Journal Description
Energies
Energies
is a peer-reviewed, open access journal of related scientific research, technology development, engineering policy, and management studies related to the general field of energy, from technologies of energy supply, conversion, dispatch, and final use to the physical and chemical processes behind such technologies. Energies is published semimonthly online by MDPI. The European Biomass Industry Association (EUBIA), Association of European Renewable Energy Research Centres (EUREC), Institute of Energy and Fuel Processing Technology (ITPE), International Society for Porous Media (InterPore), CYTED and others are affiliated with Energies and their members receive a discount on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Ei Compendex, RePEc, Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: CiteScore - Q1 (Control and Optimization)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 16.1 days after submission; acceptance to publication is undertaken in 3.3 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
- Sections: published in 41 topical sections.
- Testimonials: See what our editors and authors say about Energies.
- Companion journals for Energies include: Gases, Nanoenergy Advances, Solar and Wind.
Impact Factor:
3.0 (2023);
5-Year Impact Factor:
3.0 (2023)
Latest Articles
Coordinated Frequency Modulation Control Strategy of Wind Power and Energy Storage Considering Mechanical Load Optimization
Energies 2024, 17(13), 3198; https://doi.org/10.3390/en17133198 (registering DOI) - 28 Jun 2024
Abstract
When a doubly fed induction generator (DFIG) participates in primary frequency modulation by rotor kinetic energy control, the torque of the generator is changed sharply and the mechanical load pressure of the shaft increases rapidly, which aggravates the fatigue damage of shafting. In
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When a doubly fed induction generator (DFIG) participates in primary frequency modulation by rotor kinetic energy control, the torque of the generator is changed sharply and the mechanical load pressure of the shaft increases rapidly, which aggravates the fatigue damage of shafting. In order to alleviate the fatigue load of shafting, energy storage was added in the primary frequency modulation of a wind turbine, and a coordinated frequency modulation control strategy of wind power and energy storage based on fuzzy control was proposed. The wind-storage frequency modulation power command was allocated to reduce the response speed of the wind turbine to alleviate the load pressure on the shafting by the fuzzy controller considering the rotor speed range and the state of energy storage charge, and the remaining demand power was supplemented by energy storage. Finally, the joint simulation model based on GH Bladed–Matlab was used to verify the effectiveness of the proposed control strategy. Compared with the traditional integrated control of virtual inertia, the proposed method can reduce the load pressure and fatigue damage of the shafting while satisfying the requirement of frequency modulation.
Full article
(This article belongs to the Special Issue Renewable Energy Systems (Solar, Wind) and Grid Integration)
Open AccessReview
EOR Technology (Patents) and Science (Articles) Assessment of BRICS and nonBRICS with Growth Rates and Specializations within Responsible Global Energy Transition: A Critical Review
by
C. M. Quintella, P. D. Rodrigues, J. L. Nicoleti, E. Ramos-de-Souza, E. B. Carvalho and S. A. Hanna
Energies 2024, 17(13), 3197; https://doi.org/10.3390/en17133197 (registering DOI) - 28 Jun 2024
Abstract
To achieve a low-carbon energy transition, it is essential to ensure that, as long as fossil fuels are needed, their production is sustainable, minimizing the environmental impact and securing resources for advancing greener technologies, in alignment with SDGs 7, 13, and 14. Enhanced
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To achieve a low-carbon energy transition, it is essential to ensure that, as long as fossil fuels are needed, their production is sustainable, minimizing the environmental impact and securing resources for advancing greener technologies, in alignment with SDGs 7, 13, and 14. Enhanced oil recovery (EOR) increases the recovery rates without new developments. The recent expansion of the BRICS consortium, involving major producers, underscores the need to evaluate their EOR technologies, particularly potential gaps that could hinder global energy transition strategies. We analyzed intermediate levels of technological readiness levels (TRLs) utilizing patents (TRL4-5) and articles (TRL3) for 18 EOR methods between 2002 and 2021. Composite indicators derived from patents including compound annual growth rate, specialization, concentration, diversification, and Gini inequality were employed. Both BRICS and nonBRICS exhibited analogous distributions in the articles (particularly Norway, United Kingdom, Canada) and patents (particularly Russia, China, and Ukraine). The decline in growth rates among BRICS and negative rates in nonBRICS suggest a technological plateau for traditional methods. However, environmentally low-impact EOR methods are experiencing exponential emergence (low salinity water, MEOR, polymers and macromolecular compounds, their associations with surfactants, and WAG). Both groups are self-sufficient in EOR, ensuring a responsible and low-impact energy transition. This ensures energy quality while facilitating the maturation of renewable technologies.
