Search Results (714)

Accurate assessment of the State of Health (SOH) is critical for battery management systems in aviation. As a step towards this goal, this study presents a proof-of-concept for a novel SOH estimation method based on an Improved Particle Swarm Optimization-Extreme Learning Machine (IPSO-ELM) model, validated under controlled laboratory cycling conditions. Although traditional Extreme Learning Machines (ELM) are widely used due to their fast computation and good generalization, their random parameter initialization often leads to unstable convergence and limited accuracy. To address these limitations, this paper proposes a novel SOH estimation method based on an Improved Particle Swarm Optimization (IPSO) algorithm to optimize the key parameters of ELM. Three health indicators (HI)—constant-current charging time, equal-voltage-drop discharge time, and average discharge voltage—were extracted from charge–discharge curves as model inputs. The IPSO algorithm dynamically adjusts the inertia weight, introduces a constriction factor and a termination counter to enhance global search capability and avoid local optima. Experimental results on open-source datasets (B005, B007, B0018) and laboratory datasets (A001, A002) demonstrate that the proposed IPSO-ELM model achieves a Root-Mean-Square Error (RMSE) below 0.7% and a Mean Absolute Percentage Error (MAPE) below 0.5%. Compared with standard ELM and PSO-ELM models, it significantly outperforms them in accuracy (e.g., for B0018, RMSE is reduced to 0.21% and MAPE to 0.14%), convergence speed, and robustness, establishing a foundation for future development of aviation-ready SOH estimators. Full article

Distributed integrated energy systems embedding biomass combined heat and power (BCHP) have the potential to enhance energy supply reliability in rural areas and to support the low-carbon transformation. However, the sources and transmission paths of car-bon emissions remain difficult to quantify due to the multi-energy coupling and diverse conversion processes. To address these issues, this study develops a carbon flow tracking and scheduling strategy for BCHP-integrated distributed energy systems. First, a bio-chemical reaction process model for BCHP is established to enable a life cycle-based carbon emission accounting. Second, the flexible heat-to-power ratio characteristics of BCHP are considered to more accurately reflect multi-energy coupling under varying operating conditions. Third, a dual-objective optimal scheduling model is constructed by combining node carbon potential with operating costs, enabling the system to simultaneously minimize operating costs and carbon emissions. A case study of an integrated energy system in Anping County, Hebei Province, demonstrates that the proposed method reduces total carbon emissions by over 9.8%, increases renewable energy utilization by 15.2%, and lowers operating costs by 7.5%. The results reveal the carbon flow characteristics and emission reduction potential of rural distributed integrated energy systems embedding BCHP, providing methodological support and empirical evidence for refined low-carbon governance. Full article

The proton exchange membrane (PEM) electrolyzer is vital for converting surplus renewable energy (RE) into hydrogen, underpinning the efficient and stable operation of the electric–hydrogen system. However, frequent start–stop cycles and load variations accelerate the degradation of proton exchange membranes and catalyst layers, incurring significant lifetime costs that existing studies ignore. To explore how the PEM electrolyzer’s dynamic traits impact system performance, we introduce an optimized operation approach for the electricity–hydrogen integrated energy system (IES) that incorporates these dynamic features and the novel Loss of Life Cost (LLC) model. Initially, to rectify the inadequacy in modeling the PEM electrolyzer within the current electricity–hydrogen IES operational framework, we integrate its dynamic characteristics based on electrochemical properties and establish a quantitative relationship between operational cycles and degradation costs. This enhanced model accurately reflects how operational conditions affect the electrolyzer’s hydrogen production efficiency and lifetime consumption, enabling precise performance simulation and economic assessment. This, in turn, promotes high-quality renewable energy utilization via hydrogen production while ensuring asset longevity, meeting the rising demand for hydrogen energy applications. Building on this, we further factor in constraints related to diverse energy conversion and safe operation within the electricity–hydrogen IES, as well as the operational limits of hydrogen fuel cells, various energy storage (ES) options, cogeneration units, and other pertinent equipment, aiming to minimize the system’s total daily costs (operational plus degradation costs). Consequently, we develop an optimization operation model for the electricity–hydrogen IES that accounts for the PEM electrolyzer’s dynamic characteristics and degradation economics. Finally, through simulation examples validated against published experimental data, we comprehensively analyze how the PEM electrolyzer’s dynamic traits influence system operation, confirming the effectiveness of our proposed model and methodology. Simulation findings reveal that, under varying electrolyzer capacities, ignoring the PEM electrolyzer’s dynamic characteristics can result in a deviation in system operating. Compared with the proposed method, it can reduce the equipment degradation speed by a maximum of 5.78 times. Full article

