Energies

29 pages, 3906 KiB

Open AccessArticle

Efficiency-Based Modeling of Aeronautical Proton Exchange Membrane Fuel Cell Systems for Integrated Simulation Framework Applications

by Paolo Aliberti, Marco Minneci, Marco Sorrentino, Fabrizio Cuomo and Carmine Musto

Energies 2025, 18(4), 999; https://doi.org/10.3390/en18040999 - 19 Feb 2025

Viewed by 384

Abstract

Proton exchange membrane fuel cell system (PEMFCS)-based battery-hybridized turboprop regional aircraft emerge as a promising solution to the urgency of reducing the environmental impact of such airplanes. The development of integrated simulation frameworks consisting of versatile and easily adaptable models and control strategies [...] Read more.

Proton exchange membrane fuel cell system (PEMFCS)-based battery-hybridized turboprop regional aircraft emerge as a promising solution to the urgency of reducing the environmental impact of such airplanes. The development of integrated simulation frameworks consisting of versatile and easily adaptable models and control strategies is deemed highly strategic to guarantee proper component sizing and in-flight, onboard energy management. This need is here addressed via a novel efficiency-driven PEMFCS model and a degradation-aware battery-PEMFCS unit specification-independent control algorithm. The proposed model simplifies stack voltage and current estimation while maintaining accuracy so as to support, in conjunction with the afore-introduced versatile control strategy, the development of architectures appropriate for subsequent fully integrated (i.e., at the entire aircraft design level) simulation frameworks. The model also allows assessing the balance of plant impact on the fuel cell system’s net power, as well as the heat generated by the stack and related cooling demand. Finally, the multi-stack configuration meeting the DC bus line 270 V constraint, as currently assumed by the aviation industry, is determined. Full article

(This article belongs to the Section D: Energy Storage and Application)

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18 pages, 6572 KiB

Open AccessArticle

Development of a Digital System for Monitoring Emergency Conditions in 20 kV Distribution Networks

by Alisher Baltin, Sultanbek Issenov, Gulim Nurmaganbetova, Aliya Zhumadirova, Assel Yussupova, Alexandra Potapenko and Aliya Maussymbayeva

Energies 2025, 18(4), 998; https://doi.org/10.3390/en18040998 - 19 Feb 2025

Viewed by 323

Abstract

This article presents research on the possibilities of using information and communication technologies in monitoring systems for electrical networks with isolated neutral, aimed at improving and automating production functions in the energy sector. This aligns with the digitalization policy of Kazakhstan’s economy and [...] Read more.

This article presents research on the possibilities of using information and communication technologies in monitoring systems for electrical networks with isolated neutral, aimed at improving and automating production functions in the energy sector. This aligns with the digitalization policy of Kazakhstan’s economy and is part of similar programs in the field of the electric power industry. This article explores an approach to organizing a digital monitoring system for emergency conditions, specifically single-phase ground faults in medium-voltage lines within the range of 6–35 kV, including the new voltage class of 20 kV. A version of such a system is proposed, based on a combination of a server, a wireless information network, and remote digital voltage measurement nodes. This wireless information and communication network is designed to detect the locations of single-phase ground faults (SPGF) using specialized zero-sequence voltage sensors installed at various points along the power transmission lines, along with wireless signal transmission channels to the dispatcher’s server. To ensure protection against industrial interference, based on the results of practical environment modeling, a transmission technology most resistant to external noise is selected. This article proposes the selection of equipment necessary for implementing wireless transmission technology and develops two versions of a digital voltmeter design based on low-power programmable microcontrollers. The proposed technical solutions require further experimental validation, and therefore, the authors plan to conduct additional research and practical experiments in the future. Full article

(This article belongs to the Section A1: Smart Grids and Microgrids)

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13 pages, 2330 KiB

Open AccessArticle

High Power Density IGBT Loss Calculation Model and Analysis

by Feng Wang, Yifan Song, Wang Dou, Zhaolei Zheng, Zhuangzhuang Li, Biao Li and Jun Liu

Energies 2025, 18(4), 997; https://doi.org/10.3390/en18040997 - 19 Feb 2025

Viewed by 280

Abstract

This paper presents the establishment of an accurate loss model for high-power-density IGBT modules used in electric vehicles, leveraging the thermal simulation capabilities of the power electronics simulation software PLECS 4.1. The study aims to address the significant influence of IGBT losses on [...] Read more.

This paper presents the establishment of an accurate loss model for high-power-density IGBT modules used in electric vehicles, leveraging the thermal simulation capabilities of the power electronics simulation software PLECS 4.1. The study aims to address the significant influence of IGBT losses on the energy efficiency and reliability of electric vehicles. A simulation model was built using the SVPWM modulation strategy to drive a three-phase inverter, and the average loss method was employed to determine both conduction and switching losses. The simulation results were compared with calculations based on the datasheet, showing a deviation of less than 4%. For instance, the actual conduction loss was found to be 7.988 W, compared to the theoretical calculation of 8.16 W, with a deviation of 2.15%. Similarly, the switching loss was 22.069 W, compared to the theoretical value of 22.447 W, with a deviation of 1.71%. These results confirm that the proposed model accurately predicts losses under specified conditions. Compared with traditional methods, the model presented in this paper offers higher precision and improved simulation speed, thus proving effective for accurate loss analysis of IGBT modules and supporting further energy efficiency improvement and system optimization in electric vehicles. Full article

(This article belongs to the Special Issue Measurement Systems for Electric Machines and Motor Drives)

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44 pages, 3855 KiB

Open AccessReview

Grid Peak Shaving and Energy Efficiency Improvement: Advances in Gravity Energy Storage Technology and Research on Its Efficient Application

by Shaojun Wang, Hao Xiao, Zhaoquan Zhao, Dezhao Li, Dong Hu, Qi Hu, Chen Shen, Xingyu Zhang, Jiahao Hu, Cheng Chi, Xin Cheng, Wei Zhang, Erjun Bu, Chenxu Zhao, An Wang and Lu Wang

Energies 2025, 18(4), 996; https://doi.org/10.3390/en18040996 - 19 Feb 2025

Viewed by 429

Abstract

Global energy issues have spurred the development of energy storage technology, and gravity-based energy storage (GBES) technology has attracted much attention. This comprehensive review examines the principles, applications, and prospects of GBES technology, a promising solution for mitigating the intermittency of renewable energy [...] Read more.

