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Energies, Volume 18, Issue 19 (October-1 2025) – 23 articles

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Article
McCARD/MASTER Hanbit Unit 3 Multi-Cycle Analyses with Monte Carlo-Based Reflector Cross-Section Generation
by Jeong Woo Park and Ho Jin Park
Energies 2025, 18(19), 5065; https://doi.org/10.3390/en18195065 (registering DOI) - 23 Sep 2025
Abstract
In this study, we established a fully Monte Carlo (MC)-based McCARD/MASTER two-step core design analysis code procedure without relying on conventional deterministic code by incorporating a newly developed MC reflector cross-section generation code. For reflector cross-section generation, the MACAO code was developed and [...] Read more.
In this study, we established a fully Monte Carlo (MC)-based McCARD/MASTER two-step core design analysis code procedure without relying on conventional deterministic code by incorporating a newly developed MC reflector cross-section generation code. For reflector cross-section generation, the MACAO code was developed and used to produce the discontinuity factors required for whole-core nodal analyses; these factors were generated via the source expansion nodal method. To examine the updated McCARD/MASTER two-step code system, multi-cycle core follow calculations were performed for cycles 1 and 2 of a commercial pressurized water reactor, namely, Hanbit Unit 3. The validity of the nuclear core design parameters, including the critical boron concentration, power distribution, pin power peaking factor, and moderator temperature coefficient, was assessed through comparison with conventional deterministic DeCART2D/MASTER two-step analysis results and the related nuclear design report. Overall, the McCARD/MASTER results were found to be in good agreement, with all the results meeting the design criteria, except for the critical boron concentration at the beginning of cycle 2. To fully exploit the strengths of the MC method, the McCARD few-group constant and reflector cross-section generation system will be extended to heterogeneous nuclear core systems requiring detailed resonance treatment. Furthermore, the newly developed MACAO is expected to facilitate efficient and accurate reflector cross-section generation for the various heterogeneous core systems. Full article
(This article belongs to the Special Issue Operation Safety and Simulation of Nuclear Energy Power Plant)
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Article
Influence of Fluctuating Food Waste Concentrations on Horizontal Anaerobic Reactor Performance and Biogas Output
by Jovale Vincent Tongco, Sang Hyeok Park, Su In Kim and Seokhwan Hwang
Energies 2025, 18(19), 5064; https://doi.org/10.3390/en18195064 (registering DOI) - 23 Sep 2025
Abstract
Food waste (FW) sourced from treatment facilities is predominantly in solid form, with low water content and high variations in organic content. High organic content in FW is ideal in anaerobic digestion for bioenergy applications, but proper monitoring during start-up operations should be [...] Read more.
Food waste (FW) sourced from treatment facilities is predominantly in solid form, with low water content and high variations in organic content. High organic content in FW is ideal in anaerobic digestion for bioenergy applications, but proper monitoring during start-up operations should be employed to avoid imbalance in the acidogenic/methanogenic population due to volatile fatty acid (VFA) accumulation in the system. The seed inoculum (5 L) in each horizontal anaerobic reactor (HAR) was fed with food waste without effluent flow (filling-up phase) until it reached the final working volume of 10 L (continuous phase). The pH, alkalinity, chemical oxygen demand (COD), VFA, biogas production, methane concentration, and microbial community dynamics were set as stability indicators during reactor operation. The results revealed that introducing fluctuations in FW concentrations does not negatively affect the biogas production (1.7 ± 0.2 L/LR/d) and methane concentration (59.0 ± 2.5%). Acclimatization of the methanogenic and bacterial population was also observed. This study aimed to evaluate the influence of fluctuating FW concentrations on the process performance of horizontal anaerobic reactors, focusing on process stability, microbial dynamics, and biogas output during filling-up and continuous phases. Full article
(This article belongs to the Special Issue Biomass and Bio-Energy—3rd Edition)
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Article
Grid-Constrained Online Scheduling of Flexible Electric Vehicle Charging
by Emily van Huffelen, Roel Brouwer and Marjan van den Akker
Energies 2025, 18(19), 5063; https://doi.org/10.3390/en18195063 - 23 Sep 2025
Abstract
The rapid growth of Electric Vehicles (EVs) risks causing grid congestion. Smart charging strategies can help to prevent overload while ensuring timely charging, thereby reducing the need for costly infrastructure upgrades. We study EV charging from a scheduling perspective, assuming an aggregator manages [...] Read more.
The rapid growth of Electric Vehicles (EVs) risks causing grid congestion. Smart charging strategies can help to prevent overload while ensuring timely charging, thereby reducing the need for costly infrastructure upgrades. We study EV charging from a scheduling perspective, assuming an aggregator manages charging while respecting network cable capacities. In our model, vehicles depart only after charging is complete, so delays are possible. Our aim is to minimize these delays. We consider a network of parking lots, some of which are equipped with solar panels, where the demand that can be served is limited by the cables connecting them to the grid. We propose novel scheduling strategies that combine an online variant of well-known schedule generation schemes with a destroy-and-repair heuristic. We evaluate their effectiveness in a case study with data from the city of Utrecht. Without control, network cables would be overloaded 60–70 % of the time. Our strategies completely eliminate overload, introducing an average delay of just over 1.5 min per EV in high-occupancy scenarios. This demonstrates that scheduling can significantly increase the number of EVs charged without compromising grid safety at the cost of a rather small delay. We also highlight the importance of accounting for grid topology and show the benefits of using flexible charging rates. Full article
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Article
The Influence of Vine Rootstock Type on the Energy Potential of Differentiated Material Obtained from Wine Production
by Kamila E. Klimek, Magdalena Kapłan, Grzegorz Maj, Anna Borkowska and Kamil Buczyński
Energies 2025, 18(19), 5062; https://doi.org/10.3390/en18195062 - 23 Sep 2025
Abstract
In the context of growing demand for renewable energy sources and greenhouse gas emission reductions, increasing attention is being paid to the use of agricultural waste as bioenergy feedstock. The energy potential of biomass in the form of vine stems and pomace from [...] Read more.
