Energies

22 pages, 3468 KiB

Open AccessArticle

Generation Characteristics of Gas Products in Fluidized Bed Gasification of Wood Pellets Under Oxygen-Enriched Conditions and Their Effects on Methanol Synthesis

by Xiangli Zuo, Huawei Jiang, Tianyu Gao, Man Zhang, Hairui Yang and Tuo Zhou

Energies 2025, 18(5), 1310; https://doi.org/10.3390/en18051310 - 6 Mar 2025

Viewed by 569

Abstract

Methanol synthesis can utilize the product gas from biomass gasification and the hydrogen generated from water electrolysis. Biomass gasification, as an upstream process, affects the subsequent hydrogen supplement amount and has a direct relationship with the methanol yield. Fluidized bed oxygen-enriched gasification has [...] Read more.

Methanol synthesis can utilize the product gas from biomass gasification and the hydrogen generated from water electrolysis. Biomass gasification, as an upstream process, affects the subsequent hydrogen supplement amount and has a direct relationship with the methanol yield. Fluidized bed oxygen-enriched gasification has a particular advantage for biomass and is expected to utilize the remaining oxygen from water electrolysis. In this study, the effects of operating parameters, including the equivalence ratio ER, temperature T, oxygen percentage OP in oxygen-enriched air, steam-to-wood pellets mass ratio S/W, and fluidization velocity u_g, as well as the choice of bed materials, on the volume fractions of the gas products and the gas yield from the fluidized bed oxygen-enriched gasification of wood pellets were investigated. The effects of the generation characteristics of gas products on the hydrogen supplement amount and the methanol yield were also analyzed. The results showed that the volume fraction of H₂ reached its peak values of 10.47% and 18.49% at an ER value of 0.28 and a u_g value of 0.187 m/s, respectively. The methanol yield reached its peak value of 0.54 kg/kg at a u_g value of 0.155 m/s. The volume fraction of H₂ increased from 6.13% to 11.74% with an increasing temperature from 650 °C to 850 °C, increased from 5.72% to 10.77% with an increasing OP value from 21% to 35%, and increased from 12.39% to 19.06% with an increasing S/W value from 0.16 to 0.38. The methanol yield could be improved by increasing the ER value, T value, OP value, or S/W value. When the bed materials were changed from quartz sands to dolomite granules, the H₂ volume fraction significantly increased and the hydrogen supplement amount required for methanol synthesis reduced. Full article

(This article belongs to the Special Issue Catalytic Hydrogen Production and Hydrogen Energy Utilization)

► Show Figures

Figure 1

18 pages, 9081 KiB

Open AccessArticle

Optimal Bidding Capacity of Virtual Power Plant Incorporating Power-to-X Resources on Day-Ahead Energy Market

by Kyeong-Hee Cho, Hyung-Chul Jo, Wanbin Son, Soon-Young Kwon and Gilsung Byeon

Energies 2025, 18(5), 1309; https://doi.org/10.3390/en18051309 - 6 Mar 2025

Viewed by 660

Abstract

Sector coupling technology, which is also called power-to-X (P2X) technology, refers to the conversion of renewable energy system (RES) outputs into various forms of energy, enhancing the utility of RESs and facilitating the development of sustainable energy systems. However, given the diverse characteristics [...] Read more.

Sector coupling technology, which is also called power-to-X (P2X) technology, refers to the conversion of renewable energy system (RES) outputs into various forms of energy, enhancing the utility of RESs and facilitating the development of sustainable energy systems. However, given the diverse characteristics of different P2X systems, the effective integration and operation of P2X resources are critical. This study aimed to propose a method for optimizing bidding capacities in power generation projects by integrating various P2X resources—including power-to-mobility, power-to-gas, and power-to-heat—as well as energy storage system (ESS) resources to improve flexibility and stabilize output. This study modeled the diverse characteristics of P2X resources and established objective functions and constraints. The optimization method for the integrated operational plan was developed using mixed integer linear programming. The results demonstrate that by considering the specific characteristics of each P2X and ESS resource, optimal resource allocation could effectively mitigate the variability of RES output and determine feasible bidding capacities. The proposed method is expected to contribute to mitigating RES variability, advancing sustainable energy transitions, reducing greenhouse gas emissions, and enhancing the flexibility of power systems. Full article

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

► Show Figures

Figure 1

28 pages, 4873 KiB

Open AccessReview

The Role of Environmental Product Declarations in the Decarbonization of Building Materials and Components

by Francesco Asdrubali, Gianluca Grazieschi and Dante Maria Gandola

Energies 2025, 18(5), 1308; https://doi.org/10.3390/en18051308 - 6 Mar 2025

Viewed by 614

Abstract

As energy efficiency measures have reduced the operational carbon footprint of buildings, the significance of embodied carbon has increased. Efforts by all construction players, including material and component manufacturers, are needed to avoid burdens shifting towards embodied impacts. Environmental Product Declarations (EPDs) can [...] Read more.

As energy efficiency measures have reduced the operational carbon footprint of buildings, the significance of embodied carbon has increased. Efforts by all construction players, including material and component manufacturers, are needed to avoid burdens shifting towards embodied impacts. Environmental Product Declarations (EPDs) can represent useful instruments to push the decarbonization of construction materials. This study examines EPDs to assess the embodied GWP of insulation materials, bricks, concrete, cement, steel, and natural stones. The variance structure of the GWP was studied for each material, the main variation parameters were detected, and statistically significant categories were identified. For each category reference values were calculated (i.e., mean or median values, lower and upper interquartile ranges, and box plot whiskers) which can be useful for manufacturers to reduce the impact of their products, for EPD verifiers to detect outliers, and for designers to determine safety coefficients for using EPD data in the early design stage. Consolidated results were achieved for materials produced through standardized processes whose GWP variability was mainly structured around universal physical properties or production techniques. More localized or artisanal products demonstrate higher decarbonization potential but require further segmentation and additional GWP data to establish more robust reduction benchmarks. Full article

(This article belongs to the Section G: Energy and Buildings)

► Show Figures

Figure 1

19 pages, 15944 KiB

Open AccessArticle

Comparative Study of Different Gases for Packed-Bed Thermal Energy Storage Systems

by Ayah Marwan Rabi’, Jovana Radulovic and James M. Buick

Energies 2025, 18(5), 1307; https://doi.org/10.3390/en18051307 - 6 Mar 2025

Viewed by 402

Abstract

In recent years, packed-bed systems for large-scale applications have emerged as a highly promising design for Thermal Energy Storage systems because of their high thermal efficiency and economic feasibility. Large-scale application systems typically include packed-bed thermal energy stores as essential components, enabling effective [...] Read more.

