Pub Date : 2026-03-01Epub Date: 2026-02-27DOI: 10.1016/j.nexus.2026.100686
Khalid M. Alzahrani , Maria Fernanda Rojas-Michaga , Lin Ma , Derek Ingham , Mohamed Pourkashanian
Previous studies demonstrated the feasibility of vertical axis wind turbine (VAWT)-driven reverse osmosis (RO) units integrated with compressed air energy storage (CAES) to manage renewable energy intermittency. However, an integrated multi-objective strategy for optimal configuration was missing. This study addresses this gap by developing and applying a novel integrated framework coupling multi-objective optimisation with life cycle assessment (LCA) to evaluate technical, economic, and environmental performance. The system was modelled using six design variables, exploring 118,800 configurations to balance annual water production, levelised cost of water (LCOW), and global warming potential (GWP). Machine learning techniques were used to develop surrogate models to identify Pareto-optimal solutions, while a TOPSIS analysis selected four scenarios representing diverse stakeholder priorities. Results revealed that the sizing and number of VAWTs are the dominant factors influencing both LCOW and GWP. The optimisation yielded an LCOW-prioritised scenario that achieved a cost of 1.39 US$/m³, while the GWP-prioritised scenario reached a footprint of 0.70 kg CO₂eq/m³. This work provides a novel methodology for the simultaneous techno-economic and environmental design of off-grid water infrastructure, establishing optimal strategies for renewable desalination to address global water scarcity.
{"title":"Multi-objective optimisation of a seawater reverse osmosis desalination system driven by vertical axis wind turbines: Technical, economic, and environmental perspectives","authors":"Khalid M. Alzahrani , Maria Fernanda Rojas-Michaga , Lin Ma , Derek Ingham , Mohamed Pourkashanian","doi":"10.1016/j.nexus.2026.100686","DOIUrl":"10.1016/j.nexus.2026.100686","url":null,"abstract":"<div><div>Previous studies demonstrated the feasibility of vertical axis wind turbine (VAWT)-driven reverse osmosis (RO) units integrated with compressed air energy storage (CAES) to manage renewable energy intermittency. However, an integrated multi-objective strategy for optimal configuration was missing. This study addresses this gap by developing and applying a novel integrated framework coupling multi-objective optimisation with life cycle assessment (LCA) to evaluate technical, economic, and environmental performance. The system was modelled using six design variables, exploring 118,800 configurations to balance annual water production, levelised cost of water (LCOW), and global warming potential (GWP). Machine learning techniques were used to develop surrogate models to identify Pareto-optimal solutions, while a TOPSIS analysis selected four scenarios representing diverse stakeholder priorities. Results revealed that the sizing and number of VAWTs are the dominant factors influencing both LCOW and GWP. The optimisation yielded an LCOW-prioritised scenario that achieved a cost of 1.39 US$/m³, while the GWP-prioritised scenario reached a footprint of 0.70 kg CO₂eq/m³. This work provides a novel methodology for the simultaneous techno-economic and environmental design of off-grid water infrastructure, establishing optimal strategies for renewable desalination to address global water scarcity.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100686"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396690","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 : 2026-03-01Epub Date: 2026-01-10DOI: 10.1016/j.nexus.2026.100641
Mohammad Mynul Islam Mahin, Md Jawad Bin Rouf, Shah Murtoza Morshed, Sheak Salman, Md Shihab Shakur, Mohammad Morshed, Md. Parvez
Energy forecasting of generation, demand, sources, and prices over short-time horizons is necessary for optimization of energy management. Given the increased use of developing technologies and reliance on renewable energy sources, strategic planning, management, and operational decision-making depend on accuracy and reliability of forecasting system. Complex interconnections reside among energy features in modern day power systems. Developing nations such as Bangladesh encounter challenges, including insufficient advanced tools for power planning and policy development. Previous studies have often focused on forecasting a single energy variable, like load or demand, with little attention on multiple energy parameters, and the interrelations among them. This study introduces a Hybrid Neural-SVM Ensemble (HNSE) model to simultaneously forecast day-ahead daily total energy generation, non-renewable energy generation, fuel cost, and evening peak demand of national grid of Bangladesh. Utilizing the Power Grid Company of Bangladesh’s (PGCB) data, HNSE went through processing and hyperparameter optimization. Performance evaluation based on five statistical indices demonstrated the model's predictive capabilities, with a coefficient of determination (R2) of 0.9744, and a mean squared error (MSE) of 0.0291. Additionally, the study utilizes the Kernel-based Changepoint Detection (KernelCPD) algorithm to detect structural shifts in residuals, and two explainable artificial intelligence (XAI) methods, Local Interpretable Model-Agnostic Explanations (LIME) and SHapley Additive exPlanations (SHAP), for feature contribution analysis to provide local and global interpretability. The aim is to offer actionable guidance for policymakers and stakeholders in mitigating current energy crises in Bangladesh through strategic decision-making and support the development of sustainable energy policies in emerging economies.