In the context of growing demand for renewable energy sources and greenhouse gas emission reductions, increasing attention is being paid to the use of agricultural waste as bioenergy feedstock. The energy potential of biomass in the form of vine stems and pomace from the Regent variety of grapes, grafted onto their own roots and various types of rootstocks (125AA, SO4, 161-49), was assessed, where the control group consisted of ungrafted shrubs growing on their own roots, cultivated in south-eastern Poland. The analyses included the determination of technical and elementary parameters, pollutant emission indicators, and exhaust gas composition parameters. Compared to stems, pomace had a higher calorific value, higher C and H content, and lower dust emissions, while at the same time emitting more CO2. Stems, on the other hand, showed higher ash content and higher dust emissions, which may limit their energy potential. Among the analysed substrates, pomace from 125AA achieved the highest calorific values at a low moisture content, while biomass from substrate 161-49 was distinguished by the lowest sulphur content and a favourable emission balance. Cluster analysis showed clear grouping of substrates in terms of fuel and emission parameters, indicating the possibility of optimal substrate selection for the production of bioenergy feedstock. The results confirm that the appropriate selection of rootstocks in viticulture can significantly increase the energy value of waste biomass and reduce emissions, supporting the development of local renewable energy systems. Full article
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Article
Revolutionizing Hybrid Microgrids Enhanced Stability and Efficiency with Nonlinear Control Strategies and Optimization
by Rimsha Ghias, Atif Rehman, Hammad Iqbal Sherazi, Omar Alrumayh, Abdulrahman Alsafrani and Abdullah Alburidy
Energies 2025, 18(19), 5061; https://doi.org/10.3390/en18195061 - 23 Sep 2025
Abstract
Microgrid systems play a vital role in managing distributed energy resources like solar, wind, batteries, and supercapacitors. However, maintaining stable AC/DC bus voltages and minimizing grid reliance under dynamic conditions is challenging. Traditional control methods such as Sliding Mode Controllers (SMCs) suffer from [...] Read more.
Microgrid systems play a vital role in managing distributed energy resources like solar, wind, batteries, and supercapacitors. However, maintaining stable AC/DC bus voltages and minimizing grid reliance under dynamic conditions is challenging. Traditional control methods such as Sliding Mode Controllers (SMCs) suffer from issues like chattering and slow convergence, reducing practical effectiveness. This paper proposes a hybrid AC/DC microgrid that operates in both grid-connected and islanded modes while ensuring voltage stability and efficient energy use. A Conditional-Based Super-Twisting Sliding Mode Controller (CBSTSMC) is employed to address the limitations of conventional SMCs. The CBSTSMC enhances system performance by reducing chattering, improving convergence speed, and offering better tracking and disturbance rejection. To further refine controller performance, an Improved Grey Wolf Optimization (IGWO) algorithm is used for gain tuning, resulting in enhanced system robustness and precision. An Energy Management System (EMS) is integrated to intelligently regulate power flow based on renewable generation and storage availability. The proposed system is tested in real time using a Texas Instruments Delfino C2000 microcontroller through a Controller-in-the-Loop (CIL) setup. The simulation and hardware results confirm the system’s ability to maintain stability and reliability under diverse operating scenarios, proving its suitability for future smart grid applications. Full article
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Article
Short-Term Load Forecasting in the Greek Power Distribution System: A Comparative Study of Gradient Boosting and Deep Learning Models
by Md Fazle Hasan Shiblee and Paraskevas Koukaras
Energies 2025, 18(19), 5060; https://doi.org/10.3390/en18195060 - 23 Sep 2025
Abstract
Accurate short-term electricity load forecasting is essential for efficient energy management, grid reliability, and cost optimization. This study presents a comprehensive comparison of five supervised learning models—Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM), Gated Recurrent Unit (GRU), a hybrid (CNN-LSTM) architecture, and [...] Read more.
Accurate short-term electricity load forecasting is essential for efficient energy management, grid reliability, and cost optimization. This study presents a comprehensive comparison of five supervised learning models—Convolutional Neural Network (CNN), Long Short-Term Memory (LSTM), Gated Recurrent Unit (GRU), a hybrid (CNN-LSTM) architecture, and Light Gradient Boosting Machine (LightGBM)—using multivariate data from the Greek electricity market between 2015 and 2024. The dataset incorporates hourly load, temperature, humidity, and holiday indicators. Extensive preprocessing was applied, including K-Nearest Neighbor (KNN) imputation, time-based feature extraction, and normalization. Models were trained using a 70:20:10 train–validation–test split and evaluated with standard performance metrics: MAE, MSE, RMSE, NRMSE, MAPE, and R2. The experimental findings show that LightGBM beat deep learning (DL) models on all evaluation metrics and had the best MAE (69.12 MW), RMSE (101.67 MW), and MAPE (1.20%) and the highest R2 (0.9942) for the test set. It also outperformed models in the literature and operational forecasts conducted in the real world by ENTSO-E. Though LSTM performed well, particularly in long-term dependency capturing, it performed a bit worse in high-variance periods. CNN, GRU, and hybrid models demonstrated moderate results, but they tended to underfit or overfit in some circumstances. These findings highlight the efficacy of LightGBM in structured time-series forecasting tasks, offering a scalable and interpretable alternative to DL models. This study supports its potential for real-world deployment in smart/distribution grid applications and provides valuable insights into the trade-offs between accuracy, complexity, and generalization in load forecasting models. Full article
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Article
Experimental Study on Direct and Indirect Carbonation of Fly Ash from Fluidized Bed Combustion of Lignite
by Marek Tańczyk, Jolanta Jaschik, Andrzej Kołodziej, Anna Pawlaczyk-Kurek, Aleksandra Janusz-Cygan and Łukasz Hamryszak
Energies 2025, 18(19), 5059; https://doi.org/10.3390/en18195059 - 23 Sep 2025
Abstract
The research problem was to determine the possibility of aqueous mineral carbonation using fly ash from lignite fluidized bed combustion. Both direct and indirect routes were used. The innovative nature of the research consisted of conducting experiments at atmospheric pressure and ambient temperature [...] Read more.
