Pub Date : 2026-05-01Epub Date: 2026-01-22DOI: 10.1016/j.ecmx.2026.101600
Hamed Fazlollahtabar
Integrating volatile renewable energy into power grids requires robust optimization methods that avoid restrictive probabilistic assumptions. This study proposes a novel two-phase fuzzy model bridging operational planning and strategic market analysis. Phase 1 uses a Mamdani-type fuzzy inference system to generate realistic scenarios for solar/wind availability and demand. Phase 2 formulates a fuzzy linear program to minimize costs under uncertainty, the results of which inform a fuzzy Nash equilibrium model to analyze market participant strategies. Validated on a 10-node model with real California ISO data, our approach reduces system costs by 18.7% and maintains 99.2% reliability, outperforming stochastic and robust benchmarks. The model provides a practical decision-support tool for system operators and policymakers in renewable-dominated energy markets, demonstrating that fuzzy logic effectively captures real-world imprecision without complex data requirements.
{"title":"A fuzzy two-phase model for renewable energy system optimization under uncertainty: from operational to strategic scenario planning","authors":"Hamed Fazlollahtabar","doi":"10.1016/j.ecmx.2026.101600","DOIUrl":"10.1016/j.ecmx.2026.101600","url":null,"abstract":"<div><div>Integrating volatile renewable energy into power grids requires robust optimization methods that avoid restrictive probabilistic assumptions. This study proposes a novel two-phase fuzzy model bridging operational planning and strategic market analysis. Phase 1 uses a Mamdani-type fuzzy inference system to generate realistic scenarios for solar/wind availability and demand. Phase 2 formulates a fuzzy linear program to minimize costs under uncertainty, the results of which inform a fuzzy Nash equilibrium model to analyze market participant strategies. Validated on a 10-node model with real California ISO data, our approach reduces system costs by 18.7% and maintains 99.2% reliability, outperforming stochastic and robust benchmarks. The model provides a practical decision-support tool for system operators and policymakers in renewable-dominated energy markets, demonstrating that fuzzy logic effectively captures real-world imprecision without complex data requirements.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101600"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In line-commuted converter based high voltage direct current (LCC-HVDC), commutation failure (CF) is a main source of danger. The CF is usually suppressed by regulating the single electrical quantity. However, for the active and reactive power of inverter station, the combination of DC current and voltage, AC bus voltage, firing angle (FA) and extinction angle (EA) is the determining influence. The regulation of any electrical quantity leads to variations in power, thereby influencing the AC bus voltage and subsequently inducing variations in the DC current, DC voltage, and EA. The neglect of AC-DC coupling affects the suppression of CF and limits power transmission. The formulation of the active and reactive power of inverter station has been deduced. Considering the constraints imposed by DC current and firing advance angle (FAA), the power feasible range is established. The feasible range of AC bus voltage and power is built considering AC-DC coupling. The commutation security domain of inverter station to avoid CF is modeled. To maximize the active power, formulations of DC current and FAA are proposed. Taking into account the power transmission, an improved suppression method of subsequent CF is proposed. The CIGRE standardized model is utilized to verify the method.
