Wei Chen, Yang Wu^*, Tingting Pei, Jie Lin, Guojing Yuan

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070905 - 27 January 2026

Abstract In view of the insufficient utilization of condition-monitoring information and the improper scheduling often observed in conventional maintenance strategies for photovoltaic (PV) modules, this study proposes a predictive maintenance (PdM) strategy based on Remaining Useful Life (RUL) estimation. First, a RUL prediction model is established using the Transformer architecture, which enables the effective processing of sequential degradation data. By employing the historical degradation data of PV modules, the proposed model provides accurate forecasts of the remaining useful life, thereby supplying essential inputs for maintenance decision-making. Subsequently, the RUL information obtained from the prediction process is… More >

Zhirong Jin^1,*, Xiaorui Hou¹, Yanrong Ge¹, Tiankui Guo², Ming Chen², Shuyi Li², Tianyu Niu²

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070750 - 27 January 2026

Abstract Hydraulic fracturing serves as a critical technology for reservoir stimulation in deep coalbed methane (CBM) development, where the mechanical properties of gangue layers exert a significant control on fracture propagation behavior. To address the unclear mechanisms governing fracture penetration across coal-gangue interfaces, this study employs the Continuum-Discontinuum Element Method (CDEM) to simulate and analyze the vertical propagation of hydraulic fractures initiating within coal seams, based on geomechanical parameters derived from the deep Benxi Formation coal seams in the southeastern Ordos Basin. The investigation systematically examines the influence of geological and operational parameters on cross-interfacial fracture… More >

Kai Xie¹, Shaoqing Yuan², Dayun Zou¹, Jinran Wang^1,*, Genjun Chen¹, Ciwei Gao³, Yinghao Cao¹

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070733 - 27 January 2026

Abstract The construction of spot electricity markets plays a pivotal role in power system reforms, where market clearing systems profoundly influence market efficiency and security. Current clearing systems predominantly adopt a single-system architecture, with research focusing primarily on accelerating solution algorithms through techniques such as high-efficiency parallel solvers and staggered decomposition of mixed-integer programming models. Notably absent are systematic studies evaluating the adaptability of primary-backup clearing systems in contingency scenarios—a critical gap given redundant systems’ expanding applications in operational environments. This paper proposes a comprehensive evaluation framework for analyzing dual-system adaptability, demonstrated through an in-depth case… More >

Jiangyang Yuan¹, Jiaowen Wu¹, Yi Gao¹, Yuhao Fu², Yuntao Bu², Tianyu Chen², Hao Yu^2,*

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070715 - 27 January 2026

Abstract In the pursuit of carbon peaking and neutrality goals, multi-energy parks, as major energy consumers and carbon emitters, urgently require low-carbon operational strategies. This paper proposes an electricity-carbon synergy-driven optimization method for the low-carbon operation of multi-energy parks. The method integrates multi-energy complementary scheduling with a tiered carbon trading mechanism to balance operational security, economic efficiency, and environmental objectives. A mixed-integer linear programming model is developed to characterize the coupling relationships and dynamic behaviors of key equipment, including photovoltaic systems, ground-source heat pumps, thermal storage electric boilers, combined heat and power units, and electrical energy… More >

Junxian Ma¹, Haonan Zhao^2,*, Zhibing Hu³, Yaru Shen³, Fan Ding³, Shouqi Jiang²

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070530 - 27 January 2026

Abstract Energy storage-equipped photovoltaic (PV-storage) systems can meet frequency regulation requirements under various operating conditions, and their coordinated support for grid frequency has become a future trend. To address frequency stability issues caused by low inertia and weak damping, this paper proposes a multi-timescale frequency regulation coordinated control strategy for PV-storage integrated systems. First, a self-synchronizing control strategy for grid-connected inverters is designed based on DC voltage dynamics, enabling active inertia support while transmitting frequency variation information. Next, an energy storage inertia support control strategy is developed to enhance the frequency nadir, and an active frequency… More >