The research problem was to determine the possibility of aqueous mineral carbonation using fly ash from lignite fluidized bed combustion. Both direct and indirect routes were used. The innovative nature of the research consisted of conducting experiments at atmospheric pressure and ambient temperature (20 °C). The synthetic gas mixture with composition analogical to the flue gas (nitrogen and up to 16 vol.% of carbon dioxide) was used. The experiments proved that almost all CO2 from the gas was chemically bound at pH > 12. The sequestration capacity of studied fly ash is about 55–76 g CO2 per 1 kg of ash in the case of the indirect method, and 80–95 g CO2 per 1 kg of ash for the direct route. These values are similar to those presented in the literature, but unlike most publications, they were obtained under ambient conditions, which can significantly reduce the costs of the process. Full article
(This article belongs to the Section B3: Carbon Emission and Utilization)
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Article
Multi-Objective Optimization of Off-Grid Hybrid Renewable Energy Systems for Sustainable Agricultural Development in Sub-Saharan Africa
by Tom Cherif Bilio, Mahamat Adoum Abdoulaye and Sebastian Waita
Energies 2025, 18(19), 5058; https://doi.org/10.3390/en18195058 - 23 Sep 2025
Abstract
This study presents a novel multi-objective optimization (MOO) model for the design of an off-grid hybrid renewable energy system (HRES) to support sustainable agriculture and rural development in Sub-Saharan Africa (SSA). Based upon a case study selected in Linia (Chad), three system architectures [...] Read more.
This study presents a novel multi-objective optimization (MOO) model for the design of an off-grid hybrid renewable energy system (HRES) to support sustainable agriculture and rural development in Sub-Saharan Africa (SSA). Based upon a case study selected in Linia (Chad), three system architectures are compared under different levels of the reliability requirements (LPSP = 1%, 5%, and 10%). A Multi-Objective Particle Swarm Optimization (MOPSO) algorithm is applied to optimize the Levelized Cost of Energy (LCOE), CO2 emissions mitigation, and social impact, referring to the Human Development Index (HDI) enhancement and the job creation (JC) opportunity, using the MATLAB R2024b environment. The calculation results show that among the three configuration schemes, the PV–Wind–Battery configuration obtains the optimal techno–economic–environmental coordination, with the lowest LCOE (0.0948 $/kWh) and the largest CO2 emission reduction (9.58 × 108 kg), and the Wind–Battery system gets the most social benefit. The method developed provides users with a decision-support method for renewable energy systems (RES) integration into rural agricultural settings, taking into consideration financial cost, environmental sustainability, and community development. This information is important for policymakers and practitioners advocating for decentralized, socially inclusive clean energy access initiatives in underserved regions. Full article
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Article
Research on Adaptive Control Optimization of Battery Energy Storage System Under High Wind Energy Penetration
by Meng-Hui Wang, Yi-Cheng Chen and Chun-Chun Hung
Energies 2025, 18(19), 5057; https://doi.org/10.3390/en18195057 - 23 Sep 2025
Abstract
With the increasing penetration of renewable energy, power system frequency stability faces multiple challenges. In addition to the decline of system inertia traditionally provided by synchronous machines, uncertainties such as wind power forecast errors, converter control characteristics, and stochastic load fluctuations further exacerbate [...] Read more.
