Open Access
ISSN:0199-8595 (print)
ISSN:1546-0118 (online)
Publication Frequency:Monthly
A Proud Tradition
Established in 1904, Energy Engineering has a history of more than 120 years, making it one of the long-standing journals in the field. Throughout its long history, the journal has evolved alongside advances in energy science and technology, consistently serving as a catalyst for innovation and progress. In recent years, it has achieved steady improvements in academic quality, editorial standards, and international influence, and continues to move toward becoming a leading international journal.
Multi-faceted scholarship
Energy Engineering is an open-access, peer-reviewed journal focusing on the engineering aspects of energy research. It provides a global platform for researchers, engineers, scientists, and policy makers to publish original studies across a broad range of energy topics, including energy generation, conversion, conservation, utilization, storage, transmission, systems, technologies, management and sustainability. The journal also explores the societal impacts of energy use and policy, showcasing research that advances sustainable development and supports the transition to cleaner energy systems.
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Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.078417 - 27 March 2026
（This article belongs to the Special Issue: Recent Advance and Development in Solar Energy)
Abstract This study provides a new experimental framework to measure the static and dynamic electrical parameters for a solar panel of multiple cells. The study evaluates its static parameters, including its resultant diodes’ saturation currents, diodes’ ideality factors, series, and shunt resistances. Such parameters are essential to characterise the steady-state performance of a solar panel. Additionally, the dynamic parameters as the equivalent junction and diffusion capacitances are also experimentally measured. These parameters impact the performance of the panel at variable solar irradiance, temperature, and load conditions. A solar panel of 36 series-connected cells has been utilised… More >
Open Access
REVIEW
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072877 - 27 March 2026
Abstract For mixed-integer programming (MIP) problems in new power systems with uncertainties, existing studies tend to address uncertainty modeling or MIP solution methods in isolation. They overlook core bottlenecks arising from their coupling, such as variable dimension explosion, disrupted constraint separability, and conflicts in solution logic. To address this gap, this paper focuses on the coupling effects between the two and systematically conducts three aspects of work: first, the paper summarizes the uncertainty optimization methods suitable for addressing uncertainty-related issues in power systems, along with their respective advantages and disadvantages. It also clarifies the specific forms… More >
Open Access
EDITORIAL
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.079714 - 27 March 2026
（This article belongs to the Special Issue: Selected Papers from the SDEWES 2024 Conference on Sustainable Development of Energy, Water and Environment Systems)
Abstract The energy transition increasingly requires holistic approaches that integrate electricity, heating and cooling, water management, industrial processes, transport, and environmental considerations within coherent system frameworks. Such integration is essential for achieving deep decarbonisation while maintaining reliability, affordability, and resource efficiency across diverse regional and sectoral contexts. This Special Issue of Energy Engineering presents selected contributions from the 2024 Conferences on Sustainable Development of Energy, Water and Environment Systems (SDEWES), reflecting recent advances in modelling, system integration, and technology deployment. The included papers address a broad spectrum of challenges relevant to integrated energy–water–environment systems. These include building-sector… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072770 - 27 March 2026
Abstract With the growing integration of renewable energy sources (RESs) and smart interconnected devices, conventional distribution networks have turned to active distribution networks (ADNs) with complex system model and power flow dynamics. The rapid fluctuation of RES power may easily result in frequent voltage violation issues. Taking the flexible RES reactive power as control variables, this paper proposes a two-layer control scheme with Koopman wide neural network (WNN) based model predictive control (MPC) method for optimal voltage regulation and network loss reduction. Based on Koopman operator theory, a data-driven WNN method is presented to fit a… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072163 - 27 March 2026
Abstract Accurate forecasting of crude oil futures prices is crucial for understanding global energy market dynamics and formulating effective macroeconomic and energy strategies. However, the strong nonlinearity and multi-scale temporal characteristics of crude oil prices pose significant challenges to traditional forecasting methods. To address these issues, this study proposes a hybrid CEEMDAN–HOA–Transformer–GRU model that integrates decomposition, complexity analysis, adaptive modeling, and intelligent optimization. Specifically, Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN) is employed to decompose the original series into multi-scale components, after which entropy-based complexity analysis quantitatively evaluates each component. A differentiated modeling strategy… More >
Graphic Abstract
Open Access
REVIEW
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.074246 - 27 March 2026
（This article belongs to the Special Issue: Advancing Carbon Mitigation Strategies for a Sustainable Future)