In recent years, packed-bed systems for large-scale applications have emerged as a highly promising design for Thermal Energy Storage systems because of their high thermal efficiency and economic feasibility. Large-scale application systems typically include packed-bed thermal energy stores as essential components, enabling effective integration with renewable energy and processed heat. The packed-bed systems investigated in this paper utilise Magnesia as the storage medium and optimised parameters, which have previously been identified through research involving charging and discharging cycles of both the hot and cold storage systems when air is the heat transfer fluid. This includes solid particle diameters of 0.004 m, a material porosity of 0.2, an aspect ratio of 1 for the storage tank, and a mass flow rate of 13.7 kg/m³. This paper aims to present a comparative analysis of the influence of alternative heat transfer gases, namely air, argon, carbon dioxide, helium, hydrogen, and nitrogen, on the performance of Pumped Thermal Energy Storage hot and cold storage systems. The performance of the six gases in the storage system was evaluated using an axisymmetric model simulated with COMSOL Multiphysics 5.6 software, with the total energy stored and the capacity factor serving as key performance indicators. The results revealed that carbon dioxide gas was the most promising heat transfer fluid and that the packed bed could be operated efficiently over 72% and 76% of its range for hot and cold systems, respectively. Hydrogen, nitrogen, and air performed similarly but less adequately than carbon dioxide and had operating ranges of 55% and 75% for hot and cold storage. Helium and argon had the poorest performance, with optimal charging and discharging rates corresponding to 50% and 66%. Full article

(This article belongs to the Special Issue Ground-Source Heat Pumps and Thermal Energy Storage Systems—Energy for the Future)

► Show Figures

Figure 1

30 pages, 11936 KiB

Open AccessArticle

Research on the Health Evaluation of a Pump Turbine in Smoothing Output Volatility of the Hybrid System Under a High Proportion of Wind and Photovoltaic Power Connection

by Yan Ren, Haonan Zhang, Lile Wu, Kai Zhang, Zutian Cheng, Ketao Sun, Yuan Sun and Leiming Hu

Energies 2025, 18(5), 1306; https://doi.org/10.3390/en18051306 - 6 Mar 2025

Viewed by 406

Abstract

With the high proportion of wind and photovoltaic (PV) power connection in the new electricity system, the system output power volatility is enhanced. When the output fluctuation of the system is suppressed, the pumped storage condition is changed frequently, which leads to the [...] Read more.

With the high proportion of wind and photovoltaic (PV) power connection in the new electricity system, the system output power volatility is enhanced. When the output fluctuation of the system is suppressed, the pumped storage condition is changed frequently, which leads to the vibration enhancement of the unit and a decrease in the system safety. This paper proposes a pump turbine health evaluation model based on the combination of a weighting method and cloud model in a high proportion wind and PV power connection scenario. The wind–PV output characteristics of the complementary system in a year (8760 h) and a typical week in four seasons (168 h) are analyzed, and the characteristics of frequent working condition transitions of pumped storage units are studied against this background. A five-level health classification system including multi-dimensional evaluation indicators is established, and a multi-level health evaluation based on cloud membership quantification is realized by combining the weighting method and cloud model method. The case analysis of a pumped storage power station within a new electricity system shows that the system as a whole presents typical cloud characteristics (Ex = 76.411, En = 12.071, He = 4.014), and the membership degree in the “good” state reaches 0.772. However, the draft tube index (Ex = 62.476) and the water guide index (Ex = 50.333) have shown a deterioration trend. The results verify the applicability and reliability of the evaluation model. This study provides strong support for the safe and stable operation of pumped storage units in the context of the high-proportion wind and PV power connection, which is of great significance for the smooth operation of the new electricity system. Full article

(This article belongs to the Special Issue Planning, Operation, and Control of New Power Systems)

► Show Figures

Figure 1

18 pages, 5346 KiB

Open AccessArticle

An n-Heptane Oxidation Mechanism Suitable for Low- to High-Temperature Combustion

by Junfa Duan, Aoqing Yang, Wei Wei and Gaolin Qin

Energies 2025, 18(5), 1305; https://doi.org/10.3390/en18051305 - 6 Mar 2025

Viewed by 418

Abstract

The detailed n-heptane mechanism, which is widely used today, is suitable for a wide range of operating conditions. However, due to the large model involved, it is difficult to use this mechanism for computational fluid dynamics (CFD) simulation. In addition, the prediction accuracy [...] Read more.

The detailed n-heptane mechanism, which is widely used today, is suitable for a wide range of operating conditions. However, due to the large model involved, it is difficult to use this mechanism for computational fluid dynamics (CFD) simulation. In addition, the prediction accuracy of the existing simplified mechanism cannot meet simulation requirements with respect to low-temperature combustion and the negative temperature coefficient region. In this study, we sought to solve these problems by constructing a new simplified mechanism (NC2024) of the n-heptane chemical reaction based on the mechanism of Kuiwen Zhang using path analysis and sensitivity analysis. The mechanism involves 72 substances and 126 reactions. A comparison with the commonly used mechanism and an analysis of experimental data revealed that the NC2024 mechanism delivers high accuracy in predicting the ignition delay period under the low- to high-temperature conditions of 600–1100 K and a large pressure range of 13.5–42 bar and thus meets the accuracy requirements for CFD simulation of diesel low-temperature combustion. Full article

(This article belongs to the Section I1: Fuel)

► Show Figures

Figure 1

25 pages, 13339 KiB

Open AccessArticle

Polypyrrole Hybrid Nanocomposite Electrode Materials with Outstanding Specific Capacitance

by Andekuba Andezai and Jude O. Iroh

Energies 2025, 18(5), 1304; https://doi.org/10.3390/en18051304 - 6 Mar 2025

Viewed by 439

Abstract

This paper discusses the results of our investigation of the effect of processing parameters on the electrochemical properties of poly(vinylidene fluoride) single-walled carbon nanotube sheets and PVDF-CNTs modified by solution cast polyimide coating, followed by electrodeposition of polypyrrole. The polyimide-coated single-wall carbon nanotube [...] Read more.

This paper discusses the results of our investigation of the effect of processing parameters on the electrochemical properties of poly(vinylidene fluoride) single-walled carbon nanotube sheets and PVDF-CNTs modified by solution cast polyimide coating, followed by electrodeposition of polypyrrole. The polyimide-coated single-wall carbon nanotube sheet–PI/SWCNTs composite consists of SWCNT and PVDF (9:1) wt.% and 0.1–1 wt.% polyimide. The processing temperature varied from 90 to 250 °C. SEM images validated the nanostructure, while EDX confirmed the material composition. EIS analysis showed that the composite electrode material processed at 90 °C and followed by electrodeposition of polypyrrole has the lowest bulk resistance (65.27 Ω), higher porosity (4.59%), and the highest specific capacitance (209.16 F/g), indicating superior ion transport and charge storage. Cyclic voltammetry and cyclic charge–discharge analyses revealed that the hybrid composite electrode processed at 90 °C achieved a specific capacitance of 655.34 F/g at a scan rate of 5 mV/s, demonstrating excellent cycling stability over 10 cycles at a current density of 0.5 A/g. In contrast, composite electrodes processed at 180 °C and 250 °C showed decreased performance due in part to structural densification and low porosity. These findings underscore the critical role of processing temperatures in optimizing the electrochemical properties of PI/SWCNT composites, advancing their potential for next-generation energy storage systems. Full article

(This article belongs to the Topic Advanced Polymeric Composites: Processing, Characterization and Mechanical Behavior)

► Show Figures

Figure 1

24 pages, 24145 KiB

Open AccessArticle

Influence of Conductor Temperature on the Voltage–Current Characteristic of Corona Discharge in a Coaxial Arrangement—Experiments and Simulation

by Kayumba Grace Ilunga, Andrew Graham Swanson, Nelson Ijumba and Robert Stephen

Energies 2025, 18(5), 1303; https://doi.org/10.3390/en18051303 - 6 Mar 2025

Viewed by 464

Abstract

High-current-carrying capability with minimum thermal elongation is one of the key reasons for using high-temperature low-sag (HTLS) conductors in modern power systems. However, their higher operational temperature can significantly affect corona discharge characteristics. Corona is one of the key factors in transmission line [...] Read more.

