Melita Srpak¹, Darko Pavlovic², Predrag Brlek^3,*, Nikola Kozul³

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2026.075211 - 27 February 2026

Abstract Discussions about the future of energy sources and environmental sustainability are becoming critical on a global scale. The energy sector plays a central role in the economy, as the availability and cost of energy influence the competitiveness of economies, while the level of energy consumption impacts the standard of living for individuals. This paper aims to examine environmental challenges and steps for a sustainable transition towards a hydrogen economy, focusing on its potential as an alternative to fossil fuels and the importance of developing the hydrogen paradigm. The research methodology is based on a combination… More >

Ebtehal Chasseb Jbary^*, Alaa R. Al-Badri

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2025.074415 - 27 February 2026

Abstract Despite significant advancements in solar collector technology, persistent challenges remain in improving the overall efficiency of solar systems. This paper investigates the use of mini-channel aluminum tubes mounted on the reflective surface as preliminary heating stages to enhance the overall system thermal performance. Experimental assessments were conducted with flow rates ranging from 0.1 to 0.8 LPM and tilt angles of 180° South and 225° Southwest in Al-Kut, Iraq, from 9:00 AM to 2:00 PM. Fluid flows sequentially through five flat aluminum tubes totaling 50 channels, named stage-1, then flows through four aluminum tubes totaling 40… More >

Shaymaa Husham Abdulmalek¹, Ali Ahmed Gitan^2,*, Israa Sami Farhan², Oras Fadhil Khalaf¹, Sayf Waleed Albayati¹

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2026.074018 - 27 February 2026

Abstract The utilisation of waste in green sustainable technology can provide a clean environment and support energy demand. This work aims to design and analyse the performance of a developed indirect flat-plate Solar Air Heater (SAH) integrated with an internal thermal storage unit using Waste Automotive Oil (WAO). The SAH was designed based on the circulation of confined air around the internal thermal storage unit due to the updraft effects of hot air. Two SAHs were tested to compare the performance of WAO and water, with the results being compared to previous work that utilised phase… More >

Naveen Guguloth¹, Bishwajit Dey², Fausto Pedro García Márquez^3,*, Prasenjit Dey¹, Isaac Segovia Ramírez⁴

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2025.073971 - 27 February 2026

Abstract The increasing integration of electric vehicle (EV) loads into power systems necessitates understanding their impact on stability. Small-magnitude perturbations, if persistent, can cause low-frequency oscillations, leading to synchronism loss and mechanical stress. This work analyzes the effect of voltage-dependent EV loads on this small-signal stability. The study models an EV load within a Single-Machine Infinite Bus (SMIB) system. It specifically evaluates the influence of EV charging through the DC link capacitor of a Unified Power Flow Controller (UPFC), a key device for damping oscillations. The system’s performance is compared to a modified version equipped with More >

Samar Taha Yousif^1,2, Firas Basim Ismail^1,3,*, Ammar Al-Bazi⁴, Alaa Abdulhady Jaber⁵, Sivadass Thiruchelvam¹

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2025.073955 - 27 February 2026

Abstract Thermal power plants are the main contributors to greenhouse gas emissions. The prediction of the emission supports the decision makers and environmental sustainability. The objective of this study is to enhance the accuracy of emission prediction models, supporting more effective real-time monitoring and enabling informed operational decisions that align with environmental compliance efforts. This paper presents a data-driven approach for the accurate prediction of gas emissions, specifically nitrogen oxides (NOx) and carbon monoxide (CO), in natural gas power plants using an optimized hybrid machine learning framework. The proposed model integrates a Feedforward Neural Network (FFNN)… More >

Abdin Abdin¹, Nicola Bianchi^1,*, Andrea Voltan², Walter Faedo², Piero Cazzavillan², Alessandro Biason²

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2025.073434 - 27 February 2026

Abstract Synchronous reluctance motors (SynRM) are widely employed in industrial applications due to their high robustness, low cost, and absence of permanent magnets. In recent years, significant research efforts have focused on improving the controllability and efficiency of SynRM. Accurate rotor position information is essential for the controller to generate appropriate current and voltage references corresponding to the desired speed and load torque. Shaft-mounted position sensors are generally undesirable because of their high cost, sensitivity to harsh operating conditions, maintenance requirements, and reduced reliability in environments characterized by high vibration. Consequently, sensorless control techniques that estimate… More >

Wulfran Fendzi Mbasso^1,2, Idriss Dagal³, Manish Kumar Singla^4,5,*, Muhammad Suhail Shaikh⁶, Aseel Smerat⁷

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2026.072899 - 27 February 2026

Abstract Utility-scale PV plants increasingly operate under partial shading, soiling, temperature swings, and rapid irradiance ramps that depress yield and challenge stability on weak grids. This critical review addresses those conditions by (i) unifying a stressor-to-method taxonomy that links field stressors to global intelligent MPPT (metaheuristics and learning-based trackers) and to advanced inverter controls (adaptive/MPC and grid-forming), (ii) standardizing metrics and reporting aligned with IEC 61724-1 and IEEE 1547/1547.1 to enable fair, reproducible comparisons, and (iii) framing MPPT and grid support as a co-design problem with a DT→HIL→Field validation pathway and seedable scenarios. We identify persistent… More > Graphic Abstract

Zezhong Liu, Jinyu Guo, Xingxu Zhu^*, Junhui Li

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2025.072679 - 27 February 2026

Abstract With the increasing penetration of renewable energy, the coordination of energy storage with thermal power for frequency regulation has become an effective means to enhance grid frequency security. Addressing the challenge of improving the frequency regulation performance of a thermal-storage primary frequency regulation system while reducing its associated losses, this paper proposes a multi-dimensional cooperative optimization strategy for the control parameters of a combined thermal-storage system, considering regulation losses. First, the frequency regulation losses of various components within the thermal power unit are quantified, and a calculation method for energy storage regulation loss is proposed,… More >

Mirna Omar^1,*, Sarah Omar¹, Kamaruzzaman Sopian^1,2, Taib Iskandar Mohamad¹

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2026.072583 - 27 February 2026

Abstract Photoreforming is an emerging photocatalytic process that converts organic waste into hydrogen H₂ using solar energy, offering a dual solution for waste valorization and sustainable fuel production. This review comprehensively examines the fundamental mechanisms of photoreforming, emphasizing the critical role of photocatalyst design in optimizing hydrogen evolution. Key criteria for effective photocatalysts including suitable band edge positions, broad spectrum solar absorption, and photostability are systematically analyzed alongside advances in heterojunction engineering and defect modulation. The review further explores diverse waste-derived feedstocks, such as biomass: alcohols, saccharides, lignin and plastics: PET, PLA, polyolefins, highlighting substrate, specific challenges More > Graphic Abstract

Song Zhang, Yang Yu^*, Shuguang Li, Xue Li

Energy Engineering, Vol.123, No.3, 2026, DOI:10.32604/ee.2025.072333 - 27 February 2026

Abstract Thermal storage electric heating (TSEH), as a prevalent variable load resource, offers significant potential for enhancing system flexibility when aggregated into a cluster. To address the uncertainties of renewable energy and load forecasting in active distribution networks (ADN), this paper proposes a multi-timescale coordinated optimal dispatch strategy that incorporates TSEH clusters. It utilizes the thermal storage characteristics and short-term regulation capabilities of TSEH, along with the rapid and gradual response characteristics of resources in active distribution grids, to develop a coordinated optimization dispatch mechanism for day-ahead, intraday, and real-time stages. It provides a coordinated optimized… More > Graphic Abstract