Abstract The construction industry is a significant contributor to global CO2 emissions, and urgent innovation is needed to mitigate its environmental impact. This paper provides a comprehensive review of scalable approaches for CO2 uptake in construction materials, including the injection of CO2 into fresh concrete, the CO2 curing of precast concrete, and the use of ceramics as CO2 sinks. Among these three approaches, CO2 curing methods for concrete represent the most advanced and widely adopted strategies within industrial practice, with substantial research supporting their effectiveness and scalability. The comparison of carbonation mineralisation across three distinct material groups reveals that… More >
Graphic Abstract
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072848 - 27 March 2026
Abstract Heliostat field design for tower solar thermal plants must jointly address solar geometry, optical losses, and layout optimization under engineering constraints. We develop an end-to-end workflow that (i) adopts a consistent East–North–Up (ENU) convention for all plant- and sun-related vectors; (ii) integrates cosine efficiency, projection-based shading and blocking (SB), atmospheric transmittance, and an HFLCAL (heliostat field local calculation) truncation model into a single optical chain; and (iii) couples an Eliminate-Blocking (EB) layout prior with an improved “Cheetah” metaheuristic to search ring topology, mirror sizes, and heights while enforcing spacing, kinematics, and rated-power requirements. Projection-based SB… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.071243 - 27 March 2026
（This article belongs to the Special Issue: Construction and Control Technologies of Renewable Power Systems Based on Grid-Forming Energy Storage)
Abstract Flexibly interconnected distribution networks (FIDN) offer improved operational efficiency and operational control flexibility of power distribution systems through DC interconnection links, and have gradually become the main form of distribution networks. Aiming at the impact of constant power loads and converter transmission power variations in FIDN system stability, this paper presents an impedance reshaping based stability analysis and stabilization control to enhance the stability of the interconnected system and improve the system’s dynamic load response capability. Firstly, a small-single based equivalent impedance model of FIDN system, which consists flexibly interconnected equipment, energy storage, PV units,… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.072751 - 27 March 2026
（This article belongs to the Special Issue: Global Intelligent Optimization and Advanced Control of Photovoltaic Systems Under Complex Operating Conditions)
Abstract Photovoltaic (PV) systems in the field operate under complex, uncertain conditions rapid irradiance ramps, partial shading, temperature swings, surface soiling, and weak-grid disturbances including off-nominal frequency and voltage distortion that degrade energy yield and power quality. We propose a drift-aware, power-quality-constrained MPPT framework that co-optimizes MPPT, PLL, and current-loop gains under stochastic frequency drift, while enforcing IEEE-519 limits (per-order Ih/IL and TDD) during optimization. Unlike energy-only or THD-only methods, the design target integrates PQ constraints into the objective and is validated across calibrated drift scenarios with explicit per-order and TDD reporting. Operating scenarios are calibrated to… More >
Graphic Abstract
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072350 - 27 March 2026
（This article belongs to the Special Issue: Advances in Renewable Energy Systems: Integrating Machine Learning for Enhanced Efficiency and Optimization)
Abstract To address the issue of transient low-voltage instability in AC-DC hybrid power systems following large disturbances, conventional voltage assessment and control strategies typically adopt a sequential “assess-then-act” paradigm, which struggles to simultaneously meet the requirements for both high accuracy and rapid response. This paper proposes a transient voltage assessment and control method based on a hybrid neural network incorporated with an improved snow ablation optimization (ISAO) algorithm. The core innovation of the proposed method lies in constructing an intelligent “physics-informed and neural network-integrated” framework, which achieves the integration of stability assessment and control strategy generation.… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.072188 - 27 March 2026
（This article belongs to the Special Issue: Advanced Analytics on Energy Systems)
Abstract With the high proportion of new energy access, the traditional fault self-healing mechanism of the distribution network is challenged. Aiming at the demand for fast recovery of new distribution network faults, this paper proposes a fault self-healing cooperative strategy for the new energy distribution network based on an improved ant colony-genetic hybrid algorithm. Firstly, the graph theory adjacency matrix is used to characterize the topology of the distribution network, and the dynamic positioning of new energy nodes is realized. Secondly, based on the output model and load characteristic model of wind, photovoltaic, and energy storage,… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.075245 - 27 March 2026
Abstract A wind-turbine power system is often challenged by voltage instability, reactive power imbalance, and limited fault ride-through capability under grid disturbances. Doubly Fed Induction Generator based wind farms, owing to their partial coupling with the grid, are particularly vulnerable to voltage dips and excessive reactive power absorption during fault events. This study proposes an adaptive control strategy based on Model Reference Adaptive Control integrated with stator flux-oriented vector control to regulate active and reactive power of a DFIG-based wind farm connected to a standard IEEE 9-bus power system under fault conditions. The proposed control scheme… More >