With the increasing penetration of renewable energy, power system frequency stability faces multiple challenges. In addition to the decline of system inertia traditionally provided by synchronous machines, uncertainties such as wind power forecast errors, converter control characteristics, and stochastic load fluctuations further exacerbate the system’s sensitivity to power disturbances, increasing the risks of frequency deviation and instability. Among these factors, insufficient inertia is widely recognized as one of the most direct and critical drivers of the initial frequency response. This study focuses on this issue and explores the use of battery energy storage system (BESS) parameter optimization to enhance system stability. To this end, a simulation platform was developed in PSS®E V34 based on the IEEE New England 39-bus system, incorporating three wind turbines and two BESS units. The WECC generic models were adopted, and three wind disturbance scenarios were designed, including (i) disconnection of a single wind turbine, (ii) derating of two turbines to 50% output, and (iii) derating of three turbines to 50% output. In this study, a one-at-a-time (OAT) sensitivity analysis was first performed to identify the key parameters affecting frequency response, followed by optimization using an improved particle swarm optimization (IPSO) algorithm. The simulation results show that the minimum system frequency was 59.888 Hz without BESS control, increased to 59.969 Hz with non-optimized BESS control, and further improved to 59.976 Hz after IPSO. Compared with the case without BESS, the overall improvement was 0.088 Hz, of which IPSO contributed an additional 0.007 Hz. These results clearly demonstrate that IPSO can significantly strengthen the frequency support capability of BESS and effectively improve system stability under different wind disturbance scenarios. Full article
(This article belongs to the Section A3: Wind, Wave and Tidal Energy)
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Article
Design of a Robust Adaptive Cascade Fractional-Order Proportional–Integral–Derivative Controller Enhanced by Reinforcement Learning Algorithm for Speed Regulation of Brushless DC Motor in Electric Vehicles
by Seyyed Morteza Ghamari, Mehrdad Ghahramani, Daryoush Habibi and Asma Aziz
Energies 2025, 18(19), 5056; https://doi.org/10.3390/en18195056 - 23 Sep 2025
Abstract
Brushless DC (BLDC) motors are commonly used in electric vehicles (EVs) because of their efficiency, small size and great torque-speed performance. These motors have a few benefits such as low maintenance, increased reliability and power density. Nevertheless, BLDC motors are highly nonlinear and [...] Read more.
Brushless DC (BLDC) motors are commonly used in electric vehicles (EVs) because of their efficiency, small size and great torque-speed performance. These motors have a few benefits such as low maintenance, increased reliability and power density. Nevertheless, BLDC motors are highly nonlinear and their dynamics are very complicated, in particular, under changing load and supply conditions. The above features require the design of strong and adaptable control methods that can ensure performance over a broad spectrum of disturbances and uncertainties. In order to overcome these issues, this paper uses a Fractional-Order Proportional-Integral-Derivative (FOPID) controller that offers better control precision, better frequency response, and an extra degree of freedom in tuning by using non-integer order terms. Although it has the benefits, there are three primary drawbacks: (i) it is not real-time adaptable, (ii) it is hard to choose appropriate initial gain values, and (iii) it is sensitive to big disturbances and parameter changes. A new control framework is suggested to address these problems. First, a Reinforcement Learning (RL) approach based on Deep Deterministic Policy Gradient (DDPG) is presented to optimize the FOPID gains online so that the controller can adjust itself continuously to the variations in the system. Second, Snake Optimization (SO) algorithm is used in fine-tuning of the FOPID parameters at the initial stages to guarantee stable convergence. Lastly, cascade control structure is adopted, where FOPID controllers are used in the inner (current) and outer (speed) loops. This construction adds robustness to the system as a whole and minimizes the effect of disturbances on the performance. In addition, the cascade design also allows more coordinated and smooth control actions thus reducing stress on the power electronic switches, which reduces switching losses and the overall efficiency of the drive system. The suggested RL-enhanced cascade FOPID controller is verified by Hardware-in-the-Loop (HIL) testing, which shows better performance in the aspects of speed regulation, robustness, and adaptability to realistic conditions of operation in EV applications. Full article
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Article
Comparative Analysis of Energy and Emission Properties of Hazelnut Shell Biomass from Temperate and Subtropical Climates
by Grzegorz Maj, Anna Borkowska, Kamila E. Klimek, Saban Kordali and Ferah Yilmaz
Energies 2025, 18(19), 5055; https://doi.org/10.3390/en18195055 - 23 Sep 2025
Abstract
The aim of this research was to compare the estimation of waste biomass in the form of hazelnut husk (Corylus avellana L.) originating from two different climate zones—temperate (Poland) and subtropical (Turkey)—in terms of their energy and emission properties. This study included [...] Read more.
The aim of this research was to compare the estimation of waste biomass in the form of hazelnut husk (Corylus avellana L.) originating from two different climate zones—temperate (Poland) and subtropical (Turkey)—in terms of their energy and emission properties. This study included proximate analysis (moisture, ash, volatile matter, fixed carbon), ultimate analysis (C, H, N, S, O), determination of the (LHV) lower heating value and (HHV) higher heating value. Pollutant emission factors (CO, CO2, SO2, NOx, dust) were assessed, and stoichiometric calculations of the composition of exhaust gases were performed. The results showed statistically significant differences between samples from both climate zones. Husk from Turkey was characterised by calorific values (LHV—17.46 MJ·kg−1, HHV—18.76 MJ·kg−1) and higher carbon (43.68%) and hydrogen (7.27%) content compared to Polish husk (HHV-17.29 MJ·kg−1, LHV-16.13 MJ·kg−1, C-46.49%, H-7.05%). At the same time, higher CO2 and SO2 emission rates were observed in Turkish samples, while biomass from Poland was characterised by lower ash content and lower dust emissions. Principal component analysis (PCA) confirmed the significant influence of climate on the energy and environmental parameters of the husk. The obtained results can be the basis for optimizing the use of waste biomass in the management of waste from horticultural or agricultural production and for sustainable development in various climatic conditions. Full article
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Article
Experimental Comparison of Water-Based Cooling Methods for PV Modules in Tropical Conditions
by Nam Quyen Nguyen, Hristo Ivanov Beloev, Huy Bich Nguyen and Van Lanh Nguyen
Energies 2025, 18(19), 5054; https://doi.org/10.3390/en18195054 - 23 Sep 2025
Abstract
It is well known that temperature strongly affects the photovoltaic (PV) performance. Raising the working temperature leads to a significant decrease in PV output of the power capacity, and it also lowers power conversion efficiency. This issue is highly important for the PV [...] Read more.