{"title":"Security domain modeling and suppression of commutation failure for LCC-HVDC considering AC-DC coupling","authors":"Shoudong Xu , Jinxin Ouyang , Mingyu Pang , Taiyu Xiao , Chao Xiao","doi":"10.1016/j.ecmx.2026.101608","DOIUrl":"10.1016/j.ecmx.2026.101608","url":null,"abstract":"<div><div>In line-commuted converter based high voltage direct current (LCC-HVDC), commutation failure (CF) is a main source of danger. The CF is usually suppressed by regulating the single electrical quantity. However, for the active and reactive power of inverter station, the combination of DC current and voltage, AC bus voltage, firing angle (FA) and extinction angle (EA) is the determining influence. The regulation of any electrical quantity leads to variations in power, thereby influencing the AC bus voltage and subsequently inducing variations in the DC current, DC voltage, and EA. The neglect of AC-DC coupling affects the suppression of CF and limits power transmission. The formulation of the active and reactive power of inverter station has been deduced. Considering the constraints imposed by DC current and firing advance angle (FAA), the power feasible range is established. The feasible range of AC bus voltage and power is built considering AC-DC coupling. The commutation security domain of inverter station to avoid CF is modeled. To maximize the active power, formulations of DC current and FAA are proposed. Taking into account the power transmission, an improved suppression method of subsequent CF is proposed. The CIGRE standardized model is utilized to verify the method.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101608"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-24DOI: 10.1016/j.ecmx.2026.101552
Mohammad Sameti , Tao Fan , Anna Volkova , Zili Li
Conventional small-scale district heating (DH) systems that serve a limited number of buildings or neighbourhoods often exhibit higher specific capital costs and lower long-term efficiency compared to large-scale 4th or 5th generation DH networks. This is mainly because conventional systems typically operate at higher temperature levels and with less flexibility to integrate multiple renewable and waste heat sources, leading to greater distribution losses and reduced system synergy. In this study, underground metro space is utilized to integrate several small DHC systems into a single large-scale network, and a thermo-economic model is proposed. The metro helps lower the cost of distributing heat and makes it easier to integrate different heat sources. The cost reduction achieved in large-scale DHC systems is attributed to the use of existing conduits, reduced thermal losses, and enhanced heat exchange among the interconnected small DHC units. Additionally, this large-scale DHC network can easily accommodate future growth of consumers along it without extending the Metro and piping infrastructure and with upgrading the pumping capacity. A case study of the Dublin MetroLink, incorporating current 16 and future 26 small DHs, is analyzed to demonstrate the effectiveness of the proposed model. The primary heat sources considered are data centers and underground water from the Dublin Port Tunnel which also functions as the primary heat-transport medium. Each smaller DH along the underground route would utilize its own large-scale heat pump to extract heat from the supply line in the underground space and inject their extra/unused heat back to cover the peak demand in another smaller DHs. He case study showed 17% reduction in annualized cost over its lifetime.
{"title":"Large-scale climate-neutral district heating and cooling: Integration of local microgrids for thermal distribution","authors":"Mohammad Sameti , Tao Fan , Anna Volkova , Zili Li","doi":"10.1016/j.ecmx.2026.101552","DOIUrl":"10.1016/j.ecmx.2026.101552","url":null,"abstract":"<div><div>Conventional small-scale district heating (DH) systems that serve a limited number of buildings or neighbourhoods often exhibit higher specific capital costs and lower long-term efficiency compared to large-scale 4th or 5th generation DH networks. This is mainly because conventional systems typically operate at higher temperature levels and with less flexibility to integrate multiple renewable and waste heat sources, leading to greater distribution losses and reduced system synergy. In this study, underground metro space is utilized to integrate several small DHC systems into a single large-scale network, and a thermo-economic model is proposed. The metro helps lower the cost of distributing heat and makes it easier to integrate different heat sources. The cost reduction achieved in large-scale DHC systems is attributed to the use of existing conduits, reduced thermal losses, and enhanced heat exchange among the interconnected small DHC units. Additionally, this large-scale DHC network can easily accommodate future growth of consumers along it without extending the Metro and piping infrastructure and with upgrading the pumping capacity. A case study of the Dublin MetroLink, incorporating current 16 and future 26 small DHs, is analyzed to demonstrate the effectiveness of the proposed model. The primary heat sources considered are data centers and underground water from the Dublin Port Tunnel which also functions as the primary heat-transport medium. Each smaller DH along the underground route would utilize its own large-scale heat pump to extract heat from the supply line in the underground space and inject their extra/unused heat back to cover the peak demand in another smaller DHs. He case study showed 17% reduction in annualized cost over its lifetime.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101552"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-14DOI: 10.1016/j.ecmx.2026.101568
Gyeong Duk Nam , Hyesong An , Hee Jin Kim , Heeji Lee , Gahyeon Lee , Sungtae Park , Jong-Eun Hong , Jong-Ho Lee , Jong Hoon Joo