High-current-carrying capability with minimum thermal elongation is one of the key reasons for using high-temperature low-sag (HTLS) conductors in modern power systems. However, their higher operational temperature can significantly affect corona discharge characteristics. Corona is one of the key factors in transmission line design considerations. Corona discharge is the leading cause of audible noise, radio interference, and corona loss in power transmission systems. The influence of conductor temperature on corona discharge characteristics is investigated in this paper using experimental methods and computational simulations. A simulation framework has been developed in COMSOL Multiphysics using the physics of plasmas and electrostatics to simulate corona plasma dynamic behavior and electric field distribution. The results show that the conductor temperature enhances the ionization by electron impact, enhances the production of positive and negative ions, changes the electric field distribution, and increases the electron temperature. This analysis emphasizes that temperature-dependent conditions affect the inception and intensity of corona discharge. Additionally, an experimental model was developed to evaluate corona voltage–current characteristics under varying temperature conditions. The study presents both simulation results and a newly developed model for predicting corona current at high conductor temperatures. Full article

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

► Show Figures

Figure 1

60 pages, 7032 KiB

Open AccessReview

Advances in Numerical Modeling for Heat Transfer and Thermal Management: A Review of Computational Approaches and Environmental Impacts

by Łukasz Łach and Dmytro Svyetlichnyy

Energies 2025, 18(5), 1302; https://doi.org/10.3390/en18051302 - 6 Mar 2025

Cited by 1 | Viewed by 1192

Abstract

Advances in numerical modeling are essential for heat-transfer applications in electronics cooling, renewable energy, and sustainable construction. This review explores key methods like Computational Fluid Dynamics (CFD), the Finite Element Method (FEM), the Finite Volume Method (FVM), and multiphysics modeling, alongside emerging strategies [...] Read more.

Advances in numerical modeling are essential for heat-transfer applications in electronics cooling, renewable energy, and sustainable construction. This review explores key methods like Computational Fluid Dynamics (CFD), the Finite Element Method (FEM), the Finite Volume Method (FVM), and multiphysics modeling, alongside emerging strategies such as Adaptive Mesh Refinement (AMR), machine learning (ML), reduced-order modeling (ROM), and high-performance computing (HPC). While these techniques improve accuracy and efficiency, they also increase computational energy demands, contributing to a growing carbon footprint and sustainability concerns. Sustainable computing practices, including energy-efficient algorithms and renewable-powered data centers, offer potential solutions. Additionally, the increasing energy consumption in numerical modeling highlights the need for optimization strategies to mitigate environmental impact. Future directions point to quantum computing, adaptive models, and green computing as pathways to sustainable thermal management modeling. This study systematically reviews the latest advancements in numerical heat-transfer modeling and, for the first time, provides an in-depth exploration of the roles of computational energy optimization and green computing in thermal management. This review outlines a roadmap for efficient, environmentally responsible heat-transfer models to meet evolving demands. Full article

(This article belongs to the Special Issue High-Performance Numerical Simulation in Heat Transfer)

► Show Figures

Figure 1

21 pages, 8258 KiB

Open AccessArticle

Study on the Deflagration Characteristics of Methane–Air Premixed Gas in Sudden Expansion Pipelines

by Ning Zhou, Zhuohan Shi, Xue Li, Bing Chen, Yiting Liang, Zhaoyu Li, Chunhai Yang, Xuanya Liu, Weiqiu Huang and Xiongjun Yuan

Energies 2025, 18(5), 1301; https://doi.org/10.3390/en18051301 - 6 Mar 2025

Viewed by 451

Abstract

This study employs both experimental and numerical simulation methods to systematically investigate the influence of sudden expansion diameter ratios on methane–air premixed flame propagation, explosion overpressure, and the evolution of turbulent structures. The results show that with the increase in the diameter ratio, [...] Read more.

This study employs both experimental and numerical simulation methods to systematically investigate the influence of sudden expansion diameter ratios on methane–air premixed flame propagation, explosion overpressure, and the evolution of turbulent structures. The results show that with the increase in the diameter ratio, the flame propagation velocity and explosion overpressure present a nonlinear trend of first increasing, then decreasing, and then increasing. Specifically, when the diameter ratio is 1.5, an optimal balance between turbulence enhancement and energy dissipation is achieved, and the overpressure attenuation rate is 47.61%. However, when the diameter ratio increases to 2.0, the turbulence intensity significantly escalates, the peak flame propagation speed increases by 81%, the peak explosion overpressure increases by 69%, and the overpressure attenuation efficiency decreases, which brings greater safety challenges. Moreover, when the diameter ratio is between 1.5 and 2.0, the turbulence intensity of the premixed gas explosion flow field is significantly increased, and the stable “tulip flame” propagation velocity range is extended from 16~35 m/s to 16~42 m/s. When the diameter ratio is 2.0, a distinctive four-vortex structure is formed, with strong turbulent mixing and fast energy dissipation. The vortex structure evolves with the diameter ratio, transitioning from a symmetric and stable double-vortex form to a complex multi-vortex system. The research results provide theoretical support for the prevention of explosions. Full article

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

► Show Figures

Figure 1

22 pages, 24215 KiB

Open AccessArticle

Evaluation of Light Electric Flying-Wing Unmanned Aerial System Energy Consumption During Holding Maneuver

by Artur Kierzkowski, Bartłomiej Dziewoński, Krzysztof Kaliszuk and Mateusz Kucharski

Energies 2025, 18(5), 1300; https://doi.org/10.3390/en18051300 - 6 Mar 2025

Cited by 1 | Viewed by 440

Abstract

This study evaluates the energy consumption of a light electric flying-wing unmanned aerial system (UAS) during low-altitude holding maneuvers. Two flight patterns were investigated: circular holding at a specified altitude and a figure-eight trajectory. Test flights were conducted under varying meteorological and wind [...] Read more.

This study evaluates the energy consumption of a light electric flying-wing unmanned aerial system (UAS) during low-altitude holding maneuvers. Two flight patterns were investigated: circular holding at a specified altitude and a figure-eight trajectory. Test flights were conducted under varying meteorological and wind conditions, including scenarios where wind aligned and crossed the flight path. Key flight parameters such as pitch, yaw, heading deviation, flight altitude, ground speed, and airspeed were monitored. Concurrently, current and battery voltage were measured to compute the instantaneous power consumption of the propulsion system. This approach allowed for the determination and comparison of energy consumption across the two holding patterns. The outcomes contribute to a better understanding of power efficiency during prolonged flight maneuvers, supporting advancements in autonomous low-altitude UAS operations. Full article

(This article belongs to the Special Issue Challenges and Opportunities for Energy Economics and Policy)

► Show Figures

Figure 1

27 pages, 11438 KiB

Open AccessArticle

Investigation on the Performance and Assessment of Cylindrical Latent Heat Storage Units Within Backfill Mines Followed a Similar Experimental Methodology

by Bo Zhang, Chenjie Hou, Chao Huan, Yujiao Zhao and Xiaoyan Zhang

Energies 2025, 18(5), 1299; https://doi.org/10.3390/en18051299 - 6 Mar 2025

Viewed by 366

Abstract

The conversion and storage of renewable energy into thermal energy is an important part of the low carbon economy. The goaf of a deep mine offers the possibility of large-scale thermal energy storage due to its sufficient underground space. Since the repositories are [...] Read more.