Full article
(This article belongs to the Section H3: Fossil)
Open AccessArticle
Research on the Throttling Performance and Anti-Erosion Structure of Trapezoidal Throttle Orifices
by
Jianguo Zhao, Haotian Zheng, Chong Xie and Hanxiu Peng
Energies 2024, 17(13), 3196; https://doi.org/10.3390/en17133196 (registering DOI) - 28 Jun 2024
Abstract
The throttling performance of conventional throttle orifice structures of fluid control valves is very low. Therefore, this paper proposes a novel trapezoidal throttle orifice with excellent throttling performance. The effect of the taper of the throttle orifice on the erosion was researched. Firstly,
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The throttling performance of conventional throttle orifice structures of fluid control valves is very low. Therefore, this paper proposes a novel trapezoidal throttle orifice with excellent throttling performance. The effect of the taper of the throttle orifice on the erosion was researched. Firstly, two schemes of trapezoidal throttle orifice were proposed according to the fluid control valve. Secondly, the excellent throttling performance of the trapezoidal throttle orifice was compared and optimized. Finally, a numerical simulation method of the erosion-resistant ability of the trapezoidal throttle orifice was established. It was found that for the same throttling area, the differential pressure of the trapezoidal orifice was higher than that of the conventional rectangular orifice by about 18.6%. The taper had little effect on the gas production, which increased by only 3.3% during the 10° to 30° change. The maximum erosion was firstly reduced and then increased with increases in the angle from 0 to 25°of the taper. Moreover, the minimum was achieved at about a 20° taper angle. The above research methods provide a theoretical basis for optimizing the size and structure of orifices and the sealing reliability of fluid control valves.
Full article
Open AccessArticle
Synthesis and Performance Evaluation of Modified Polyaspartic-Acid-Based Scale Inhibitor
by
WenLong Gao, LiWei Sun, Miao Li, XiAn Ye, QingChun Gao, DongLiang Kong, JunPu An, KuoBo Wang and Fan Yang
Energies 2024, 17(13), 3195; https://doi.org/10.3390/en17133195 (registering DOI) - 28 Jun 2024
Abstract
This paper focuses on the selection and application of scale inhibitor by studying the problem of pipeline scaling in geothermal well development. Adding scale inhibitor can effectively reduce the treatment cost and achieve a good scale resistance effect, but the commonly used polyaspartic
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This paper focuses on the selection and application of scale inhibitor by studying the problem of pipeline scaling in geothermal well development. Adding scale inhibitor can effectively reduce the treatment cost and achieve a good scale resistance effect, but the commonly used polyaspartic acid scale inhibitor has problems such as poor scale inhibition effect and large use limitations. Therefore, a new modified polyaspartic acid scale inhibitor (His-Tyr-SA-PASP) was prepared using polysuccinimide (PSI) as the raw material and histidine (His), tyrosine (Tyr), and sulfonic acid (SA) as the modification reagent. When the dosage of His-Tyr-SA-PASP was 8 mg/L, the scale inhibition rate of CaCO3 was 94.40%. In addition, the scale inhibition effect of His-Tyr-SA-PASP on CaCO3 was better than that of PASP. At the same time, under the condition of a static experiment at 75 °C, according to the ion concentration of water samples in different scale zones, this paper also identified the ratio of four composite scale inhibitors. When the dosage of compound scale inhibitor was 100 mg/L, Sodium of Polyaspartic Acid–Diethylene Triamine Penta (Methylene Phosphonic Acid)–2-Phosphonobutane-1,2,4-Tricarboxylic Acid–Amino Trimethylene Phosphonic Acid–Copolymer of Maleic and Acrylic Acid = (10:10:5:1:9), (15:10:5:2.5:2.5), (12.5:5:10:1:6.5), and (15:5:10:4:1) and the scale inhibition rate was more than 95%. Under the condition of a dynamic experiment, the optimized composite scale inhibitor still showed a scale inhibition rate of more than 90%. It provides a useful reference for the practical application of water treatment in geothermal wells and has the prospect of industrial application.
