This study presents the development of a dual-stage water purification system for the treatment of grey water (GW) and saline water (SW). In the first stage, water was passed through a graded series of filtration layers arranged from coarse to fine, while the second stage employed organic packing materials—Celdek (C), coconut coir (CC), and wood shavings (WS)—to further enhance purification and humidification. Water quality was evaluated at multiple stages, with the system achieving optimum performance of 0.27 LPM production rate, 19% efficiency, and a specific filtration capacity of 265 LPM/m² when operated with saline water and Celdek packing. Results indicated that water production increased during the initial six minutes before stabilizing, with the first stage accounting for the greatest removal of impurities relative to the second. Across both stages, reductions were observed in total dissolved solids (29%), hardness (58%), chloride (50%), and sulphate (33.3%). Overall, the dual-stage water filtration–humidification unit demonstrated strong efficacy in treating both grey and saline water, delivering potable water that complies with EPA standards.
{"title":"Mitigating the water scarcity challenges by a novel Dual Stage Water Purifier Unit-An experimental study","authors":"Sampath Suranjan Salins , Sawan Shetty , Shiva Kumar , Reema Shetty","doi":"10.1016/j.nexus.2025.100614","DOIUrl":"10.1016/j.nexus.2025.100614","url":null,"abstract":"<div><div>This study presents the development of a dual-stage water purification system for the treatment of grey water (GW) and saline water (SW). In the first stage, water was passed through a graded series of filtration layers arranged from coarse to fine, while the second stage employed organic packing materials—Celdek (C), coconut coir (CC), and wood shavings (WS)—to further enhance purification and humidification. Water quality was evaluated at multiple stages, with the system achieving optimum performance of 0.27 LPM production rate, 19% efficiency, and a specific filtration capacity of 265 LPM/m² when operated with saline water and Celdek packing. Results indicated that water production increased during the initial six minutes before stabilizing, with the first stage accounting for the greatest removal of impurities relative to the second. Across both stages, reductions were observed in total dissolved solids (29%), hardness (58%), chloride (50%), and sulphate (33.3%). Overall, the dual-stage water filtration–humidification unit demonstrated strong efficacy in treating both grey and saline water, delivering potable water that complies with EPA standards.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100614"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798684","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 : 2025-12-09DOI: 10.1016/j.nexus.2025.100622
G. Shyamala , Gobinath Ravindran , George Uwadiegwu Alaneme , Ramesh T , Sukumar Dhanapalan
Recently, energy consumption has increased, necessitating higher energy production through various sources. Renewable sources such as solar, wind, and hydroelectric power can complement this demand. Hydropower through surface water can generate sufficient electricity, but their output will be significantly lower than that of the ocean-based energy production. The ocean, a powerful energy source, surpasses other renewables, but requires effective implementation and scaling to reduce carbon emissions and spur economic growth. The challenges include technological maturity, funding, market creation, regulatory issues, environmental concerns, and grid integration. This bibliometric study analyzes trends in citations and publications from 2009 to 2024 using Power BI statistical assessment and text mining tools, including bibliographic coupling of documents, sources, and authors, to explore current and emerging trends in ocean energy. In this study we have adopted a three year block period for analysis. This study investigated ocean energy cost efficiency, wave prediction, extreme weather impacts, and contributions to global electricity for sustainability, observing minor growth in ocean surface kinetic energy and significant increases in potential energy due to sea level rise, while also assessing the efficiency, mechanisms, and challenges of ocean kinetic energy harvesters for marine sensors. Large-scale deployment of ocean energy necessitates careful site selection and research to mitigate the environmental impacts on marine ecosystems and ocean-atmosphere interactions, ensuring sustainable development. Advancing reliable and cost-effective technologies, such as WECs, OTECs, and tidal energy, while overcoming the challenges of biofouling, corrosion, and scaling, is crucial for the future of ocean energy and it’s widespread commercial sustainability.
