Energies

22 pages, 1331 KiB

Open AccessArticle

Integrating Autonomous Trucks into Human-Centric Operations: A Path to Safer and More Energy-Efficient Road Transport

by Tomasz Neumann and Radosław Łukasik

Energies 2025, 18(16), 4219; https://doi.org/10.3390/en18164219 (registering DOI) - 8 Aug 2025

The increasing integration of autonomous driving technologies into heavy-duty road transport requires a clear understanding of how these systems affect professional drivers’ working time, vehicle utilization, and regulatory compliance. This study develops a model-based comparative analysis to assess the cooperation between human drivers [...] Read more.

The increasing integration of autonomous driving technologies into heavy-duty road transport requires a clear understanding of how these systems affect professional drivers’ working time, vehicle utilization, and regulatory compliance. This study develops a model-based comparative analysis to assess the cooperation between human drivers and autonomous trucks at SAE Levels 3 and 4. Using EU Regulation (EC) No 561/2006 as a legal framework, single-driver, double-driver, and ego vehicle scenarios were simulated to evaluate changes in working time classification and vehicle movement. The results indicate that Level 3 automation enables up to 13.25 h of daily vehicle movement while complying with working time regulations, compared with the 10-h limit for conventional operation. Level 4 automation further extends the effective movement time to 14.25 h in double-crew configurations, offering opportunities for increased efficiency without violating labor codes. The novelty of this work lies in the quantitative modeling of human–machine collaboration in professional transport under real regulatory constraints. These findings provide a foundation for regulatory updates, tachograph adaptation to AI-driven vehicles, and the design of hybrid driver roles. Future research will focus on validating these models in real-world transport operations and assessing the implications of Level 5 autonomy for logistics networks and labor markets. Full article

(This article belongs to the Special Issue Digitalization and Automation in the Transportation: Pathways Toward Decarbonization, Enhanced Energy Efficiency and Energy Conservation)

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15 pages, 1447 KiB

Open AccessReview

Optimizing Helium Exploration: Noble Gas Isotopes as Probes for Migration–Enrichment Processes

by Chunhui Cao, Liwu Li, Zhongping Li and Huanhuan Zhao

Energies 2025, 18(16), 4218; https://doi.org/10.3390/en18164218 (registering DOI) - 8 Aug 2025

Abstract

Helium, as a strategic resource with broad applications in industry and science, has drawn increasing global attention due to its scarcity and non-renewable nature. Noble gas isotopes, especially those of helium, neon, and argon, provide unique geochemical tracers for understanding helium genesis, migration, [...] Read more.

Helium, as a strategic resource with broad applications in industry and science, has drawn increasing global attention due to its scarcity and non-renewable nature. Noble gas isotopes, especially those of helium, neon, and argon, provide unique geochemical tracers for understanding helium genesis, migration, and accumulation. This short review summarizes recent advances in the application of noble gas isotope techniques to helium resource research. It covers (1) the fundamental isotope systematics and transport mechanisms, (2) key analytical methods for gas extraction and measurement, and (3) typical case studies illustrating helium source identification and reservoir evaluation. In particular, we highlight three emerging trends: (i) field-adaptable analytical protocols for diverse geological samples, (ii) diffusion models incorporating nanoscale confinement effects, and (iii) isotopic ratio-based frameworks for guiding helium exploration strategies. These integrative approaches offer new insights into the “carrier–pathway–trap” paradigm in helium migration systems and support more effective helium resource assessment. Full article

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17 pages, 1299 KiB

Open AccessArticle

Studying Voltage Fluctuations in the MV Distribution Grid with a Renewable Energy Source

by Yuriy Varetsky, Małgorzata Fedorczak-Cisak and Beata Kushka

Energies 2025, 18(16), 4217; https://doi.org/10.3390/en18164217 (registering DOI) - 8 Aug 2025

Abstract

The increasing penetration of renewable energy sources (RESs), such as photovoltaic and wind power plants, into the medium-voltage distribution grid creates significant concerns regarding voltage control at local substations. Understanding the specifics of the RES operation impact on the phenomenon and propagation of [...] Read more.