Full article
(This article belongs to the Section H: Geo-Energy)
Open AccessArticle
Photovoltaic Capacity Management for Investment Effectiveness
by
Tomasz Brzęczek and Łukasz Hadaś
Energies 2024, 17(13), 3194; https://doi.org/10.3390/en17133194 (registering DOI) - 28 Jun 2024
Abstract
The production of photovoltaic utility varies within the day/night cycle. At night, photovoltaic cells do not produce anything. However, their day-light production, unconsumed on a current basis and exported to the grid, is compensated for with supply from the grid at night. This
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The production of photovoltaic utility varies within the day/night cycle. At night, photovoltaic cells do not produce anything. However, their day-light production, unconsumed on a current basis and exported to the grid, is compensated for with supply from the grid at night. This scheme of exploitation is called net-metering and is considered herein. Solar energy produced by a prosumer and fed into the grid has to be equal to the electricity supplied from the grid at night; otherwise, a shortage or waste of photovoltaic production occurs. The above finding leads us to the proposition for the optimal solution of photovoltaic capacity. We derived a closed-form capacity solution to the maximized non-linear profit function. It solves harmonic and 2-point production functions that vary symmetrically around the mean production. To verify the solution methodology, harmonic and 2-point models from empirical production data are estimated. Then, the solution is presented together with its return rate and internal return rate. The main finding is that the unit cost of the grid electricity, photovoltaic capacity unit cost and exploitation time all affect the total profit and return rate values while not impacting the optimal capacity of the photovoltaics. The optimal capacity depends on the prosumer’s energy consumption volume and on the natural conditions of production captured here by the technology efficiency coefficient estimated from the production time series.
Full article
(This article belongs to the Special Issue Editorial Board Members’ Collection Series: Renewable Energy Policy and Economics)
Open AccessArticle
A Grid-Wide Comprehensive Evaluation Method of Power Quality Based on Complex Network Theory
by
Yang Xiang, Yan Lin, Yan Zhang, Jinchen Lan, Meimei Hao, Lianhui Wang, Jiang Wang and Liang Qin
Energies 2024, 17(13), 3193; https://doi.org/10.3390/en17133193 (registering DOI) - 28 Jun 2024
Abstract
To achieve a hierarchical and quantitative evaluation of grid-wide power quality in the distribution network, reflecting the overall power quality level of the distribution network, a comprehensive evaluation method for power quality in a grid-wide system based on complex network theory is proposed.
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To achieve a hierarchical and quantitative evaluation of grid-wide power quality in the distribution network, reflecting the overall power quality level of the distribution network, a comprehensive evaluation method for power quality in a grid-wide system based on complex network theory is proposed. Firstly, based on the propagation characteristics of power quality disturbances, a power quality evaluation index system is constructed. Secondly, to reflect the constraint effect of the local power quality level of nodes on the overall power quality level of the distribution system, corresponding indices such as improved node degree, improved node electrical betweenness, and node self-healing capability are proposed based on complex network theory, and the power quality influence degree of nodes is calculated. Then, the GRA-ANP (Grey Relational Analysis–Analytic Network Process) subjective weight calculation method is improved by introducing grey relational analysis to address the impact of differences in different decision-making results. Based on power quality monitoring data, the entropy weight method is used for objective weighting. To avoid the partiality of a single weight evaluation result, the game equilibrium algorithm is employed to calculate the comprehensive weight of each power quality index. Subsequently, considering the correlation and dependency among indices, the VIKOR (VIseKriterijumska Optimizacija I Kompromisno Resenje) method is used to obtain the power quality grade of each node. Combining this with the calculation of the power quality influence degree of nodes, the overall power quality grade of the distribution network is determined, achieving a hierarchical and quantitative evaluation of power quality in the entire distribution system. Finally, through a case study analysis of an improved 13-node distribution network, it is verified that the proposed method can fully extract data information and produce comprehensive and accurate power quality assessment results by comparing it with other methods. This provides strong support for the safe and stable operation of the distribution system and the subsequent optimization and management of power quality.