{"title":"Harnessing the future of renewable energy: Integrated insights of ocean energy","authors":"G. Shyamala , Gobinath Ravindran , George Uwadiegwu Alaneme , Ramesh T , Sukumar Dhanapalan","doi":"10.1016/j.nexus.2025.100622","DOIUrl":"10.1016/j.nexus.2025.100622","url":null,"abstract":"<div><div>Recently, energy consumption has increased, necessitating higher energy production through various sources. Renewable sources such as solar, wind, and hydroelectric power can complement this demand. Hydropower through surface water can generate sufficient electricity, but their output will be significantly lower than that of the ocean-based energy production. The ocean, a powerful energy source, surpasses other renewables, but requires effective implementation and scaling to reduce carbon emissions and spur economic growth. The challenges include technological maturity, funding, market creation, regulatory issues, environmental concerns, and grid integration. This bibliometric study analyzes trends in citations and publications from 2009 to 2024 using Power BI statistical assessment and text mining tools, including bibliographic coupling of documents, sources, and authors, to explore current and emerging trends in ocean energy. In this study we have adopted a three year block period for analysis. This study investigated ocean energy cost efficiency, wave prediction, extreme weather impacts, and contributions to global electricity for sustainability, observing minor growth in ocean surface kinetic energy and significant increases in potential energy due to sea level rise, while also assessing the efficiency, mechanisms, and challenges of ocean kinetic energy harvesters for marine sensors. Large-scale deployment of ocean energy necessitates careful site selection and research to mitigate the environmental impacts on marine ecosystems and ocean-atmosphere interactions, ensuring sustainable development. Advancing reliable and cost-effective technologies, such as WECs, OTECs, and tidal energy, while overcoming the challenges of biofouling, corrosion, and scaling, is crucial for the future of ocean energy and it’s widespread commercial sustainability.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100622"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927131","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 : 2025-12-09DOI: 10.1016/j.nexus.2025.100623
Mustafa M. Amin , Ajay Sharma , Mohammad M. Hossain , Muhammad N. Siddiquee
This study investigated the application of heavy vacuum gas oil (HVGO) as a feedstock for high-value carbon fiber precursor production through controlled autoxidation. HVGO, initially had no asphaltenes, was subjected to varying oxidation conditions, such as blowing without mixing and bubbling with mixing at different temperatures with and without addition of tetralin (a naphthenic-aromatic hydrocarbon), to enhance its asphaltenes content and modify its physicochemical properties required for carbon fiber formation. The elemental analysis and physicochemical characterization of the HVGO samples after oxidation showed that the autoxidation significantly enhanced the asphaltenes content, with the highest asphaltenes yield of 47.2 wt. %, viscosity of 117.6 Pa.s, and softening point of 210 °C achieved after 72 hours at 190°C using 5% tetralin and air blowing without mixing. It also found that tetralin addition maintaining limited oxygen conditions would help to form heavier products, desirable as carbon fiber precursor. The melt spinning of the asphaltenes from oxidized HVGO with tetralin, provided green fibers with diameters of 70 µm and carbonized fibers with diameters of 40 to 50 µm, as detected by SEM imaging analysis. The mass residues of the oxidized HVGO samples and the carbon fibers were confirmed by TGA analysis. All these observations indicated that the controlled autoxidation, especially when tetralin was added, was a potential pathway to turn low-value HVGO into high-value carbon fiber precursors. Understanding the current research can also be applied to produce high-value carbon materials for CNT, graphene, and carbon materials for energy storage applications.
{"title":"Controlled autoxidation of HVGO to produce high-value carbon fibers precursors: the role of oxygen availability and naphthenic-aromatic hydrocarbons","authors":"Mustafa M. Amin , Ajay Sharma , Mohammad M. Hossain , Muhammad N. Siddiquee","doi":"10.1016/j.nexus.2025.100623","DOIUrl":"10.1016/j.nexus.2025.100623","url":null,"abstract":"<div><div>This study investigated the application of heavy vacuum gas oil (HVGO) as a feedstock for high-value carbon fiber precursor production through controlled autoxidation. HVGO, initially had no asphaltenes, was subjected to varying oxidation conditions, such as blowing without mixing and bubbling with mixing at different temperatures with and without addition of tetralin (a naphthenic-aromatic hydrocarbon), to enhance its asphaltenes content and modify its physicochemical properties required for carbon fiber formation. The elemental analysis and physicochemical characterization of the HVGO samples after oxidation showed that the autoxidation significantly enhanced the asphaltenes content, with the highest asphaltenes yield of 47.2 wt. %, viscosity of 117.6 Pa.s, and softening point of 210 °C achieved after 72 hours at 190°C using 5% tetralin and air blowing without mixing. It also found that tetralin addition maintaining limited oxygen conditions would help to form heavier products, desirable as carbon fiber precursor. The melt spinning of the asphaltenes from oxidized HVGO with tetralin, provided green fibers with diameters of 70 µm and carbonized fibers with diameters of 40 to 50 µm, as detected by SEM imaging analysis. The mass residues of the oxidized HVGO samples and the carbon fibers were confirmed by TGA analysis. All these observations indicated that the controlled autoxidation, especially when tetralin was added, was a potential pathway to turn low-value HVGO into high-value carbon fiber precursors. Understanding the current research can also be applied to produce high-value carbon materials for CNT, graphene, and carbon materials for energy storage applications.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100623"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798685","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 : 2025-12-09DOI: 10.1016/j.nexus.2025.100627
Yitong Liu , Chao Zhou , Ahmad Riaz