The increasing penetration of renewable energy sources (RESs), such as photovoltaic and wind power plants, into the medium-voltage distribution grid creates significant concerns regarding voltage control at local substations. Understanding the specifics of the RES operation impact on the phenomenon and propagation of voltage fluctuations in the distribution grid is important for engineering solutions in the RES design and operation practice. The presented article describes an algorithm for estimating the impact of RES on voltage fluctuations in the medium-voltage grid. The algorithm utilises a RES fixed power factor control mode and is implemented in a grid model developed using software for power flow calculations. The study shows the impact of various RES power factor types on the nature of voltage fluctuations in the distribution grid. The RES operation with lagging reactive power factors, as a method of reducing voltage fluctuation magnitudes, results in a more complex nature of voltage fluctuation propagation compared to those with leading power factor. Based on simulations of a true medium-voltage grid, the possibility of optimal mitigation of voltage fluctuations in a grid by selecting the required RES reactive power factor has been proven. The presented model also allows for calculating changes in distribution grid energy losses depending on the RES reactive power factors, ensuring a practical solution of the control strategy. Full article

(This article belongs to the Special Issue Technology for Analysis and Control of Power Quality)

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20 pages, 1303 KiB

Open AccessArticle

Evaluation System of AC/DC Strong–Weak Balance Relationship and Stability Enhancement Strategy for the Receiving-End Power Grid

by Hui Cai, Mingxin Yan, Xingning Han, Guoteng Wang, Quanquan Wang and Ying Huang

Energies 2025, 18(16), 4216; https://doi.org/10.3390/en18164216 (registering DOI) - 8 Aug 2025

Abstract

With the maturation of ultra-high-voltage direct current (UHVDC) technology, DC grids are taking on a more critical role in power systems. However, their impact on AC grids has become more pronounced, particularly in terms of frequency, short-circuit current level, and power flow control [...] Read more.

With the maturation of ultra-high-voltage direct current (UHVDC) technology, DC grids are taking on a more critical role in power systems. However, their impact on AC grids has become more pronounced, particularly in terms of frequency, short-circuit current level, and power flow control capabilities, which also affects the power supply reliability of the receiving-end grid. To comprehensively evaluate the balance between AC and DC strength at the receiving-end, this paper proposes a multidimensional assessment system that covers grid strength and operational security under various operating conditions. Furthermore, a rationality evaluation model for the AC/DC strong–weak balance relationship is developed based on the entropy weight method, forming a complete evaluation framework for assessing the AC/DC strong–weak balance in the receiving-end power grid. Finally, to address strength imbalances in grid, a structural optimization method for the receiving-end grid is designed by combining network decoupling techniques with modular multilevel converter-based HVDC (MMC–HVDC), serving as a strategy for enhancing grid stability. The proposed strategy is validated through simulations in a typical test system using PSD-BPA, demonstrating its effectiveness in optimizing power flow characteristics, improving system stability, reducing the risk of short-circuit current overloads and large-scale blackouts, and maintaining efficient system operation. Full article

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25 pages, 15062 KiB

Open AccessArticle

Power Allocation and Capacity Optimization Configuration of Hybrid Energy Storage Systems in Microgrids Using RW-GWO-VMD

by Honghui Liu, Donghui Li, Zhong Xiao, Qiansheng Qiu, Xinjie Tao, Qifeng Qian, Mengxin Jiang and Wei Yu

Energies 2025, 18(16), 4215; https://doi.org/10.3390/en18164215 (registering DOI) - 8 Aug 2025

Abstract

Optimizing the power allocation and capacity configuration of hybrid energy storage systems (HESS) is crucial for enhancing grid stability, power quality and renewable energy utilization in wind–solar complementary microgrids. However, the conventional configuration methods exhibit inaccuracy and low reliability. To achieve the optimal [...] Read more.

Optimizing the power allocation and capacity configuration of hybrid energy storage systems (HESS) is crucial for enhancing grid stability, power quality and renewable energy utilization in wind–solar complementary microgrids. However, the conventional configuration methods exhibit inaccuracy and low reliability. To achieve the optimal capacity configuration of HESS in wind–solar complementary microgrids, a power allocation strategy and a capacity optimization configuration model for HESS consisting of vanadium redox flow batteries (VRBs) and supercapacitors (SCs) were proposed based on parameter-optimized variational mode decomposition (VMD). Firstly, the number of mode decomposition (K) and the penalty factor (α) of VMD were optimized using the random walk grey wolf optimizer (RW-GWO) algorithm, and the HESS power signal was decomposed by RW-GWO-VMD. Secondly, an optimal capacity configuration model was formulated, taking into account the whole life cycle cost of HESS, and particle swarm optimization (PSO) algorithm was applied to optimize HESS capacity while satisfying operational constraints on charge/discharge power, state of charge (SOC) range, and permissible rates of load deficit and energy loss. Thirdly, the optimal capacity allocation was obtained by minimizing the whole life cycle cost of HESS, with the frequency division threshold N serving as the optimization parameter. Finally, comprehensive comparison and analysis of proposed methods were conducted through simulation experiments. The results demonstrated that the whole life cycle cost of RW-GWO-VMD was 7.44% lower than that of EMD, 1.00% lower than that of PSO-VMD, 0.72% lower than that of AOA-VMD, and 0.27% lower than that of GWO-VMD. Full article