Global energy issues have spurred the development of energy storage technology, and gravity-based energy storage (GBES) technology has attracted much attention. This comprehensive review examines the principles, applications, and prospects of GBES technology, a promising solution for mitigating the intermittency of renewable energy sources and enhancing grid stability. GBES harnesses potential energy by elevating solid or liquid mediums, offering distinct advantages over other energy storage technologies such as pumped hydro storage and batteries. The study examines various GBES configurations, emphasizing the importance of system design, control strategies, and efficiency. This review also evaluates the economic, environmental, and social benefits of GBES, emphasizing its cost-effectiveness and potential for local economic growth. The need for policy support, technological innovation, and a robust regulatory framework is highlighted to promote the widespread adoption of GBES, which holds significant potential for enhancing grid stability and supporting the integration of renewable energy. Full article

(This article belongs to the Special Issue Advanced Energy Storage Technologies and Applications (AESAs), 2nd Edition)

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25 pages, 6800 KiB

Open AccessArticle

Deep-Fuzzy Logic Control for Optimal Energy Management: A Predictive and Adaptive Framework for Grid-Connected Microgrids

by Muhammed Cavus, Dilum Dissanayake and Margaret Bell

Energies 2025, 18(4), 995; https://doi.org/10.3390/en18040995 - 19 Feb 2025

Cited by 1 | Viewed by 472

Abstract

This paper introduces a novel energy management framework, Deep-Fuzzy Logic Control (Deep-FLC), which combines predictive modelling using Long Short-Term Memory (LSTM) networks with adaptive fuzzy logic to optimise energy allocation, minimise grid dependency, and preserve battery health in grid-connected microgrid (MG) systems. Integrating [...] Read more.

This paper introduces a novel energy management framework, Deep-Fuzzy Logic Control (Deep-FLC), which combines predictive modelling using Long Short-Term Memory (LSTM) networks with adaptive fuzzy logic to optimise energy allocation, minimise grid dependency, and preserve battery health in grid-connected microgrid (MG) systems. Integrating LSTM-based predictions provides foresight into system parameters such as state of charge, load demand, and battery health, while fuzzy logic ensures real-time adaptive control. Results demonstrate that Deep-FLC achieves a 25.7% reduction in operational costs compared to the conventional system and a 17.5% saving cost over the Fuzzy Logic Control (FLC) system. Additionally, Deep-FLC delivers the highest battery efficiency of 61% and constraints depth of discharge to below 2% per time step, resulting in a reduction of the state of health degradation to less than 0.2% over 300 h. By combining predictive analytics with adaptive control, this study addresses the limitations of standalone approaches and establishes Deep-FLC as a robust, efficient, and sustainable energy management solution. Key novel contributions include the integration of advanced prediction mechanisms with fuzzy control and its application to battery-integrated grid-connected MG systems. Full article

(This article belongs to the Special Issue Key Functionalities in Battery Management Systems for Transportation Electrification)

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26 pages, 3839 KiB

Open AccessReview

Smart Grid Fault Mitigation and Cybersecurity with Wide-Area Measurement Systems: A Review

by Chisom E. Ogbogu, Jesse Thornburg and Samuel O. Okozi

Energies 2025, 18(4), 994; https://doi.org/10.3390/en18040994 - 19 Feb 2025

Viewed by 596

Abstract

Smart grid reliability and efficiency are critical for uninterrupted service, especially amidst growing demand and network complexity. Wide-Area Measurement Systems (WAMS) are valuable tools for mitigating faults and reducing fault-clearing time while simultaneously prioritizing cybersecurity. This review looks at smart grid WAMS implementation [...] Read more.

Smart grid reliability and efficiency are critical for uninterrupted service, especially amidst growing demand and network complexity. Wide-Area Measurement Systems (WAMS) are valuable tools for mitigating faults and reducing fault-clearing time while simultaneously prioritizing cybersecurity. This review looks at smart grid WAMS implementation and its potential for cyber-physical power system (CPPS) development and compares it to traditional Supervisory Control and Data Acquisition (SCADA) infrastructure. While traditionally used in smart grids, SCADA has become insufficient in handling modern grid dynamics. WAMS differ through utilizing phasor measurement units (PMUs) to provide real-time monitoring and enhance situational awareness. This review explores PMU deployment models and their integration into existing grid infrastructure for CPPS and smart grid development. The review discusses PMU configurations that enable precise measurements across the grid for quicker, more accurate decisions. This study highlights models of PMU and WAMS deployment for conventional grids to convert them into smart grids in terms of the Smart Grid Architecture Model (SGAM). Examples from developing nations illustrate cybersecurity benefits in cyber-physical frameworks and improvements in grid stability and efficiency. Further incorporating machine learning, multi-level optimization, and predictive analytics can enhance WAMS capabilities by enabling advanced fault prediction, automated response, and multilayer cybersecurity. Full article

(This article belongs to the Special Issue AI Facilitated Cyber–Physical Energy Systems—Planning, Operation, and Markets)

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24 pages, 5848 KiB

Open AccessArticle

Transient Stability Analysis and Emergency Generator Tripping Control Based on Spatio-Temporal Graph Deep Learning

by Shuaibo Wang, Jie Zeng, Jie Zhang, Zhuohang Liang, Yihua Zhu and Shufang Li

Energies 2025, 18(4), 993; https://doi.org/10.3390/en18040993 - 19 Feb 2025

Viewed by 242

Abstract

This paper addresses the challenge of achieving fast and accurate transient stability analysis and emergency control in power systems, which are crucial for reliable grid operation under disturbances. To this end, we propose a spatio-temporal graph deep learning approach leveraging Diffusion Convolutional Gated [...] Read more.

This paper addresses the challenge of achieving fast and accurate transient stability analysis and emergency control in power systems, which are crucial for reliable grid operation under disturbances. To this end, we propose a spatio-temporal graph deep learning approach leveraging Diffusion Convolutional Gated Recurrent Units (DCGRUs) for transient stability assessment and coherent generator group prediction. Unlike traditional methods, our approach explicitly represents transient responses as spatio-temporal graph data, capturing both topological and dynamic dependencies. The DCGRU model effectively extracts these features, and the predicted coherent generator groups are incorporated into the single-machine infinite-bus equivalence method to design an emergency generator tripping scheme. Simulation analysis results on both benchmark and real-world power grids validate the proposed method’s feasibility and effectiveness in enhancing transient stability analysis and emergency control. Full article

(This article belongs to the Special Issue Application of Advanced Control Theories to Power Electronics and Power Systems)

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19 pages, 984 KiB

Open AccessArticle

Analysis of Corporate Acceptance of Hydrogen Energy Technology Based on the Extended Technology Acceptance Model

by Jianchao Hou and Han Wang

Energies 2025, 18(4), 1013; https://doi.org/10.3390/en18041013 - 19 Feb 2025

Viewed by 413

Abstract

Hydrogen holds an important strategic position in the energy systems of many countries. Many studies have analyzed the acceptance of hydrogen energy technology from the public’s perspective, but few have examined it from the corporate perspective. This paper establishes a technology acceptance model [...] Read more.

Hydrogen holds an important strategic position in the energy systems of many countries. Many studies have analyzed the acceptance of hydrogen energy technology from the public’s perspective, but few have examined it from the corporate perspective. This paper establishes a technology acceptance model and employs structural equation modeling to investigate the factors affecting the acceptance of hydrogen energy technology within enterprises. After conducting questionnaire surveys among employees of energy enterprises, electric power companies, and new energy vehicle manufacturers, the results indicate that, while most of the interviewed enterprises have positive attitudes towards hydrogen technology, their willingness to develop hydrogen business does not appear to be correspondingly positive. In addition, government trust, perceived benefit, and social influence positively impact corporate acceptability indirectly, whereas perceived risk exhibits a negative indirect effect on corporate acceptance. Finally, this paper discusses the results of the above studies and makes corresponding policy recommendations. Full article

(This article belongs to the Section C: Energy Economics and Policy)

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35 pages, 4135 KiB

Open AccessArticle

Application of Systems Analysis Methods to Construct a Virtual Model of the Field

by Yury Ilyushin, Victoria Nosova and Andrei Krauze

Energies 2025, 18(4), 1012; https://doi.org/10.3390/en18041012 - 19 Feb 2025

Viewed by 339

Abstract

Recently, the rate of offshore oil production has increased, which creates a need to develop technical solutions for the implementation of more efficient processes on offshore platforms. A relevant solution is the development and application of digital twins. Offshore production platforms are specially [...] Read more.