Dexiecia Anak Francis¹, Jalal Tavalaei¹, Hadi Nabipour Afrouzi^2,*

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070501 - 27 January 2026

Abstract Wave energy is a promising form of marine renewable energy that offers a sustainable pathway for electricity generation in coastal regions. Despite Malaysia’s extensive coastline, the exploration of wave energy in Sarawak remains limited due to economic, technical, and environmental challenges that hinder its implementation. Compared to other renewable energy sources, wave energy is underutilized largely because of cost uncertainties and the lack of local performance data. This research aims to identify the most suitable coastal zone in Sarawak that achieves an optimal balance between energy potential, cost-effectiveness, and environmental impact, particularly in relation to… More >

Lei Zhao¹, Lihui Ma², Junwen Chen³, Pan Zhang², Jiang Bian^4,*, Dong Sun²

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070290 - 27 January 2026

Abstract Shock waves in the nozzle during supersonic separation under different conditions can disrupt the flow field’s thermodynamic equilibrium. While it contributes to the recovery of pressure energy, it also leads to the dissipation of mechanical energy. This study aimed to investigate the effects of changes in back pressure on the shock wave position and its subsequent impact on the refrigeration performance of nozzles. A mathematical model for the supersonic gas in a nozzle was established and evaluated via experiments. The results show that when the back pressure is less than 0.2 MPa, no shock wave… More >

Mehran Karimi¹, Hesamodin Heidarigoujani¹, Mehdi Jahangiri^1,*, Milad Torabi Anaraki², Daryosh Mohamadi Janaki³

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.070190 - 27 January 2026

Abstract The technical, economic, and environmental performance of solar hot-water (SWH) systems for Swedish residential apartments—where approximately 80% of household energy is devoted to space heating and sanitary hot-water production—was assessed. Two collector types, flat plate (FP) and evacuated tube (ET), were simulated in TSOL Pro 5.5 for five major cities (Stockholm, Göteborg, Malmö, Uppsala, Linköping). Climatic data and cold-water temperatures were sourced from Meteonorm 7.1, and economic parameters were derived from recent national statistics and literature. All calculations explicitly accounted for heat losses from collectors, storage tanks, and internal and external piping systems, and established… More >

Chenxuan Zhang, Yongqing Qi^*, Ximin Cao, Yanchi Zhang

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.069878 - 27 January 2026

Abstract To enhance the low-carbon economic efficiency and increase the utilization of renewable energy within integrated energy systems (IES), this paper proposes a low-carbon dispatch model integrating power-to-gas (P2G), carbon capture and storage (CCS), hydrogen fuel cell (HFC), and combined heat and power (CHP). The P2G process is refined into a two-stage structure, and HFC is introduced to enhance hydrogen utilization. Together with CCS and CHP, these devices form a multi-energy conversion system coupling electricity, heat, cooling, and gas. A ladder-type carbon trading approach is adopted to flexibly manage carbon output by leveraging marginal cost adjustments.… More >

Hongsheng Su, Zhensheng Teng^*, Zihan Zhou

Energy Engineering, Vol.123, No.2, 2026, DOI:10.32604/ee.2025.069495 - 27 January 2026

Abstract Addressing the limitations of inadequate stochastic disturbance characterization during wind turbine degradation processes that result in constrained modeling accuracy, replacement-based maintenance practices that deviate from actual operational conditions, and static maintenance strategies that fail to adapt to accelerated deterioration trends leading to suboptimal remaining useful life utilization, this study proposes a Time-Based Incomplete Maintenance (TBIM) strategy incorporating reliability constraints through stochastic differential equations (SDE). By quantifying stochastic interference via Brownian motion terms and characterizing nonlinear degradation features through state influence rate functions, a high-precision SDE degradation model is constructed, achieving 16% residual reduction compared to… More >