Full article
(This article belongs to the Special Issue Power Quality and Disturbances in Modern Distribution Networks)
Open AccessArticle
Electro-Hydraulic Variable-Speed Drive Network Technology—First Experimental Validation
by
Lasse Schmidt and Mikkel van Binsbergen-Galán
Energies 2024, 17(13), 3192; https://doi.org/10.3390/en17133192 (registering DOI) - 28 Jun 2024
Abstract
The improvement of the energy efficiency of hydraulic systems remains an essential challenge for industry, and the demand for more sustainable solutions is increasing. A main focus in this endeavor is the ability to eliminate or strongly reduce the use of throttle control
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The improvement of the energy efficiency of hydraulic systems remains an essential challenge for industry, and the demand for more sustainable solutions is increasing. A main focus in this endeavor is the ability to eliminate or strongly reduce the use of throttle control valves which have been the preferred control element in industrial hydraulic systems for decades. Components have been subject to continuous evolution, and current industrial grade hydraulic pumps and motors are both efficient and reliable. Even though few percentages of energy efficiency can still be achieved, the main achievements in terms of efficiency are associated with novel system designs rather than further development of components. An area subject to increasing attention is the field of variable-speed displacement control, allowing to avoid the main control valve throttle losses. Systems using this technology are, however, mainly developed as standalone drive systems, necessitating maximum force, speed, and power installed in each axis, with limited hydraulic power distribution capability compared to valve-controlled systems. An emerging field addressing this challenge is that of so-called electro-hydraulic variable-speed drive networks, which allow to completely eliminate the use of control valves and enable power sharing both electrically and hydraulically, potentially reducing the necessary installed power in many cases. The idea of such a technology was first proposed in 2022, and so far developments reported in the literature have mainly been of a theoretical nature. This article presents the first ever experimental results for a dual-cylinder electro-hydraulic variable-speed drive network prototype. The prototype was developed for an industrial application, but has initially been implemented in a laboratory testbench. Extensive data acquisition has been conducted while subject to the associated industrial motion cycle, under different load conditions. The data obtained are further used in combination with models to predict the total efficiency of the drive network prototype under higher loads than what could be achieved in the laboratory, suggesting a total efficiency from the electric supply to the cylinder pistons of 68%. Re-configuring the prototype to a known standalone drive system structure implies comparable efficiencies. Finally, the drive network is theoretically compared to a valve drive solution, generally suggesting that the prototype drive network can provide efficiency improvements of at least 40% in comparison.
Full article
(This article belongs to the Special Issue Energy, Electrical and Power Engineering 2024)
Open AccessReview
Turning Food Loss and Food Waste into Watts: A Review of Food Waste as an Energy Source
by
Florentios Economou, Irene Voukkali, Iliana Papamichael, Valentina Phinikettou, Pantelitsa Loizia, Vincenzo Naddeo, Paolo Sospiro, Marco Ciro Liscio, Christos Zoumides, Diana Mihaela Țîrcă and Antonis A. Zorpas
Energies 2024, 17(13), 3191; https://doi.org/10.3390/en17133191 (registering DOI) - 28 Jun 2024
Abstract
Food loss (FL) and food waste (FW) have become severe global problems, contributing to resource inefficiency and environmental degradation. Approximately 6% of greenhouse gas emissions (GHGs) are derived from FW, which is usually discarded in landfills, emitting methane, a gas that is 28
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Food loss (FL) and food waste (FW) have become severe global problems, contributing to resource inefficiency and environmental degradation. Approximately 6% of greenhouse gas emissions (GHGs) are derived from FW, which is usually discarded in landfills, emitting methane, a gas that is 28 times more harmful than CO2. Diverting the path of FW towards the energy industry represents a promising avenue to mitigate the environmental impact and save resources while generating energy substitutes. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) approach was utilized to conduct a systematic literature review on 10 different conversion processes used to convert FL and FW into energy. Anaerobic bioconversion integrated with pyrolysis emerges as a potential eco-friendly and promising solution for FW management, nutrient recovery and energy production in various forms, including biogas, heat, biohydrogen and biochar. Despite its potential, the anaerobic digestion of FW still faces some challenges related to the production of intermediate harmful compounds (VOCs, NH3, H2S), which necessitate precise process control and optimization. Nonetheless, converting FW into energy can provide economic and environmental benefits in the context of the circular economy. This review offers insightful information to stakeholders, academics and policymakers who are interested in utilizing FW as a means of producing sustainable energy by summarizing the important findings of ten different waste-to-energy processing methods and their potential for improved energy recovery efficiency.
Full article
Open AccessArticle
Operation Optimization of Regional Integrated Energy Systems with Hydrogen by Considering Demand Response and Green Certificate–Carbon Emission Trading Mechanisms
by
Ji Li, Lei Xu, Lihua Wang, Yang Kou, Yingli Huo and Weile Liang
Energies 2024, 17(13), 3190; https://doi.org/10.3390/en17133190 (registering DOI) - 28 Jun 2024
Abstract
Amidst the growing imperative to address carbon emissions, aiming to improve energy utilization efficiency, optimize equipment operation flexibility, and further reduce costs and carbon emissions of regional integrated energy systems (RIESs), this paper proposes a low-carbon economic operation strategy for RIESs. Firstly, on
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Amidst the growing imperative to address carbon emissions, aiming to improve energy utilization efficiency, optimize equipment operation flexibility, and further reduce costs and carbon emissions of regional integrated energy systems (RIESs), this paper proposes a low-carbon economic operation strategy for RIESs. Firstly, on the energy supply side, energy conversion devices are utilized to enhance multi-energy complementary capabilities. Then, an integrated demand response model is established on the demand side to smooth the load curve. Finally, consideration is given to the RIES’s participation in the green certificate–carbon trading market to reduce system carbon emissions. With the objective of minimizing the sum of system operating costs and green certificate–carbon trading costs, an integrated energy system optimization model that considers electricity, gas, heat, and cold coupling is established, and the CPLEX solver toolbox is used for model solving. The results show that the coordinated optimization of supply and demand sides of regional integrated energy systems while considering multi-energy coupling and complementarity effectively reduces carbon emissions while further enhancing the economic efficiency of system operations.