{"title":"Multivariate time series energy forecasting using a hybrid neural-SVM ensemble model: A data-driven approach for energy management in Bangladesh","authors":"Mohammad Mynul Islam Mahin, Md Jawad Bin Rouf, Shah Murtoza Morshed, Sheak Salman, Md Shihab Shakur, Mohammad Morshed, Md. Parvez","doi":"10.1016/j.nexus.2026.100641","DOIUrl":"10.1016/j.nexus.2026.100641","url":null,"abstract":"<div><div>Energy forecasting of generation, demand, sources, and prices over short-time horizons is necessary for optimization of energy management. Given the increased use of developing technologies and reliance on renewable energy sources, strategic planning, management, and operational decision-making depend on accuracy and reliability of forecasting system. Complex interconnections reside among energy features in modern day power systems. Developing nations such as Bangladesh encounter challenges, including insufficient advanced tools for power planning and policy development. Previous studies have often focused on forecasting a single energy variable, like load or demand, with little attention on multiple energy parameters, and the interrelations among them. This study introduces a Hybrid Neural-SVM Ensemble (HNSE) model to simultaneously forecast day-ahead daily total energy generation, non-renewable energy generation, fuel cost, and evening peak demand of national grid of Bangladesh. Utilizing the Power Grid Company of Bangladesh’s (PGCB) data, HNSE went through processing and hyperparameter optimization. Performance evaluation based on five statistical indices demonstrated the model's predictive capabilities, with a coefficient of determination (R<sup>2</sup>) of 0.9744, and a mean squared error (MSE) of 0.0291. Additionally, the study utilizes the Kernel-based Changepoint Detection (KernelCPD) algorithm to detect structural shifts in residuals, and two explainable artificial intelligence (XAI) methods, Local Interpretable Model-Agnostic Explanations (LIME) and SHapley Additive exPlanations (SHAP), for feature contribution analysis to provide local and global interpretability. The aim is to offer actionable guidance for policymakers and stakeholders in mitigating current energy crises in Bangladesh through strategic decision-making and support the development of sustainable energy policies in emerging economies.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100641"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977276","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 : 2026-03-01Epub Date: 2025-12-09DOI: 10.1016/j.nexus.2025.100616
Naseem Akhtar , Syahidah Akmal Muhammad , Muhammad Izzuddin Syakir , Hamza Mohamed Flafel , Pahmi Husain , Sulgiye Park , Faisal M. Alfaisal , Shamshad Alam
Sustainable groundwater management is critically hampered by a disconnect between water quality assessment and environmental impact (EI) of its extraction infrastructure, particularly at the micro-level. This study applied a novel micro-nexus lens to bridge this gap by developing a holistic sustainability profile for a single agricultural pumping well in Labu Kubong, Malaysia. The objectives were outlined as follows: (i) to characterize hydrochemical properties and evaluate groundwater suitability for paddy irrigation utilizing Piper, Gibbs, Wilcox, and United States Salinity Laboratory (USSL) diagrams; (ii) to pinpoint dominant environmental hotspots from raw materials and energy consumption using a cradle-to-gate Life Cycle Assessment (LCA); (iii) to validate LCA reliability with Monte Carlo uncertainty analysis; and (iv) to synthesize the hydrochemical and LCA results into a holistic sustainability balance sheet (HSBS). The Piper diagram results indicated calcium-magnesium-bicarbonate-type water, with rock weathering identified as the predominant geochemical process by the Gibbs diagram. The groundwater was classified as excellent for irrigation (C2-S1 class) by Wilcox and USSL diagrams. Counter-intuitively, LCA revealed that dominant EI originated not from operational energy consumption (1.65 %) but from the embodied footprint of the raw materials from groundwater extraction infrastructure. Raw material production, particularly polyethylene terephthalate (61.6 %), copper for the submersible pump (14.8 %), gravel packing (4.51 %), steel (3.5 %), copper wire for the electrical cable (2.05 %), polyvinyl chloride (1.12 %), and high-density polyethylene (0.0062 %), were the primary contributors. This integrated micro-nexus paradigm offers HSBS, highlighting a significant paradox whereby intrinsic groundwater suitability for paddy agriculture and unsuitability for drinking without treatment due to elevated concentrations of iron (1.71 mg/L), manganese (0.173 mg/L), and arsenic (0.04 mg/L) occur alongside significant extrinsic EI resulting from its extraction infrastructure. This HSBS provides policymakers a crucial tool for integrated management decisions, enabling balanced consideration of usability, operational risk, and life cycle impacts to support truly sustainable groundwater management.
