Energies

23 pages, 2591 KiB

Open AccessArticle

Bi-Level Game-Theoretic Bidding Strategy for Large-Scale Renewable Energy Generators Participating in the Energy–Frequency Regulation Market

by Ran Gao, Shuyan Hui, Bingtuan Gao and Xiaofeng Liu

Energies 2025, 18(10), 2604; https://doi.org/10.3390/en18102604 (registering DOI) - 17 May 2025

Abstract

The proportion of grid-connected renewable energy, represented by wind and photovoltaic power, continues to rise. The intermittence and volatility of the power output of renewable energy bring serious challenges to the secure and stable operation of the power system. Adopting a market-based approach [...] Read more.

The proportion of grid-connected renewable energy, represented by wind and photovoltaic power, continues to rise. The intermittence and volatility of the power output of renewable energy bring serious challenges to the secure and stable operation of the power system. Adopting a market-based approach to promote the active participation of producers in frequency regulation and other auxiliary service markets besides the energy market is the only way to comprehensively solve the problems of power system security, stability, and economic benefits. Therefore, for the future bidding decision scenario of large-scale renewable energy generators participating in the energy–frequency regulation market, a bi-level game-theoretic bidding model based on mean-field game and non-cooperative game theory is proposed. The inner level is a mean-field game among large-scale renewable energy generators of the same type, and the outer level is a non-cooperative game among different types of generators. A combination of fixed-point iteration and finite-difference method is employed to solve the proposed bi-level bidding decision model. Case analysis indicates that the proposed model can effectively realize the bidding decision optimization for large-scale renewable energy generators in the energy–frequency regulation market. Furthermore, in comparison to traditional proportional bidding model, the proposed model enables renewable energy generators to secure higher profits in the energy–frequency regulation market. Full article

(This article belongs to the Section A: Sustainable Energy)

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18 pages, 1952 KiB

Open AccessArticle

Comparison of Eddy Current Loss Calculation Techniques for Axial Flux Motors with Printed Circuit Board Windings

by Andreas Bauer, Daniel Dieterich and Sven Urschel

Energies 2025, 18(10), 2603; https://doi.org/10.3390/en18102603 (registering DOI) - 17 May 2025

Abstract

In slotless machines, the winding conductors are exposed to the magnetic air gap field, which causes additional eddy current losses, thus decreasing efficiency and affecting thermal utilization. This is the case, inter alia, for axial flux motors equipped with printed circuit board windings, [...] Read more.

In slotless machines, the winding conductors are exposed to the magnetic air gap field, which causes additional eddy current losses, thus decreasing efficiency and affecting thermal utilization. This is the case, inter alia, for axial flux motors equipped with printed circuit board windings, where the winding is made of copper–fiberglass epoxy laminations and located in the air gap. The dominant influencing factors are primarily the width of the conducting tracks and the magnetic air gap flux density and frequency. The evaluation time is a crucial constraint when calculating thousands of different designs for design space exploration or performing multi-objective optimizations. Finite element simulations can achieve very precise results, but unlike semi-analytical approximation functions, they are very time-consuming and therefore not the method of choice for design space exploration. This publication provides a comprehensive overview of a selection of different eddy current loss calculation techniques that are applicable for rectangular tracks and round wire windings. A comparison of the calculated results for a finite element simulation is presented for a slotless axial flux machine with printed circuit board windings and rectangular tracks. The calculation time consumed is also compared. The current density distribution of planar conductors of air gap windings differs from that in electrical steel sheets. In contrast to the methods based on steel sheets, only the adapted methods for conductors in air gaps offer acceptable accuracy. A recommendation is provided for the method that offers the best balance between accuracy and computation time for the early-stage design of slotless axial flux machines. Full article

(This article belongs to the Special Issue Advances in Permanent Magnet Synchronous Generator)

14 pages, 914 KiB

Open AccessArticle

Fast and Interpretable Probabilistic Solar Power Forecasting via a Multi-Observation Non-Homogeneous Hidden Markov Model

by Jiaxin Zhang and Siyuan Shang

Energies 2025, 18(10), 2602; https://doi.org/10.3390/en18102602 (registering DOI) - 17 May 2025

Abstract

The increasing complexity and uncertainty associated with high renewable energy penetration require forecasting methods that provide more comprehensive information for risk analysis and energy management. This paper proposes a novel probabilistic forecasting model for solar power generation based on a non-homogeneous multi-observation Hidden [...] Read more.

