSOL and PVGIS to test the robustness of the presented approach, and the pros/cons of the features of the east−west and south orientation are discussed comparatively. The obtained results are promising for the ideal placement of solar systems along with the use of optimizers to further e... [more]

The transition from the current energy architecture to a new model is evident and inevitable. The coming future promises innovative and increasingly rigorous projects and challenges for everyone involved in this value chain. Technological developments have allowed the emergence of new concepts, such as renewable energy communities, decentralized renewable energy production, and even energy storage. These factors have incited consumers to play a more active role in the electricity sector and contribute considerably to the achievement of environmental objectives. With the introduction of renewable energy communities, the need to develop new management and optimization tools, mainly in generation and load management, arises. Thus, this paper proposes a platform capable of clustering consumers and prosumers according to their energy and geographical characteristics to create renewable energy communities. Thus, this paper proposes a platform capable of clustering consumers and prosumers acc... [more]

Condition monitoring of wind turbines is progressively increasing to maintain the continuity of clean energy supply to power grids. This issue is of great importance since it prevents wind turbines from failing and overheating, as most wind turbines with doubly fed induction generators (DFIG) are overheated due to faults in generator bearings. Bearing fault detection has become a main topic targeting the optimum operation, unscheduled downtime, and maintenance cost of turbine generators. Wind turbines are equipped with condition monitoring devices. However, effective and reliable fault detection still faces significant difficulties. As the majority of health monitoring techniques are primarily focused on a single operating condition, they are unable to effectively determine the health condition of turbines, which results in unwanted downtimes. New and reliable strategies for data analysis were incorporated into this research, given the large amount and variety of data. The development... [more]

The present article investigates viscous fluid flow’s heat and mass transfers over a stretching/shrinking sheet using the single and multi-wall carbon nanotube models. The analysis considers the effects of thermal radiation, induced slip, mass transpiration, and inclined magnetic force. The effect of the carbon nanotube model on fluid flow has not been considered in previous studies. By exploiting the similarity variable, the governing nonlinear partial differential equations are converted into nonlinear ordinary differential equation. The derived equations are solved analytically, and we obtained an exact solution for the velocity and energy conservation equation. The physical parameters of interest such as induced slip parameter, suction/injection, magnetic field, thermal radiation, and shear stress are analyzed and presented graphically. In particular, we show that the fluid flow in a single wall carbon nanotube transfers more energy than the multivalued nanotubes.

Nowadays, the Ukrainian electricity industry is experiencing difficult conditions, as it is operating in a mode of depletion of its production potential. At the same time, the transition to sustainable and renewable energy is the necessary basis for the country’s welfare and for ensuring its energy security. Therefore, today we cannot do without the additional attraction of sources of funding from investors. The purpose of the survey is to study the pattern and effectiveness of investments and identify links and dependencies between key technical and economic parameters and investments in renewable energy sources. To achieve this goal, the authors divided the study into four successive stages, which made it possible to study the subject of the study comprehensively. As a result of the study, results have been obtained that complement the existing theoretical, methodological, and practical developments. Mathematical calculations (using the example of the largest wind power plants in the... [more]

Uncertainties are widely present in the design and simulation of aero-engine combustion systems. Common non-probabilistic convex models are only capable of processing independent or correlated uncertainty variables, while conventional precise probabilistic sensitivity analysis based on ideal conditions also fails due to the presence of uncertainties. Given the above-described problem, an imprecise p-box sensitivity analysis method is proposed in this study in accordance with a multi-dimensional parallelepiped model, comprising independent and correlated variables in a unified framework to effectively address complex hybrid uncertainty problems where the two variables co-exist. The concepts of the correlation angle and correlation coefficient of any two parameters are defined. A multi-dimensional parallelepiped model is built as the uncertainty domain based on the marginal intervals and correlation characteristics of all parameters. The correlated variables in the initial parameter spac... [more]