{"title":"Water-energy nexus: Integrating hydrochemical characterization and life cycle assessment for a holistic profile of agricultural groundwater sustainability","authors":"Naseem Akhtar , Syahidah Akmal Muhammad , Muhammad Izzuddin Syakir , Hamza Mohamed Flafel , Pahmi Husain , Sulgiye Park , Faisal M. Alfaisal , Shamshad Alam","doi":"10.1016/j.nexus.2025.100616","DOIUrl":"10.1016/j.nexus.2025.100616","url":null,"abstract":"<div><div>Sustainable groundwater management is critically hampered by a disconnect between water quality assessment and environmental impact (EI) of its extraction infrastructure, particularly at the micro-level. This study applied a novel micro-nexus lens to bridge this gap by developing a holistic sustainability profile for a single agricultural pumping well in Labu Kubong, Malaysia. The objectives were outlined as follows: (i) to characterize hydrochemical properties and evaluate groundwater suitability for paddy irrigation utilizing Piper, Gibbs, Wilcox, and United States Salinity Laboratory (USSL) diagrams; (ii) to pinpoint dominant environmental hotspots from raw materials and energy consumption using a cradle-to-gate Life Cycle Assessment (LCA); (iii) to validate LCA reliability with Monte Carlo uncertainty analysis; and (iv) to synthesize the hydrochemical and LCA results into a holistic sustainability balance sheet (HSBS). The Piper diagram results indicated calcium-magnesium-bicarbonate-type water, with rock weathering identified as the predominant geochemical process by the Gibbs diagram. The groundwater was classified as excellent for irrigation (C2-S1 class) by Wilcox and USSL diagrams. Counter-intuitively, LCA revealed that dominant EI originated not from operational energy consumption (1.65 %) but from the embodied footprint of the raw materials from groundwater extraction infrastructure. Raw material production, particularly polyethylene terephthalate (61.6 %), copper for the submersible pump (14.8 %), gravel packing (4.51 %), steel (3.5 %), copper wire for the electrical cable (2.05 %), polyvinyl chloride (1.12 %), and high-density polyethylene (0.0062 %), were the primary contributors. This integrated micro-nexus paradigm offers HSBS, highlighting a significant paradox whereby intrinsic groundwater suitability for paddy agriculture and unsuitability for drinking without treatment due to elevated concentrations of iron (1.71 mg/L), manganese (0.173 mg/L), and arsenic (0.04 mg/L) occur alongside significant extrinsic EI resulting from its extraction infrastructure. This HSBS provides policymakers a crucial tool for integrated management decisions, enabling balanced consideration of usability, operational risk, and life cycle impacts to support truly sustainable groundwater management.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100616"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747040","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 : 2026-03-01Epub Date: 2025-12-09DOI: 10.1016/j.nexus.2025.100617
Mohammadreza Gholami , Sobhan Dorahaki , Mohammad Habib Reza , Lazhar Ben-Brahim , S M Muyeen
Given the global drive toward sustainable agricultural practices, semi-transparent photovoltaic (STPV) technology offers a dual benefit of generating renewable energy while still permitting a portion of sunlight essential for plant growth. Unlike traditional photovoltaic installations limited to roof surfaces, this work investigates the innovative use of STPV panels on vertical wall surfaces to maximize solar harvesting. By conducting an hourly irradiance analysis for a full calendar year, we evaluated the solar energy potential of different greenhouse sections (roof and walls) in Qatar's climatic conditions. The results reveal a significant contribution from wall-mounted STPV installations, which generated 83.77 % of the total annual energy compared to roof-mounted systems. Among the walls, the East Wall (EW) contributed consistently, achieving an annual average of 0.35 kWh/m², while the South Wall (SW) and West Wall (WW) also provided meaningful outputs of 0.19 kWh/m² and 0.22 kWh/m² respectively. In contrast, the North Roof (NR) and North Wall (NW) sections demonstrated the lowest energy outputs, with annual averages of 0.01 kWh/m² and 0.05 kWh/m², underscoring limited solar access due to their orientation. Sensitivity analysis further indicated that panel efficiency plays a crucial role in energy generation, with potential production reaching 18,904 kWh annually at a 20 % efficiency rate, significantly higher than the baseline 7 % efficiency considered in this study.