Coking significantly degrades hydrocarbon-fueled system performance, making its analysis a critical challenge. Real-time monitoring of coking is typically conducted using current–voltage (I–V) or impedance spectroscopy. In most studies, systems have been considered stable against coking if no electrochemical degradation is observed. This study proposes the use of gas chromatography (GC) to investigate in situ coking behavior. Although quantifying coking using GC is inherently challenging owing to error margins, a normalization methodology was developed by systematically varying steam-to-carbon (S/C) ratios, allowing for a reliable analysis of relative coking trends despite absolute quantification limitations. The normalized values were defined as Δcoking, which represents an indicator of relative carbon deposition trends rather than the absolute amount of deposited carbon. The errors associated with the analysis process were minimized by fixing all the variables except for the hydrocarbon flow rate. In methane-utilized solid oxide fuel cells (SOFCs), performance remains stable at an S/C ratio of 1.5 or higher, which indicates that coking may not occur. However, applying a normalization methodology reveals coking behaviors that cannot be detected through electrochemical analysis alone. The reproducibility of the in situ GC-based coking analysis technique was validated by comparing carbon coking behavior between bare and coke-resistant catalyst-infiltrated anodes. The cell decorated with catalysts exhibited significantly lower Δcoking values under varying S/C ratios, confirming the method’s reliability in evaluating coking resistance. This highlights the limitations of traditional approaches for detecting subtle coking phenomena and demonstrates the value of GC for precise coking analysis, thereby advancing the understanding and mitigation of coking in hydrocarbon-fueled systems.
{"title":"Unveiling carbon coking in hydrocarbon-fueled systems via normalized in situ gas chromatography","authors":"Gyeong Duk Nam , Hyesong An , Hee Jin Kim , Heeji Lee , Gahyeon Lee , Sungtae Park , Jong-Eun Hong , Jong-Ho Lee , Jong Hoon Joo","doi":"10.1016/j.ecmx.2026.101568","DOIUrl":"10.1016/j.ecmx.2026.101568","url":null,"abstract":"<div><div>Coking significantly degrades hydrocarbon-fueled system performance, making its analysis a critical challenge. Real-time monitoring of coking is typically conducted using current–voltage (I–V) or impedance spectroscopy. In most studies, systems have been considered stable against coking if no electrochemical degradation is observed. This study proposes the use of gas chromatography (GC) to investigate in situ coking behavior. Although quantifying coking using GC is inherently challenging owing to error margins, a normalization methodology was developed by systematically varying steam-to-carbon (S/C) ratios, allowing for a reliable analysis of relative coking trends despite absolute quantification limitations. The normalized values were defined as Δcoking, which represents an indicator of relative carbon deposition trends rather than the absolute amount of deposited carbon. The errors associated with the analysis process were minimized by fixing all the variables except for the hydrocarbon flow rate. In methane-utilized solid oxide fuel cells (SOFCs), performance remains stable at an S/C ratio of 1.5 or higher, which indicates that coking may not occur. However, applying a normalization methodology reveals coking behaviors that cannot be detected through electrochemical analysis alone. The reproducibility of the in situ GC-based coking analysis technique was validated by comparing carbon coking behavior between bare and coke-resistant catalyst-infiltrated anodes. The cell decorated with catalysts exhibited significantly lower Δcoking values under varying S/C ratios, confirming the method’s reliability in evaluating coking resistance. This highlights the limitations of traditional approaches for detecting subtle coking phenomena and demonstrates the value of GC for precise coking analysis, thereby advancing the understanding and mitigation of coking in hydrocarbon-fueled systems.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101568"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039768","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-18DOI: 10.1016/j.ecmx.2026.101585
Md. Kawsar Hossain , Abu Saleh Molla , Prangon Chowdhury , Faysal Amin Tanvir , Omar Farrok
Despite achieving universal access to electricity, Bangladesh faces severe energy issues that hinder its sustainable development. The country experiences frequent power outages, transmission losses, and overreliance on imported fuels. Many rural communities still face unreliable electricity, despite having plenty of untapped renewable resources. Existing studies have discussed microgrids’ technical, economic, and environmental aspects in different regions. To the best of the authors’ knowledge, none have evaluated detailed implementation challenges or their contribution to sustainable development. In this regard, this paper investigates how microgrids can transform Bangladesh’s energy landscape while meeting sustainability goals. It identifies key barriers to adoption such as weak infrastructure, cybersecurity risks, financial constraints, complex funding arrangements, difficulties in public–private partnerships, and challenges around social acceptance. It also reviews the technical requirements and policy frameworks within the country’s wider development agenda. Potential sites for microgrid deployment are mapped out, along with the policies needed to integrate them into the grid. Using SWOT and PESTLE frameworks, this paper observes factors influencing microgrid adoption, considering Bangladesh’s geographical and socioeconomic conditions. Based on the assessment, this study finds that microgrids can offer viable solutions to current energy problems by reducing import dependency, creating local employment, and delivering reliable rural power supply. However, regulatory ambiguity, limited technical capacity, high capital costs, and poor inter-agency coordination present significant obstacles. It can stimulate economic growth, enhance educational and healthcare services, and strengthen climate resilience. This analysis provides actionable recommendations for policymakers, investors, and development organisations addressing similar energy access challenges in other developing nations.