Amid intensifying global climate change and a deepening energy crisis, the high energy consumption of agricultural greenhouses has become increasingly problematic. To address this issue and enhance environmental control within modern agricultural greenhouses, this study proposes an optimized design for a solar photovoltaic thermal (PVT) integrated system tailored for northern solar greenhouses. This design aims to achieve greenhouse energy self-sufficiency and promote sustainable agricultural development. The study outlines a system optimization methodology and a PVT unit layout strategy. This strategy includes double-sided placement on both interior and exterior surfaces of the bilateral gable walls, the use of adjustable racks on the rear wall, and the configuration of an internal heat dissipation system within the greenhouse. These measures collectively enhance the system's year-round comprehensive energy utilization efficiency. Using a typical solar greenhouse case in Shouguang City, Shandong Province, a system performance evaluation model is established. Theoretical analysis indicates that the system generates 35,422 kWh of electricity and 208,945 MJ of heat annually. This achieves an electrical energy self-sufficiency rate of 130.9 % and a thermal energy self-sufficiency rate of 139.4 %, effectively resolving the seasonal mismatch between energy supply and demand in the greenhouse. Comprehensive techno-economic analysis shows a total system investment of approximately CNY 172,300. The static investment payback period is 6.25 years, while accounting for equipment performance degradation yields a dynamic payback period of 9.1 years and an internal rate of return (IRR) of 10.6 %, demonstrating sound economic feasibility. Sensitivity analysis identifies initial investment costs and electricity price fluctuations as key factors influencing system economics. Environmental benefit assessment reveals that the system can displace 17.4 tons of standard coal annually, reducing CO₂ emissions by approximately 45.5 tons. Over a projected 25-year operational lifespan, cumulative CO₂ emission reductions are estimated at approximately 1139 tons. This study provides a technically viable, economically feasible, and environmentally friendly solution to the high energy consumption challenge of agricultural greenhouses, demonstrating significant practical value for advancing sustainable agriculture and optimizing energy structures.
{"title":"Optimization design and techno-economic assessment of integrated solar photovoltaic thermal systems for modern agricultural greenhouses","authors":"Yitong Liu , Chao Zhou , Ahmad Riaz","doi":"10.1016/j.nexus.2025.100627","DOIUrl":"10.1016/j.nexus.2025.100627","url":null,"abstract":"<div><div>Amid intensifying global climate change and a deepening energy crisis, the high energy consumption of agricultural greenhouses has become increasingly problematic. To address this issue and enhance environmental control within modern agricultural greenhouses, this study proposes an optimized design for a solar photovoltaic thermal (PVT) integrated system tailored for northern solar greenhouses. This design aims to achieve greenhouse energy self-sufficiency and promote sustainable agricultural development. The study outlines a system optimization methodology and a PVT unit layout strategy. This strategy includes double-sided placement on both interior and exterior surfaces of the bilateral gable walls, the use of adjustable racks on the rear wall, and the configuration of an internal heat dissipation system within the greenhouse. These measures collectively enhance the system's year-round comprehensive energy utilization efficiency. Using a typical solar greenhouse case in Shouguang City, Shandong Province, a system performance evaluation model is established. Theoretical analysis indicates that the system generates 35,422 kWh of electricity and 208,945 MJ of heat annually. This achieves an electrical energy self-sufficiency rate of 130.9 % and a thermal energy self-sufficiency rate of 139.4 %, effectively resolving the seasonal mismatch between energy supply and demand in the greenhouse. Comprehensive techno-economic analysis shows a total system investment of approximately CNY 172,300. The static investment payback period is 6.25 years, while accounting for equipment performance degradation yields a dynamic payback period of 9.1 years and an internal rate of return (IRR) of 10.6 %, demonstrating sound economic feasibility. Sensitivity analysis identifies initial investment costs and electricity price fluctuations as key factors influencing system economics. Environmental benefit assessment reveals that the system can displace 17.4 tons of standard coal annually, reducing CO₂ emissions by approximately 45.5 tons. Over a projected 25-year operational lifespan, cumulative CO₂ emission reductions are estimated at approximately 1139 tons. This study provides a technically viable, economically feasible, and environmentally friendly solution to the high energy consumption challenge of agricultural greenhouses, demonstrating significant practical value for advancing sustainable agriculture and optimizing energy structures.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100627"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798686","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 : 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":"2025-12-09","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 : 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":"2025-12-09","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 : 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":"2025-12-09","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}
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":"2025-12-09","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}
Achieving universal electricity access in Senegal by 2030 remains a major policy challenge due to persistent spatial disparities in infrastructure, population density, and resource availability. This study conducts a nationwide, spatially explicit assessment of least-cost electrification pathways using OnSSET. The analysis develops context-specific scenarios to plan optimal technology mixes across rural and peri‑urban areas, based on differentiated tiers of electricity access. By integrating high-resolution geospatial, demographic, and techno-economic data, the model identifies the most economically viable solutions for achieving universal access. Results indicate that grid extension is the least-cost option for approximately 93.7 % of the population, largely concentrated in peri‑urban areas with high population density and proximity to existing grid infrastructure. In contrast, solar PV mini-grids (MG PV) and stand-alone PV (SA PV) systems are optimal for 0.7 % and 5.6 % of the population, respectively, mainly in remote, sparsely populated rural settlements. The total investment required to achieve universal electricity access by 2030 is estimated at USD 269.8 million, corresponding to 116.1 MW of additional installed capacity.