The increasing complexity and uncertainty associated with high renewable energy penetration require forecasting methods that provide more comprehensive information for risk analysis and energy management. This paper proposes a novel probabilistic forecasting model for solar power generation based on a non-homogeneous multi-observation Hidden Markov Model (HMM). The model is purely data-driven, free from restrictive assumptions, and features a lightweight structure that enables fast updates and transparent reasoning—offering a practical alternative to computationally intensive neural network approaches. The proposed framework is first formalized through an extension of the classical HMM and the derivation of its core inference procedures. A method for estimating the probability density distribution of solar power output is introduced, from which point forecasts are extracted. Thirteen model variants with different observation-dependency structures are constructed and evaluated using real PV operational data. Experimental results validate the model’s effectiveness in generating both prediction intervals and point forecasts, while also highlighting the influence of observation correlation on forecasting performance. The proposed approach demonstrates strong potential for real-time solar power forecasting in modern power systems, particularly where speed, adaptability, and interpretability are critical. Full article

(This article belongs to the Section A2: Solar Energy and Photovoltaic Systems)

14 pages, 507 KiB

Open AccessArticle

Study on the Influence of Grounding Resistance on Cable Fault Overvoltage

by Baotong Song, Sihan Wang, Changyuan Xiang, Xiaoyue Chen and Ju Tang

Energies 2025, 18(10), 2601; https://doi.org/10.3390/en18102601 (registering DOI) - 17 May 2025

Abstract

The cable grounding connecting method and grounding resistance have a significant influence on the cable fault overvoltage. This paper considers a 500 kV long cable project in Beijing as the research object; a model was implemented in ATP-EMTP, and simulation results show how [...] Read more.

The cable grounding connecting method and grounding resistance have a significant influence on the cable fault overvoltage. This paper considers a 500 kV long cable project in Beijing as the research object; a model was implemented in ATP-EMTP, and simulation results show how grounding resistance and its connection method influence the cable fault overvoltage. When the grounding resistances are all set to the same value along the cable, as the grounding resistance increases, the frequency of overvoltage at the cable fault point also increases. When all grounding resistances along the cable are set to same value, if a connection method considering conduction impedance is adopted, the fault point frequency overvoltage also increases. If the grounding resistance at both ends of the cable are connected to the substation, the sequence impedance of the cable will decrease, resulting in a reduction in the fault point overvoltage. Additionally, this paper analyzes the influence of grounding material on the cable line sequence impedance. When the grounding resistance value is set to 5 Ω according to the national standard, the cable line fault overvoltage under single-phase grounding fault with load reduction is simulated and analyzed, and it is found that connecting the grounding devices at both ends of the cable to the substation can effectively suppress the overvoltage along the cable. Full article

(This article belongs to the Section F3: Power Electronics)

15 pages, 2210 KiB

Open AccessArticle

Life Cycle Assessment of an Oscillating Water Column-Type Wave Energy Converter

by Heshanka Singhapurage, Pabasari A. Koliyabandara and Gamunu Samarakoon

Energies 2025, 18(10), 2600; https://doi.org/10.3390/en18102600 (registering DOI) - 17 May 2025

Abstract

Among different kinds of renewable energy sources, ocean wave energy offers a promising source of low-carbon electricity. However, despite this potential, ocean wave energy systems can have notable environmental impacts, which remain underexplored. Environmental life cycle assessment (LCA) is a method that can [...] Read more.

Among different kinds of renewable energy sources, ocean wave energy offers a promising source of low-carbon electricity. However, despite this potential, ocean wave energy systems can have notable environmental impacts, which remain underexplored. Environmental life cycle assessment (LCA) is a method that can be used to evaluate the environmental impact of these systems. But few LCAs have been conducted for wave energy converters (WECs), and no prior studies specifically address onshore oscillating water column (OWC) devices, leaving a clear gap in this field. This research provides a cradle-to-gate LCA for an OWC device, using the 500 kW LIMPET OWC plant, located on the Isle of Islay in Scotland, as a case study. The assessment investigated the environmental impacts of the plant across 19 impact categories. OpenLCA 2.0 software was used for the analysis, with background data sourced from the Ecoinvent database version 3.8. The ReCiPe 2016 Midpoint (H) and Cumulative Energy Demand (CED) methods were used for the impact assessment. The results revealed a Global Warming Potential (GWP) of 56 kg CO₂ eq/kWh and a carbon payback period of 0.14 years. The energy payback period is significantly higher at 196 years, largely due to the plant’s inefficient energy capture and recurring operational failures reported. These findings highlight that although ocean wave energy is a renewable energy source, WEC’s efficiency and reliability are key factors for sustainable electricity generation. Furthermore, the findings conclude the need for selecting eco-friendly construction materials in OWC construction, namely chamber construction, and the advancement of energy-harnessing mechanisms, such as in Power Take-off (PTO) systems, to improve energy efficiency and reliability. Moreover, the importance of material recycling at the end-of-life stage, which was not accounted for in this cradle-to-gate analysis yet, is underscored for offsetting a portion of the associated environmental impacts. This research contributes novel insights into sustainable construction practices for OWC devices, offering valuable guidance for future wave energy converter designs. Full article