{"title":"Evaluating year-round solar energy harvesting in semi-transparent PV-integrated greenhouses with roof and wall installation in an even-span design","authors":"Mohammadreza Gholami , Sobhan Dorahaki , Mohammad Habib Reza , Lazhar Ben-Brahim , S M Muyeen","doi":"10.1016/j.nexus.2025.100617","DOIUrl":"10.1016/j.nexus.2025.100617","url":null,"abstract":"<div><div>Given the global drive toward sustainable agricultural practices, semi-transparent photovoltaic (STPV) technology offers a dual benefit of generating renewable energy while still permitting a portion of sunlight essential for plant growth. Unlike traditional photovoltaic installations limited to roof surfaces, this work investigates the innovative use of STPV panels on vertical wall surfaces to maximize solar harvesting. By conducting an hourly irradiance analysis for a full calendar year, we evaluated the solar energy potential of different greenhouse sections (roof and walls) in Qatar's climatic conditions. The results reveal a significant contribution from wall-mounted STPV installations, which generated 83.77 % of the total annual energy compared to roof-mounted systems. Among the walls, the East Wall (EW) contributed consistently, achieving an annual average of 0.35 kWh/m², while the South Wall (SW) and West Wall (WW) also provided meaningful outputs of 0.19 kWh/m² and 0.22 kWh/m² respectively. In contrast, the North Roof (NR) and North Wall (NW) sections demonstrated the lowest energy outputs, with annual averages of 0.01 kWh/m² and 0.05 kWh/m², underscoring limited solar access due to their orientation. Sensitivity analysis further indicated that panel efficiency plays a crucial role in energy generation, with potential production reaching 18,904 kWh annually at a 20 % efficiency rate, significantly higher than the baseline 7 % efficiency considered in this study.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100617"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799044","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 : 2026-03-01Epub Date: 2025-12-09DOI: 10.1016/j.nexus.2025.100613
Jesper Knutsson , Jörgen Wallin
Hot water circulation (HWC) systems in multifamily buildings face a fundamental trade-off: maintaining temperatures sufficient to suppress Legionella pneumophila (≥50 °C) while minimizing the 2.5–4.3 TWh annual energy loss these systems represent in Sweden alone. This study employed a novel dual approach combining controlled laboratory experiments with real-world validation to address this challenge. We constructed a full-scale test rig simulating a 20-apartment building to quantify thermal losses and microbial dynamics under varying flow rates and temperatures. This was complemented by a field validation encompassing 56 water samples from 31 multifamily buildings. The results demonstrate that when optimizing the system to maintain a regulatory required return temperature of 50 °C, thermal heat losses were nearly identical between low-flow (0.2 m/s) and high-flow (0.5 m/s) operation. The decisive factor was pump energy, where high-flow operation required 3.4 times more power than low-flow operation (108 W vs. 32 W). This resulted in a total annual energy saving of approximately 12% for the low-flow strategy, entirely attributable to reduced electricity consumption for the pump. Periodic thermal shocks at 60–65 °C effectively reduced L. pneumophila concentrations, indicating that continuous high-temperature operation is not required for microbial control. Field sampling revealed that 23% of samples tested positive for legionella, with problematic cases strongly linked to design flaws like towel warmers connected to the HWC loop. These findings indicate that a risk-based strategy combining low-flow circulation (0.2 m/s), a baseline return temperature of 50 °C, and periodic thermal shocks can significantly reduce system energy consumption while maintaining legionella safety.