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Graphical abstract

5 pages, 139 KiB

Open AccessEditorial

Economic Analysis and Policies in the Energy Sector

by George Halkos

Energies 2025, 18(16), 4214; https://doi.org/10.3390/en18164214 (registering DOI) - 8 Aug 2025

Abstract

The aim of this Special Issue is to consider economic analysis in terms of the most up-to-date and advanced empirical and theoretical methods applied to energy problems. The main purpose of this Special Issue is to feature the theoretical and empirical practice of [...] Read more.

The aim of this Special Issue is to consider economic analysis in terms of the most up-to-date and advanced empirical and theoretical methods applied to energy problems. The main purpose of this Special Issue is to feature the theoretical and empirical practice of sustainable policy performance measurement. The progress of the green economy includes methodological issues in order to indicate and present spatio-temporal patterns of resource and energy use and associated pollution. Results will be discussed in support of sustainable energy policies. This Special Issue seeks the methodological framework to contribute to sustainable energy policy development, provide energy policy initiatives targeted to socio-economic goods/benefits, to capture sustainability obstacles and negative environmental impacts, and highlight links and interactions between economic and environmental systems. The expected outcome is to set targets, propose models for sustainable growth and energy policies, and analyze policy interactions. Full article

(This article belongs to the Special Issue Economic Analysis and Policies in the Energy Sector)

14 pages, 3487 KiB

Open AccessArticle

Analysis of the Effectiveness of the Energy-Efficient Gravity Filtration Process in Terms of Its Application as the Third Stage of Wastewater Treatment

by Kazimierz Szymański, Jacek Piekarski, Tomasz Dąbrowski, Krzysztof Piaskowski, Renata Świderska-Dąbrowska and Katarzyna Ignatowicz

Energies 2025, 18(16), 4213; https://doi.org/10.3390/en18164213 (registering DOI) - 8 Aug 2025

Abstract

The energy self-sufficiency of wastewater treatment plants has become an essential aspect of sustainable water and energy resource management. On the other hand, due to the expansion of urban conglomerations and agricultural activities, as well as more frequent and erratic meteorological phenomena (e.g., [...] Read more.

The energy self-sufficiency of wastewater treatment plants has become an essential aspect of sustainable water and energy resource management. On the other hand, due to the expansion of urban conglomerations and agricultural activities, as well as more frequent and erratic meteorological phenomena (e.g., droughts), the majority of EU nations are confronted with water scarcity and the deterioration of water quality. As a consequence, EU member states pledged to implement “tertiary treatment” in all municipal wastewater treatment facilities by the end of 2040. This publication presents an analysis of the efficiency of an energy-efficient gravity cloth disk filter used for treating municipal wastewater in a treatment plant located in a tourist resort in Poland, operating under variable hydraulic loading conditions. Gravity cloth disk filters appear to be the least energy-consuming. The energy consumption of disk filters was 13 Wh/m³ in 2024. The filter ensures the leveling of disturbances in the operation of earlier treatment stages, particularly in terms of retaining total suspended solids (TSSs). The achieved efficiency of TSS removal was 45%. The TSS value in the outflow from the filter did not exceed the limit value from the permit (35 mg/L). When operated correctly, additional filtration and disinfection may become essential components of a wastewater treatment plant, enabling the achievement of wastewater quality that supports water recovery for technological and agricultural purposes, particularly in small, non-industrial areas. They should also consume less energy than other advanced technologies used in the third and fourth stages of wastewater treatment. Full article

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12 pages, 1380 KiB

Open AccessArticle

Influence of Green Algae on the Surface Wetting Characteristics of Porcelain Insulators

by Xiaolai Li, Xiangdong Wu, Shiqiang Yang, Beichen Gao, Liang Li and Bin Cao

Energies 2025, 18(16), 4212; https://doi.org/10.3390/en18164212 (registering DOI) - 8 Aug 2025

Abstract

Insulator pollution flashover is a serious fault in power transmission systems, with surface wetting being a key prerequisite for its occurrence. The unique electrostatic properties of HVDC transmission networks promote pollution accumulation and alter wetting behavior. In southwest China’s warm, humid mountainous regions, [...] Read more.