Upon the challenges of climate change and the demand for energy sustainability, nuclear power (NP) units not only provide clean electricity but are also equipped for cogeneration to achieve energy cascade utilization; this represents a key avenue for improving the overall efficiency and achieving the comprehensive utilization of nuclear energy. However, following the heating retrofitting stage, there exists a risk that the supply control valve of the unit may accidentally open completely during operation, which increases the risk of over-powering. Therefore, this study designs response schemes for second-generation large pressurized water reactor NP plants (NPPs) under the accidental full-open condition of the heat-supply control valve. Specifically, an integrated model encompassing the nuclear steam supply system, secondary circuit system, thermal energy supply system (TESS), and related control systems was constructed using the optimal estimation program and 3KeyMaster simulation platform. Subsequently, two response schemes were designed for the accidental full-open valve scenario under two operation modes—namely, the “Reactor Follows Turbine + TESS” and “Turbine Follows TESS” modes. Finally, on the basis of the established simulation platform, the scenario of accidental full opening of the heat-supply control valve was simulated and verified. Ultimately, the results indicate that the response scheme implemented under the “Turbine Follows TESS” mode is more effective in suppressing nuclear overpower when the heat supply control valve accidentally opens fully. Thus, overall, this study provides a feasible accident response strategy and critical technical reference for NPPs involving cogeneration and energy cascade utilization. Full article

Cogeneration system optimization in refineries confronts the challenge of simultaneously integrating design parameter selection and topological configuration. The literature typically addresses these aspects separately: parametric optimization with fixed topology or configuration optimization for specific nominal conditions. This work develops a comprehensive methodology integrating exhaustive parametric exploration with superstructure-based optimization through mixed-integer nonlinear programming (MINLP), applied to the Miguel Hidalgo refinery in Tula, Mexico. The systematic procedure generates superstructures considering all viable expansion and tempering routes under steam quality restrictions ($x\ge 0.88$), evaluating 84–105 combinations of generation pressure ($P_{\mathrm{HRSG}}=70$–140 bar) and superheater outlet temperature ($T_{s_4}=500$–560 °C). The analysis reveals three topologically distinct configurations identified as generating maximum power under different operating conditions and characterizes how transitions between high-performing configurations occur at discrete thermodynamic thresholds that correlate with constraint activation contradicting the conventional assumption of continuous parameter-configuration relationships. Multi-criteria evaluation positions Configuration 1 as the recommended design, generating 25% increase in electric generation, 11% improvement in utilization factor ($UF$: $0.640\to 0.710$) and 20% reduction in specific fuel consumption ($SFC$: $0.259\to 0.207$ kg/kWh). The methodology is directly generalizable to other refineries through universal thermodynamic principles, with a systematic five-step procedure applicable to any multi-pressure steam demand profile. The characterization of discrete transition phenomena and the associated methodology for their thermodynamic explanation challenges the conventional assumption of continuous parameter–configuration relationships in optimization approaches, with immediate implications for the design of flexible cogeneration systems in refineries worldwide. Full article