Recently, the rate of offshore oil production has increased, which creates a need to develop technical solutions for the implementation of more efficient processes on offshore platforms. A relevant solution is the development and application of digital twins. Offshore production platforms are specially protected objects due to the high risk of environmental pollution. Therefore, such objects are especially distinguished for the implementation of advanced technological solutions. In this study, the authors conduct a study of the input, output, and resulting parameters that affect the production process. Using the theory of systems analysis, they determine the list of critical factors and build a conceptual and then a mathematical model of the field. It differs from existing analogues by the introduction of additional parameters that provide higher modeling accuracy. Based on the resulting mathematical model, a neural network is trained to identify the optimal operating mode. An assessment of the economic feasibility of the provided development is carried out. Full article

(This article belongs to the Section K: State-of-the-Art Energy Related Technologies)

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27 pages, 14341 KiB

Open AccessArticle

Investigation on Thermal Performance of a Battery Pack Cooled by Refrigerant R134a in Ribbed Cooling Channels

by Tieyu Gao, Jiadian Wang, Haonan Sha, Hao Yang, Chenguang Lai, Xiaojin Fu, Guangtao Zhai and Junxiong Zeng

Energies 2025, 18(4), 1011; https://doi.org/10.3390/en18041011 - 19 Feb 2025

Viewed by 320

Abstract

This study numerically investigates the thermal performance of a refrigerant-based battery thermal management system (BTMS) under various operating conditions. A validated numerical model is used to examine the effects of cooling channel rib configurations (rib spacing and rib angles) and refrigerant parameters (mass [...] Read more.

This study numerically investigates the thermal performance of a refrigerant-based battery thermal management system (BTMS) under various operating conditions. A validated numerical model is used to examine the effects of cooling channel rib configurations (rib spacing and rib angles) and refrigerant parameters (mass flow rate and saturation temperature) on battery thermal behavior. Additionally, the impact of discharge C-rates is analyzed. The results show that a rib spacing of 11 mm and a rib angle of 60° reduce the maximum battery temperature by 0.8 °C (cooling rate of 2%) and improve temperature uniformity, though at the cost of a 130% increase in pressure drop. Increasing the refrigerant mass flow rate lowers the maximum temperature by up to 10%, but its effect on temperature uniformity diminishes beyond 20 kg/h. A lower saturation temperature enhances cooling but increases internal temperature gradients, while a higher saturation temperature improves uniformity at the expense of a slightly higher maximum temperature. Under high discharge rates (12C), the system’s cooling capacity becomes limited, leading to significant temperature rises. These findings provide insights that can aid in optimizing BTMS design to balance cooling performance, energy efficiency, and temperature uniformity. Full article

(This article belongs to the Topic Enhanced Heat Transfer and Advanced Energy Conversion Technology, 2nd Edition)

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21 pages, 4196 KiB

Open AccessArticle

Driving the Energy Transition in Colombia for Off-Grid Regions: Microgrids and Non-Conventional Renewable Energy Sources

by Jaime Alberto Cerón, Eduardo Gómez-Luna and Juan C. Vasquez

Energies 2025, 18(4), 1010; https://doi.org/10.3390/en18041010 - 19 Feb 2025

Viewed by 377

Abstract

At present, the Colombian government is faced with the challenge of guaranteeing access to energy services for all its inhabitants. However, as there are isolated populations or populations with difficult access to conventional electricity grids in the country, it is necessary to seek [...] Read more.

At present, the Colombian government is faced with the challenge of guaranteeing access to energy services for all its inhabitants. However, as there are isolated populations or populations with difficult access to conventional electricity grids in the country, it is necessary to seek innovative and appropriate solutions to the conditions and needs of the so-called non-interconnected zones (NIZs), which allow the generation and consumption of energy in a local, efficient, and safe way for all users. For this reason, this research consisted of studying and proposing technological solutions that use distributed energy resources, making the most of the energy potential in each area, as a proposed solution to the problems faced by NIZs with energy shortages. As a result, a series of proposals with microgrids are obtained, taking advantage of their flexible characteristics and using NRES as energy sources, mitigating pollution and contributing to the energy transition sought by the Colombian government. Full article

(This article belongs to the Special Issue Integration of Distributed Energy Resources (DERs): 2nd Edition)

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20 pages, 20133 KiB

Open AccessArticle

Numerical Simulation of CO₂ Immiscible Displacement Based on Three-Dimensional Pore Structure

by Feng Shi, Xiaoshan Li, Gen Kou, Huan Liu, Sai Liu, Zhen Liu, Ziheng Zhao and Xiaoyu Jiang

Energies 2025, 18(4), 1009; https://doi.org/10.3390/en18041009 - 19 Feb 2025

Viewed by 289

Abstract

CO₂-enhanced tight oil production can increase crude oil recovery while part of the injected CO₂ is geologically sequestered. This process is influenced by factors such as gas injection rate, oil/gas viscosity ratio, and contact angle. Understanding how these factors affect [...] Read more.

CO₂-enhanced tight oil production can increase crude oil recovery while part of the injected CO₂ is geologically sequestered. This process is influenced by factors such as gas injection rate, oil/gas viscosity ratio, and contact angle. Understanding how these factors affect recovery during CO₂ non-mixed-phase substitution is essential for improving CO₂-enhanced tight oil production technology. In this study, three-dimensional pore structure was numerically simulated using physical simulation software. The effects of three key parameters—the gas injection rate, contact angle and viscosity slope—on flow displacement during a CO₂ non-mixed-phase drive were analyzed. In addition, the study compares the fluid transport behavior under mixed-phase and non-mixed-phase conditions at the pore scale. The simulation results show that increasing the replacement velocity significantly expands the diffusion range of CO₂ and reduces the capillary fingering phenomenon. In addition, the saturation of CO₂ increases with the increase in the viscosity ratio, which further improves the diffusion range of CO₂. The wetting angle is not simply linearly related to the drive recovery, and the recovery is closely related to the interfacial tension and capillary force under the influence of wettability. The recoveries under mixed-phase conditions were slightly higher than those under unmixed-phase conditions. During the mixed-phase replacement process, CO₂ is dissolved into the crude oil, resulting in oil volume expansion, which improves the distance and extent of CO₂ permeation. Full article

(This article belongs to the Section H: Geo-Energy)

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18 pages, 1406 KiB

Open AccessReview

Production Efficiency of Advanced Liquid Biofuels: Prospects and Challenges

by Tamás Mizik, Christian Barika Igbeghe and Zsuzsanna Deák

Energies 2025, 18(4), 1008; https://doi.org/10.3390/en18041008 - 19 Feb 2025

Viewed by 305

Abstract

Renewable sources are becoming more critical in light of global warming and the recent energy crisis. As a renewable energy source, biofuels may play an essential role in this process, especially in the transport sector. Advanced biofuels provide a great opportunity, as their [...] Read more.