{"title":"Transforming sustainable energy through microgrids: Bangladesh perspectives","authors":"Md. Kawsar Hossain , Abu Saleh Molla , Prangon Chowdhury , Faysal Amin Tanvir , Omar Farrok","doi":"10.1016/j.ecmx.2026.101585","DOIUrl":"10.1016/j.ecmx.2026.101585","url":null,"abstract":"<div><div>Despite achieving universal access to electricity, Bangladesh faces severe energy issues that hinder its sustainable development. The country experiences frequent power outages, transmission losses, and overreliance on imported fuels. Many rural communities still face unreliable electricity, despite having plenty of untapped renewable resources. Existing studies have discussed microgrids’ technical, economic, and environmental aspects in different regions. To the best of the authors’ knowledge, none have evaluated detailed implementation challenges or their contribution to sustainable development. In this regard, this paper investigates how microgrids can transform Bangladesh’s energy landscape while meeting sustainability goals. It identifies key barriers to adoption such as weak infrastructure, cybersecurity risks, financial constraints, complex funding arrangements, difficulties in public–private partnerships, and challenges around social acceptance. It also reviews the technical requirements and policy frameworks within the country’s wider development agenda. Potential sites for microgrid deployment are mapped out, along with the policies needed to integrate them into the grid. Using SWOT and PESTLE frameworks, this paper observes factors influencing microgrid adoption, considering Bangladesh’s geographical and socioeconomic conditions. Based on the assessment, this study finds that microgrids can offer viable solutions to current energy problems by reducing import dependency, creating local employment, and delivering reliable rural power supply. However, regulatory ambiguity, limited technical capacity, high capital costs, and poor inter-agency coordination present significant obstacles. It can stimulate economic growth, enhance educational and healthcare services, and strengthen climate resilience. This analysis provides actionable recommendations for policymakers, investors, and development organisations addressing similar energy access challenges in other developing nations.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101585"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-21DOI: 10.1016/j.ecmx.2026.101605
Helder R.O. Rocha , Sara Abou Dargham , Jimmy Romanos , Wesley Costa , Roy Roukos , Jair A.L. Silva , Heinrich Wörtche
Methane, the primary component of natural gas, emits less carbon dioxide than other petroleum-based fuels but faces challenges in efficient storage and transportation. Advanced adsorption materials provide a safe and cost-effective solution, with metal–organic frameworks (MOFs) emerging as promising candidates for natural gas storage and delivery in vehicles. This research employed AI-Driven Optimization (AiDO) to identify optimal parameters for enhancing methane uptake while simultaneously improving both gravimetric and volumetric delivery. We developed and validated three machine learning models: eXtreme Gradient Boosting (XGBoost), Kolmogorov–Arnold Network (KAN), and Convolutional Neural Network (CNN), using experimental data. All models demonstrated strong predictive performance, with XGBoost achieving outstanding results, including a Root Mean Squared Error (RMSE) of 0.0103 and a coefficient of determination () of 0.9722. When integrated into an optimization framework, the XGBoost model identified optimal conditions for methane delivery, predicting a room temperature gravimetric delivery of 724.14 cm3/g, and a volumetric delivery of 602.21 cm3/cm3 from 65 to 5 bar. Sensitivity analysis validated the robustness of the AiDO methodology, highlighting its potential to effectively reduce costs and enhance the performance of porous MOFs.