(This article belongs to the Section B2: Clean Energy)

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21 pages, 806 KiB

Open AccessArticle

Offshore Wind Farm Supply Chains and Regional Development: The Role of Ports in Economic and Logistical Growth in the Central Baltic Region

by Weronika Kosek, Waldemar Woźniak, Norbert Chamier-Gliszczynski and Wiesław Staniuk

Energies 2025, 18(10), 2599; https://doi.org/10.3390/en18102599 (registering DOI) - 17 May 2025

Abstract

The development of offshore wind energy has emerged as a key driver of economic growth and energy transition in Europe, with the Baltic Sea region playing a crucial role in this transformation. This paper examines the impact of offshore wind farm (OWF) supply [...] Read more.

The development of offshore wind energy has emerged as a key driver of economic growth and energy transition in Europe, with the Baltic Sea region playing a crucial role in this transformation. This paper examines the impact of offshore wind farm (OWF) supply chains on regional economic development, focusing on the strategic role of ports in facilitating these operations. Particular emphasis is placed on Port Ustka, which has been identified as a potential logistics and service hub for offshore wind projects in Poland’s Exclusive Economic Zone. The study explores the integration of local ports into offshore wind supply chains and their contribution to industrial development, job creation, and infrastructure modernization. Through an analysis of infrastructure parameters, logistical capabilities, and economic impacts, the paper assesses the feasibility of Port Ustka as a service base for major offshore wind projects, such as Baltica 2 and 3. The findings highlight the importance of port infrastructure investments, supply chain optimization, and policy support in maximizing the economic benefits of offshore wind development. By evaluating the challenges and opportunities associated with offshore wind logistics, this paper provides strategic insights for policymakers, investors, and industry stakeholders. The research underscores the necessity of modernizing port facilities, improving transport connections, and fostering local supply chain participation to enhance the efficiency and sustainability of offshore wind operations in the Central Baltic Region. Full article

(This article belongs to the Special Issue Global Research and Trends in Offshore Wind, Wave, and Tidal Energy)

18 pages, 2852 KiB

Open AccessArticle

Evaluating Performance of Metal-Organic Complexes as Electrodes in Hydrogen Peroxide Fuel Cells

by Faraz Alderson, Raveen Appuhamy and Stephen Andrew Gadsden

Energies 2025, 18(10), 2598; https://doi.org/10.3390/en18102598 (registering DOI) - 17 May 2025

Abstract

With increasing energy demands, fuel cells are a popular avenue for portability and low waste emissions. Hydrogen fuel cells are popular due to their potential output power and clean waste. However, due to storage and transport concerns, hydrogen peroxide fuel cells are a [...] Read more.

With increasing energy demands, fuel cells are a popular avenue for portability and low waste emissions. Hydrogen fuel cells are popular due to their potential output power and clean waste. However, due to storage and transport concerns, hydrogen peroxide fuel cells are a promising alternative. Although they have a lower output potential compared to hydrogen fuel cells, peroxide can act as both the oxidizing and reducing agent, simplifying the structure of the cell. In addition to reducing the complexity, hydrogen peroxide is stable in liquid form and can be stored in less demanding methods. This paper investigates chelated metals as electrode material for hydrogen peroxide fuel cells. Chelated metal complexes are ring-like structures that form from binding organic or inorganic compounds with metal ions. They are used in medical imaging, water treatment, and as catalysts for reactions. Copper(II) phthalocyanine, phthalocyanine green, poly(copper phthalocyanine), bis(ethylenediamine)copper(II) hydroxide, iron(III) ferrocyanine, graphene oxide decorated with Fe3O4, zinc phthalocyanine, magnesium phthalocyanine, manganese(II) phthalocyanine, cobalt(II) phthalocyanine are investigated as electrode materials for peroxide fuel cells. In this study, the performance of these materials is evaluated using cyclic voltammetry. The voltammograms are compared, as well as observations are made during the materials’ use to measure their effectiveness as electrode material. There has been limited research comparing the use of these chelated metals in the context of hydrogen peroxide fuel cells. Through this research, the goal is to further the viability of hydrogen peroxide fuel cells. Poly(copper phthalocyanine) and graphene oxide doped with iron oxides had strong redox catalytic activity for use in acidic peroxide single-compartment fuel cells, where the poly(copper phthalocyanine) electrode compound generated the highest peak power density of 7.92 mW/cm