Renewable sources are becoming more critical in light of global warming and the recent energy crisis. As a renewable energy source, biofuels may play an essential role in this process, especially in the transport sector. Advanced biofuels provide a great opportunity, as their potential feedstocks do not compete with food production. Based on a systematic literature review, this study aims to provide a comprehensive overview of the prospects and challenges of advanced liquid biofuels. Out of the identified 508 articles, 188 were abstract-screened, providing 67 articles for in-depth screening. Finally, 57 articles were reviewed. Although advanced biofuels are not yet economically viable, it is evident that every step of the production process can be optimized. Moreover, technological advancements, such as the use of novel catalysts and co-catalysts, nanotechnology, and genetic and metabolic engineering, offer great opportunities for enhanced production efficiency, which is key for their production to be profitable. Full article

(This article belongs to the Special Issue Environmentally Friendly Biofuel Production: 2nd Edition)

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26 pages, 7525 KiB

Open AccessArticle

Agrivoltaics, Opportunities for Hydrogen Generation, and Market Developments

by Torsten Clemens, Andreas Lunzer, Martin Hunyadi-Gall and Pablo Gil

Energies 2025, 18(4), 1007; https://doi.org/10.3390/en18041007 - 19 Feb 2025

Viewed by 388

Abstract

To achieve deep decarbonization, renewable energy generation must be substantially increased. The technologies with the lowest levelized cost of electricity (LCOE) are land-based photovoltaics (PVs) and wind energy. Agri-PVs offer the potential for dual land use, combining energy generation with agricultural activities. However, [...] Read more.

To achieve deep decarbonization, renewable energy generation must be substantially increased. The technologies with the lowest levelized cost of electricity (LCOE) are land-based photovoltaics (PVs) and wind energy. Agri-PVs offer the potential for dual land use, combining energy generation with agricultural activities. However, the costs of agri-PVs are higher than those of ground-mounted PV. To enhance the competitiveness of agri-PV, we investigate the synergies between agri-PVs and hydrogen electrolysis through process simulation. Additionally, we analyse current technological developments in agri-PVs based on a market analysis of start-up companies. Our results indicate that the levelized cost of hydrogen (LCOH) can be comparable for agri-PVs and ground-mounted PVs due to the somewhat smoother electricity generation for the same installed capacity. The market analysis reveals the emergence of a technology ecosystem that integrates agri-PVs with next-generation agricultural technologies, such as sensors, robotics, and artificial intelligence (AI) agents, along with localized electricity generation forecasting. The integrated agri-PV and hydrogen generation system has significant global scaling potential for renewable energy generation. Furthermore, it positively impacts local economies and energy resilience, may reduce water scarcity in agriculture, and leverages advancements in AI, robotics, PV, and hydrogen generation technologies. Full article

(This article belongs to the Special Issue Renewable Energy and Energy Storage for Distributed Energy Generation Systems)

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27 pages, 5623 KiB

Open AccessArticle

Torque Ripple Minimization for Switched Reluctance Motor Drives Based on Harris Hawks–Radial Basis Function Approximation

by Jackson Oloo and Szamel Laszlo

Energies 2025, 18(4), 1006; https://doi.org/10.3390/en18041006 - 19 Feb 2025

Viewed by 224

Abstract

Switched reluctance motor drives are becoming attractive for electric vehicle propulsion systems due to their simple and cheap construction. However, their operation is degraded by torque ripples due to the salient nature of the stator and rotor poles. There are several methods of [...] Read more.

Switched reluctance motor drives are becoming attractive for electric vehicle propulsion systems due to their simple and cheap construction. However, their operation is degraded by torque ripples due to the salient nature of the stator and rotor poles. There are several methods of mitigating torque ripples in switched reluctance motors (SRMs). Apart from changing the geometrical design of the motor, the less costly technique involves the development of an adaptive switching strategy. By selecting suitable turn-on and turn-off angles, torque ripples in SRMs can be significantly reduced. This work combines the benefits of Harris Hawks Optimization (HHO) and Radial Basis Functions (RBFs) to search and estimate optimal switching angles. An objective function is developed under constraints and the HHO is utilized to perform search stages for optimal switching angles that guarantee minimal torque ripples at every speed and current operating point. In this work, instead of storing the

θ_{o n}, θ_{o f f}

values in a look-up table, the values are passed on to an RBF model to learn the nonlinear relationship between the columns of data from the HHO and hence transform them into high-dimensional outputs. The values are used to train an enhanced neural network (NN) in an adaptive switching strategy to address the nonlinear magnetic characteristics of the SRM. The proposed method is implemented on a current chopping control-based SRM 8/6, 600 V model. Percentage torque ripples are used as the key performance index of the proposed method. A fuzzy logic switching angle compensation strategy is implemented in numerical simulations to validate the performance of the HHO-RBF method. Full article

(This article belongs to the Special Issue Advanced Electric Powertrain Technologies for Electric Vehicles)

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24 pages, 8996 KiB

Open AccessArticle

Design of a Three-Input, Single-Output DC–DC Converter for Electric Charging Station

by Sivaram Natarajan Vijayanathan, Lavanya Anbazhagan, Jagabar Sathik Mohamed Ali, Divya Navamani Jayachandran, Pradeep Vishnuram, CH. Naga Sai Kalyan, Mustafa Abdullah and Rajkumar Singh Rathore

Energies 2025, 18(4), 1005; https://doi.org/10.3390/en18041005 - 19 Feb 2025

Viewed by 163

Abstract

This article presents a novel four-port DC–DC converter designed to integrate photovoltaics, fuel cells, and supercapacitors with one DC charging single-output port with a reduced component count. The proposed converter ensures an efficient power management strategy to manage the load power demand and [...] Read more.

This article presents a novel four-port DC–DC converter designed to integrate photovoltaics, fuel cells, and supercapacitors with one DC charging single-output port with a reduced component count. The proposed converter ensures an efficient power management strategy to manage the load power demand and optimize the power flow from the sources. The power management controller helps enhance the performance of the system by dynamically prioritizing the sources based on their availability and the demand of the load. A comprehensive reliability analysis is conducted to measure the converter’s robustness under varying load conditions, proving its suitability for real-world applications. The proposed topology’s performance was validated in three different scenarios for 1 kW using a simulation tool, and experiments in the laboratory were conducted. The failure rate and efficiency of the system are analyzed, and the converter promises a 96.5% efficiency for 1 kW and a failure rate of 4.6216 × 10⁶ failures per hour. The simulation and experimental results validate the converter’s performance, highlighting its superior efficiency, reliability, and scalability. Full article

(This article belongs to the Special Issue Key Technologies and Challenges for Power Electronics System—2nd Edition)

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16 pages, 14946 KiB

Open AccessArticle

The Tectonic Control on Shale Oil Migration and Accumulation of the Lower Jurassic Daanzhai Member of the Ziliujing Formation, Sichuan Basin, China

by Zhuopei Li, Haihua Zhu, Minglei Wang, Benjian Zhang, Yadong Zhou, Haitao Hong, Yucong Li and Xingzhi Wang

Energies 2025, 18(4), 1004; https://doi.org/10.3390/en18041004 - 19 Feb 2025

Viewed by 285

Abstract

In order to understand the tectonic control on shale oil migration and accumulation, samples of the Daanzhai Member of the Lower Jurassic Ziliujing Formation from the well core in a tectonically stable area and upright anticline outcrop were selected for total organic carbon [...] Read more.