{"title":"AI-driven optimization approaches of metal–organic frameworks for enhanced methane delivery","authors":"Helder R.O. Rocha , Sara Abou Dargham , Jimmy Romanos , Wesley Costa , Roy Roukos , Jair A.L. Silva , Heinrich Wörtche","doi":"10.1016/j.ecmx.2026.101605","DOIUrl":"10.1016/j.ecmx.2026.101605","url":null,"abstract":"<div><div>Methane, the primary component of natural gas, emits less carbon dioxide than other petroleum-based fuels but faces challenges in efficient storage and transportation. Advanced adsorption materials provide a safe and cost-effective solution, with metal–organic frameworks (MOFs) emerging as promising candidates for natural gas storage and delivery in vehicles. This research employed AI-Driven Optimization (AiDO) to identify optimal parameters for enhancing methane uptake while simultaneously improving both gravimetric and volumetric delivery. We developed and validated three machine learning models: eXtreme Gradient Boosting (XGBoost), Kolmogorov–Arnold Network (KAN), and Convolutional Neural Network (CNN), using experimental data. All models demonstrated strong predictive performance, with XGBoost achieving outstanding results, including a Root Mean Squared Error (RMSE) of 0.0103 and a coefficient of determination (<span><math><msup><mrow><mi>R</mi></mrow><mrow><mn>2</mn></mrow></msup></math></span>) of 0.9722. When integrated into an optimization framework, the XGBoost model identified optimal conditions for methane delivery, predicting a room temperature gravimetric delivery of 724.14 cm<sup>3</sup>/g, and a volumetric delivery of 602.21 cm<sup>3</sup>/cm<sup>3</sup> from 65 to 5 bar. Sensitivity analysis validated the robustness of the AiDO methodology, highlighting its potential to effectively reduce costs and enhance the performance of porous MOFs.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101605"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-17DOI: 10.1016/j.ecmx.2026.101564
Amir Nourmohammadi , Majid Siavashi , Hossein Pourrahmani , Mohammad Mehdi Hesampour
Proton exchange membrane fuel cells (PEMFCs) are considered an advanced technology for clean energy usage due to their high efficiency and zero emissions. However, effective water management in the gas diffusion layer (GDL), particularly the formation and removal of liquid water droplets, remains a major challenge. In this study, a three-dimensional two-phase flow model based on the lattice Boltzmann method combined with the volume of fluid (LBM-VOF) approach is developed using the Palabos platform to simulate droplet dynamics at the pore scale of the GDL. The model is validated against existing numerical and experimental data. The main novelty of this study is to show the impacts of key geometric parameters, including porosity, fiber diameter, contact angle, and inlet velocity for conventional fiber-based structures, followed by the report of the best-performing values. Results reveal that mesh-based geometries, especially the hexagonal arrangement, significantly enhance water removal. In particular, the MultiOctagon 70% and Hexagon 70% configurations reduce water saturation and removal time by 42.16% and 44.99%, and by 47.61% and 43.99%, respectively, compared to the random fiber-based structure with 70% porosity and 8 µm fiber diameter. These findings highlight the potential of GDL designs to improve water management and overall PEMFC performance.