^{2}

and cell output potential of 0.634 V. Full article

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

15 pages, 2030 KiB

Open AccessArticle

Carbon Dot-Modulated Phase-Change Composites for Wide Temperature Range and High-Density Heat Storage and Release

by Jingya Liang, Ning Li, Jie Wu, Qing Chang, Jinlong Yang and Shengliang Hu

Energies 2025, 18(10), 2597; https://doi.org/10.3390/en18102597 (registering DOI) - 16 May 2025

Abstract

Organic phase-change materials (PCMs) offer great promise in addressing challenges in thermal energy storage and heat management, but their applications are greatly limited by low energy density and a rigid phase transition temperature. Herein, by introducing carbon dots (CDs) with abundant oxygen-related groups, [...] Read more.

Organic phase-change materials (PCMs) offer great promise in addressing challenges in thermal energy storage and heat management, but their applications are greatly limited by low energy density and a rigid phase transition temperature. Herein, by introducing carbon dots (CDs) with abundant oxygen-related groups, we develop a novel kind of erythritol (ET)-based composite PCMs (CD-ETs) featuring an enhanced latent heat storage capacity and a reduced degree of supercooling compared to pure ETs. The optimally formulated CD-ETs increase the latent heat storage capacity from 377.3 to 410.2 J·g⁻¹ and the heat release capacity from 209.0 to 240.2 J·g⁻¹ compared to the pristine ETs. Moreover, the subcooled degree of CD-ETs is more than 30 °C lower than that of pristine ETs. By successively encapsulating CD-ETs and CD-containing polyethylene glycol (PEG) with a low melting point in a reduced graphene oxide-modified melamine sponge, the resultant shape-stabilized system not only prevents leakage of molten PCMs but also allows for a wide response temperature window and promotes the heat transfer ability of melted PEG in close contact with solid CD-ETs. Stepped melting and crystallization guarantee phase changes in high-melting-point ETs via solar heating, Joule heating or a combination thereof. Specifically, the melting enthalpy of this system is as high as 306.5 J·g⁻¹, and its cold crystallization enthalpy reaches 196.5 J·g⁻¹, surpassing numerous organic PCMs. This work provides a facile and efficient strategy for the design of ideal thermal energy storage materials to meet the needs of application scenarios in a cost-effective manner. Full article

(This article belongs to the Section J1: Heat and Mass Transfer)

16 pages, 5209 KiB

Open AccessArticle

Effects of Driving Current Ripple Fluctuations on the Liquefied Layer of the Armature–Rail Interface in Railguns

by Wen Tian, Gongwei Wang, Ying Zhao, Weikang Zhao, Weiqun Yuan and Ping Yan

Energies 2025, 18(10), 2596; https://doi.org/10.3390/en18102596 (registering DOI) - 16 May 2025

Abstract

During the electromagnetic launching process, the actual current input into the launcher is obtained by controlling the discharge of the pulsed power supply. Generally, the waveform of the pulse current is determined by the discharge characteristics and discharge time of the pulse power [...] Read more.

During the electromagnetic launching process, the actual current input into the launcher is obtained by controlling the discharge of the pulsed power supply. Generally, the waveform of the pulse current is determined by the discharge characteristics and discharge time of the pulse power supply. Due to the limitation of control accuracy, the driving current is not an ideal trapezoidal wave, but there is a certain fluctuation (current ripple) in the flat top portion of the trapezoidal wave. The fluctuation of the current will affect the thickness of the liquefied layer at the armature–rail interface as well as the magnitude of the contact pressure, thereby inducing instability at the armature–rail interface and generating micro-arcs, which result in a reduction in the service life of the rails within the launcher. Consequently, it is imperative to conduct an in-depth analysis of the influence of current ripple on the liquefied layer during electromagnetic launching. In this paper, a thermoelastic magnetohydrodynamic model is constructed by coupling temperature, stress, and electromagnetic fields, which are predicated on the Reynolds equation of the metal liquefied layer at the armature–rail contact interface. The effects of current fluctuations on the melting rate of the surface of the armature, the thickness of the liquefied layer, and the hydraulic pressure of the liquefied layer under four different current ripple coefficients (RCs) were analyzed. The results show the following: (1) The thickness and the pressure of the liquefied layer at the armature–rail interface fluctuate with the fluctuation of the current, and, the larger the ripple coefficient, the greater the fluctuations in the thickness and pressure of the liquefied layer. (2) The falling edge of the current fluctuation leads to a decrease in the hydraulic pressure of the liquefied layer, which results in the instability of the liquefied layer between the armature and rails. (3) As the ripple coefficient increases, the time taken for the liquefied layer to reach a stable state increases. In addition, a launching experiment was also conducted in this paper, and the results showed that, at the falling edge of the current fluctuation, the liquefied layer is unstable, and a phenomenon such as the ejection of molten armature and transition may occur. The results of the experiment and simulations mutually confirm that the impact of current fluctuations on the armature–rail interface increases with increases in the ripple coefficient. Full article