Full article
(This article belongs to the Section A5: Hydrogen Energy)
Open AccessArticle
Assessment of the Heat Transfer Conditions in the Cavity of a Rotating Circular Saw
by
Jan Stegmann, Moritz Baumert, Stephan Kabelac, Christian Menze, Johannes Ramme and Hans-Christian Möhring
Energies 2024, 17(13), 3189; https://doi.org/10.3390/en17133189 (registering DOI) - 28 Jun 2024
Abstract
To improve machining processes concerning the usage of lubricants, knowledge of the thermo-mechanical and thermo-fluid interactions at the cutting zone is of great importance. This study focuses on the description of the convective heat transfer which occurs during circular sawing when the lubricant
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To improve machining processes concerning the usage of lubricants, knowledge of the thermo-mechanical and thermo-fluid interactions at the cutting zone is of great importance. This study focuses on the description of the convective heat transfer which occurs during circular sawing when the lubricant is provided via an internal coolant supply. The highly complex flow field inside the cavity of the sawing process is separated into two distinct flow forms, an impingement and a channel flow. With the aid of experimental and numerical studies, the heat transfer characteristics of these two flow forms have been examined for water and a lubricant used in the circular sawing process. Studies have been conducted over a wide range of Reynolds numbers (impingement flow: , channel flow: ). Additionally, the variation in the inlet temperature of the fluid, as well as the variation in heating power, has been studied. Overall, the impingement flow yields a significantly higher heat transfer than the channel flow with Nußelt-numbers ranging from 120 to 230, whereas the Nußelt-numbers in the case of the channel flow range from 20 to 160. For both flow forms, the use of the lubricant results in a better heat transfer compared with the usage of water. With the aid of these studies, correlations to describe the heat transfer have been derived. The provided correlations are to be used in a coupled numerical model of the chip formation process which also includes the effects of the heat transfer to the coolant lubricant.
Full article
(This article belongs to the Topic Applied Heat Transfer)
Open AccessArticle
Three-Level Secure Smart Protection for Ring Grid-Connected Distributed Generation
by
Mostafa Bakkar, Santiago Bogarra, Felipe Córcoles, Ahmed Aboelhassan, Shuo Wang and Javier Iglesias
Energies 2024, 17(13), 3188; https://doi.org/10.3390/en17133188 (registering DOI) - 28 Jun 2024
Abstract
The penetration increase in distributed generators (DGs) into smart grids (SGs) will lead to new challenges, especially in protection systems. In the case of ring grids, the behavior of the short-circuit current is affected by DGs, and the medium voltage (MV) transformer connections
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The penetration increase in distributed generators (DGs) into smart grids (SGs) will lead to new challenges, especially in protection systems. In the case of ring grids, the behavior of the short-circuit current is affected by DGs, and the medium voltage (MV) transformer connections significantly influence the changes; therefore, the protection strategies must be adapted for these scenarios. This study provides a comprehensive protection system for the MV distribution system (DS), including reconfigurable smart ring grids. The proposed protection methods contain three protection algorithms. The first protection algorithm relies on communication among all protective devices (PDs) in the grid, whereas the second protection method uses communication among PDs along the same line. Then, a third algorithm built on the local data of each PD is suggested as a backup to prevent communication issues and offer more reliable protection. MATLABTM SIMULINK simulations and experimental results on a scalable hardware grid were also employed to validate the protection algorithms.