The conversion and storage of renewable energy into thermal energy is an important part of the low carbon economy. The goaf of a deep mine offers the possibility of large-scale thermal energy storage due to its sufficient underground space. Since the repositories are built inside the goaf backfill and there are few studies on their heat storage capacity and effectiveness, this paper builds an experimental platform based on the similarity theory and selects the geometric similarity ratio of 1:15 to study the phase change heat storage performance of the backfill mine heat storage. Under the typical operating conditions, the temperature distribution of the PCM inside the cylindrical storage unit was analyzed. At the end of heat storage, the temperature distribution of the PCM was 0.93–0.98, but at the end of heat release, the temperature distribution of the PCM was not uniform. At the same time, the heat is reasonably corrected, so that the thermal energy charging effectiveness is increased to 0.98, and the total effectiveness of thermal energy charge and discharge remains 0.87. The parameters of the storage unit are analyzed in detail by changing the water temperature, the flow velocity and the ratio of heat storage and release time of the circulating medium. The experimental results show that when the heat release water temperature is constant and only the heat storage water temperature is changed, the higher the water temperature, the higher the total effectiveness of thermal energy charge and discharge. On the contrary, when the heat storage water temperature is constant and the heat release water temperature is reduced to 14 °C, the total effectiveness of the heat release is increased by 7.5%. When the flow state is in transition, the total effectiveness decreases. The longer the heat storage/release time, the smaller the TSTD_ave inside the PCM and the more uniform the temperature distribution. By restoring the experimental data to the engineering prototype, the repositories installed in the goaf were able to store and extract 422.88 GJ and 375.97 GJ of heat, respectively. Finally, the environmental assessment of the C-LHSU showed that the carbon emissions per unit heating area of the CFB, GWHF and GHF were reduced by 88.1%, 84.2% and 83.0%, respectively. The experimental results show that the cylindrical phase change heat reservoir has higher heat transfer energy efficiency, which provides a theoretical basis and engineering reference for efficient heat storage and utilization in deep mine goafs. Full article

(This article belongs to the Section B: Energy and Environment)

► Show Figures

Figure 1

22 pages, 11838 KiB

Open AccessArticle

Catalytic Performance of Iron-Based Oxygen Carriers Mixed with Converter Steel Slags for Hydrogen Production in Chemical Looping Gasification of Brewers’ Spent Grains

by Miao Yuan, Huawei Jiang, Xiangli Zuo, Cuiping Wang, Yanhui Li and Hairui Yang

Energies 2025, 18(5), 1298; https://doi.org/10.3390/en18051298 - 6 Mar 2025

Viewed by 436

Abstract

Iron-based oxygen carriers (OCs) have received much attention due to their low costs, high mechanical strengths and high-temperature stabilities in the chemical looping gasification (CLG) of biomass, but their chemical reactivity is very ordinary. Converter steel slags (CSSs) are steelmaking wastes and rich [...] Read more.

Iron-based oxygen carriers (OCs) have received much attention due to their low costs, high mechanical strengths and high-temperature stabilities in the chemical looping gasification (CLG) of biomass, but their chemical reactivity is very ordinary. Converter steel slags (CSSs) are steelmaking wastes and rich in Fe₂O₃, CaO and MgO, which have good oxidative ability and good stability as well as catalytic effects on biomass gasification. Therefore, the composite OCs prepared by mechanically mixing CSSs with iron-based OCs are expected to be used to increase the hydrogen production in the CLG of biomass. In this study, the catalytic performance of CSS/Fe₂O₃ composite OCs prepared by mechanically mixing CSSs with iron-based OCs on the gasification of brewers’ spent grains (BSGs) were investigated in a tubular furnace experimental apparatus. The results showed that when the weight ratio of the CSSs in composite OCs was 0.5, the relative volume fraction of hydrogen reached the maximum value of 49.1%, the product gas yield was 0.85 Nm³/kg and the gasification efficiency was 64.05%. It could be found by X-ray diffraction patterns and scanning electron microscope characterizations that the addition of CSSs helped to form MgFe₂O₄, which are efficient catalysts for H₂ production. Owing to the large and widely distributed surface pores of CSSs, mixing them with iron-based OCs was beneficial for catalytic steam reforming to produce hydrogen. Full article

(This article belongs to the Section A5: Hydrogen Energy)

► Show Figures

Figure 1

20 pages, 9044 KiB

Open AccessArticle

Simulation of Low-Salinity Water-Alternating Impure CO₂ Process for Enhanced Oil Recovery and CO₂ Sequestration in Carbonate Reservoirs

by Kwangduk Seo, Bomi Kim, Qingquan Liu and Kun Sang Lee

Energies 2025, 18(5), 1297; https://doi.org/10.3390/en18051297 - 6 Mar 2025

Viewed by 471

Abstract

This study investigates the combined effects of impurities in CO₂ stream, geochemistry, water salinity, and wettability alteration on oil recovery and CO₂ storage in carbonate reservoirs and optimizes injection strategy to maximize oil recovery and CO₂ storage ratio. Specifically, it [...] Read more.

This study investigates the combined effects of impurities in CO₂ stream, geochemistry, water salinity, and wettability alteration on oil recovery and CO₂ storage in carbonate reservoirs and optimizes injection strategy to maximize oil recovery and CO₂ storage ratio. Specifically, it compares the performance of pure CO₂ water-alternating gas (WAG), impure CO₂-WAG, pure CO₂ low-salinity water-alternating gas (LSWAG), and impure CO₂-LSWAG injection methods from perspectives of enhanced oil recovery (EOR) and CO₂ sequestration. CO₂-enhanced oil recovery (CO₂-EOR) is an effective way to extract residual oil. CO₂ injection and WAG methods can improve displacement efficiency and sweep efficiency. However, CO₂-EOR has less impact on the carbonate reservoir because of the complex pore structure and oil-wet surface. Low-salinity water injection (LSWI) and CO₂ injection can affect the complex pore structure by geochemical reaction and wettability by a relative permeability curve shift from oil-wet to water-wet. The results from extensive compositional simulations show that CO₂ injection into carbonate reservoirs increases the recovery factor compared with waterflooding, with pure CO₂-WAG injection yielding higher recovery factor than impure CO₂-WAG injection. Impurities in CO₂ gas decrease the efficiency of CO₂-EOR, reducing oil viscosity less and increasing interfacial tension (IFT) compared to pure CO₂ injection, leading to gas channeling and reduced sweep efficiency. This results in lower oil recovery and lower storage efficiency compared to pure CO₂. CO₂-LSWAG results in the highest oil-recovery factor as surface changes. Geochemical reactions during CO₂ injection also increase CO₂ storage capacity and alter trapping mechanisms. This study demonstrates that the use of impure CO₂-LSWAG injection leads to improved oil recovery and CO₂ storage compared to pure CO₂-WAG injection. It reveals that wettability alteration plays a more significant role for oil recovery and geochemical reaction plays crucial role in CO₂ storage than CO₂ purity. According to optimization, the greater the injection of gas and water, the higher the oil recovery, while the less gas and water injected, the higher the storage ratio, leading to improved storage efficiency. This research provides valuable insights into parameters and injection scenarios affecting enhanced oil recovery and CO₂ storage in carbonate reservoirs. Full article

(This article belongs to the Special Issue Oil Recovery and Simulation in Reservoir Engineering)

► Show Figures

Figure 1

25 pages, 4705 KiB

Open AccessArticle

An Analysis of the Increase in Energy Efficiency of Photovoltaic Installations by Using Bifacial Modules

by Dariusz Kurz, Arkadiusz Dobrzycki, Ewelina Krawczak, Jarosław Jajczyk, Jakub Mielczarek, Waldemar Woźniak, Michał Sąsiadek, Olga Orynycz, Karol Tucki and Ewa Badzińska

Energies 2025, 18(5), 1296; https://doi.org/10.3390/en18051296 - 6 Mar 2025

Viewed by 682

Abstract

This work concerns the experimental verification of changes in the energy efficiency of photovoltaic installations through the use of bifacial modules. For this purpose, an experimental stand was designed and built for the comparative analysis of the efficiency of two types of photovoltaic [...] Read more.