{"title":"Optimizing energy efficiency and legionella control in hot water circulation systems: laboratory validation and field assessment in Swedish multifamily buildings","authors":"Jesper Knutsson , Jörgen Wallin","doi":"10.1016/j.nexus.2025.100613","DOIUrl":"10.1016/j.nexus.2025.100613","url":null,"abstract":"<div><div>Hot water circulation (HWC) systems in multifamily buildings face a fundamental trade-off: maintaining temperatures sufficient to suppress <em>Legionella pneumophila</em> (≥50 °C) while minimizing the 2.5–4.3 TWh annual energy loss these systems represent in Sweden alone. This study employed a novel dual approach combining controlled laboratory experiments with real-world validation to address this challenge. We constructed a full-scale test rig simulating a 20-apartment building to quantify thermal losses and microbial dynamics under varying flow rates and temperatures. This was complemented by a field validation encompassing 56 water samples from 31 multifamily buildings. The results demonstrate that when optimizing the system to maintain a regulatory required return temperature of 50 °C, thermal heat losses were nearly identical between low-flow (0.2 m/s) and high-flow (0.5 m/s) operation. The decisive factor was pump energy, where high-flow operation required 3.4 times more power than low-flow operation (108 W vs. 32 W). This resulted in a total annual energy saving of approximately 12% for the low-flow strategy, entirely attributable to reduced electricity consumption for the pump. Periodic thermal shocks at 60–65 °C effectively reduced L. <em>pneumophila</em> concentrations, indicating that continuous high-temperature operation is not required for microbial control. Field sampling revealed that 23% of samples tested positive for legionella, with problematic cases strongly linked to design flaws like towel warmers connected to the HWC loop. These findings indicate that a risk-based strategy combining low-flow circulation (0.2 m/s), a baseline return temperature of 50 °C, and periodic thermal shocks can significantly reduce system energy consumption while maintaining legionella safety.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100613"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145712478","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 : 2026-03-01Epub Date: 2025-12-11DOI: 10.1016/j.nexus.2025.100619
Opeyemi A. Iresemowo, Vincent O. Nyamori, Olatunde S. Olatunji
The detection of antibiotic residues, particularly tetracyclines (TC), is crucial due to their potential risks to public health and environmental safety. This study reports the development of a selective and sensitive electrochemical sensor based on reduced graphene oxide functionalized with emeraldine salt and palladium nanoparticles (rGO-ES-Pd) for the detection of TC in simulated samples, urine, surface water, and wastewater. The rGO-ES-Pd nanocomposite was synthesised via a wet chemical method and drop-cast onto a glassy carbon electrode (GCE) to fabricate the rGO-ES-Pd/GCE sensor. To evaluate the impact of different polyaniline oxidation states, three additional nanocomposites, rGO-EB-Pd (emeraldine base), rGO-PG-Pd (pernigraniline), and rGO-LE-Pd (leucoemeraldine), were also prepared and tested. Comprehensive characterisation was performed using transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Among the tested nanocomposites, the rGO-ES-Pd/GCE sensor exhibited the highest electrocatalytic activity for TC detection, with a pH-dependent peak current response in the potential range of 0.1–0.4 V. The sensor demonstrated a wide linear detection range (0.01–5.0 × 10−6 M) and a low detection limit (1.51 × 10−7 M). Selectivity studies in the presence of common interfering substances, ibuprofen, erythromycin, and amoxicillin, revealed minimal interference and a low relative standard deviation (RSD) of 3.29 %, confirming the robustness of the sensor. The developed electrochemical method was successfully applied to detect TC in real environmental (river water, wastewater influent) and biological (urine) samples, showing excellent reproducibility and long-term stability.
{"title":"High-performance electrochemical sensing of tetracycline via functionalised reduced graphene oxide nanocomposites","authors":"Opeyemi A. Iresemowo, Vincent O. Nyamori, Olatunde S. Olatunji","doi":"10.1016/j.nexus.2025.100619","DOIUrl":"10.1016/j.nexus.2025.100619","url":null,"abstract":"<div><div>The detection of antibiotic residues, particularly tetracyclines (TC), is crucial due to their potential risks to public health and environmental safety. This study reports the development of a selective and sensitive electrochemical sensor based on reduced graphene oxide functionalized with emeraldine salt and palladium nanoparticles (rGO-ES-Pd) for the detection of TC in simulated samples, urine, surface water, and wastewater. The rGO-ES-Pd nanocomposite was synthesised via a wet chemical method and drop-cast onto a glassy carbon electrode (GCE) to fabricate the rGO-ES-Pd/GCE sensor. To evaluate the impact of different polyaniline oxidation states, three additional nanocomposites, rGO-EB-Pd (emeraldine base), rGO-PG-Pd (pernigraniline), and rGO-LE-Pd (leucoemeraldine), were also prepared and tested. Comprehensive characterisation was performed using transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FTIR), powder X-ray diffraction (XRD), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). Among the tested nanocomposites, the rGO-ES-Pd/GCE sensor exhibited the highest electrocatalytic activity for TC detection, with a pH-dependent peak current response in the potential range of 0.1–0.4 V. The sensor demonstrated a wide linear detection range (0.01–5.0 × 10<sup>−6</sup> M) and a low detection limit (1.51 × 10<sup>−7</sup> M). Selectivity studies in the presence of common interfering substances, ibuprofen, erythromycin, and amoxicillin, revealed minimal interference and a low relative standard deviation (RSD) of 3.29 %, confirming the robustness of the sensor. The developed electrochemical method was successfully applied to detect TC in real environmental (river water, wastewater influent) and biological (urine) samples, showing excellent reproducibility and long-term stability.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100619"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798689","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 : 2026-03-01Epub Date: 2026-02-03DOI: 10.1016/j.nexus.2026.100645
Amna A.M. Bashir, William T. Riddell, Jagadish Torlapati
Energy use in drinking water systems varies significantly across utilities due to differences in operating conditions, and system configuration, posing challenges for consistent energy benchmarking. In this study, we present data collection, alignment and benchmarking approach based on a long-term operational data set from a water utility company operated in five geographical regions in New Jersey. The framework enabled quantification and comparison of total energy consumption and water production, across raw water, treatment and finished water facilities. The total energy and carbon intensity metrics were calculated using the aligned dataset supporting the comparative benchmarking approach. Energy and carbon intensities were calculated for all regions combined, by region, and by specific function of drinking water facilities, resulting in overall averages of 0.7 kWh/m³ and 0.24 kg CO2e/m3, respectively. Additionally, this study highlights that factors such as topography, applied treatment technologies and the spatial distribution of water consumers are positively correlated with energy requirements for pumping and treatment.