Full article
(This article belongs to the Section A1: Smart Grids and Microgrids)
Open AccessArticle
C-Rate- and Temperature-Dependent State-of-Charge Estimation Method for Li-Ion Batteries in Electric Vehicles
by
Eyyup Aslan and Yusuf Yasa
Energies 2024, 17(13), 3187; https://doi.org/10.3390/en17133187 (registering DOI) - 28 Jun 2024
Abstract
Li-ion batteries determine the lifespan of an electric vehicle. High power and energy density and extensive service time are crucial parameters in EV batteries. In terms of safe and effective usage, a precise cell model and SoC estimation algorithm are indispensable. To provide
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Li-ion batteries determine the lifespan of an electric vehicle. High power and energy density and extensive service time are crucial parameters in EV batteries. In terms of safe and effective usage, a precise cell model and SoC estimation algorithm are indispensable. To provide an accurate SoC estimation, a current- and temperature-dependent SoC estimation algorithm is proposed in this paper. The proposed SoC estimation algorithm and equivalent circuit model (ECM) of the cells include current and temperature effects to reflect real battery behavior and provide an accurate SoC estimation. For including current and temperature effects in the cell model, lookup tables have been used for each parameter of the model. Based on the proposed ECM, the unscented Kalman filter (UKF) approach is utilized for estimating SoC since this approach is satisfactory for nonlinear systems such as lithium-ion batteries. The experimental results reveal that the proposed approach provides superior accuracy when compared to conventional methods and it is promising in terms of meeting electric vehicle requirements.
Full article
Open AccessReview
Control and Stability of Grid-Forming Inverters: A Comprehensive Review
by
Marzie Mirmohammad and Sahar Pirooz Azad
Energies 2024, 17(13), 3186; https://doi.org/10.3390/en17133186 (registering DOI) - 28 Jun 2024
Abstract
The large integration of inverter-based resources will significantly alter grid dynamics, leading to pronounced stability challenges due to fundamental disparities between inverter-based and traditional energy systems. While grid-following inverters (GFLIs) dominate current inverter configurations, their increased penetration into the grid can result in
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The large integration of inverter-based resources will significantly alter grid dynamics, leading to pronounced stability challenges due to fundamental disparities between inverter-based and traditional energy systems. While grid-following inverters (GFLIs) dominate current inverter configurations, their increased penetration into the grid can result in major stability issues. In contrast, grid-forming inverters (GFMIs) excel over GFLIs by offering features like standalone operation, frequency support, and adaptability in weak grid scenarios. GFMIs, unlike GFLIs, control the AC voltage and frequency at the common coupling point, impacting the inverter dynamic response to grid disturbances and overall stability. Despite the existing literature highlighting differences between GFLIs and GFMIs and their control strategies, a comprehensive review of GFMIs’ stability and the effects of their control schemes on grid stability is lacking. This paper provides an in-depth evaluation of GFMIs’ stability, considering various control schemes and their dynamics. It also explores different types of power system stability, introduces new stability concepts that correspond to power grids with integrated inverters, i.e., resonance and converter-driven stability, and reviews small-signal and transient stability analyses, which are the main two types of GFMI stability studied in the literature. The paper further assesses existing studies on GFMI stability, pinpointing research gaps for future investigations.
Full article
(This article belongs to the Section F: Electrical Engineering)
Open AccessArticle
Real-Time Implementable Integrated Energy and Cabin Temperature Management for Battery Life Extension in Electric Vehicles
by
Mattia Mauro, Atriya Biswas, Carlo Fiorillo, Hao Wang, Ezio Spessa, Federico Miretti, Ryan Ahmed, Angelo Bonfitto and Ali Emadi
Energies 2024, 17(13), 3185; https://doi.org/10.3390/en17133185 (registering DOI) - 28 Jun 2024
Abstract
Among many emerging technologies, battery electric vehicles (BEVs) have emerged as a prominent and highly supported solution to stringent emissions regulations. However, despite their increasing popularity, key challenges that might jeopardize their further spread are the lack of charging infrastructure, battery life degradation,
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Among many emerging technologies, battery electric vehicles (BEVs) have emerged as a prominent and highly supported solution to stringent emissions regulations. However, despite their increasing popularity, key challenges that might jeopardize their further spread are the lack of charging infrastructure, battery life degradation, and the discrepancy between the actual and promised all-electric driving range. The primary focus of this paper is to formulate an integrated energy and thermal comfort management (IETM) strategy. This strategy optimally manages the electrical energy required by the heating, ventilation, and air conditioning (HVAC) unit, the most impacting auxiliary in terms of battery load, to minimize battery life degradation over any specific drive cycle while ensuring the actual cabin temperature hovers within the permissible tolerance limit from the reference cabin temperature and the driver-requested traction power is always satisfied. This work incorporates a state-of-health (SOH) estimation model, a high-fidelity cabin thermodynamics model, and an HVAC model into the forward-approach simulation model of a commercially available BEV to showcase the impact and efficacy of the proposed IETM strategy for enhancing battery longevity. The instantaneous optimization problem of IETM is solved by the golden-section search method leveraging the convexity of the objective function. Simulated results under different driving scenarios show that the improvement brought by the proposed ITEM controller can minimize battery health degradation by up to 4.5% and energy consumption by up to 2.8% while maintaining the cabin temperature deviation within permissible limits from the reference temperature.