This research was conducted to study the flame instability of syngas derived from raw municipal solid waste (MSW) and its potential as a natural gas (NG) replacement in power generation. MSW syngas is a mixture of various components such as methane (CH4), nitrogen (N2), oxygen (O2), and hydrogen (H2), whereas NG is mainly composed of CH4 (>70%) and CO2 (>10%). The flame characteristics of these two gases are quite different thus a direct replacement of NG with MSW syngas is impossible. Improvements to MSW syngas combustion are needed through the augmentation of the gas with CH4 and H2 active additives at various ratios so that its flame characteristics are comparable to those of NG. A typical MSW syngas composed of 16.2% methane (CH4), 13.5% hydrogen (H2), 69.1% nitrogen (N2), and 0.6% oxygen (O2) (by vol.) is available in Thailand with great potential for use as an NG replacement. In this study, this gas is used as a representative fuel for improvement and is referred to as simulated... [more]

Renewable energy sources, such as wind turbines, have become much more prevalent in recent years, and thus a popular form of energy generation. This is in part due to the ‘Fit for 55’ EU initiative, and in part, to rising fossil fuel prices, as well as the perceived requirement for nations to have power independence, and due to the influence of renewable energy sources we can see a marked increase in large wind farms in particular. However, wind farms by their very nature are highly inconsistent regarding power generation and are weather-dependent, thus presenting several challenges for transmission system operators. One of the options to overcome these issues is a system being able to forecast the generated power in a wide-ranging period—ranging from 15 min up to 36 h, and with an adequate resolution. Such a system would better help manage the power grid and allow for greater utilization of the green energy produced. In this document, we present a process of development for such a sys... [more]

Green hydrogen, produced using renewable energy, is nowadays one of the most promising alternatives to fossil fuels for reducing pollutant emissions and in turn global warming. In particular, the use of hydrogen as fuel for internal combustion engines has been widely analyzed over the past few years. In this paper, the authors show the results of some experimental tests performed on a hydrogen-fueled CFR (Cooperative Fuel Research) engine, with particular reference to the combustion. Both the air/fuel (A/F) ratio and the engine compression ratio (CR) were varied in order to evaluate the influence of the two parameters on the combustion process. The combustion duration was divided in two parts: the flame front development (characterized by laminar flame speed) and the rapid combustion phase (characterized by turbulent flame speed). The results of the hydrogen-fueled engine have been compared with results obtained with gasoline in a reference operating condition. The increase in engine C... [more]

The latest Intergovernmental Panel on Climate Change special report, on the impacts of global warming of 1 [...]

After the economic shock caused by COVID-19, with relevant effects on both the supply and demand for energy assets, there was greater interest in understanding the relationships between key energy prices. In order to contribute to a deeper understanding of energy price relationships, this paper analyzes the dynamics between the weekly spot prices of oil, natural gas and benchmark ethanol in the US markets. The analysis period started on 23 June 2006 and ended on 10 June 2022. This study used the DMCA cross-correlation coefficient in a dynamic way, using sliding windows. Among the main results, it was found that: (i) in the post-pandemic period, oil and natural gas were not correlated, in both short- and long-term timescales; and (ii) ethanol was negatively associated with natural gas in the most recent post-pandemic period, especially in short-term scales. The results of the present study are potentially relevant for both market and public agents regarding investment diversification st... [more]

Worldwide power and energy systems are changing significantly [...]

The last decade has seen a significant increase in electromobility. With this trend, it will be necessary to start dealing with the subsequent recycling and disposal of electric vehicles, including the batteries. Currently, the battery is one of the most expensive components of an electric vehicle, which in part hinders their sufficient competitiveness with the internal combustion engine. Furthermore, the lifetime of a battery for use in an electric vehicle is assumed to be 8−10 years/160,000 km, after which the battery capacity drops to 80% of the initial capacity. However, it transpires that a battery at the end of its life in an electric vehicle does not need to be disposed of immediately, but can be used in other applications wherein the emphasis is not so strictly on an excellent power and capacity capability related to its volume or weight. Thus, reusing batteries can help reduce their cost for use in electric vehicles, increase their utility value, and reduce the environmental i... [more]