It is well known that temperature strongly affects the photovoltaic (PV) performance. Raising the working temperature leads to a significant decrease in PV output of the power capacity, and it also lowers power conversion efficiency. This issue is highly important for the PV systems operating in tropical climate areas such as southern Viet Nam. Developing the cooling methods applied for reducing the PV module temperature might be the solution to this problem and has attracted many researchers and industrial sectors. However, the existing research might not sufficiently address the comparative evaluation of multiple active water-based cooling methods on power conservation efficiency, power output, and cost implications under high-temperature conditions in tropical areas. This study is a case study that aims at conducting some experimental investigations for active water-based cooling methods applied to PV modules in Ho Chi Minh City, South Viet Nam. There are four active water-based cooling methods, including the spraying liquid method (SL), the dripping droplet method (DD), tube heat exchanger method (TE), and the liquid flowing on the PV surface method (LF), that have been developed and experimentally investigated. The voltage, current, temperature, and humidity of the PV cells have been automatically recorded in every one-minute interval via sensors and electronic devices. The experimental results indicate that the surface temperature, the power conversion efficiency, and the output power of PV module are developed toward the useful and positive direction with four cooling methods. In detail, the SL is the best one, in which it leads the PV temperature to reduce from 52 °C to 34–35 °C, the output power increases up to 6.3%, its power conversion efficiency improves up to 2%, while the water flow rate is at its lowest with 0.65 L/min. Similarly, LF also creates results that are similar to SL, but it needs a higher amount of cooling water, which is up to 3.27 L/min. The other methods, like DD and TE, have less power conversion efficiency compared to the SL; it improves only around 1 to 1.3%. These results might be useful for improving the benefits of PV power generation in some tropical regions and contributing to the green energy development in the world. Full article
(This article belongs to the Section A2: Solar Energy and Photovoltaic Systems)
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Article
Hybrid Artificial Neural Network and Perturb & Observe Strategy for Adaptive Maximum Power Point Tracking in Partially Shaded Photovoltaic Systems
by Braulio Cruz, Luis Ricalde, Roberto Quintal-Palomo, Ali Bassam and Roberto I. Rico-Camacho
Energies 2025, 18(19), 5053; https://doi.org/10.3390/en18195053 - 23 Sep 2025
Abstract
Partial shading in photovoltaic (PV) systems causes multiple local maximum power points (LMPPs), complicating tracking and reducing energy efficiency. Conventional maximum power point tracking (MPPT) methods, such as Perturb and Observe (P&O), often fail because of oscillations and entrapment at local maxima. To [...] Read more.
Partial shading in photovoltaic (PV) systems causes multiple local maximum power points (LMPPs), complicating tracking and reducing energy efficiency. Conventional maximum power point tracking (MPPT) methods, such as Perturb and Observe (P&O), often fail because of oscillations and entrapment at local maxima. To address these shortcomings, this study proposes a hybrid MPPT strategy combining artificial neural networks (ANNs) and the P&O algorithm to enhance tracking accuracy under partial shading while maintaining implementation simplicity. The research employs a detailed PV cell model in MATLAB/Simulink (2019b) that incorporates dynamic shading to simulate non-uniform irradiance. Within this framework, an ANN trained with the Levenberg–Marquardt algorithm predicts global maximum power points (GMPPs) from voltage and irradiance data, guiding and accelerating subsequent P&O operation. In the hybrid system, the ANN predicts the maximum power points (MPPs) to provide initial estimates, after which the P&O fine-tunes the duty cycle optimization in a DC-DC converter. The proposed hybrid ANN–P&O MPPT method achieved relative improvements of 15.6–49% in tracking efficiency, 16–20% in stability, and 14–54% in convergence speed compared with standalone P&O, depending on the irradiance scenario. This research highlights the potential of ANN-enhanced MPPT systems to maximize energy harvest in PV systems facing shading variability. Full article
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Article
Genetic Algorithm-Based Hybrid Deep Learning Framework for Stability Prediction of ABO3 Perovskites in Solar Cell Applications
by Samad Wali, Muhammad Irfan Khan, Miao Zhang and Abdul Shakoor
Energies 2025, 18(19), 5052; https://doi.org/10.3390/en18195052 - 23 Sep 2025
Abstract
The intrinsic structural stability of ABO3 perovskite materials is a pivotal factor determining their efficiency and durability in photovoltaic applications. However, accurately predicting stability, commonly measured by the energy above hull metric, remains challenging due to the complex interplay of compositional, crystallographic, [...] Read more.
The intrinsic structural stability of ABO3 perovskite materials is a pivotal factor determining their efficiency and durability in photovoltaic applications. However, accurately predicting stability, commonly measured by the energy above hull metric, remains challenging due to the complex interplay of compositional, crystallographic, and electronic features. To address this challenge, we propose a streamlined hybrid machine learning framework that combines the sequence modeling capability of Long Short-Term Memory (LSTM) networks with the robustness of Random Forest regressors. A genetic algorithm-based feature selection strategy is incorporated to identify the most relevant descriptors and reduce noise, thereby enhancing both predictive accuracy and interpretability. Comprehensive evaluations on a curated ABO3 dataset demonstrate strong performance, achieving an R2 of 0.98 on training data and 0.83 on independent test data, with a Mean Absolute Error (MAE) of 8.78 for training and 21.23 for testing, and Root Mean Squared Error (RMSE) values that further confirm predictive reliability. These results validate the effectiveness of the proposed approach in capturing the multifactorial nature of perovskite stability while ensuring robust generalization. This study highlights a practical and reliable pathway for accelerating the discovery and optimization of stable perovskite materials, contributing to the development of more durable next-generation solar technologies. Full article
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Article
Development of a Spark-Ignited Combustion Strategy for 100% Ammonia (NH3) Operation in Internal Combustion Engines
by Annalena Braun, Moritz Grüninger, Daniel Bäck, Tomas Carlsson, Jakob Ängeby, Olaf Toedter and Thomas Koch
Energies 2025, 18(19), 5051; https://doi.org/10.3390/en18195051 - 23 Sep 2025
Abstract
Ammonia (NH3) is a promising carbon-free fuel for internal combustion engines, but its low reactivity and poor ignition properties present significant challenges for stable operation. This study presents the development and experimental validation of a spark-ignited combustion process that enables stable [...] Read more.