Graphic Abstract
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.073012 - 27 March 2026
（This article belongs to the Special Issue: Advances in Renewable Energy Systems: Integrating Machine Learning for Enhanced Efficiency and Optimization)
Abstract The accuracy of photovoltaic (PV) power prediction is significantly influenced by meteorological and environmental factors. To enhance ultra-short-term forecasting precision, this paper proposes an interpretable feedback prediction method based on a parallel dual-stream Temporal Convolutional Network-Bidirectional Long Short-Term Memory (TCN-BiLSTM) architecture incorporating a spatiotemporal attention mechanism. Firstly, during data preprocessing, the optimal historical time window is determined through autocorrelation analysis while highly correlated features are selected as model inputs using Pearson correlation coefficients. Subsequently, a parallel dual-stream TCN-BiLSTM model is constructed where the TCN branch extracts localized transient features and the BiLSTM branch captures long-term… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.072166 - 27 March 2026
（This article belongs to the Special Issue: Trends of Offshore Wind Technologies: Support Structure Design, Health monitoring, HVDC transmission, Control and Optimization)
Abstract When the converter bus voltage of a voltage source converter-based high voltage direct current (VSC-HVDC) system drops below a certain predetermined threshold, the system enters low-voltage ride-through (LVRT) mode to avoid overcurrent and potential equipment failure, during which it operates as a controlled current source. The influence mechanism of LVRT control strategies on short-circuit current and overall system stability remains not yet fully and systematically investigated. First, this paper provides an overview of several LVRT strategies for VSC-HVDC systems and examines their effects on short-circuit current contribution. Next, it analyzes in detail the mechanisms through… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.075393 - 27 March 2026
（This article belongs to the Special Issue: Advancements in Energy Resources and Their Processes, Systems, Materials and Policies for Affordable Energy Sustainability)
Abstract Limited adoption of solar energy in the Northwestern region of Russia is associated with insufficient data on annual solar radiation indicators and on the potential of solar collectors for water heating. The study aims to evaluate the potential of solar water heating for domestic use in Northwestern Russia, using Tyumen city as the case. In this region, the number of cloudy days ranges from 5% to 50%, with cloud cover increasing in winter. New data on the total solar radiation, availability duration, and cloud cover have been collected. Solar irradiance could reach 900 MJ/m2 during summer… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072246 - 27 March 2026
（This article belongs to the Special Issue: Integration of Hybrid Renewable Energy Systems for Sustainable Development)
Abstract Further investigation is warranted into the collaborative function of carbon capture and electrolysis-to-gas conversion technologies within integrated electro-gas energy systems, as well as optimized scheduling that addresses the variability of wind and solar energy, to promote multi-energy complementarity and energy decarbonization while enhancing the capacity to absorb new energy. This work presents an optimized scheduling model for electro-gas integrated energy systems that include hydrogen storage, utilizing information gap decision theory (IGDT). A model is constructed that integrates the synergistic functions of carbon capture and storage (CCS), power-to-gas (P2G), and gas turbine units through electrical coupling.… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072189 - 27 March 2026
Abstract This paper develops an innovative computational model for assessing the Carbon Emission Factor (CEF) of provincial power systems that incorporates inter-provincial electricity transfers and hybrid generation portfolios combining conventional and renewable sources. A key contribution lies in evaluating how deep regulation of thermal power plants influence the carbon intensity of coal-fired generation and coal-fired generation together with high penetration renewables. Furthermore, the study quantitatively analyzes the role of renewable energy consumption and the prospective application of Carbon Capture and Storage (CCS) in reducing system-wide CEF. Based on this framework, the paper proposes phased carbon emission… More >
Graphic Abstract
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.075837 - 27 March 2026
（This article belongs to the Special Issue: Advancements in Energy Resources and Their Processes, Systems, Materials and Policies for Affordable Energy Sustainability)
Abstract The current study aims to improve the performance of the electrohydraulic servo system (EHSS) by increasing the volumetric efficiency of the pump and reducing electrical power consumption to a minimum value. An experimental setup has been designed and built to control the cylinder position using a programmable logic controller to provide the appropriate motor speed from the AC drive to control the velocity of the hydraulic actuator; the induction motor is driven by an AC drive using a tune proportional-integral-variable frequency drive (TPI-VFD) space vector modulation (SVM) hybrid technology. Theoretically, it was analyzed and simulated… More >
Graphic Abstract
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072678 - 27 March 2026
（This article belongs to the Special Issue: Trends of Offshore Wind Technologies: Support Structure Design, Health monitoring, HVDC transmission, Control and Optimization)