In order to understand the tectonic control on shale oil migration and accumulation, samples of the Daanzhai Member of the Lower Jurassic Ziliujing Formation from the well core in a tectonically stable area and upright anticline outcrop were selected for total organic carbon (TOC) content analysis, rock pyrolysis, fluorescence scanning, and scanning electron microscopy. The results show the following: (1) In the tectonically stable area, the TOC of shale oil reservoirs is positively correlated with S₁, and a high OSI interval usually occurs in high-TOC shales. The oil content of the limestone lamina decreases with an increasing distance from black shale. The vertical migration of shale oil into or across the lamina is not obvious and is mainly micro-scale. (2) The migration pathway includes a lamina interface, shell–clay interface, calcite cleavage, feldspar or calcite dissolution pores, and quartz or kaolinite intergranular pores. Large-scale shale oil migration time occurs at the peak of oil generation. (3) In the area of strong tectonic deformation, the formation of fractures in limestone further promotes the migration of oil from shale into the lamina. (4) The re-migration of shale oil during the uplift and deformation period involves three processes: upward migration in a clay matrix, then entry and migration along the limestone–shale interface from the lateral pinch-out points of the lamina, migration into the lamina joints, and then short diffusion into the limestone. (5) The migration of shale oil in the Daanzhai shale was controlled by the history of hydrocarbon generation and tectonic deformation and occurred in several stages. Full article

(This article belongs to the Section H: Geo-Energy)

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26 pages, 3831 KiB

Open AccessArticle

Validation of a Heat Pump System Model for Energy Recycling in Grocery Stores Through On-Site Energy Monitoring

by Niklas Söderholm, Mikko Gröndahl, Tuomo Niemelä, Juha Jokisalo, Risto Kosonen and Long Ni

Energies 2025, 18(4), 1003; https://doi.org/10.3390/en18041003 - 19 Feb 2025

Viewed by 287

Abstract

This paper presents a validated simulation model for heat pump-based energy recycling systems, with a focus on heat recovery applications in grocery stores. Heat is recovered through heat pumps from a subcritical CO₂-based refrigeration system, with exhaust air heat recovery used [...] Read more.

This paper presents a validated simulation model for heat pump-based energy recycling systems, with a focus on heat recovery applications in grocery stores. Heat is recovered through heat pumps from a subcritical CO₂-based refrigeration system, with exhaust air heat recovery used on demand according to the heating demand. The model is validated through a case study on a Finnish hypermarket-sized grocery store, where the heat pump system has been operational since 2020. Multi-objective energy optimization is used to validate the model by estimating critical decision variable values and providing error estimates compared to the measured data. The calibrated energy system model has a maximum mean bias error, MBE, of ±5% and a 10–15% coefficient of variation of root mean squared error, CV(RMSE), for the heat pump-related energy balance. Energy optimizations indicate that the control algorithm of the investigated heat pump system can be enhanced to reduce district heating consumption by 12%. The study emphasizes the need for numerous input parameters tailored to a system-specific layout to accurately reproduce the heat pump system’s control algorithm. Compared to a typical transcritical CO₂ booster system with heat recovery, the novel heat recovery system shows superior heat recovery potential and a high total COP for both heating and cooling. Full article

(This article belongs to the Section J: Thermal Management)

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30 pages, 4323 KiB

Open AccessArticle

A Multilayer Perceptron Feedforward Neural Network and Particle Swarm Optimization Algorithm for Optimizing Biogas Production

by Arief Abdurrakhman, Lilik Sutiarso, Makhmudun Ainuri, Mirwan Ushada and Md Parvez Islam

Energies 2025, 18(4), 1002; https://doi.org/10.3390/en18041002 - 19 Feb 2025

Viewed by 535

Abstract

Efficient biogas production significantly impacts greenhouse gas (GHG) emissions and carbon sequestration by reducing emissions and enhancing carbon storage. Nonetheless, the consistency and optimization of biogas production are hindered by fluctuations in key input variables, namely, pH, moisture content, organic loading rate (OLR), [...] Read more.

Efficient biogas production significantly impacts greenhouse gas (GHG) emissions and carbon sequestration by reducing emissions and enhancing carbon storage. Nonetheless, the consistency and optimization of biogas production are hindered by fluctuations in key input variables, namely, pH, moisture content, organic loading rate (OLR), and temperature, which significantly impact the quality of agricultural waste biomass and biogas production. Any fluctuations in these variables can affect biogas productivity. This study aims to provide valuable optimization parameters for maximum biogas production using rice straw and cow dung as agricultural waste biomass for biogas input materials. Therefore, machine learning techniques such as multilayer perceptron feedforward neural networks with a particle swarm optimization (PSO) combination generate optimal values for each variable for maximum biogas production. This study uses three variants of the training function for neural networks, namely gradient descent with momentum and adaptive learning rate, gradient descent with momentum, and gradient descent with adaptive learning rate. The findings reveal that, under an optimum pH value of 6.0000, a humidity of 62.3176%, an OLR of 67.6823 kg.m³/day, and a temperature of 37.0482 °C, biogas production has the potential to increase to 2.91 m³/day with a high accuracy testing value of R² = 0.90. These methods in use accurately predict the optimal parameters, with a maximum deviation of 8.48% from experimentally derived values and mean square error (MSE) of 0.0051243. This study emphasizes the benefits of using multilayer perceptron feedforward neural networks and particle swarm optimization to optimize operational parameters and accurately predict biogas production. Full article

(This article belongs to the Special Issue Environmental Applications of Bioenergy and Biomass, 2nd Edition)

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25 pages, 3614 KiB

Open AccessReview

Challenges and Opportunities for Aquifer Thermal Energy Storage (ATES) in EU Energy Transition Efforts—An Overview

by Katarina Marojević, Tomislav Kurevija and Marija Macenić

Energies 2025, 18(4), 1001; https://doi.org/10.3390/en18041001 - 19 Feb 2025

Viewed by 416

Abstract

Aquifer Thermal Energy Storage (ATES) systems are a promising solution for sustainable energy storage, leveraging underground aquifers to store and retrieve thermal energy for heating and cooling. As the global energy sector faces rising energy demands, climate change, and the depletion of fossil [...] Read more.