This work concerns the experimental verification of changes in the energy efficiency of photovoltaic installations through the use of bifacial modules. For this purpose, an experimental stand was designed and built for the comparative analysis of the efficiency of two types of photovoltaic panels: bifacial (bPV) and monofacial (mPV). The tests consisted of placing the panels at different heights above the ground surface and at different angles. During the tests, three substrates with different albedo were taken into account: green grass, gray concrete (fabric), and white snow (polystyrene). The tests for both types of panels were carried out simultaneously (in parallel), which guaranteed the same environmental conditions (temperature and solar radiation intensity). Based on the results of the voltage and current measurements for different angles of PV module inclination and, for bPV panels, different heights above the ground surface and different types of substrate, a series of current–voltage characteristics and power characteristics were plotted. The “additional” energy efficiency of bifacial panels compared to monofacial panels was also determined. It was shown that under favorable conditions, using bifacial panels instead of monofacial panels can increase the production of electricity by more than 56% from structures of the same dimensions. The research results can be of great value when designing photovoltaic installations. Full article

(This article belongs to the Special Issue Combined Application of Solar Power Generation and Energy Storage Technology)

► Show Figures

Figure 1

23 pages, 12732 KiB

Open AccessArticle

Design of a Simplified Experimental Test Case to Study Rotor–Stator Interactions in Hydraulic Machinery

by Benoit Dussault, Yves St-Amant and Sébastien Houde

Energies 2025, 18(5), 1295; https://doi.org/10.3390/en18051295 - 6 Mar 2025

Viewed by 439

Abstract

Because of the introduction of significant amounts of electricity from intermittent energy, such as solar and wind, on power grids, hydraulic turbines undergo more transient operation with varying rotation speeds. Start and stop sequences are known to induce significant mechanical stress in the [...] Read more.

Because of the introduction of significant amounts of electricity from intermittent energy, such as solar and wind, on power grids, hydraulic turbines undergo more transient operation with varying rotation speeds. Start and stop sequences are known to induce significant mechanical stress in the runner, decreasing its lifespan. Complex fluid–structure interactions are responsible for those high-stress levels, but the precise mechanisms are still elusive, even if many experimental and numerical studies were devoted to the subject. One possible mechanism identified through limited measurements on large turbines operating in powerhouses is rotor–stator interactions. It is already known that rotor–stator interaction (RSI) in constant-speed operating conditions can lead to runner failure when the RSI frequency is close to the natural frequencies of specific structural modes. Start and stop sequence investigations show that RSI can induce a transient resonance while the runner is accelerating/decelerating, which generates a frequency sweep that excites the structure. Studying transient RSI-induced resonance of structural modes associated with hydraulic turbine runners is complex because of the geometry and the potential impacts from other flow-induced excitations. This paper presents the development and validation of an experimental setup specifically designed to reproduce RSI-induced resonances in a rotating circular structure with cyclic periodicity mimicking the structural behavior of a Francis runner. Such a setup does not exist in the literature and will be beneficial for studying RSI during speed variations, with the potential to provide valuable insights into the dynamic behavior of turbines during transient conditions. The paper outlines the different design steps and the construction and validation of the experiment and its simplified runner. It presents important results from preliminary analyses that outline the approach’s success in investigating transient RSI in hydraulic turbines. Full article

(This article belongs to the Special Issue Energy Conversion and Management: Hydraulic Machinery and Systems)

► Show Figures

Figure 1

11 pages, 3243 KiB

Open AccessArticle

Research on the Decomposition Characteristics of Methane Hydrates Exploited by the NH₄Cl/NaNO₂ System

by Jihong Zhang, Yi Wan, Ming Li, Yanan Wang and Xinjian Tan

Energies 2025, 18(5), 1294; https://doi.org/10.3390/en18051294 - 6 Mar 2025

Viewed by 393

Abstract

Considering the influence of the system conversion rate on hydrate decomposition kinetics and energy utilization during the decomposition process of pure methane hydrate in the NH₄Cl/NaNO₂ system (an in situ chemical heat generation system), this study carried out hydrate decomposition [...] Read more.

Considering the influence of the system conversion rate on hydrate decomposition kinetics and energy utilization during the decomposition process of pure methane hydrate in the NH₄Cl/NaNO₂ system (an in situ chemical heat generation system), this study carried out hydrate decomposition experiments in the NH₄Cl/NaNO₂ system under different decomposition conditions at low temperature and high pressure (3 °C, 8 MPa) and calculated the decomposition efficiency, reaction conversion rate, and methane energy efficiency. The results showed that, based on the differences in the kinetic behavior of hydrate decomposition, the decomposition process was divided into an unstable stage, a stable stage, and a decay stage. When the chemical reaction entered the stable stage, the hydrate decomposition process became stable, and it formed a stable dynamic response mode consisting of an exothermic chemical system and endothermic decomposition of hydrate. Four reactant concentrations (3 mol/L, 4 mol/L, 5 mol/L, and 6 mol/L) and three hydrochloric acid concentrations (0.0178 mol/L, 0.0225 mol/L, and 0.0356 mol/L) were designed. This proved that increases in the reactant concentration and H⁺ concentration both improved the decomposition efficiency and energy efficiency of pure methane hydrate, but reactant concentrations up to 6 mol/L reduced the decomposition efficiency due to the formation of side reactions, and H⁺ concentrations up to 0.0356 mol/L produced toxic reddish-brown nitrogen oxides. The overall decomposition efficiency of Cases 1–6 was up to 72.92%, the conversion rate was 25–45%, and the methane energy efficiency was higher than 3.5. The experiment proved the feasibility of exploiting pure methane hydrate in this self-generating heat system, which provides a new idea for the application of this system in hydrate exploitation. Full article

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

► Show Figures

Figure 1

18 pages, 8922 KiB

Open AccessArticle

A Comprehensive Case Study of a Full-Size BIPV Facade

by Niklas Albinius, Björn Rau, Maximilian Riedel and Carolin Ulbrich

Energies 2025, 18(5), 1293; https://doi.org/10.3390/en18051293 - 6 Mar 2025

Viewed by 567

Abstract

Building-integrated photovoltaic (BIPV) systems present a promising avenue for integrating renewable energy generation into urban environments. However, they pose unique challenges, including higher planning efforts and reduced yield generation compared to conventional rooftop systems. Despite these challenges, the double use of area and [...] Read more.

Building-integrated photovoltaic (BIPV) systems present a promising avenue for integrating renewable energy generation into urban environments. However, they pose unique challenges, including higher planning efforts and reduced yield generation compared to conventional rooftop systems. Despite these challenges, the double use of area and the high potential in urban landscapes offer compelling advantages. Modules have become highly customizable to fit architect’s requirements in sustainable yet also aesthetic building material. This paper discusses the results of a “living laboratory” in Berlin, which is both a typical building with a ventilated curtain wall and a unique showcase for BIPV technology. Through careful analysis of various factors, including module positioning, ventilation, and shading, this study demonstrates the feasibility and practicality of BIPV integration. The “living lab” not only highlights the technical viability of BIPV systems but also underscores their potential to enhance architectural aesthetics and promote sustainability and carbon-neutrality in urban landscapes. Full article

(This article belongs to the Special Issue Sustainable Design and Optimization of Building Integrated Photovoltaics (BIPV))

► Show Figures

Figure 1

19 pages, 12313 KiB

Open AccessArticle

Numerical Study of the Effect of Winglets with Multiple Sweep Angles on Wind Turbine Blade Performance

by Bayu K. Wardhana and Byeongrog Shin

Energies 2025, 18(5), 1292; https://doi.org/10.3390/en18051292 - 6 Mar 2025

Viewed by 390

Abstract

A numerical study was conducted on winglet designs with multiple sweep angles for improving the performance of horizontal axis wind turbine (HAWT) blades, and their effect on reducing the wing tip vortex was investigated by CFD analysis. The effects of sweep angles were [...] Read more.