Insulator pollution flashover is a serious fault in power transmission systems, with surface wetting being a key prerequisite for its occurrence. The unique electrostatic properties of HVDC transmission networks promote pollution accumulation and alter wetting behavior. In southwest China’s warm, humid mountainous regions, algae adhesion on DC insulators significantly affects surface wetting, increasing the risk of flashover under extreme weather conditions. This study proposes a surface-conductivity–based method to measure the water absorption of pollution layers on insulators. It quantitatively assesses the impact of algae on wetting characteristics, including saturated water absorption and salt loss rate. Experimental results show that in fog, saturated water absorption decreases as the tilt angle increases, while soluble salt content decreases over wetting time. NSDD has a minimal effect on saturated absorption. Moreover, the presence of algae significantly alters wetting behavior, increasing saturated water absorption by 27–47% and reducing salt loss. These findings provide an insight into the role of biological contamination in pollution flashover processes in high-humidity regions. Full article

(This article belongs to the Special Issue Recent Progress, Challenges and Outlooks of Insulation System in HVDC: 2nd Edition)

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21 pages, 2951 KiB

Open AccessReview

Achieving the Sustainable Agricultural Development Goals by Adopting the New Energy Electric Agricultural Machinery: An Analysis of Opportunities and Challenges of China

by Hongguang Yang, Fujie Ding, Fengwei Gu, Feng Wu, Zhaoyang Yu, Peng Zhang, Jiangtao Wang and Zhichao Hu

Energies 2025, 18(16), 4211; https://doi.org/10.3390/en18164211 (registering DOI) - 8 Aug 2025

Abstract

New energy is a type of renewable energy that has the characteristics of protecting the environment and conserving energy. Agriculture is an industry that concerns the national economy and people’s livelihood. Agricultural mechanization is a key factor in achieving high-quality agricultural development. At [...] Read more.

New energy is a type of renewable energy that has the characteristics of protecting the environment and conserving energy. Agriculture is an industry that concerns the national economy and people’s livelihood. Agricultural mechanization is a key factor in achieving high-quality agricultural development. At present, China is the world’s largest producer and user of agricultural machinery. The use of traditional agricultural machinery powered mainly by internal combustion engines is currently the main source of carbon emissions in China’s agricultural production. How to achieve effective application and sustainable development of electric new energy technology in agricultural machinery is the primary issue facing China and countries around the world. This article takes the application and development status of electric new energy technology in agricultural machinery as the research object. Firstly, we provided an overview of China’s primary energy production and utilization as well as the national agricultural mechanization situation. Secondly, the research and application status of new energy electric agricultural machinery in China were elaborated on. Finally, some major challenges and opportunities faced by China’s development of new energy electric agricultural machinery were analyzed. We firmly believe that China’s active development of new energy technologies in agricultural machinery plays an important role and practical significance in building a community with a shared future for mankind, reducing carbon emissions from agricultural production, and achieving sustainable agricultural development goals. Full article

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

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8 pages, 203 KiB

Open AccessEditorial

Energy Storage and Energy Efficiency in Buildings and Cities

by Barbara Widera, Marta Skiba and Małgorzata Sztubecka

Energies 2025, 18(16), 4210; https://doi.org/10.3390/en18164210 (registering DOI) - 8 Aug 2025

Abstract

The primary challenge for European society today is to strike a balance between maximizing energy efficiency and environmental care, while also ensuring an accessible and safe living environment. The research presented in this Special Issue addressed various aspects of energy storage methods and [...] Read more.

The primary challenge for European society today is to strike a balance between maximizing energy efficiency and environmental care, while also ensuring an accessible and safe living environment. The research presented in this Special Issue addressed various aspects of energy storage methods and covered advances in the energy efficiency of buildings and cities in light of the climate change awareness and the need to reduce energy consumption and the carbon footprint from the built environment. Results of empirical and modelling research were compared to advanced simulations and measurements rooted in real-world case studies performed with the purpose of extending the knowledge on holistic sustainable design towards efficient energy use. Key aspects enabling improvements in the energy performance of buildings and contributing to the achievement of climate goals cover thermal comfort and overheating in buildings and cities, including district heating, hydrogen energy storage, renewable energy source integration, carbon emissions, and the economic benefits of building deep renovation. The research findings help us to understand the critical importance of transforming the built environment into renewable energy sources while supporting the energy efficiency of buildings, cities, and neighbourhoods. Full article

(This article belongs to the Special Issue Research of Energy Storage and Energy Efficiency in Buildings and Cities)

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Energies, Volume 18, Issue 16 (August-2 2025) – 10 articles

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