In this article operational problems associated with the use of landfill biogas as an alternative fuel in cogeneration systems, with particular emphasis on micro-installations based on the Perkins 4008-30 TRS2 combustion engine are presented. Such installations are commonly used in cogeneration systems, whose importance in obtaining stable electric and thermal energy is growing, especially when taking into account the additional reduction in environmental impact through biogas combustion. Reducing emissions of biogas, which consists of approximately 60% methane and approximately 35% carbon dioxide, directly reduces emissions of a greenhouse gas (GHG) with a high global warming potential (GWP). In this study the characteristics of the landfill, the biogas purification system, the measurement system and the energy balance of the entire process, biogas production → electric energy → thermal energy, are presented and the importance of this type of installation in the context of a low-carbon economy is discussed. Attention is also drawn to the operational problems of the cogeneration system, which led to its failure, requiring comprehensive repairs of the internal combustion engine. Full article

To overcome the limitations of static operation modes in traditional cogeneration and the intermittency of renewable energy, this paper proposes a scenario-assisted adaptive robust optimization framework with a dispatch resolution for Integrated Energy Systems (IES). A closed-loop cascading mechanism is established, integrating biomass co-firing, Carbon Capture and Storage (CCS), and Power-to-Gas (P2G) technologies, where captured ${\mathrm{CO}}_2$ reacts with green hydrogen to produce synthetic natural gas, thereby closing the carbon cycle. Specifically, a dynamic model for hydrogen-blending gas turbines is developed, characterizing the thermodynamic performance under variable hydrogen blending ratios (0–20%), which enables the system to adaptively adjust fuel composition in response to real-time fluctuations in wind and solar power. Furthermore, a tiered carbon trading mechanism is introduced to internalize environmental costs and constrain emissions. Simulation results demonstrate that the proposed variable blending strategy effectively mitigates wind curtailment, reducing curtailment costs to 0.31 million ¥, and creates a “double-peak, double-valley” carbon emission profile, reducing the net load peak-to-valley difference by 18.5%. The proposed framework achieves a balance between economic efficiency and deep decarbonization, attaining an optimal unit carbon reduction cost of 0.142 ¥/kWh, demonstrating improved economic and environmental performance of dynamic electro-carbon-hydrogen coupling under variable operating conditions. Full article

Waste heat capture and reuse from battery storage systems for cogeneration of heat and power has the potential to both improve their energy efficiency and reduce the carbon footprint. This study performs a comparison of technologies capable of converting the waste heat extracted to a useful purpose. This analysis is accomplished using the literature data as a basis for an analytical hierarchy process (AHP) applying technological efficiency, cost effectiveness, footprint and integration, and safety and environmental concerns as the criteria. Of these, cost effectiveness was found to be dominant, with technological efficiency also showing high importance. Heat pumps were found to be the most effective based on the objective and criteria of this analysis. This study dictates a pathway that allows stakeholders and decision makers to determine a route by which site-specific comparisons may be made, aiding them to navigate the complex interplay of competing objectives. Full article

The integration of hydrogen into natural-gas-fired gas turbines represents a promising transitional pathway for reducing greenhouse gas emissions in industrial power generation. This study presents a comparative thermodynamic and environmental assessment of a Solar Titan 130 gas turbine operating in combined heat and power (CHP) mode under two fueling conditions: conventional natural gas and a hydrogen-enriched CH₄/H₂ (80/20 vol.%) blend. The analysis combines validated operational data for natural gas with analytical thermodynamic modeling for the blended-fuel scenario to evaluate key performance indicators, including thermal efficiency, specific fuel consumption, power output, and carbon dioxide emissions. The results indicate that hydrogen enrichment leads to an increase in thermal efficiency from 34.1% to 36.6% and a reduction in specific CO₂ emissions by approximately 13.7%, while maintaining similar thermal input within the adopted steady-state modeling framework. Compressor power consumption decreases, and net electrical output increases slightly under hydrogen-enriched operation, contributing to improved overall energy performance. Although the hydrogen-blended regime is assessed through modeling, the findings suggest that moderate hydrogen addition can enhance efficiency and environmental performance in industrial gas turbines without fundamental structural redesign of the turbine core, assuming appropriate fuel supply and control system adaptation. The study provides practical insights into the feasibility of hydrogen-assisted operation in existing CHP installations and supports its role in near-term decarbonization strategies. Full article