(This article belongs to the Section F1: Electrical Power System)

16 pages, 866 KiB

Open AccessArticle

Operating Properties of the Inductive Current Transformer and Evaluation of Requirements for Its Compliance with the IEC 61869-1 WB2 Class Extension for Frequency up to 20 kHz

by Michal Kaczmarek

Energies 2025, 18(10), 2595; https://doi.org/10.3390/en18102595 (registering DOI) - 16 May 2025

Abstract

Nanocrystalline material provides an opportunity to improve the wideband performance of inductive current transformers and enables the possibility of ensuring their transformation accuracy for distorted and sinusoidal current from 50 Hz up to 20 kHz. Introduced in the year 2023, the standard IEC [...] Read more.

Nanocrystalline material provides an opportunity to improve the wideband performance of inductive current transformers and enables the possibility of ensuring their transformation accuracy for distorted and sinusoidal current from 50 Hz up to 20 kHz. Introduced in the year 2023, the standard IEC 61869-1 defines optional wideband accuracy classes for inductive current transformers with the WB2 class extension for harmonic frequencies up to 20 kHz. In this paper, design requirements in order to develop high accuracy 0.1-WB2 class wideband inductive current transformers compliant with the standards IEC 61869-1/2 are presented. It is shown that the main emphasis and design difficulties in ensuring high transformation accuracy still concern the lowest frequency of wideband operation—the fundamental component. However, it is of high importance that in order to obtain the highest possible wideband transformation accuracy of inductive current transformer for the low order higher harmonics, we ensure the lowest possible self-distortion of secondary current by minimalization of the load of its secondary winding is achieved—it should operate close to the short circuit conditions. Therefore, the low-power inductive CT should be designed and used for measurements in the power grid, as they will ensure the highest wideband transformation accuracy. Full article

(This article belongs to the Section F: Electrical Engineering)

33 pages, 863 KiB

Open AccessReview

Trigeneration Systems: A State-of-the-Art Review

by Arthur Dupuy, Adalia Andreea Percembli (Chelmuș), Lavinia Grosu, Khanh-Hung Tran and Alexandru Dobrovicescu

Energies 2025, 18(10), 2594; https://doi.org/10.3390/en18102594 (registering DOI) - 16 May 2025

Abstract

As the world’s population grows and energy demand increases, there is a need to switch from fossil fuels to renewable energy. In order to preserve the environment and meet these growing demands, especially for cooling applications, trigeneration systems could be the answer. The [...] Read more.

As the world’s population grows and energy demand increases, there is a need to switch from fossil fuels to renewable energy. In order to preserve the environment and meet these growing demands, especially for cooling applications, trigeneration systems could be the answer. The aim of this work is to provide a structured overview of the current state of the art in the field of trigeneration (CCHP) systems. Firstly, these systems and their applications are presented. An overview of the different indicators used to describe the performance of these systems is given. A comparison between CCHP (combined cooling, heat, and power) systems is made. Finally, improvements and other concepts found in the literature are presented. This review will later serve as a basis for the exergo-economic optimization of a low-temperature CCHP system based on renewable energy sources. Therefore, more attention is given to the technologies used for such systems. Full article

(This article belongs to the Section F: Electrical Engineering)

16 pages, 4633 KiB

Open AccessArticle

Research on Energy Management Strategy for Mining Trucks with Methanol Range-Extender and Hybrid Energy Storage System

by Yafeng Ren, Yusheng Luo, Wenwen Lu and Jiaxin Qin

Energies 2025, 18(10), 2593; https://doi.org/10.3390/en18102593 (registering DOI) - 16 May 2025

Abstract

In the field of mining transportation, methanol range-extended powertrain systems are emerging as the preferred solution to address heavy-duty transport challenges in mining areas, leveraging their low-carbon emissions and long-range endurance. However, conventional energy storage technologies face trade-offs between energy density, power density, [...] Read more.