Aquifer Thermal Energy Storage (ATES) systems are a promising solution for sustainable energy storage, leveraging underground aquifers to store and retrieve thermal energy for heating and cooling. As the global energy sector faces rising energy demands, climate change, and the depletion of fossil fuels, transitioning to renewable energy sources is imperative. ATES systems contribute to these efforts by reducing greenhouse gas (GHG) emissions and improving energy efficiency. This review uses the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) methodology as a systematic approach to collect and analyze relevant literature. It highlights trends, gaps, and advancements in ATES systems, focusing on simulation methods, environmental impacts, and economic feasibility. Tools like MODFLOW, FEFLOW, and COMSOL Multiphysics are emphasized for optimizing design and system performance. Europe is identified as a continent with the most favorable predispositions for ATES implementation due to its diverse and abundant aquifer systems, strong policy frameworks supporting renewable energy, and advancements in subsurface energy technologies. Full article

(This article belongs to the Special Issue Development and Utilization in Geothermal Energy)

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13 pages, 2924 KiB

Open AccessArticle

Enhancement of Bio-H₂ Purification Performance in a Multi-Stage Desulfurization Process Using Mining Waste and LaNi₅

by Shuto Kitayama, Mayu Hamazaki, Shoichi Kumon, Kimitaka Sato and Kiyoshi Dowaki

Energies 2025, 18(4), 1000; https://doi.org/10.3390/en18041000 - 19 Feb 2025

Viewed by 256

Abstract

The fuel-cell (FC) power system, utilizing biohydrogen from biomass resources, is a promising alternative to fossil fuels. However, hydrogen sulfide (H₂S) in bio-syngas can severely degrade FC performance and increase environmental impact, necessitating impurity removal. This study investigates a multi-stage desulfurization [...] Read more.

The fuel-cell (FC) power system, utilizing biohydrogen from biomass resources, is a promising alternative to fossil fuels. However, hydrogen sulfide (H₂S) in bio-syngas can severely degrade FC performance and increase environmental impact, necessitating impurity removal. This study investigates a multi-stage desulfurization process using neutralized sediment (NS) and a metal hydride (LaNi₅) as H₂S adsorbents. NS, a mining waste material, can potentially reduce environmental impact when repurposed as an adsorbent, with its performance influenced by pore configuration and Fe content. However, the purified gas does not fully meet FC fuel specifications. To address this, LaNi₅, which selectively absorbs and releases hydrogen, was incorporated to achieve higher purification levels. In our study, H₂S adsorption tests were conducted using two fixed-bed flow reactors heated to 250 °C, where a gas mixture containing 196 ppm of H₂S flowed through the system. The proposed multi-stage system achieved a breakthrough time of 182.5 h with purified gas remaining under 0.1 ppm and an adsorption capacity of 16.4 g/g-sorbent. These results demonstrate the high desulfurization performance achieved using NS and LaNi₅. Full article

(This article belongs to the Special Issue Chemical and Biochemical Processes for Utilization of Renewable Energy Sources II)

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35 pages, 1798 KiB

Open AccessArticle

Identifying Resilience Factors of Power Company Business Models

by Joanna Staszewska and Lilla Knop

Energies 2025, 18(4), 992; https://doi.org/10.3390/en18040992 - 18 Feb 2025

Viewed by 282

Abstract

The paper focuses on the issue of the resilience of energy company business models under energy transition conditions. The main aim of this paper is to identify the key factors responsible for the resilience of an energy company’s business model. This paper presents [...] Read more.

The paper focuses on the issue of the resilience of energy company business models under energy transition conditions. The main aim of this paper is to identify the key factors responsible for the resilience of an energy company’s business model. This paper presents an excerpt from research on the resilience of energy company business models and the development of a system for assessing the resilience of the energy company business model. The research used a systems approach and a multi-criteria method of hierarchical analysis of decision-making problems, the so-called AHP (Analytic Hierarchy Process). Its selected elements were adapted to solve the scientific problem presented in this paper. Additionally, an approach to building resilient business model strategies was used in the research process. The research instrument adopted for the analyses was a model using the concept of the so-called New Era of Innovation. It was supplemented with the elements of the Canvas model. The results of the research in the form of identified key resilience factors of the energy company’s business model are presented in this article. Of the 79 resilience factors analyzed, 28 were identified as being key to the resilience of the business model. These findings formed the basis for the development of a business model resilience assessment system. The research indicates that learning about the key factors responsible for the resilience of an energy company’s business model is an important and necessary part of the tool for assessing resilience. Full article

(This article belongs to the Section C: Energy Economics and Policy)

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22 pages, 917 KiB

Open AccessReview

Controlled Application of Nanoparticles for Remediation in Oil and Gas Application: Strategies, Challenges, and Innovations

by Esther O. Yusuf, Ityona Amber, Simon Officer and Gbenga F. Oluyemi

Energies 2025, 18(4), 991; https://doi.org/10.3390/en18040991 - 18 Feb 2025

Viewed by 401

Abstract

This review provides a detailed examination of strategies for controlling the deposition of nanoparticles in porous media, emphasising the factors influencing their long-term stability and the challenges faced in practical applications. The review explores fundamental mechanisms of nanoparticle retention, including surface modification, intelligent [...] Read more.

This review provides a detailed examination of strategies for controlling the deposition of nanoparticles in porous media, emphasising the factors influencing their long-term stability and the challenges faced in practical applications. The review explores fundamental mechanisms of nanoparticle retention, including surface modification, intelligent materials, and optimised injection techniques, while discussing environmental and operational variables such as flow velocity, pH, ionic strength, and particle size. The review highlights innovative strategies to maintain nanoparticle stability over time, including responsive ligands, smart nanoparticles, self-healing coatings, and encapsulation techniques. Real-world case studies, including projects from Lockheed Martin, NanoRem, and NANO IRM, illustrate the practical application of these strategies in environmental remediation, emphasising the need for regulatory compliance and long-term monitoring. Overall, this review offers critical insights into the controlled application of nanoparticles for remediation, providing a roadmap for addressing the technical and regulatory challenges associated with their deployment in porous media. Full article

(This article belongs to the Section H: Geo-Energy)

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15 pages, 8142 KiB

Open AccessArticle

Study on the Propagation Law of CO₂ Displacement in Tight Conglomerate Reservoirs in the Mahu Depression, Xinjiang, China

by Long Tan, Jigang Zhang, Jing Zhang, Ruihai Jiang, Jianhua Qin, Yan Dong, Zhenlong Deng, Ping Song, Chenguang Cui, Wenya Zhai and Fengqi Tan

Energies 2025, 18(4), 990; https://doi.org/10.3390/en18040990 - 18 Feb 2025

Viewed by 322

Abstract

To achieve the efficient utilization of low-permeability tight sand and gravel reservoirs with strong heterogeneity in the Mahu oil area of Xinjiang, CO₂ injection is used to improve oil recovery. The sweep pattern of the injected gas is closely related to the [...] Read more.