Ammonia (NH3) is a promising carbon-free fuel for internal combustion engines, but its low reactivity and poor ignition properties present significant challenges for stable operation. This study presents the development and experimental validation of a spark-ignited combustion process that enables stable engine operation using 100% liquid NH3 as a single fuel. A modified single cylinder research engine, equipped with NH3 port fuel injection and a high-energy capacitive ignition system was used to investigate combustion behavior under various load conditions. The results show that stable, knock-free combustion with pure NH3 is feasible at every operating point without any ignition aids like diesel fuel or hydrogen (H2). The full load conditions of a diesel engine can be represented with an indicated efficiency of 50% using this combustion process. The emission measurements show nitrogen oxides (NOx) and NH3 emissions in a 1:1 ratio, which is advantageous for a passive SCR system. Increased nitrous oxides (N2O) formation occurs at low loads and cold combustion chamber temperatures. This work demonstrates the technical viability of carbon-free NH3 combustion in spark-ignited (SI) engines and represents a promising step towards net-zero combustion. Full article
(This article belongs to the Topic Clean and Low Carbon Energy, 2nd Edition)
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Article
Low-Carbon Dispatch Method Considering Node Carbon Emission Controlling Based on Carbon Emission Flow Theory
by Xi Wu, Qiuyu Chen, Weitao Zheng, Jingyu Xie, Danhong Xie, Hancheng Chen, Xiang Yu and Chen Yang
Energies 2025, 18(19), 5050; https://doi.org/10.3390/en18195050 - 23 Sep 2025
Abstract
Fair sharing of carbon emission responsibilities is an important direction for the low carbonization of power systems. This paper proposes a new low-carbon dispatch method (N-LCD), which takes node carbon emissions as a constraint for power system decision-making, so as to adapt to [...] Read more.
Fair sharing of carbon emission responsibilities is an important direction for the low carbonization of power systems. This paper proposes a new low-carbon dispatch method (N-LCD), which takes node carbon emissions as a constraint for power system decision-making, so as to adapt to the current management needs of power carbon footprint. The N-LCD model is built on the traditional optimal power flow (OPF) or low-carbon dispatch (LCD) model, integrating carbon flow equations and constraints and introducing a bidirectional power flow component to solve the problem of unknown carbon flow direction in power flow optimization. Empirical analysis proves the effectiveness of the N-LCD model in ensuring the fair share of carbon emission responsibilities and solving low-carbon unit commitment optimization based on carbon nodal emission control. Full article
(This article belongs to the Special Issue Simulation and Modeling for Low-Carbon Energy Systems)
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Article
Heat Transfer Characteristics of Multi-Inlet Rotating Disk Cavity
by Han Xiao, Xueying Li and Jing Ren
Energies 2025, 18(19), 5049; https://doi.org/10.3390/en18195049 - 23 Sep 2025
Abstract
The secondary air system plays important roles in gas turbines, such as cooling hot-end components, sealing the rim, and balancing axial forces. In this paper, the flow structure and the heat transfer characteristics of the rotating disk cavity with two inlets and single [...] Read more.
The secondary air system plays important roles in gas turbines, such as cooling hot-end components, sealing the rim, and balancing axial forces. In this paper, the flow structure and the heat transfer characteristics of the rotating disk cavity with two inlets and single outlet is studied by CFD (Computational Fluid Dynamics) approach. The effect and mechanism under higher rotational speed and larger mass flow rate are also discussed. The results show that a large-scale vortex is induced by the central inlet jet in the low-radius region of the cavity, while the flow structure in the high-radius region is significantly influenced by rotational speed and flow rate. Increasing the rotational speed generally enhances heat transfer because it amplifies the differential rotational linear velocity between the disk surface and nearby wall flow, consequently thinning the boundary layer. Increasing the mass flow rate enhances heat transfer through two primary mechanisms: firstly, it elevates the turbulence intensity of the near-wall fluid; secondly, the higher radial velocity results in a thinner boundary layer. Full article
(This article belongs to the Section J1: Heat and Mass Transfer)
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5589 KB  
Article
Thermal and Fluid Flow Performance Optimization of a Multi-Fin Multi-Channel Cooling System for PEMFC Using CFD and Experimental Validation
by Fitri Adi Iskandarianto, Djatmiko Ichsani and Fadlilatul Taufany
Energies 2025, 18(19), 5048; https://doi.org/10.3390/en18195048 - 23 Sep 2025
Abstract
Efficient thermal management is critical for sustaining the performance and durability of Proton Exchange Membrane Fuel Cells (PEMFCs), where excessive operating temperatures accelerate material degradation and reduce power output. Previous studies have explored various cooling channel designs; however, limited research integrates zigzag multi-fin [...] Read more.