In the field of mining transportation, methanol range-extended powertrain systems are emerging as the preferred solution to address heavy-duty transport challenges in mining areas, leveraging their low-carbon emissions and long-range endurance. However, conventional energy storage technologies face trade-offs between energy density, power density, and cycle life: lithium-ion batteries (Li-ion) have a high energy density but short cycle life, while supercapacitors (SCs) have a high power density and long cycle life but low energy density. To address these limitations, a hybrid energy storage system (HESS) combining Li-ion and supercapacitors (SCs) is proposed as the energy storage unit for the methanol range-extended mining truck (MRMT) in this study. Firstly, the power architecture of MRMT with HESS is designed. Then, the range-extender, Li-ion battery, and SCs are matched and selected based on the operating conditions of the mining truck. Finally, a whole vehicle energy management strategy is developed, and the vehicle power system performance is simulated by combining MATLAB/Simulink (R2022a) with AVL-Cruise (R2019.2). Comparison with conventional single Li-ion range-extender system reveals that the MRMT with HESS reduces methanol consumption by 6.4% and extends the cycle life of Li-ion by 353.4%. This study provides a technological path for the green transformation of mine transportation that is both economical and sustainable. Full article

(This article belongs to the Section E: Electric Vehicles)

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23 pages, 3249 KiB

Open AccessReview

Challenges and Research Progress in Zinc Anode Interfacial Stability

by Jing Li, Qianxin Liu, Zixuan Zhou, Yaqi Sun, Xidong Lin, Tao Yang and Funian Mo

Energies 2025, 18(10), 2592; https://doi.org/10.3390/en18102592 - 16 May 2025

Abstract

Aqueous zinc-ion batteries are regarded a promising energy storage system due to their high safety, low cost, high theoretical specific capacity (820 mAh g⁻¹), and low redox potential (−0.76 V). However, in practice, uneven Zn²⁺ deposition on the surface of [...] Read more.

Aqueous zinc-ion batteries are regarded a promising energy storage system due to their high safety, low cost, high theoretical specific capacity (820 mAh g⁻¹), and low redox potential (−0.76 V). However, in practice, uneven Zn²⁺ deposition on the surface of the zinc anode can lead to the uncontrolled growth of zinc dendrites, which can puncture the separator and trigger a short-circuit in the cell. In addition, the inherent thermodynamic instability of weakly acidic electrolytes is prone to trigger side reactions like hydrogen evolution reaction and corrosion, further weakening the stability of the zinc anode. These problems not only affect the cycle life of the battery, but also lead to a significant decrease in electrochemical performance. Therefore, how to effectively inhibit the unwanted side reactions and guide the uniform deposition of Zn²⁺ to suppress the growth of dendrites becomes a key challenge in constructing a stable zinc anode/electrolyte interface. Therefore, this paper systematically combs through the main bottlenecks and root causes that hinder the interfacial stability of zinc anodes at present, and summarizes the existing solutions and the progress made. On this basis, this paper also analyzes the application potential of polymer materials in enhancing the interfacial stability of zinc anodes, which provides new ideas for the direction of subsequent research. Full article

24 pages, 1797 KiB

Open AccessArticle

Structural Obstacles to Energy Transition in Türkiye and Holistic Solution Proposals: A Political, Economic and Social Dimensional Analysis

by Muhammed Ernur Akiner

Energies 2025, 18(10), 2591; https://doi.org/10.3390/en18102591 (registering DOI) - 16 May 2025

Abstract

This study aims to analyze the multi-dimensional structural obstacles in Türkiye’s energy transition process and offer solutions for a sustainable, fair, and holistic transition. The study simultaneously evaluated energy policies’ economic, environmental, and social impacts; quantitative data, qualitative interviews, spatial analysis, and scenario [...] Read more.

This study aims to analyze the multi-dimensional structural obstacles in Türkiye’s energy transition process and offer solutions for a sustainable, fair, and holistic transition. The study simultaneously evaluated energy policies’ economic, environmental, and social impacts; quantitative data, qualitative interviews, spatial analysis, and scenario modeling techniques were used together. Türkiye’s 2023 energy panorama was examined and compared to the European Union averages. Structural differences in fundamental indicators such as energy intensity, supply security, pricing, and renewable resource use were revealed. According to EPDK, TÜİK, and TEİAŞ, Türkiye’s renewable energy share (42%) fell behind the EU average (63%), energy intensity was high (6.8 MJ per US dollar of GDP), and dependence on fossil fuels (coal 30%, natural gas 25%) threatened energy security. The findings show that the main obstacles to energy transition are insufficient financing, lack of political will, technological incompatibilities, and institutional coordination problems. In this context, the study proposes short-term to long-term transition policies. A multi-layered solution framework was presented, from energy cooperatives to carbon pricing, from net-zero laws to regional development plans. These policies can increase the renewable energy rate to 65% by 2035 and reduce carbon emissions by 50%. The study is one of the first systematic analyses to address energy transition in Türkiye with a holistic approach and is a strategic reference for policymakers. Full article