To achieve the efficient utilization of low-permeability tight sand and gravel reservoirs with strong heterogeneity in the Mahu oil area of Xinjiang, CO₂ injection is used to improve oil recovery. The sweep pattern of the injected gas is closely related to the development of reservoir pores and throats. Firstly, a three-dimensional model of the average pore-throat radius was established based on complete two-dimensional nuclear magnetic resonance scanning data of the target layer’s full-diameter core in the Wuerhe Formation. Subsequently, an online NMR injection CO₂ continuous oil displacement experiment was conducted using tight conglomerate rock cores to clarify the rules of CO₂ oil displacement in each pore-throat interval. Finally, the three-dimensional pore-throat model was combined with microscopic utilization patterns to quantitatively characterize the reservoir utilization rate of the CO₂ displacement oil and guide on-site dynamic analysis. The research results indicate that the reservoir space of the Wuerhe Formation is mainly composed of residual intergranular pores, accounting for 40.9% of the pores, followed by intragranular dissolution pores and shrinkage pores. The proportion of pore-throat coordination numbers less than 1 is relatively high, reaching 86.3%. The average pore-throat radius calculation model, established using online NMR data from the continuous coring of full-diameter cores, elucidates the characteristics of the average pore-throat radius in the Wuerhe Formation reservoir. Based on gas displacement experiments that explored the pore-throat behavior at the microscale, the calibrated CO₂ injection oil recovery rate was determined to be 43.9%, and the proportion of reserves utilized within the main range during CO₂ displacement amounted to 60.77%. The injection pressure is negatively correlated with the maximum pore-throat radius of the gas injection well group, and negatively correlated with the proportion of the 0.9~2 μm distribution of large pore throats in each gas injection well group. Full article

(This article belongs to the Special Issue Advanced Transport in Porous Media for CO₂ Storage and EOR)

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25 pages, 8959 KiB

Open AccessArticle

Numerical Analysis of the Characteristic Chemical Timescale of a C₂H₄/O₂ Non-Premixed Rotating Detonation Engine

by Mohammed Niyasdeen Nejaamtheen, Bu-Kyeng Sung and Jeong-Yeol Choi

Energies 2025, 18(4), 989; https://doi.org/10.3390/en18040989 - 18 Feb 2025

Viewed by 317

Abstract

A three-dimensional numerical investigation using ethylene–oxygen was conducted to examine the characteristics of detonation waves in a non-premixed rotating detonation engine (RDE) across three equivalence ratio conditions: fuel-lean, stoichiometric, and fuel-rich. The study aims to identify the distinct timescales associated with detonation wave [...] Read more.

A three-dimensional numerical investigation using ethylene–oxygen was conducted to examine the characteristics of detonation waves in a non-premixed rotating detonation engine (RDE) across three equivalence ratio conditions: fuel-lean, stoichiometric, and fuel-rich. The study aims to identify the distinct timescales associated with detonation wave propagation within the combustor and to analyze their impact on detonation wave behavior, emphasizing the influence of equivalence ratio and injector behavior on detonation wave characteristics. The results indicate that the wave behavior varies with mixture concentration, with the ethylene injector demonstrating greater stiffness compared to the oxygen injector. In lean mixtures, characterized by excess oxidizer, waves exhibit less intensity and slower progression toward equilibrium, resulting in prolonged reaction times. Rich mixtures, with excess fuel, also show a delayed approach to equilibrium and an extended chemical reaction timescale. In contrast, the near-stoichiometric mixture achieves efficient combustion with the highest thermicity, rapidly reaching equilibrium and exhibiting the shortest chemical reaction timescale. Overall, the induction timescale is generally 2–3 times longer than its respective chemical reaction timescale, while the equilibrium timescale spans a broad range, reflecting the complex, rapid dynamics inherent in these chemical processes. This study identifies the role of the characteristic chemical timescale in influencing the progression of pre-detonation deflagration in practical RDEs. Prolonged induction times in non-ideal conditions, such as those arising from equivalence ratio variations, promote incomplete reactions, thereby contributing to pre-detonation phenomena and advancing our understanding of the underlying flow physics. Full article

(This article belongs to the Special Issue High-Speed Aerodynamics and High Energy and Efficiency Aerospace Propulsion System: Modeling and Optimization)

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22 pages, 3550 KiB

Open AccessArticle

Economic Feasibility of Using Municipal Solid Waste and Date Palm Waste for Clean Energy Production in Qatar

by Ahmad Mohamed S. H. Al-Moftah, Mohammad Alnajideen, Fatima Alafifi, Pawel Czyzewski, Hao Shi, Mohammad Alherbawi, Rukshan Navaratne and Agustin Valera-Medina

Energies 2025, 18(4), 988; https://doi.org/10.3390/en18040988 - 18 Feb 2025

Viewed by 542

Abstract

The transition to clean energy is crucial for mitigating the impacts of climate change and achieving sustainable development. Reliance on fossil fuels, which are integral to manufacturing and transportation, remains a major contributor to greenhouse gas (GHG) emissions. Biomass gasification presents a renewable [...] Read more.

The transition to clean energy is crucial for mitigating the impacts of climate change and achieving sustainable development. Reliance on fossil fuels, which are integral to manufacturing and transportation, remains a major contributor to greenhouse gas (GHG) emissions. Biomass gasification presents a renewable energy alternative that can significantly reduce emissions. However, proper disposal of municipal solid waste (MSW) and agricultural residues, such as date palm waste (DPW), is an increasing global challenge, including in Qatar. This study evaluates the economic feasibility of implementing an MSW and DPW gasification plant for clean electricity generation in Qatar. The country’s growing population and economic development have led to substantial waste production, making it an ideal location for waste-to-energy (WTE) initiatives. Using discounted cash flow (DCF) analysis, the study estimates the capital cost of a 373 MW_th facility at approximately $12.07 million, with annual operating costs of about $4.09 million and revenue of $26.88 million in 2023. The results indicate a net present value (NPV) of $245.77 million, a return on investment (ROI) of 84.80%, a payback period of approximately 5 years over a 20-year project lifetime and a net reduction of 206,786 tonnes CO₂ annually. These findings demonstrate the economic viability of biomass gasification in Qatar while contributing to reduced GHG emissions and advancing the country’s sustainability goals under Qatar National Vision 2030. Full article

(This article belongs to the Special Issue Novel and Emerging Energy Systems)

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33 pages, 10355 KiB

Open AccessArticle

Optimizing IoT Energy Efficiency: Real-Time Adaptive Algorithms for Smart Meters with LoRaWAN and NB-IoT

by Kanar Alaa Al-Sammak, Sama Hussein Al-Gburi, Ion Marghescu, Ana-Maria Claudia Drăgulinescu, Cristina Marghescu, Alexandru Martian, Nawar Alaa Hussein Al-Sammak, George Suciu and Khattab M. Ali Alheeti

Energies 2025, 18(4), 987; https://doi.org/10.3390/en18040987 - 18 Feb 2025

Viewed by 791

Abstract

Real-time monitoring, data-driven decisions, and energy consumption optimization have reached a new level with IoT advancement. However, a significant challenge faced by intelligent nodes and IoT applications resides in their energy requirements in the long term, especially in the case of gas or [...] Read more.