A numerical study was conducted on winglet designs with multiple sweep angles for improving the performance of horizontal axis wind turbine (HAWT) blades, and their effect on reducing the wing tip vortex was investigated by CFD analysis. The effects of sweep angles were examined through NREL Phase VI turbine blades considering a wind speed range of 7 to 25 m/s. Numerical simulations were performed using RANS equations and the SST k–ω turbulence model. The interaction of the blade rotation and wind flow was modeled using a moving reference frame method. The numerical results were found to be in good agreement with the inferences drawn from the experiments for a baseline blade without a winglet, thereby validating the computational method. The investigations revealed that multi-swept winglets predicted a 14.6% torque increment, providing higher power output than single-swept winglets compared to the baseline blade at a wind speed of 15 m/s. Implementing multiple sweep angles in winglet design can improve the blade performance effectively without further increments in winglet length. Full article

(This article belongs to the Special Issue CFD Simulation in Energy Engineering Research)

► Show Figures

Figure 1

50 pages, 8171 KiB

Open AccessReview

A Review on the Overall Performance of Metal Hydride-Based Hydrogen Storage Systems

by Puchanee Larpruenrudee, Nick S. Bennett, Zhen Luo, M. J. Hossain, Nawshad Haque, Emilie Sauret, Robert Fitch and Mohammad S. Islam

Energies 2025, 18(5), 1291; https://doi.org/10.3390/en18051291 - 6 Mar 2025

Viewed by 735

Abstract

Metal hydride-based hydrogen storage (MHHS) has been used for several purposes, including mobile and stationary applications. In general, the overall MHHS performance for both applications depends on three main factors, which are the appropriate selection of metal hydride material uses, design configurations of [...] Read more.

Metal hydride-based hydrogen storage (MHHS) has been used for several purposes, including mobile and stationary applications. In general, the overall MHHS performance for both applications depends on three main factors, which are the appropriate selection of metal hydride material uses, design configurations of the MHHS based on the heat exchanger, and overall operating conditions. However, there are different specific requirements for the two applications. The weight of the overall MHHS is the key requirement for mobile applications, while hydrogen storage capacity is the key requirement for stationary applications. Based on these requirements, several techniques have been recently used to enhance MHHS performance by mostly considering the faster hydrogen absorption/desorption reaction. Considering metal hydride (MH) materials, their low thermal conductivity significantly impacts the hydrogen absorption/desorption reaction. For this purpose, a comprehensive understanding of these three main factors and the hydrogen absorption/desorption reaction is critical and it should be up to date to obtain the suitable MHHS performance for all related applications. Therefore, this article reviews the key techniques, which have recently been applied for the enhancement of MHHS performance. In the review, it is demonstrated that the design and layout of the heat exchanger greatly affect the performance of the internal heat exchanger. The initial temperature of the heat transfer fluid and hydrogen supply pressure are the main parameters to increase the hydrogen sorption rate and specific heating power. The higher supply pressure results in the improvement in specific heating power. For the metal hydride material selection under the consideration of mobile applications and stationary applications, it is important to strike trade-offs between hydrogen storage capacity, weight, material cost, and effective thermal conductivity. Full article

(This article belongs to the Special Issue Advances in Hydrogen and Energy Transition)

► Show Figures

Figure 1

17 pages, 3676 KiB

Open AccessArticle

Investigation of Component Interactions During the Hydrothermal Process Using a Mixed-Model Cellulose/Hemicellulose/Lignin/Protein and Real Cotton Stalk

by Shengjun Guo, Jiachen Zuo, Xiao Yang, Hui Wang, Lihua Cheng and Libo Zhang

Energies 2025, 18(5), 1290; https://doi.org/10.3390/en18051290 - 6 Mar 2025

Cited by 1 | Viewed by 449

Abstract

Converting agricultural and forestry waste into high-value-added bio-oil via hydrothermal liquefaction (HTL) reduces incineration pollution and alleviates fuel oil shortages. Current research focuses on adjusting HTL parameters like temperature, time, catalyst, and pretreatment. Few studies explore raw material composition and its interactions with [...] Read more.

Converting agricultural and forestry waste into high-value-added bio-oil via hydrothermal liquefaction (HTL) reduces incineration pollution and alleviates fuel oil shortages. Current research focuses on adjusting HTL parameters like temperature, time, catalyst, and pretreatment. Few studies explore raw material composition and its interactions with bio-oil properties, limiting guidance for future multi-material hydrothermal co-liquefaction. In view of the above problems, the lignocellulosic model in this paper used cellulose, hemicellulose, lignin, and protein as raw materials. At a low hydrothermal temperature (220 °C), the yield and properties of hydrothermal bio-oil were used as indicators to explore the influence of the proportional content of different model components on the interaction in the hydrothermal process through its simple binary blending and multivariate blending. Then, compared with the hydrothermal liquefaction process of cotton stalk, the interaction between components in the hydrothermal process of real lignocellulose was explored. The results demonstrated significant interactions among cellulose, lignin, and hemicellulose in cotton stalks. The relative strength of component interactions was ranked by yield (wt.%) and property modulation as follows: cellulose–lignin (C-L, 6.82%, synergistic enhancement) > cellulose–hemicellulose (C-X, 1.83%, inhibitory effect) > hemicellulose–lignin (X-L, 1.32%, non-significant interaction). Glycine supplementation enhanced bio-oil yields, with the most pronounced effect observed in cellulose–glycine (C-G) systems, where hydrothermal bio-oil yield increased from 2.29% to 4.59%. Aqueous-phase bio-oil exhibited superior high heating values (HHVs), particularly in hemicellulose–glycine (X-G) blends, which achieved the maximum HHV of 29.364 MJ/kg among all groups. Meanwhile, the characterization results of hydrothermal bio-oil under different mixing conditions showed that the proportion of model components largely determined the composition and properties of hydrothermal bio-oil, which can be used as a regulation method for the synthesis of directional chemicals. Cellulose–lignin (C-L) interactions demonstrated the strongest synergistic enhancement, reaching maximum efficacy at a 3:1 mass ratio. This study will deepen the understanding of the composition of lignocellulose raw materials in the hydrothermal process, promote the establishment of a hydrothermal product model of lignocellulose, and improve the yield of bio-oil. Full article

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

► Show Figures

Figure 1

34 pages, 11575 KiB

Open AccessArticle

Energy-Saving Design Strategies for Industrial Heritage in Northeast China Under the Concept of Ultra-Low Energy Consumption

by Shiqi Yang, Hui Ma, Na Li, Sheng Xu and Fei Guo

Energies 2025, 18(5), 1289; https://doi.org/10.3390/en18051289 - 6 Mar 2025

Viewed by 462

Abstract

Countries around the world have developed standards for ultra-low energy consumption building design and future plans. Unfortunately, these standards lack specific requirements for industrial heritage. As an important carrier of urban context, history, and the transmission of residents’ memories, industrial heritage cannot be [...] Read more.