(This article belongs to the Special Issue Energy Saving, Efficiency, and Conversion in Renewable and Sustainable Energy)

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17 pages, 7031 KiB

Open AccessArticle

Bearing Capacity of Offshore Wind Power Suction Bucket with Supports Under Extreme Wind and Waves

by Changfeng Yuan, Qiming Zhang, Husheng Luo and Kaiwen Zhang

Energies 2025, 18(10), 2590; https://doi.org/10.3390/en18102590 - 16 May 2025

Abstract

In this study, we analyzed an offshore wind turbine suction bucket foundation with supports, referred to as the supported suction bucket foundation. A numerical model of a typical 3MW wind turbine suction bucket foundation was established, and the accuracy of the numerical modeling [...] Read more.

In this study, we analyzed an offshore wind turbine suction bucket foundation with supports, referred to as the supported suction bucket foundation. A numerical model of a typical 3MW wind turbine suction bucket foundation was established, and the accuracy of the numerical modeling method was validated. The daily wind and wave extreme data for 2022 monitored by a station in the eastern China Sea were converted into loads and applied to the conventional and supported suction bucket foundations. The bearing capacity of the two bucket foundations was, thus, compared and analyzed. The results show that the supported suction bucket foundation reduces the foundation displacement and amplitude. Also, the support structure effectively reduces the soil displacement around the bucket. The maximum displacement of the outer soil of the bucket decreases by about 89.8%, while that of the inner soil of the bucket decreases by about 70.7%. Increasing the supports can reduce the separation of the top lid from the inner soil below it. Further, the supported suction bucket foundation can effectively reduce the plastic strain of the soil around the bucket and reduce the plastic strain difference between the inner and outer soil of the bucket. Full article

(This article belongs to the Special Issue Offshore Wind Support Structure Design)

19 pages, 3555 KiB

Open AccessArticle

A Power Decoupling Control Strategy for Multi-Port Bidirectional Grid-Connected IPT Systems

by Xuewei Pan, Peiwen Ma, Zhouchi Cai and Danyang Bao

Energies 2025, 18(10), 2589; https://doi.org/10.3390/en18102589 - 16 May 2025

Abstract

In the context of vehicle-to-grid (V2G) applications, single-port bidirectional inductive power transfer (BDIPT) systems have difficulty coping with the growing demand for electric vehicles. This paper proposes a multi-port BDIPT system based on an LCC-LCC compensation network. A multi-phase-shift (MPS) control with more [...] Read more.

In the context of vehicle-to-grid (V2G) applications, single-port bidirectional inductive power transfer (BDIPT) systems have difficulty coping with the growing demand for electric vehicles. This paper proposes a multi-port BDIPT system based on an LCC-LCC compensation network. A multi-phase-shift (MPS) control with more degrees of freedom is proposed, where the external phase shift angle controls the power transmission direction and the internal phase shift angle controls the transmitted power magnitude. Independent multi-port operation for the multi-port BDIPT system can be achieved. Finally, the theoretical results are verified by experiments. The experimental results show that the LCC-LCC-based multi-port BDIPT system can achieve independent control of the transmission power at each port. Full article

(This article belongs to the Special Issue Voltage/Frequency/Power Quality Monitoring and Control in Smart Grids)

22 pages, 3361 KiB

Open AccessArticle

Research on Intelligent Vehicle Tracking Control and Energy Consumption Optimization Based on Dilated Convolutional Model Predictive Control

by Lanxin Li, Wenhui Pei and Qi Zhang

Energies 2025, 18(10), 2588; https://doi.org/10.3390/en18102588 - 16 May 2025

Abstract

To address the limitations of low modeling accuracy in physics-based methods—which often lead to poor vehicle-tracking performance and high energy consumption—this paper proposes an intelligent vehicle modeling and trajectory tracking control method based on a dilated convolutional neural network (DCNN). First, an effective [...] Read more.