{"title":"Geometric design of gas diffusion layer of PEMFCs to improve water management using multiphase lattice Boltzmann method","authors":"Amir Nourmohammadi , Majid Siavashi , Hossein Pourrahmani , Mohammad Mehdi Hesampour","doi":"10.1016/j.ecmx.2026.101564","DOIUrl":"10.1016/j.ecmx.2026.101564","url":null,"abstract":"<div><div>Proton exchange membrane fuel cells (PEMFCs) are considered an advanced technology for clean energy usage due to their high efficiency and zero emissions. However, effective water management in the gas diffusion layer (GDL), particularly the formation and removal of liquid water droplets, remains a major challenge. In this study, a three-dimensional two-phase flow model based on the lattice Boltzmann method combined with the volume of fluid (LBM-VOF) approach is developed using the Palabos platform to simulate droplet dynamics at the pore scale of the GDL. The model is validated against existing numerical and experimental data. The main novelty of this study is to show the impacts of key geometric parameters, including porosity, fiber diameter, contact angle, and inlet velocity for conventional fiber-based structures, followed by the report of the best-performing values. Results reveal that mesh-based geometries, especially the hexagonal arrangement, significantly enhance water removal. In particular, the MultiOctagon 70% and Hexagon 70% configurations reduce water saturation and removal time by 42.16% and 44.99%, and by 47.61% and 43.99%, respectively, compared to the random fiber-based structure with 70% porosity and 8 µm fiber diameter. These findings highlight the potential of GDL designs to improve water management and overall PEMFC performance.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101564"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-27DOI: 10.1016/j.ecmx.2026.101634
Qiuyan Xu, Greig Mordue
The aviation industry has committed to achieving net zero carbon emissions by 2050, with sustainable aviation fuel (SAF) identified as the most promising solution. The transition to SAF is mainly influenced by technological advancements, production capacities, and policy incentives. However, the rapidly evolving and diverse nature of SAF technologies complicates the landscape, resulting in a lack of value chain transparency and difficulties in understanding regional patterns in the SAF transition. This study addresses these challenges by constructing and analyzing a global database of SAF-related patents to examine SAF technology development trends, regional differences in innovation and patenting activities, the distribution of SAF technology domains, and key players in the supply chain. The analysis reveals regional disparities in innovation ecosystems and gaps in policy design while providing insights into the roles of stakeholders across the SAF value chain. Informed by these findings, the study makes policy recommendations aimed at addressing regional disparities, harmonizing SAF mandates, and aligning production with market dynamics, thereby supporting the sustainable decarbonization of aviation systems.
{"title":"The transition to sustainable aviation fuel: insights from patent analysis and policy implications","authors":"Qiuyan Xu, Greig Mordue","doi":"10.1016/j.ecmx.2026.101634","DOIUrl":"10.1016/j.ecmx.2026.101634","url":null,"abstract":"<div><div>The aviation industry has committed to achieving net zero carbon emissions by 2050, with sustainable aviation fuel (SAF) identified as the most promising solution. The transition to SAF is mainly influenced by technological advancements, production capacities, and policy incentives. However, the rapidly evolving and diverse nature of SAF technologies complicates the landscape, resulting in a lack of value chain transparency and difficulties in understanding regional patterns in the SAF transition. This study addresses these challenges by constructing and analyzing a global database of SAF-related patents to examine SAF technology development trends, regional differences in innovation and patenting activities, the distribution of SAF technology domains, and key players in the supply chain. The analysis reveals regional disparities in innovation ecosystems and gaps in policy design while providing insights into the roles of stakeholders across the SAF value chain. Informed by these findings, the study makes policy recommendations aimed at addressing regional disparities, harmonizing SAF mandates, and aligning production with market dynamics, thereby supporting the sustainable decarbonization of aviation systems.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101634"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080380","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-02-03DOI: 10.1016/j.ecmx.2026.101652
S. Masoud Hosseini , A. Afshar Ebrahimi
This study examines the recycling of heavy cycle oil (HCO), light cycle oil (LCO), and heavy naphtha (HN) into the feed of a residue fluid catalytic cracking (RFCC) reactor to evaluate their effects on product yield distribution. The objective is to develop strategies for steering RFCC operations toward higher-value products. The recycled streams, rich in aromatic compounds, were tested in a fixed fluidized bed microreactor (ACE test) using a commercial RFCC equilibrium catalyst. The NOFs (neat oil fractions), namely HCO, LCO and HN, and blended feeds with atmospheric residue (ATR) were cracked at 520 °C under varying catalyst-to-oil (C/O) ratios. Conversion of the NOFs followed the order HN (99 wt%) > LCO (87.5 wt%) > HCO (42 wt%), with corresponding gasoline yields of 69, 51, and 14 wt%. For blended feeds, ATR + HN achieved the highest conversion (79.1 wt%) and gasoline yield (51 wt%), while ATR + LCO generated the most olefins. Results demonstrate that mono-aromatics act as gasoline precursors, whereas di-aromatics favor LCO formation. Increasing C/O ratio enhanced gasoline and olefin yields while reducing LCO and main cycle oil. These findings highlight the potential of recycling side streams to optimize RFCC performance and improve refinery fuel flexibility.