Full article
(This article belongs to the Special Issue Energy Management Systems of Electric Vehicles: New Trends and Dynamic Futures)
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Open AccessArticle
Study on the Operation Optimization of Medium-Depth U-Type Ground Source Heat Pump Systems
by
Chaohui Zhou, Yue Hu, Yuce Liu, Rujie Liu, Yongqiang Luo, Xiao Wang and Huiheng Luo
Energies 2024, 17(13), 3184; https://doi.org/10.3390/en17133184 (registering DOI) - 28 Jun 2024
Abstract
Deep geothermal energy is a sustainable and renewable spacing heating source. Although many studies have discussed the design optimization of deep borehole systems, few have accomplished optimization and in-depth analysis of system operation control. In this study, an analytical model of the U-type
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Deep geothermal energy is a sustainable and renewable spacing heating source. Although many studies have discussed the design optimization of deep borehole systems, few have accomplished optimization and in-depth analysis of system operation control. In this study, an analytical model of the U-type deep borehole heat exchanger is proposed, and the average relative error between the simulated outlet temperatures and experimental data is −3.2%. Then, this paper presents an integrated model for the operation optimization study of the U-type deep-borehole ground source heat pump system. The optimal control of flow rate is adopted to match the variation in heating load. Compared with the constant-flow rate (110 m3/h) operation mode, the variable flow rate method reduces the power consumption of the heat pump and circulating pump by 22.1%, from 288,423 kW·h to 224,592 kW·h, during 2112 h of operation. In addition, the system has a larger RHS and COP when the thermal conductivity of the backfill material increases. When the borehole depth increases by 200 m from 2300 m, the energy consumption of the circulating pump will drop from 85,844 kW·h to 56,548 kW·h. The COP of the heat pump unit will decrease approximately linearly as the heating load increases, and the total power consumption will increase accordingly. This work can provide guidance for the design and optimization of U-shaped GSHP systems.
Full article
(This article belongs to the Special Issue Ground-Source Heat Pumps and Thermal Energy Storage Systems—Energy for the Future)
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Open AccessReview
Advancements and Challenges of Ammonia as a Sustainable Fuel for the Maritime Industry
by
Antonio Chavando, Valter Silva, João Cardoso and Daniela Eusebio
Energies 2024, 17(13), 3183; https://doi.org/10.3390/en17133183 - 28 Jun 2024
Abstract
The maritime industry needs sustainable, low-emission fuels to reduce the environmental impact. Ammonia is one of the most promising alternative fuels because it can be produced from renewable energy, such as wind and solar. Furthermore, ammonia combustion does not emit carbon. This review
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The maritime industry needs sustainable, low-emission fuels to reduce the environmental impact. Ammonia is one of the most promising alternative fuels because it can be produced from renewable energy, such as wind and solar. Furthermore, ammonia combustion does not emit carbon. This review article covers the advantages and disadvantages of using ammonia as a sustainable marine fuel. We start by discussing the regulations and environmental concerns of the shipping sector, which is responsible for around 2% to 3% of global energy-related CO2 emissions. These emissions may increase as the maritime industry grows at a compound annual growth rate of 4.33%. Next, we analyze the use of ammonia as a fuel in detail, which presents several challenges. These challenges include the high price of ammonia compared to other fossil fuels, the low reactivity and high toxicity of ammonia, NOx, and N2O emissions resulting from incomplete combustion, an inefficient process, and NH3 slipping. However, we emphasize how to overcome these challenges. We discuss techniques to reduce NOx and N2O emissions, co-combustion to improve reactivity, waste heat recovery strategies, the regulatory framework, and safety conditions. Finally, we address the market trends and challenges of using ammonia as a sustainable marine fuel.