Wastewater treatment plants increasingly rely on anaerobic digestion and biogas utilization to reduce operational costs, enhance energy self-sufficiency, and support circular-economy objectives. This study provides a comprehensive, year-round assessment of sludge production, sludge characteristics relevant to digestion, biogas generation, and energy performance at a municipal wastewater treatment plant. The plant generated on average 68.0 m³/d of thickened primary sludge and 24.0 m³/d of excessive sludge (total 92 m³/d), with low daily variability throughout the year. Biogas production remained highly stable, with an annual average of approximately 1300 m³/d and limited daily variation. Although monthly averages ranged from 1004 to 1728 m³/d, within-month variability was low to moderate, indicating that digestion processes responded consistently to changes in sludge quantity and composition. The weak correlation between sludge volume and biogas output (r = 0.29) showed that, besides sludge quantity, factors such as organic content and digester operating conditions also influence biogas yield. Energy performance indicators demonstrated strong self-sufficiency potential: the facility produced 1,095,047 kWh of electricity, covering 56.72% of its annual demand. The high coefficient of determination for self-sufficiency (R² = 0.871) confirmed a strong linear relationship between biogas-derived energy production and reduced grid dependence. Operational correlations further highlighted system coherence, with cogenerator and boiler usage strongly inversely related (r = −0.85) and biogas production positively associated with heat output (r = 0.66). Overall, the results demonstrate a stable and efficient sludge-to-energy system and provide a detailed dataset supporting future optimization of anaerobic digestion processes. Full article

This study investigates the gasification of pistachio shells for the co-production of biochar and renewable energy, integrating process simulation, energy recovery, and techno-economic–environmental assessment. The investigation has been carried out by experimental tests in a 30 kg/h downdraft gasification–cogeneration system and process simulation. The zero-dimensional simulation model, validated against first-hand experimental data, was used to evaluate two operational scenarios differing in biochar yield (10% and 17%) and energy yield. The integration of the gasification–CHP system with a representative pistachio-processing facility (500 t yr⁻¹ shell availability) demonstrated annual useful energy outputs ranging from 574 to 900 MWh yr⁻¹ (as the sum of heat and electricity). The techno-economic analysis yielded operating profits of 96,720–117,637 € yr⁻¹, return on investment (ROI) between 15.5% yr⁻¹ and 18.85% yr⁻¹, and payback periods of 6.45 and 5.3 years for the high- and low-char scenarios, respectively. The environmental assessment revealed total CO₂-equivalent savings of 241–279 t yr⁻¹, with biochar sequestration contributing up to 41% of avoided emissions. Overall, the results confirm that higher carbon conversion to syngas enhances energy, environmental and economic performance, while higher biochar yields favour fixing carbon in the soil, according to the assumed scenarios’ conditions. The proposed framework demonstrates a scalable, sustainable solution for coupling pistachio-shell gasification with industrial energy and a material valorization pathway. Full article

To address the challenges of difficult feature extraction for rolling bearing vibration signals, low efficiency in optimizing diagnostic model parameters, and the tendency to get trapped in local optima, this paper proposes an improved ICEEMDAN feature extraction method based on Bayesian optimization and adaptive noise signal ratio enhancement (BAYES-ICEEMDAN-SNR) and combines it with the improved Coriolis force optimization algorithm (ITOC) to optimize the least squares support vector machine (LSSVM) fault diagnosis model. Firstly, Bayesian optimization is used to adaptively determine the noise parameters and introduce a dynamic signal-to-noise ratio adjustment mechanism to enhance the robustness of feature extraction; secondly, Chebyshev chaotic mapping, Cauchy mutation, and dynamic reverse learning strategies are applied to enhance the global search and local escape capabilities of ITOC, thereby optimizing the hyperparameters of LSSVM; and finally, the Keesey-Chestnut University bearing dataset and Huazhong University of Science and Technology gear dataset are used for verification. The experimental results show that the average fault identification accuracy of the proposed method reaches over 97%, which is superior to that of the comparison models, and the effectiveness of each core improvement module of the proposed model is verified through ablation experiments, providing an effective solution for intelligent fault diagnosis of rolling bearings and gears. Full article