Real-time monitoring, data-driven decisions, and energy consumption optimization have reached a new level with IoT advancement. However, a significant challenge faced by intelligent nodes and IoT applications resides in their energy requirements in the long term, especially in the case of gas or water smart meters. This article proposes an algorithm for smart meters’ energy consumption optimization based on IoT, LoRaWAN, and NB-IoT using microcontroller-based development boards, PZEM004T energy meters, Dragino LoRaWAN shield, or BG96 NB-IoT modules. The algorithm adjusts the transmission time based on the change in data in real-time. According to the experimental results, the energy consumption and the number of packets transmitted significantly decreased using LoRaWAN or NB-IoT, saving up to 76.11% and 86.81% of the transmitted packets, respectively. Additionally, the outcome highlights a notable percentage reduction in the energy consumption spike frequency, with NB-IoT achieving an 87.3% reduction and LoRaWAN slightly higher at 88.5%. This study shows that adaptive algorithms are very effective in extending the lifetime of IoT nodes, thereby providing a solid baseline for scalable, lightweight, energy-monitoring IoT applications. The results could help shape the development of smart energy metering systems and sustainable IoT. Full article

(This article belongs to the Collection Featured Papers in Electrical Power and Energy System)

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14 pages, 3354 KiB

Open AccessArticle

Simulation and Analysis of Different Bipolar Plate Geometrical Parameters on the Performance of PEM Fuel Cells Applying the Taguchi Method

by Raquel Busqué, Matias Bossio, Enric Rovira and Albert Brigido

Energies 2025, 18(4), 986; https://doi.org/10.3390/en18040986 - 18 Feb 2025

Viewed by 376

Abstract

This study examines the impact of key stamping process parameters on metallic bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) performance using computational fluid dynamics (CFD) combined with thermal and electrochemical simulations and applying the design of experiments based on the Taguchi [...] Read more.

This study examines the impact of key stamping process parameters on metallic bipolar plates for Proton Exchange Membrane Fuel Cell (PEMFC) performance using computational fluid dynamics (CFD) combined with thermal and electrochemical simulations and applying the design of experiments based on the Taguchi method. An exhaustive study on this topic is not found in the literature, and this study aims to identify the most influential parameters and their interactions to optimize channel geometries for enhanced PEMFC performance within manufacturing limits. Main effects analysis revealed the BP–GDL contact length-to-pitch ratio as the most influential parameter, achieving the best performance at its higher end (0.4). The external radius showed improved performance at a lower value (0.14 mm), while pitch and channel height had smaller effects, favoring lower values (1 mm and 0.3 mm, respectively). The channel angle exhibited minimal impact but slightly improved performance at 35°. Interaction analysis highlighted a complex relationship between pitch and angle, indicating that their combined effects on current density vary with specific value combinations. A higher pitch (2.5 mm) reduced performance with lower angles, whereas a lower pitch (1 mm) improved performance with reduced angles. Finally, two new geometrical designs derived from these optimized parameter combinations enhanced fuel cell performance by 1.97% and 1.23% over the baseline, demonstrating the Taguchi method’s value in optimizing the geometrical design of metallic bipolar plates in PEMFCs. These findings contribute to advancing more efficient and practical fuel cell technologies. Full article

(This article belongs to the Special Issue Hydrogen Energy Technologies: Recent Advances in Production, Storage and Applications—2nd Edition)

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23 pages, 8148 KiB

Open AccessArticle

Flexible On-Grid and Off-Grid Control for Electric–Hydrogen Coupling Microgrids

by Zhengyao Wang, Fulin Fan, Hang Zhang, Kai Song, Jinhai Jiang, Chuanyu Sun, Rui Xue, Jingran Zhang and Zhengjian Chen

Energies 2025, 18(4), 985; https://doi.org/10.3390/en18040985 - 18 Feb 2025

Viewed by 339

Abstract

With the widespread integration of renewable energy into distribution networks, energy storage systems are playing an increasingly critical role in maintaining grid stability and sustainability. Hydrogen, as a key zero-carbon energy carrier, offers unique advantages in the transition to low-carbon energy systems. To [...] Read more.

With the widespread integration of renewable energy into distribution networks, energy storage systems are playing an increasingly critical role in maintaining grid stability and sustainability. Hydrogen, as a key zero-carbon energy carrier, offers unique advantages in the transition to low-carbon energy systems. To facilitate the coordination between hydrogen and renewables, this paper proposes a flexible on-grid and off-grid control method for an electric–hydrogen hybrid AC-DC microgrid which integrates photovoltaic panels, battery energy storage, electrolysers, a hydrogen storage tank, and fuel cells. The flexible control method proposed here employs a hierarchical structure. The upper level adopts a power management strategy (PMS) that allocates power to each component based on the states of energy storage. The lower level utilises the master–slave control where master and slave converters are regulated by virtual synchronous generator (VSG) and active and reactive power (PQ) control, respectively. In addition, a pre-synchronisation control strategy which does not rely on traditional phase-locked loops is introduced to enable a smooth transition from the off-grid to on-grid mode. The electric–hydrogen microgrid along with the proposed control method is modelled and tested under various operating modes and scenarios. The simulation results demonstrate that the proposed control method achieves an effective power dispatch within microgrid and maintains microgrid stability in on- and off-grid modes as well as in the transition between the two modes. Full article

(This article belongs to the Section A1: Smart Grids and Microgrids)

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18 pages, 2461 KiB

Open AccessArticle

Improvement of Mass Transfer Characteristics for the Gas-Liquid System in a Vortex Counterflow Apparatus

by Vsevolod Sklabinskyi, Ivan Pavlenko, Maksym Skydanenko, Sylwia Włodarczak, Andżelika Krupińska, Marek Ochowiak and Izabela Kruszelnicka

Energies 2025, 18(4), 984; https://doi.org/10.3390/en18040984 - 18 Feb 2025

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Abstract

This article aims to increase the intensity of mass transfer between gas and liquid in counterflow gas–liquid flow, one of the key problems in designing mass transfer equipment. For this purpose, analytical and experimental studies were carried out to evaluate the main features [...] Read more.

This article aims to increase the intensity of mass transfer between gas and liquid in counterflow gas–liquid flow, one of the key problems in designing mass transfer equipment. For this purpose, analytical and experimental studies were carried out to evaluate the main features of operating processes in a vortex counterflow apparatus. In particular, the presented research substantiates the possibility of achieving several theoretical stages of concentration change in a single atomizing stage of the vortex counterflow mass transfer apparatus. The corresponding experimental stand was developed to carry out experimental studies. Afterward, the efficiency of the vortex counterflow mass transfer apparatus was evaluated. The model was based on material balance and flow rate equations, allowing for the determination of mass transfer and intensity ratio. After comparing the analytical expressions with the experimental results, the regression dependence for evaluating the main parameter of the proposed mathematical model was obtained. An increase in steam consumption led to increased steam velocities, affecting the droplets. This fact proved an increase in the intensity of mass transfer processes. The studies substantiated the achievement of several theoretical stages of concentration change and increased the efficiency of a vortex counterflow mass transfer apparatus. From a practical viewpoint, the experimental studies confirmed that when the height and radius ratio is less than 0.6–0.7, it is possible to create a plane vortex countercurrent motion of gas and liquid flows with a significant increase in peripheral gas velocities along the radius of the vortex chamber. Full article

(This article belongs to the Section K: State-of-the-Art Energy Related Technologies)

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