Countries around the world have developed standards for ultra-low energy consumption building design and future plans. Unfortunately, these standards lack specific requirements for industrial heritage. As an important carrier of urban context, history, and the transmission of residents’ memories, industrial heritage cannot be overlooked in urban development. This study uses DesignBuilder energy simulation software to model industrial heritage (taking the Changchun Tractor Factory as an example) and compares the energy consumption before and after renovation strategies. The results show that in the Case 4 plan, after implementing the renovation strategy, heating energy consumption can be reduced by about 11,648 (kWh/m²) over the heating season, the total primary energy was reduced by about 4 million (kgce/tce), and total energy consumption decreases by approximately 95%. This demonstrates the effectiveness of the industrial heritage reuse design strategy proposed in this paper. It provides a new direction for reuse design under ultra-low energy consumption requirements in related case studies. Full article

(This article belongs to the Special Issue Advanced Research on Heat Exchangers Networks and Heat Recovery)

► Show Figures

Figure 1

14 pages, 2903 KiB

Open AccessArticle

Structural Feasibility of a Wind Turbine Blade Inspired by an Owl Airfoil

by Dean Sesalim and Jamal Naser

Energies 2025, 18(5), 1288; https://doi.org/10.3390/en18051288 - 6 Mar 2025

Viewed by 433

Abstract

Geometrical solutions for aerodynamic limitations comprise a major development towards improving the wind energy capture efficiency and aerodynamic performance of wind turbines. However, the implementation of some mechanisms such as considerably thin airfoils have been a hurdle due to the available manufacturing methods [...] Read more.

Geometrical solutions for aerodynamic limitations comprise a major development towards improving the wind energy capture efficiency and aerodynamic performance of wind turbines. However, the implementation of some mechanisms such as considerably thin airfoils have been a hurdle due to the available manufacturing methods and cost effectiveness. Moreover, the analysis has been mostly focused on analyzing and optimizing the aerodynamic aspect of wind turbines, independently of the structural performance necessary to support the optimized aerodynamic performance. Therefore, this paper analyzes the fluid–structure interaction (FSI) of a wind turbine with a relatively thin airfoil section using computational fluid dynamics (CFD) and finite element analysis (FEA) to evaluate the total displacement as well as the stresses acting on the blade as the results of the aerodynamic pressure distribution. Using the structural design, geometrical scales, and material properties of baseline model, the structural performance reflected by the thin airfoil design is isolated. Not only did the thin airfoil reduce the volume of the material and, therefore, the weight of the modified blade, but it was also able to provide high rigidity, which is necessary to support better aerodynamic performance. This was found to be influenced by the structural shape of the turbine blade, resulting in a maximum total deformation of less than 5.9 × 10⁻⁷ m, which is very negligible in comparison to the scale of the turbine blade in this analysis. Full article

(This article belongs to the Special Issue Advances in Fluid Dynamics and Wind Power Systems: 2nd Edition)

► Show Figures

Figure 1

22 pages, 21431 KiB

Open AccessArticle

Investigation of Flow Characteristics in Rotating Distributary and Confluence Cavities

by Kuan Zheng, Huan Ma, Hongchuang Sun and Jiang Qin

Energies 2025, 18(5), 1287; https://doi.org/10.3390/en18051287 - 6 Mar 2025

Viewed by 378

Abstract

Power generation is an important part of air vehicle energy management when developing long-endurance and reusable hypersonic aircraft. In order to utilize an air turbine power generation system on board, fuel-based rotating cooling has been researched to cool the turbine’s rotor blades. For [...] Read more.

Power generation is an important part of air vehicle energy management when developing long-endurance and reusable hypersonic aircraft. In order to utilize an air turbine power generation system on board, fuel-based rotating cooling has been researched to cool the turbine’s rotor blades. For fuel-cooling air turbines, each blade corresponds to a separate cooling channel. All the separate cooling channels cross together and form a distributary cavity and a confluence cavity in the center of the disk. In order to determine the flow characteristics in the distributary and confluence cavities, computational fluid dynamics (CFD) simulations using the shear–stress–transport turbulence model were carried out under the conditions of different rotating speeds and different mass flow rates. The results showed great differences between non-rotating flow and rotating flow conditions in the distributary and confluence cavities. The flow in the distributary and confluence cavities has rotational velocity, with obvious layering distribution regularity. Moreover, a high-speed rotational flow surface is formed in the confluence cavity of the original structure, due to the combined functions of centrifugal force, inertia, and the Coriolis force. Great pressure loss occurs when fluid passes through the high-speed rotational flow surface. This pressure loss increases with the increase in rotating speed and mass flow rate. Finally, four structures were compared, and an optimal structure with a separated outlet channel was identified as the best structure to eliminate this great pressure loss. Full article

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

► Show Figures

Figure 1

20 pages, 909 KiB

Open AccessArticle

Evaluation of Political and Economic Factors Affecting Energy Policies: Addressing Contemporary Challenges from Taiwan’s Perspective

by Bireswar Dutta

Energies 2025, 18(5), 1286; https://doi.org/10.3390/en18051286 - 6 Mar 2025

Viewed by 505

Abstract

The shift to sustainable energy requires a thorough understanding of the elements affecting policy adoption, especially regarding political and economic dynamics. Current approaches, such as the technology acceptance model (TAM), theory of planned behavior (TPB), and unified theory of acceptance and use of [...] Read more.

The shift to sustainable energy requires a thorough understanding of the elements affecting policy adoption, especially regarding political and economic dynamics. Current approaches, such as the technology acceptance model (TAM), theory of planned behavior (TPB), and unified theory of acceptance and use of technology (UTAUT), mainly emphasize individual behavioral aspects, often neglecting macro-level implications. This research uses the hybrid model for energy policy adoption (HMEPA) to bridge this gap, including economic and political factors with behavioral theories to evaluate energy policy acceptability. We propose that social impact, attitudes toward the policy, and financial and political considerations substantially affect stakeholders’ acceptance intentions. We gathered 421 valid answers from people in Taiwan using a questionnaire survey and analyzed the data using structural equation modeling (SEM). The findings demonstrate that whereas effort expectation and enabling circumstances have little impact, social influence and attitude are the most significant determinants of policy adoption intention. Moreover, political variables influence attitudes and social dynamics, while economic policy impacts performance expectations, perceived behavioral control, and enabling circumstances. These results underscore the need to synchronize policy plans with political and economic realities. Policymakers may use these findings to formulate stakeholder-oriented policies that promote sustainable energy transitions. Full article

(This article belongs to the Special Issue Economic and Political Determinants of Energy—Contemporary Challenges)

► Show Figures

Figure 1

15 pages, 887 KiB

Open AccessArticle

Decarbonizing the Construction Sector: Strategies and Pathways for Greenhouse Gas Emissions Reduction

by Charikleia Karakosta and Jason Papathanasiou

Energies 2025, 18(5), 1285; https://doi.org/10.3390/en18051285 - 6 Mar 2025

Viewed by 674

Abstract

The construction sector is a significant contributor to global greenhouse gas (GHG) emissions, necessitating urgent decarbonization efforts to align with international climate goals such as the Paris Agreement and the European Green Deal. This study explores a comprehensive framework for construction companies to [...] Read more.