Biomass-based energy systems represent a strategic and dispatchable renewable option for sustainable energy transitions in Latin America, where agricultural and agro-industrial residues provide significant potential for circular economy integration. This study presents a PRISMA-compliant systematic literature review synthesizing dominant biomass conversion pathways in the region, with emphasis on biofuels and bioelectricity applications and their reported technical, techno-economic, and environmental indicators. A comprehensive search of Scopus, IEEE Xplore, and ScienceDirect yielded 64 peer-reviewed studies published between 2010 and 2025. Results show a marked growth in scientific output after 2016, although evidence remains concentrated in Brazil, Colombia, and Mexico. Anaerobic digestion emerges as the most frequently assessed route, particularly for agro-industrial effluents, municipal organic waste, livestock residues, and wastewater streams, followed by combustion-based cogeneration linked to sugarcane industries. Electricity generation and biomethane dominate evaluated outputs. Overall, the review highlights technological maturity alongside persistent barriers, including fragmented supply chains, investment constraints, and limited harmonized reporting, underscoring the need for standardized frameworks and system-scale deployment across the region. Full article

The paper presents an analysis of the status and development trends of Polish Waste-to-Energy (WtE) installations in the context of improving the level of energy recovery measured by the R1 indicator of the Waste Framework Directive (R1 is a regulatory indicator of the R1/D10 classification, not the thermodynamic efficiency of the installation). Based on the standardised annual operating energy balances of six mature municipal waste incineration plants from 2020 to 2024 and partial data for 2025, electricity and heat production, auxiliary media consumption and waste fuel parameters were compared, and R1 was calculated in the Ep, Ef, Ew and Ei systems. The R1 values were then compared with heat collection conditions and modernisation implementations (integration with the heating network, exhaust gas condensation, advanced control/predictive algorithms), treating the ‘before/after’ comparisons as an observational assessment, without inferring strict causality. The average R1 for the facilities studied in 2020–2024 was 0.864, with the highest values recorded for installations in Kraków (R1 = 1.123 in 2024). The results indicate that a high and growing R1 is primarily associated with cogeneration and stable heat management in district heating systems, and that upgrades aimed at additional heat recovery and process stabilisation can further support this trend, in line with the ‘energy efficiency first’ principle. A novelty of the study is the standardised, long-term benchmarking of full-scale data for six installations using a uniform R1 methodology. Full article

Hydrogen is a promising clean energy vector capable of decarbonizing future energy systems. This study explores blue hydrogen production via a modified autothermal reforming process, integrated with oxy-fuel combustion and carbon capture technologies. The process achieves approximately 99.8% carbon dioxide capture while co-generating electricity, improving both environmental and economic performance. A detailed techno-economic analysis for Alberta, Canada, shows that hydrogen can be produced at a competitive cost of $1.70 per kilogram, depending on natural gas supply pressure, with CO₂ emissions of just 3.82 kg-CO₂/kg-H₂, meeting stringent international low-carbon thresholds. Key parameters like natural gas supply pressure, oxygen-to-methane ratio, and turbine pressure ratio were optimized for flexibility, efficiency, and cost-effectiveness. Sensitivity analysis identified financial, policy, and grid decarbonization factors as key drivers of production costs. Compared to other methods, this process stands out for its superior environmental and economic outcomes, particularly in regions with ample natural gas and carbon capture infrastructure. The study underscores the importance of process innovation in advancing sustainable blue hydrogen. Full article