由于运行条件和系统配置的差异，饮用水系统的能源使用在不同的公用事业中差异很大，这对一致的能源基准提出了挑战。在本研究中，我们基于一家在新泽西州五个地理区域运营的水务公司的长期运营数据集，提出了数据收集、校准和基准方法。该框架能够量化和比较总能源消耗和水产量，包括原水、处理和成品水设施。总能源和碳强度指标是使用支持比较基准方法的对齐数据集计算的。按地区和饮用水设施的特定功能计算了所有地区的能源和碳强度，得出的总体平均值分别为0.7 kWh/m³和0.24 kg CO2e/m3。此外，该研究还强调了地形、应用处理技术和水消费者的空间分布等因素与抽水和处理的能源需求呈正相关。
{"title":"Quantifying and benchmarking drinking water treatment facilities in 5 geographical regions in New Jersey, USA using energy and carbon intensity metrics","authors":"Amna A.M. Bashir, William T. Riddell, Jagadish Torlapati","doi":"10.1016/j.nexus.2026.100645","DOIUrl":"10.1016/j.nexus.2026.100645","url":null,"abstract":"<div><div>Energy use in drinking water systems varies significantly across utilities due to differences in operating conditions, and system configuration, posing challenges for consistent energy benchmarking. In this study, we present data collection, alignment and benchmarking approach based on a long-term operational data set from a water utility company operated in five geographical regions in New Jersey. The framework enabled quantification and comparison of total energy consumption and water production, across raw water, treatment and finished water facilities. The total energy and carbon intensity metrics were calculated using the aligned dataset supporting the comparative benchmarking approach. Energy and carbon intensities were calculated for all regions combined, by region, and by specific function of drinking water facilities, resulting in overall averages of 0.7 kWh/m³ and 0.24 kg CO<sub>2</sub>e/m<sup>3</sup>, respectively. Additionally, this study highlights that factors such as topography, applied treatment technologies and the spatial distribution of water consumers are positively correlated with energy requirements for pumping and treatment.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100645"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396205","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 : 2026-03-01Epub Date: 2026-02-09DOI: 10.1016/j.nexus.2026.100650
Ali R. Alruzuq , Joann Mossa
The devastating impacts of flooding can be mitigated by strengthening the integration between hydrodynamic modeling and remote sensing, thereby improving floodplain management and the accuracy of inundation mapping. However, the relationship between river discharge and floodplain response remains insufficiently quantified in many large river systems, limiting reliable estimation of inundation extent, flood volumes, and floodplain connectivity. This study evaluates the hydraulic behavior of the Lower Apalachicola River and its associated floodplain within the Wewahitchka-Sumatra reaches using a two-dimensional HEC-RAS modeling framework. A high-resolution LiDAR-Sonar integrated digital elevation model (DEM) and terrain surfaces generated using the Relative Elevation Model (REM) approach were implemented to simulate floodplain inundation depth and extent under representative low-flow (175.3 m³/s) and high-flow (4360.8 m³/s) conditions observed during the 2015-2016 flood event. The REM centerline method was applied to smooth channel elevations, resulting in systematically deeper channel representation relative to the LiDAR-Sonar DEM. Model performance was evaluated using inundation extents derived from Landsat-8, MODIS, and Sentinel-1 satellite imagery. Results indicate that differences in inundation extent between DEM-based and REM-based simulations increase with flow magnitude, with areal differences of 9.93% and 4.02% under low- and high-flow conditions, respectively. DEM-based HEC-RAS simulations consistently produced larger flood extents than REM-based simulations, primarily due to differences in the representation of main-channel elevation. Maximum flood-water depth differences of 0.78 m and 0.76 m were observed for DEM and REM simulations under low- and high-flow conditions, respectively. Overall, the findings confirm the robustness of the HEC-RAS 2D framework for simulating floodplain inundation in large, low-gradient river systems and demonstrate the value of integrating high-resolution topographic data with complementary modeling approaches. The proposed framework offers a transferable methodology for floodplain management, restoration assessment, and improved understanding of river-floodplain connectivity under varying hydrologic conditions.