Efficient thermal management is critical for sustaining the performance and durability of Proton Exchange Membrane Fuel Cells (PEMFCs), where excessive operating temperatures accelerate material degradation and reduce power output. Previous studies have explored various cooling channel designs; however, limited research integrates zigzag multi-fin geometries with both computational and experimental validation for fin width optimization under high-velocity cooling. This study presents a combined Computational Fluid Dynamics (CFD) simulation using ANSYS Fluent and experimental investigation of a multi-fin multi-channel cooling system for PEMFCs. The effects of fin widths (0.3–1.0 mm), inlet flow velocities (0.6–3.0 m/s), and cooling media (air, 20% ethylene glycol (EG) solution) were analyzed with respect to cathode surface temperature, power density, and cooling efficiency. Results show that a 0.3 mm fin width with 3.0 m/s inlet velocity reduced the cathode temperature by ~13 K and increased power density by ~40%. The optimized zigzag configuration improved heat transfer uniformity, achieving cooling efficiencies up to 67.0%. Experimental validation confirmed the CFD results with less than 3% deviation. The findings highlight the potential of optimized multi-fin designs to enhance PEMFC thermal stability and electrical output, offering a practical approach for advanced fuel cell thermal management systems. Full article
(This article belongs to the Special Issue Proton-Exchange Membrane (PEM) Fuel Cells and Water Electrolysis)
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3904 KB  
Article
Design and Implementation of a Misalignment Experimental Data Management Platform for Wind Power Equipment
by Jianlin Cao, Qiang Fu, Pengchao Li, Bingchang Zhao, Zhichao Liu and Yanjie Guo
Energies 2025, 18(19), 5047; https://doi.org/10.3390/en18195047 - 23 Sep 2025
Abstract
Key drivetrain components in wind turbines are prone to misalignment faults due to long-term operation under fluctuating loads and harsh environments. Because misalignment develops gradually rather than occurring instantly, reliable evaluation of structural designs and surface treatments requires long-duration, multi-sensor, and multi-condition experiments [...] Read more.
Key drivetrain components in wind turbines are prone to misalignment faults due to long-term operation under fluctuating loads and harsh environments. Because misalignment develops gradually rather than occurring instantly, reliable evaluation of structural designs and surface treatments requires long-duration, multi-sensor, and multi-condition experiments that generate massive heterogeneous datasets. Traditional data management relying on manual folders and USB drives is inefficient, redundant, and lacks traceability. To address these challenges, this study presents a dedicated misalignment experimental data management platform specifically designed for wind power applications. The innovation lies in its ability to synchronize vibration, electrostatic, and laser alignment data streams in long-term tests, establish a traceable and reusable data structure linking experimental conditions with sensor outputs, and integrate laboratory results with field SCADA data. Built on Laboratory Information Management System (LIMS) principles and implemented with an MVC + Spring Boot + B/S architecture, the platform supports end-to-end functions including multi-sensor data acquisition, structured storage, automated processing, visualization, secure sharing, and cross-role collaboration. Validation on drivetrain shaft assemblies confirmed its ability to handle multi-terabyte datasets, reduce manual processing time by more than 80%, and directly integrate processed results into fault identification models. Overall, the platform establishes a scalable digital backbone for wind turbine misalignment research, supporting structural reliability evaluation, predictive maintenance, and intelligent operation and maintenance. Full article
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24 pages, 1249 KB  
Article
Do Environmental Taxes and Green Electricity Matter for Environmental Quality? Fresh Evidence in France Based on Fourier Methods
by Seyed Alireza Athari, Kwaku Addia, Dervis Kirikkaleli, Souha Hanna Al Geitany, Latifa Al Fadhel and Chafic Saliba
Energies 2025, 18(19), 5046; https://doi.org/10.3390/en18195046 - 23 Sep 2025
Abstract
The environment has generally served as the foundation and support of human existence and survival over the years through agricultural development, health supply, industrialization, and transportation. This process has resulted in massive environmental degradation. In this postindustrial period, global consensus calls for taking [...] Read more.
The environment has generally served as the foundation and support of human existence and survival over the years through agricultural development, health supply, industrialization, and transportation. This process has resulted in massive environmental degradation. In this postindustrial period, global consensus calls for taking steps to rebalance the degraded environment by planning economic development and social progress while preserving the quality of the environment. In recent years, experts have recognized key factors affecting the quality of the environment where policy is required. The study seeks to explore the impacts of ecological taxes and green electricity on the quality of the environment in France. The work employed Fourier ADL cointegration, novel Fourier autoregressive distributive lag econometric (N-ARDL), and Fourier Toda Yamamoto causality methods. The outcomes of the N-ARDL long-run cointegration estimates imply that both environmental tax and green electricity improve environmental quality in France. Furthermore, the Fourier Toda Yamamoto causality test denotes that both green electricity and environmental tax affect environmental quality in France without a rebound effect. The results recommend that since the “bonus–malus” system of France has suffered a significant rebound effect, the economy could reverse this with environmental taxes focused on reducing pollution. Additionally, the government of France could commit to its current alternative energy plan of 560 TWh of decarbonized electricity yearly from 463 TWh, given the fact that the energy sector is responsible for approximately 11% of total greenhouse gas (GHG) emissions. Full article
(This article belongs to the Special Issue Renewable Fuels: A Key Step Towards Global Sustainability)
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22 pages, 7371 KB  
Article
Online Junction Temperature Measurement for Power MOSFETs Using the Body Diode Under Varying Forward Currents
by Xueli Zhu, Yajie Huang, Donglai Zhang, Yuepeng Zhang, Jun Wu, Bowen Jiang, Linzhong Xia, Bo Gao and Changwei Lv
Energies 2025, 18(19), 5045; https://doi.org/10.3390/en18195045 - 23 Sep 2025
Abstract
Power metal-oxide-semiconductor field-effect transistors (MOSFETs) provide numerous advantages and are widely utilized in various power circuits. The junction temperature plays a critical role in determining the reliability, performance, and operational lifetime of power MOSFETs. Therefore, accurate monitoring of the junction temperature of power [...] Read more.