{"title":"Direct recycling of heavy cycle oil, light cycle oil and heavy naphtha to the RFCC reactor feed: Study on product yield distribution","authors":"S. Masoud Hosseini , A. Afshar Ebrahimi","doi":"10.1016/j.ecmx.2026.101652","DOIUrl":"10.1016/j.ecmx.2026.101652","url":null,"abstract":"<div><div>This study examines the recycling of heavy cycle oil (HCO), light cycle oil (LCO), and heavy naphtha (HN) into the feed of a residue fluid catalytic cracking (RFCC) reactor to evaluate their effects on product yield distribution. The objective is to develop strategies for steering RFCC operations toward higher-value products. The recycled streams, rich in aromatic compounds, were tested in a fixed fluidized bed microreactor (ACE test) using a commercial RFCC equilibrium catalyst. The NOFs (neat oil fractions), namely HCO, LCO and HN, and blended feeds with atmospheric residue (ATR) were cracked at 520 °C under varying catalyst-to-oil (C/O) ratios. Conversion of the NOFs followed the order HN (99 wt%) > LCO (87.5 wt%) > HCO (42 wt%), with corresponding gasoline yields of 69, 51, and 14 wt%. For blended feeds, ATR + HN achieved the highest conversion (79.1 wt%) and gasoline yield (51 wt%), while ATR + LCO generated the most olefins. Results demonstrate that mono-aromatics act as gasoline precursors, whereas di-aromatics favor LCO formation. Increasing C/O ratio enhanced gasoline and olefin yields while reducing LCO and main cycle oil. These findings highlight the potential of recycling side streams to optimize RFCC performance and improve refinery fuel flexibility.</div></div>","PeriodicalId":37131,"journal":{"name":"Energy Conversion and Management-X","volume":"30 ","pages":"Article 101652"},"PeriodicalIF":7.6,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146189852","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-05-01Epub Date: 2026-01-27DOI: 10.1016/j.ecmx.2026.101614
Alexander Cyfka , Matthias Jordan , Jürgen Vollmer , Daniela Thrän
The climate crisis requires a transition to a climate neutral energy system, particularly in sectors that are hard to decarbonize. For these sectors, biomass-based energy carriers often represent a comparatively cost-effective decarbonization option. Given limited suitable land availability and high energy demand, identifying land-efficient solutions for renewable energy production is crucial. The present study is concerned with the collection and harmonization of data on the multi-land-use concepts of agricultural photovoltaics (Agri-PV) and agroforestry. Both concepts are considered here as systems capable of contributing to renewable energy supply, through electricity generation and biomass production for energy use. The objective is to integrate these concepts into a model of the German energy system and use the energy system optimization model BENOPTex to evaluate their economic viability. In various sensitivity analysis, we determine the most cost-effective land allocation for energy production on the 2.16 million hectares currently used for energy crops. Results indicate that, under current yield and cost assumptions, neither Agri-PV nor agroforestry systems outperform monoculture systems (e.g. Miscanthus) or ground-mounted PV. However, the analysis identifies yield and cost thresholds at which specific combinations become competitive. For example, a Miscanthus-sugar beet agroforestry system becomes viable with a 6% yield increase in Miscanthus compared to the monoculture yield. Despite their current economic disadvantages, Agri-PV and agroforestry offer non-monetized benefits including biodiversity enhancement and climate resilience. The study concludes that bridging the economic gap may require valuing these co-benefits or achieving significant cost and yield improvements through research and innovation.
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