{"title":"Advancements in large floodplain inundation mapping: Integrated computational modeling and remote sensing techniques","authors":"Ali R. Alruzuq , Joann Mossa","doi":"10.1016/j.nexus.2026.100650","DOIUrl":"10.1016/j.nexus.2026.100650","url":null,"abstract":"<div><div>The devastating impacts of flooding can be mitigated by strengthening the integration between hydrodynamic modeling and remote sensing, thereby improving floodplain management and the accuracy of inundation mapping. However, the relationship between river discharge and floodplain response remains insufficiently quantified in many large river systems, limiting reliable estimation of inundation extent, flood volumes, and floodplain connectivity. This study evaluates the hydraulic behavior of the Lower Apalachicola River and its associated floodplain within the Wewahitchka-Sumatra reaches using a two-dimensional HEC-RAS modeling framework. A high-resolution LiDAR-Sonar integrated digital elevation model (DEM) and terrain surfaces generated using the Relative Elevation Model (REM) approach were implemented to simulate floodplain inundation depth and extent under representative low-flow (175.3 m³/s) and high-flow (4360.8 m³/s) conditions observed during the 2015-2016 flood event. The REM centerline method was applied to smooth channel elevations, resulting in systematically deeper channel representation relative to the LiDAR-Sonar DEM. Model performance was evaluated using inundation extents derived from Landsat-8, MODIS, and Sentinel-1 satellite imagery. Results indicate that differences in inundation extent between DEM-based and REM-based simulations increase with flow magnitude, with areal differences of 9.93% and 4.02% under low- and high-flow conditions, respectively. DEM-based HEC-RAS simulations consistently produced larger flood extents than REM-based simulations, primarily due to differences in the representation of main-channel elevation. Maximum flood-water depth differences of 0.78 m and 0.76 m were observed for DEM and REM simulations under low- and high-flow conditions, respectively. Overall, the findings confirm the robustness of the HEC-RAS 2D framework for simulating floodplain inundation in large, low-gradient river systems and demonstrate the value of integrating high-resolution topographic data with complementary modeling approaches. The proposed framework offers a transferable methodology for floodplain management, restoration assessment, and improved understanding of river-floodplain connectivity under varying hydrologic conditions.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100650"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147396208","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 : 2026-03-01Epub Date: 2026-02-09DOI: 10.1016/j.nexus.2026.100652
Xiangping Hu , Vedant Ballal , Gabriele Martinelli , Geir-Arne Fuglstad , Alessandro Nocente , Roberto Iacono , Bo Huang , Francesco Cherubini
Europe has experienced severe droughts that impacted electricity generation from both renewable and fossil sources. Yet, the response of national electricity systems to drought and the resulting impacts on emissions of CO₂ and air pollutants remain insufficiently understood. This study combines monthly historical electricity generation data (2017–2023) with runoff anomalies, used as a proxy for drought conditions, across 25 European countries. A regression-based counterfactual analysis is applied to quantify the country-level response of electricity systems to drier-than-average conditions. Estimated drought-induced changes in fossil-based generation are subsequently translated into emissions of greenhouse gases and air pollutants using fuel- and country-specific emission factors. We find that electricity generation from hydropower and other renewables is reduced during dry periods, while reliance on fossil fuels and imports increases. Drought induced 141±35 million tonnes of CO₂-equivalent emissions between 2017 and 2023, corresponding to 31 % of the emissions that Europe could release by 2040 under its most ambitious climate goals. Emissions are mainly driven by increased use of natural gas (48 %), coal (22 %), lignite (21 %), and imports (8 %). In France and Portugal, drought-induced emissions account for around 10 % of total fossil-based electricity emissions. The estimated monetized social cost of these emissions is 26 billion USD. Emissions of air pollutants show an average increase of about 2.5 %, though they widely vary across countries. These findings underscore the need for targeted adaptation strategies to reduce the power sector’s vulnerability to drought and to maintain progress toward energy security and decarbonization targets