Power metal-oxide-semiconductor field-effect transistors (MOSFETs) provide numerous advantages and are widely utilized in various power circuits. The junction temperature plays a critical role in determining the reliability, performance, and operational lifetime of power MOSFETs. Therefore, accurate monitoring of the junction temperature of power MOSFETs is essential to ensure the safe operation of power circuit systems. In bridge or motor drive circuits, MOSFETs often operate in a freewheeling state via the body diode, where the freewheeling current is typically variable. The proposed method for junction temperature measurement utilizes the body diode and is designed to accommodate varying forward currents. It also accounts for the temperature-dependent ideality factor to improve measurement accuracy. By integrating the forward voltage and forward current of the body diode, this approach reduces the required sampling frequency. To validate the method’s effectiveness, three representative types of power MOSFETs, a Si MOSFET (IRF520), a SiC MOSFET (C2M0080120D), and an aerospace-grade radiation-hardened MOSFET (RSCS25045T1RH), were used to measure junction temperatures before and after irradiation. Following ideality factor correction, the maximum absolute error compared to reference measurements from thermocouples and a thermal imager remained within 2 K across the temperature range of 300 K to 420 K. Experimental results confirm the feasibility of the proposed method. Full article
(This article belongs to the Special Issue Advancements in Power Electronics for Power System Applications)
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18 pages, 602 KB  
Article
Study of the Spatio-Temporal Effects of Digital Economic Development on Hydropower Resource Mismatch
by Fangming Xie, Huimin Ma, Xiangjun Kong, Jialei Jiang and Zhenbin Chen
Energies 2025, 18(19), 5044; https://doi.org/10.3390/en18195044 - 23 Sep 2025
Abstract
Optimizing the allocation of hydropower resources is essential for aligning high-quality economic growth with China’s carbon neutrality goals. Due to constraints such as market segmentation and government regulation, the resource allocation function of the Chinese market has not been effectively utilized, which leads [...] Read more.
Optimizing the allocation of hydropower resources is essential for aligning high-quality economic growth with China’s carbon neutrality goals. Due to constraints such as market segmentation and government regulation, the resource allocation function of the Chinese market has not been effectively utilized, which leads to hydropower resources being allocated inefficiently. In the digital age, it is valuable to investigate whether digital economic development can rectify the misallocation of hydropower resources and whether the corrective effects exhibit temporal dynamics and spatial heterogeneity. Accordingly, this study employs panel data collected from 30 provincial-level administrative regions in China from 2000 to 2023, employing the production function method combined with a counterfactual analysis framework for quantifying the degree of hydropower resource mismatch. Additionally, panel vector autoregression models and panel threshold regression utilized for discussing spatio-temporal effects of digital economic development on hydropower resource mismatch. Empirical results demonstrate that digital economic development significantly curbs hydropower resource misallocation, albeit with a discernible time lag. When the digital economy experiences a positive impulse shock, its impact on the hydropower resources mismatch emerges in the first lag period, peaks in the second lag period, and then stabilizes. Secondly, the corrective impact of digital economic development on hydropower resources mismatch is contingent upon the level of regional industrialization, which is more pronounced in regions with higher levels of industrialization. In conclusion, this paper offers evidence-based policy recommendations to facilitate the localized implementation of digital economy policies and enhance the efficiency of hydropower resources allocation. Full article
(This article belongs to the Special Issue Energy Security, Transition, and Sustainable Development)
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24 pages, 3764 KB  
Article
The Evaluation of the Effect of Power Circuit Configuration Changes on the Level of Harmonics Generated by the Hoisting Machine Drive System
by Tomasz Siostrzonek and Zbigniew Mikoś
Energies 2025, 18(19), 5043; https://doi.org/10.3390/en18195043 - 23 Sep 2025
Abstract
The quality of electrical energy in mining plants is still a topic that is not directly linked to occupational safety and the efficiency of the mining process. Modernisation of hoisting machines should be carried out, taking into account the impact of such a [...] Read more.
The quality of electrical energy in mining plants is still a topic that is not directly linked to occupational safety and the efficiency of the mining process. Modernisation of hoisting machines should be carried out, taking into account the impact of such a drive on the mine’s power grid. A hoisting machine is one of the largest consumers of electricity in this grid and, as such, can pose a real threat to its proper functioning. The aim of the study was to determine the impact of the hoisting machine drive system on the mine network after a thorough modernisation process. Measurements were taken before and after the process. The assessment was carried out in two aspects, i.e., the measurement results obtained after the modernisation were compared with the applicable regulations. The second approach was to compare the results before and after modernisation. In the authors’ opinion, this second approach is a way of preventing potential phenomena that may occur in the network as a result of the operation of the power electronic system and should complement the analysis described in the regulations. The assessment of the current operation of the system in relation to the previous one makes it possible to evaluate the correctness of the solution applied and may provide guidelines for further steps in the event of a failure or unsafe events. Full article
(This article belongs to the Special Issue Technology for Analysis and Control of Power Quality)
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