To address the limitations of low modeling accuracy in physics-based methods—which often lead to poor vehicle-tracking performance and high energy consumption—this paper proposes an intelligent vehicle modeling and trajectory tracking control method based on a dilated convolutional neural network (DCNN). First, an effective dataset was constructed by incorporating historical state information, such as longitudinal tire forces and vehicle speed, to accurately capture vehicle dynamic characteristics and reflect energy variations during motion. Next, a dilated convolutional vehicle system model (DCVSM) was designed by combining vehicle dynamics with data-driven modeling techniques. This model was then integrated into a model predictive control (MPC) framework. By solving a nonlinear optimization problem, a dilated convolutional model predictive controller (DCMPC) was developed to enhance tracking accuracy and reduce energy consumption. Finally, a co-simulation environment based on CarSim and Simulink was used to evaluate the proposed method. Comparative analyses with a traditional MPC and a neural network-based MPC (NNMPC) demonstrated that the DCMPC consistently exhibited superior trajectory tracking performance under various test scenarios. Furthermore, by computing the tire-slip energy loss rate, the proposed method was shown to offer significant advantages in improving energy efficiency. Full article

(This article belongs to the Special Issue Challenges, Trends and Achievements in Electric Vehicle Research and Development in the Era of Vehicle Electrification)

16 pages, 5956 KiB

Open AccessArticle

Transmitting Double-D Coil to Wirelessly Recharge the Battery of a Drone with a Receiving Coil Integrated in the Landing Gear

by Wassim Boumerdassi, Tommaso Campi, Silvano Cruciani, Francesca Maradei and Mauro Feliziani

Energies 2025, 18(10), 2587; https://doi.org/10.3390/en18102587 - 16 May 2025

Abstract

The aim of this work is the design of a 200 W transmitting coil for a high-power wireless power transfer (WPT) system based on magnetic resonant coupling (MRC) to charge the battery of a drone in 1 h equipped with a WPT receiving [...] Read more.

The aim of this work is the design of a 200 W transmitting coil for a high-power wireless power transfer (WPT) system based on magnetic resonant coupling (MRC) to charge the battery of a drone in 1 h equipped with a WPT receiving coil integrated into the landing gear. This innovative solution is based on the use of the landing gear as the receiving coil, thereby obviating the need for an additional component (e.g., separate receiving coil). The proposed landing gear is fabricated from aluminum, to reduce weight, and to improve mechanical robustness and electrical performance. Consequently, the design reduces overall weight and system complexity while minimizing potential destabilization of the drone’s flight dynamics. However, a specific design of the primary coil is required to ensure high efficiency even in case of an inaccurate landing of the drone on a ground pad. To this aim, a double-D configuration is here proposed and optimized for the transmitting coil, while a double coil receiver in combination with a charge controller that uses a maximum power point tracking (MPPT) algorithm is integrated into the landing gear. The results obtained from the simulations demonstrate that the proposed WPT system has excellent electrical efficiency and very high tolerance to coil misalignment in terms of the coupling coefficient due to imprecise landing. The transmission efficiency of the final test prototype can reach 95% with a coupling coefficient of k = 0.16, and it can drop to a minimum of 85% when misalignment occurs resulting in k = 0.06. Full article

(This article belongs to the Special Issue Advances in Wireless Power Transfer Technologies and Applications)

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21 pages, 452 KiB

Open AccessArticle

Heat-Loss Based Method for Real-Time Monitoring Method for Hydroelectric Power Plant Efficiency

by Lorenzo Battisti, Lorenzo Tieghi and Soheil Fattahi

Energies 2025, 18(10), 2586; https://doi.org/10.3390/en18102586 - 16 May 2025

Abstract

In energy transition scenarios, hydropower remains the largest source of renewable electricity generation. However, with respect to other means of renewable energy exploitation, like wind turbines or photovoltaics, very few technological advancements are to be expected, due to the technological maturity of hydropower [...] Read more.

In energy transition scenarios, hydropower remains the largest source of renewable electricity generation. However, with respect to other means of renewable energy exploitation, like wind turbines or photovoltaics, very few technological advancements are to be expected, due to the technological maturity of hydropower turbines. Therefore, an increase in power production of hydropower plants can only be possible thanks to an optimization of the operation and maintenance policies, leading to improved performance, reducing energy losses and downtimes. This work proposes a practical approach to the continuous monitoring of the operational conditions of hydropower plants through the non-invasive measurement of the electrical efficiency of the generator group. To achieve this, a heat-loss based method is introduced, which enables the measurement of both the electrical generator losses and the electrical input power, along with their associated uncertainties. This method is applicable for plants of any size, does not require a production shutdown, and, since it is applied to the electrical generator, can be used with different turbine types, including Kaplan, Francis, and Pelton. It also relies on relatively simple instruments such as thermo-cameras, thermo-resistances, thermo-couples, and flow meters to measure key variables, including cooling water inlet and outlet temperatures, electrical machine external and frame temperatures, undisturbed ambient temperature, electrical power absorbed, and cooling water flow rate. The proposed methodology has been tested and validated through the application to a laboratory test rig. In all test conditions, the heat loss-based method showed a smaller relative error than the standard efficiency measurement methods. Full article

(This article belongs to the Special Issue Advances in Renewable Energy Power Forecasting and Integration: 2nd Edition)

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