{"title":"Impacts of drought on electricity production, fossil carbon emissions, and air pollution in Europe","authors":"Xiangping Hu , Vedant Ballal , Gabriele Martinelli , Geir-Arne Fuglstad , Alessandro Nocente , Roberto Iacono , Bo Huang , Francesco Cherubini","doi":"10.1016/j.nexus.2026.100652","DOIUrl":"10.1016/j.nexus.2026.100652","url":null,"abstract":"<div><div>Europe has experienced severe droughts that impacted electricity generation from both renewable and fossil sources. Yet, the response of national electricity systems to drought and the resulting impacts on emissions of CO₂ and air pollutants remain insufficiently understood. This study combines monthly historical electricity generation data (2017–2023) with runoff anomalies, used as a proxy for drought conditions, across 25 European countries. A regression-based counterfactual analysis is applied to quantify the country-level response of electricity systems to drier-than-average conditions. Estimated drought-induced changes in fossil-based generation are subsequently translated into emissions of greenhouse gases and air pollutants using fuel- and country-specific emission factors. We find that electricity generation from hydropower and other renewables is reduced during dry periods, while reliance on fossil fuels and imports increases. Drought induced 141±35 million tonnes of CO₂-equivalent emissions between 2017 and 2023, corresponding to 31 % of the emissions that Europe could release by 2040 under its most ambitious climate goals. Emissions are mainly driven by increased use of natural gas (48 %), coal (22 %), lignite (21 %), and imports (8 %). In France and Portugal, drought-induced emissions account for around 10 % of total fossil-based electricity emissions. The estimated monetized social cost of these emissions is 26 billion USD. Emissions of air pollutants show an average increase of about 2.5 %, though they widely vary across countries. These findings underscore the need for targeted adaptation strategies to reduce the power sector’s vulnerability to drought and to maintain progress toward energy security and decarbonization targets</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100652"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188896","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}
The current study focused on Tana River Basin in Kenya, home to the Bura irrigation scheme (BIS). The BIS faces water supply shortages during critical months of crop development. This study aimed to evaluate the available water resources and crop performance using the Soil and Water Assessment Tool (SWAT) and AquaCrop, respectively, under historical and future shared socioeconomic pathways (SSPs) at the BIS. SWAT estimated the total available flows (TAF) at the BIS intake, whereas AquaCrop estimated crop water requirements (CWR), yields, and water productivity (Wpet) of rice and maize at various carbon (IV) oxide (CO2) levels. The study suggested that the TAF will remain relatively low during the early critical crop development stages in the main cropping season, August-October. Maize yields remained steady over the two cropping seasons under both constant and elevated CO2 levels in the historical and future periods, as opposed to those of rice. Elevated CO2 levels led to diminishing CWR. Moreover, rice showed a stronger response to elevated CO2 than maize. As a result, maize which is less affected by variations in CO2 and temperatures and has less crop water requirements will be better suited than rice for cultivation in the BIS under climate change. To ensure a sustainable water supply in the scheme, the government should increase rainwater harvesting during periods of high TAF. Moreover, there should be a focus on introducing crops that are tolerant to water and temperature stresses and that can reap the most from the elevated CO2 levels.
{"title":"Assessing water resources availability and crop performance under climate change in Kenya's Bura irrigation scheme using SWAT and AquaCrop","authors":"Daniel Mwendwa Wambua , Hiroaki Somura , Toshitsugu Moroizumi , Morihiro Maeda","doi":"10.1016/j.nexus.2025.100624","DOIUrl":"10.1016/j.nexus.2025.100624","url":null,"abstract":"<div><div>The current study focused on Tana River Basin in Kenya, home to the Bura irrigation scheme (BIS). The BIS faces water supply shortages during critical months of crop development. This study aimed to evaluate the available water resources and crop performance using the Soil and Water Assessment Tool (SWAT) and AquaCrop, respectively, under historical and future shared socioeconomic pathways (SSPs) at the BIS. SWAT estimated the total available flows (TAF) at the BIS intake, whereas AquaCrop estimated crop water requirements (CWR), yields, and water productivity (Wpet) of rice and maize at various carbon (IV) oxide (CO<sub>2</sub>) levels. The study suggested that the TAF will remain relatively low during the early critical crop development stages in the main cropping season, August-October. Maize yields remained steady over the two cropping seasons under both constant and elevated CO<sub>2</sub> levels in the historical and future periods, as opposed to those of rice. Elevated CO<sub>2</sub> levels led to diminishing CWR. Moreover, rice showed a stronger response to elevated CO<sub>2</sub> than maize. As a result, maize which is less affected by variations in CO<sub>2</sub> and temperatures and has less crop water requirements will be better suited than rice for cultivation in the BIS under climate change. To ensure a sustainable water supply in the scheme, the government should increase rainwater harvesting during periods of high TAF. Moreover, there should be a focus on introducing crops that are tolerant to water and temperature stresses and that can reap the most from the elevated CO<sub>2</sub> levels.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100624"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798687","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}
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