The construction sector is a significant contributor to global greenhouse gas (GHG) emissions, necessitating urgent decarbonization efforts to align with international climate goals such as the Paris Agreement and the European Green Deal. This study explores a comprehensive framework for construction companies to map and reduce their GHG emissions through a structured four-step approach: defining emission scopes, conducting GHG inventories, setting reduction targets, and planning actionable reductions. Four key pathways are proposed: electricity decarbonization through renewable energy adoption and energy efficiency measures; direct emissions reduction via fleet electrification and infrastructure optimization; recycling and resource efficiency improvements through waste diversion and material reuse; and supply chain emissions reduction by enforcing sustainability standards and responsible sourcing practices. The analysis highlights the importance of integrating technological, organizational, and policy-driven solutions, such as rooftop photovoltaic systems, virtual power purchase agreements, waste management strategies, and supplier codes of conduct aligned with global sustainability benchmarks. The study concludes that construction companies can achieve significant emission reductions by adopting a structured, multi-pathway approach; emphasizing progress over perfection; and aligning their strategies with national and international climate targets. This research provides actionable insights for the construction sector to transition toward a net-zero future by 2050. Full article

(This article belongs to the Section G: Energy and Buildings)

► Show Figures

Figure 1

17 pages, 1054 KiB

Open AccessArticle

A Method for Restoring Power Supply to Distribution Networks Considering the Coordination of Multiple Resources Under Typhoon-Induced Waterlogging Disasters

by Hao Dai, Dafu Liu, Guowei Liu, Hao Deng, Lisheng Xin, Longlong Shang, Ziyu Liu, Ziwen Xu, Jiaju Shi and Chen Chen

Energies 2025, 18(5), 1284; https://doi.org/10.3390/en18051284 - 6 Mar 2025

Viewed by 600

Abstract

Recently, frequent typhoons and waterlogging disasters have caused severe damage to the power distribution networks in coastal cities. In response to this issue, how to efficiently develop recovery plans and achieve flexible resource coordination has become key for urban power grids in regard [...] Read more.

Recently, frequent typhoons and waterlogging disasters have caused severe damage to the power distribution networks in coastal cities. In response to this issue, how to efficiently develop recovery plans and achieve flexible resource coordination has become key for urban power grids in regard to coping with extreme natural disasters. Therefore, this article proposes a multi type flexible resource collaborative scheduling method for power supply restoration in distribution networks which realizes cooperation between maintenance teams and mobile energy storage in the scenario of wind and flood composite disasters, simultaneously completing the transfer of important loads through topology reconstruction. Firstly, a damage model for distribution network nodes and lines under wind–flood composite disasters was established to address the impact of typhoons and waterlogging disasters on the distribution network. Then, based on the inherent characteristics of multiple types of flexible resources, various collaborative recovery models for flexible resources after disasters were established. Finally, the effectiveness of the proposed method was verified through the coupling example of a 33-node distribution network and a 30-node transportation network. Full article

(This article belongs to the Special Issue Advanced Design and Optimization for Integrated Power and Energy Systems)

► Show Figures

Figure 1

25 pages, 3834 KiB

Open AccessArticle

Stochastic Capacity Expansion Model Accounting for Uncertainties in Fuel Prices, Renewable Generation, and Demand

by Naga Srujana Goteti, Eric Hittinger and Eric Williams

Energies 2025, 18(5), 1283; https://doi.org/10.3390/en18051283 - 6 Mar 2025

Viewed by 861

Abstract

Capacity expansion models for electricity grids typically use deterministic optimization, addressing uncertainty through ex-post analysis by varying input parameters. This paper presents a stochastic capacity expansion model that integrates uncertainty directly into optimization, enabling the selection of a single strategy robust across a [...] Read more.

Capacity expansion models for electricity grids typically use deterministic optimization, addressing uncertainty through ex-post analysis by varying input parameters. This paper presents a stochastic capacity expansion model that integrates uncertainty directly into optimization, enabling the selection of a single strategy robust across a defined range of uncertainties. Two cost-based risk objectives are explored: “risk-neutral” minimizes expected total system cost, and “risk-averse” minimizes the most expensive 5% of the cost distribution. The model is applied to the U.S. Midwest grid, accounting for uncertainties in electricity demand, natural gas prices, and wind generation patterns. While uncertain gas prices lead to wind additions, wind variability leads to reduced adoption when explicitly accounted for. The risk-averse objective produces a more diverse generation portfolio, including six GW more solar, three GW more biomass, along with lower current fleet retirements. Stochastic objectives reduce mean system costs by 4.5% (risk-neutral) and 4.3% (risk-averse) compared to the deterministic case. Carbon emissions decrease by 1.5% under the risk-neutral objective, but increase by 3.0% under the risk-averse objective due to portfolio differences. Full article

(This article belongs to the Special Issue Renewable Energy Power Generation and Power Demand Side Management)

► Show Figures

Figure 1

17 pages, 954 KiB

Open AccessArticle

Leveraging Explainable Artificial Intelligence in Solar Photovoltaic Mappings: Model Explanations and Feature Selection

by Eduardo Gomes, Augusto Esteves, Hugo Morais and Lucas Pereira

Energies 2025, 18(5), 1282; https://doi.org/10.3390/en18051282 - 5 Mar 2025

Cited by 1 | Viewed by 513

Abstract

This work explores the effectiveness of explainable artificial intelligence in mapping solar photovoltaic power outputs based on weather data, focusing on short-term mappings. We analyzed the impact values provided by the Shapley additive explanation method when applied to two algorithms designed for tabular [...] Read more.

This work explores the effectiveness of explainable artificial intelligence in mapping solar photovoltaic power outputs based on weather data, focusing on short-term mappings. We analyzed the impact values provided by the Shapley additive explanation method when applied to two algorithms designed for tabular data—XGBoost and TabNet—and conducted a comprehensive evaluation of the overall model and across seasons. Our findings revealed that the impact of selected features remained relatively consistent throughout the year, underscoring their uniformity across seasons. Additionally, we propose a feature selection methodology utilizing the explanation values to produce more efficient models, by reducing data requirements while maintaining performance within a threshold of the original model. The effectiveness of the proposed methodology was demonstrated through its application to a residential dataset in Madeira, Portugal, augmented with weather data sourced from SolCast. Full article

(This article belongs to the Topic Smart Energy Systems, 2nd Edition)

► Show Figures

Figure 1

29 pages, 13513 KiB

Open AccessArticle

A Physical-Based Electro-Thermal Model for a Prismatic LFP Lithium-Ion Cell Thermal Analysis

by Alberto Broatch, Pablo Olmeda, Xandra Margot and Luca Agizza

Energies 2025, 18(5), 1281; https://doi.org/10.3390/en18051281 - 5 Mar 2025

Viewed by 452

Abstract

This article presents an electro-thermal model of a prismatic lithium-ion cell, integrating physics-based models for capacity and resistance estimation. A 100 Ah prismatic cell with LFP-based chemistry was selected for analysis. A comprehensive experimental campaign was conducted to determine electrical parameters and assess [...] Read more.

This article presents an electro-thermal model of a prismatic lithium-ion cell, integrating physics-based models for capacity and resistance estimation. A 100 Ah prismatic cell with LFP-based chemistry was selected for analysis. A comprehensive experimental campaign was conducted to determine electrical parameters and assess their dependencies on temperature and C-rate. Capacity tests were conducted to characterize the cell’s capacity, while an OCV test was used to evaluate its open circuit voltage. Additionally, Hybrid Pulse Power Characterization tests were performed to determine the cell’s internal resistive-capacitive parameters. To describe the temperature dependence of the cell’s capacity, a physics-based Galushkin model is proposed. An Arrhenius model is used to represent the temperature dependence of resistances. The integration of physics-based models significantly reduces the required test matrix for model calibration, as temperature-dependent behavior is effectively predicted. The electrical response is represented using a first-order equivalent circuit model, while thermal behavior is described through a nodal network thermal model. Model validation was conducted under real driving emissions cycles at various temperatures, achieving a root mean square error below 1% in all cases. Furthermore, a comparative study of different cell cooling strategies is presented to identify the most effective approach for temperature control during ultra-fast charging. The results show that side cooling achieves a 36% lower temperature at the end of the charging process compared to base cooling. Full article

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

► Show Figures

Figure 1

Journal Menu

Journal Browser

Energies, Volume 18, Issue 5 (March-1 2025) – 297 articles

Further Information

Guidelines

MDPI Initiatives

Follow MDPI