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(This article belongs to the Special Issue Renewable Fuels for Internal Combustion Engines: 2nd Edition)
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Open AccessArticle
Life Estimation of HVDC Cables Subjected to Fast and Slow Polarity Reversals
by
Bassel Diban, Giovanni Mazzanti, Massimo Marzinotto and Antonio Battaglia
Energies 2024, 17(13), 3182; https://doi.org/10.3390/en17133182 - 28 Jun 2024
Abstract
This paper aims at estimating the life of extruded HVDC cable insulation subjected to fast and slow voltage polarity reversals (VPRs). An ad hoc MATLAB code is used for the transient electric field simulation in the cable insulation thickness by solving numerically Gauss,
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This paper aims at estimating the life of extruded HVDC cable insulation subjected to fast and slow voltage polarity reversals (VPRs). An ad hoc MATLAB code is used for the transient electric field simulation in the cable insulation thickness by solving numerically Gauss, ohm, and current continuity equations beside a macroscopic conductivity equation. A transient temperature is also considered during slow VPR transients. The results show a significant localized reduction in the life of the inner insulation, making the life distribution non-monotonous inside the insulation thickness. The results show that fast VPRs are the most stressing transients in this study. The longer the duration of the zero-voltage period in slow VPR, the less stressed the insulation, hence, the longer the local life in the inner insulation of the cable. The latter is justified by the charge relaxation during slow VPRs.
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(This article belongs to the Section F1: Electrical Power System)
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Open AccessReview
Recent Developments in Hydrocyclone Technology for Oil-in-Water Separation from Produced Water
by
Okwunna Maryjane Ekechukwu, Taimoor Asim and Haval Kukha Hawez
Energies 2024, 17(13), 3181; https://doi.org/10.3390/en17133181 - 28 Jun 2024
Abstract
The treatment of produced water is a major challenge faced by oil and gas industries worldwide. As a result of the increase in industrial activities, the generation of produced water has increased significantly. The most commonly used method for produced water oil–water separation
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The treatment of produced water is a major challenge faced by oil and gas industries worldwide. As a result of the increase in industrial activities, the generation of produced water has increased significantly. The most commonly used method for produced water oil–water separation is de-oiling hydrocyclone technology due to its simple construction, compact design, easy maintenance, and high efficiency. A wide breadth of scientific research studies has been carried out on performance evaluation, design optimisation, geometric parametrisation, external interventions, etc., to enhance the performance of hydrocyclones. These studies mostly rely on either experimental data obtained from the field, in laboratories under a controlled environment, or the application of numerical techniques for oil-in-water separation. Considering the extensive research studies published on hydrocyclone technology, this study aims to provide a comprehensive review of recent technological advancements in hydrocyclone technology in order to identify key areas where scientific research efforts should be concentrated. This will help make well-informed decisions for strategic investments in this wide area of research. Furthermore, it will widen the scope of applicability of hydrocyclones in the industrial sector.
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(This article belongs to the Section B: Energy and Environment)
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Open AccessArticle
Pathways to the Large-Scale Adoption of Residential Photovoltaics in Saudi Arabia
by
Abeer Alshehri, Patrick James and AbuBakr Bahaj
Energies 2024, 17(13), 3180; https://doi.org/10.3390/en17133180 - 28 Jun 2024
Abstract
This survey of predominantly middle–high-income owner-occupier households in the Kingdom of Saudi Arabia (KSA) assessed household perspectives to residential photovoltaics (PVs) (n = 268). Higher-income households were statistically more likely to (i) accept financial payback times of more than 12 months for the
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This survey of predominantly middle–high-income owner-occupier households in the Kingdom of Saudi Arabia (KSA) assessed household perspectives to residential photovoltaics (PVs) (n = 268). Higher-income households were statistically more likely to (i) accept financial payback times of more than 12 months for the CAPEX cost of a PV system, and (ii) be prepared to contribute up to SAR 10,000 (USD 2666) towards the CAPEX cost of a system. A multiple logistic regression analysis indicated that a high household education level and the dwelling tenure (owner) are key variables that positively influence PV acceptability. Median apartment and villa households in this survey had annual electricity demands of 22,969 kWh and 48,356 kWh, respectively. The available roof area per apartment and villa was assessed, considering parapet shading and roof furniture limitations (the presence of AC units, etc.), at 20 m2 and 75 m2, respectively. This would accommodate either a 4 kWp apartment system or a 10 kWp villa system mounted horizontally. Time-of-use tariffs or grant subsidies towards the cost of a PV system will be required to enable the surveyed households to meet their stated economic conditions for purchasing a PV system. This indicates that PV policies in KSA will need to be adapted to encourage the uptake of PVs.
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(This article belongs to the Special Issue Low-Carbon Integrated Energy System with Renewable Generations: Characterization, Modelling, and Optimization)
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