Abstract Fatigue loads on wind turbines are critical factors that significantly influence operational lifespan and reliability. The passive yaw control of wind turbines often fails to capture the dynamic gradient changes of wind speed and direction in the wind field, leading to an increased risk of load overload, severely affecting operational lifespan and reducing power generation efficiency. This impact is even more pronounced during the passage of a cold front. To address this issue, this paper proposes an independent variable-pitch control method that optimizes predictions by utilizing the spatiotemporal relationship between pre-observed cold front patterns and… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072787 - 27 March 2026
（This article belongs to the Special Issue: Operation and Control of Grid-connected New Energy and Emerging Loads)
Abstract The increasing penetration of renewable energy sources (RES) imposes stringent flexibility requirements on thermal power units (TPUs). Integrating molten salt thermal storage systems (MSTS) and thermal-electric coupling technologies into TPUs has the potential to improve their operational flexibility and regulation capability. However, existing research seldom investigates the combined effects of MSTS retrofitting and thermal-electric output coupling on short-term dispatchability, especially under rapid load variation conditions. This study proposes a comprehensive modeling and multi-timescale optimization framework for MSTS-retrofitted TPUs with rapid load variation capability, enabling coordinated thermal and electrical dispatch in both day-ahead and real-time stages.… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.073233 - 27 March 2026
（This article belongs to the Special Issue: Enhanced Oil and Gas Recovery in Unconventional Reservoirs)
Abstract To investigate the long-term fracture conductivity behavior of propped fractures under the high-temperature and high-pressure conditions of deep shale gas reservoirs in the Sichuan Basin, this study systematically analyzed the effects of closure stress, proppant concentration, formation temperature, and proppant size combination. Conductivity experiments were conducted using the HXDL-2C long-term proppant conductivity evaluation system under simulated reservoir conditions to determine the time-dependent evolution of fracture conductivity. The results showed that the 50-h conductivity retention of the rock-plate experiments ranged from 22% to 28%. With increasing closure stress, fracture conductivity exhibited a rapid decline. Under a… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.076278 - 27 March 2026
（This article belongs to the Special Issue: Thermal Engineering Technology Innovation and Sustainable Development)
Abstract The use of alternative fuels to generate mechanical and thermal energy in engines is a promising and sought-after technological area with its own unique advantages and characteristics. Consequently, enhancing the technical, economic, and environmental efficiency of gas engines fueled by propane-butane mixture and syngas through optimized operating cycle parameters (including valve timing, ignition timing angle, fuel mixture composition, and compression ratio) is a pressing imperative for scientific and energy sectors. The aim of the study was to investigate and compare the performance of an engine with different compression ratios running on a propane-butane mixture and… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072906 - 27 March 2026
Abstract Lithium-ion (Li-ion) batteries stand as the dominant energy storage solution, despite their widespread adoption, precisely determining the state of charge (SOC) continues to pose significant difficulties, with direct implications for battery safety, operational reliability, and overall performance. Current SOC estimation techniques often demonstrate limited accuracy, particularly when confronted with complex operational scenarios and wide temperature variations, where their generalization capacity and dynamic adaptation prove insufficient. To address these shortcomings, this work presents a PSO-TCN-Transformer network model for SOC estimation. This research uses the Particle Swarm Optimization (PSO) method to automatically configure the architectural parameters of… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2025.072416 - 27 March 2026
Abstract Re-fracturing horizontal wells is a critical strategy for enhancing recovery from tight oil reservoirs, but its success depends on the evaluation of candidate wells and locations. This process is complicated by production-induced alterations in reservoir pressure and geomechanical responses. This study introduces a workflow to evaluate re-fracturing potential by integrating coupled fluid flow and geomechanical modeling for the production of initial hydraulic fractures. We developed a numerical model that simulates the poroelastic response of a tight oil reservoir to depletion from an initial set of hydraulic fractures. To quantify the re-fracturing potential along the horizontal… More >
Open Access
ARTICLE
Energy Engineering, Vol.123, No.4, 2026, DOI:10.32604/ee.2026.075576 - 27 March 2026
（This article belongs to the Special Issue: Science, Engineering, and Policy Innovations Driving the Global Energy Transition)
Abstract An integral part of the effort to reduce greenhouse gas emissions is carbon footprint accounting. EPA categorizes facility carbon footprints in three scopes. Scope-2 emissions include electricity, heat or steam purchased from a utility provider. This paper evaluates the existing calculation methods for scope-2 CO2 emissions for purchased electricity. The electricity grid in US is complex and is divided spatially into states, eGRID regions, balancing authorities (BAs), and utilities. Up to hourly temporal granularity can be obtained from available datasets. A matrix is developed that categorizes different datasets based on the complexity to calculate the carbon… More >
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