Beyond quantifying cost-optimal solutions, the study demonstrates the potential of open-source geospatial models like OnSSET to support transparent, data-driven planning in developing country contexts. It also highlights key policy implications, emphasizing the need for integrated national electrification strategies that combine centralized and decentralized systems to address regional disparities. Limitations of the study include uncertainties in input data quality, static demand assumptions, and the exclusion of non-technical barriers such as institutional capacity and financing constraints. Nonetheless, the findings provide a valuable decision-support basis for Senegal’s ongoing energy transition and broader Sustainable Development Goal 7 (SDG7) objectives.
{"title":"Least-cost electrification pathways for Senegal by 2030: A nationwide analysis using open-source spatial electrification tool (OnSSET)","authors":"Adama Sarr , Aldo Bischi , Umberto Desideri , Cheikh Mouhamed Fadel Kebe","doi":"10.1016/j.nexus.2025.100621","DOIUrl":"10.1016/j.nexus.2025.100621","url":null,"abstract":"<div><div>Achieving universal electricity access in Senegal by 2030 remains a major policy challenge due to persistent spatial disparities in infrastructure, population density, and resource availability. This study conducts a nationwide, spatially explicit assessment of least-cost electrification pathways using OnSSET. The analysis develops context-specific scenarios to plan optimal technology mixes across rural and peri‑urban areas, based on differentiated tiers of electricity access. By integrating high-resolution geospatial, demographic, and techno-economic data, the model identifies the most economically viable solutions for achieving universal access. Results indicate that grid extension is the least-cost option for approximately 93.7 % of the population, largely concentrated in peri‑urban areas with high population density and proximity to existing grid infrastructure. In contrast, solar PV mini-grids (MG PV) and stand-alone PV (SA PV) systems are optimal for 0.7 % and 5.6 % of the population, respectively, mainly in remote, sparsely populated rural settlements. The total investment required to achieve universal electricity access by 2030 is estimated at USD 269.8 million, corresponding to 116.1 MW of additional installed capacity.</div><div>Beyond quantifying cost-optimal solutions, the study demonstrates the potential of open-source geospatial models like OnSSET to support transparent, data-driven planning in developing country contexts. It also highlights key policy implications, emphasizing the need for integrated national electrification strategies that combine centralized and decentralized systems to address regional disparities. Limitations of the study include uncertainties in input data quality, static demand assumptions, and the exclusion of non-technical barriers such as institutional capacity and financing constraints. Nonetheless, the findings provide a valuable decision-support basis for Senegal’s ongoing energy transition and broader Sustainable Development Goal 7 (SDG7) objectives.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100621"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747039","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 : 2025-12-09DOI: 10.1016/j.nexus.2025.100625
M.A. Zaed , John Paul , Saima Aktar , Jeeja Jacob , K.H. Tan , Paul Thomas
MXenes, a class of two-dimensional materials, exhibit exceptional electrical conductivity, catalytic activity, and rapid charge-discharge characteristics, making them highly promising for energy-related applications, such as supercapacitors, batteries, water splitting, and fuel cell catalysis. Despite extensive research on the physicochemical properties and laboratory-scale synthesis of MXenes, a critical gap remains in understanding the feasibility and economic viability of commercial-scale MXene production. This study addresses this gap by systematically evaluating precursor materials, synthesis routes, scalability constraints, and environmental impacts associated with the manufacturing of MXenes. Through a comparative analysis of synthesis parameters and process economics, critical factors influencing consistent large-scale production were identified. The results demonstrate that optimized acid etching and post-processing methods can achieve high yield and reproducible MXene synthesis, effectively addressing significant scalability challenges. Compared with previous laboratory-focused studies, these findings provide more substantial evidence that industrial-scale MXene production can be both technically feasible and economically viable. The accompanying economic assessment further indicates cost-effectiveness, while market analysis reveals increasing demand across the energy, environmental, and electronic sectors. By integrating insights from technical optimization, cost modeling, and market trends, this work establishes a practical framework for advancing the industrialization of MXene. Overall, the study bridges the gap between laboratory research and real-world application, offering actionable guidance for achieving scalable, sustainable, and commercially competitive MXene manufacturing.
{"title":"A comprehensive analysis on feasibility and economic viability of commercial-scale MXene synthesis","authors":"M.A. Zaed , John Paul , Saima Aktar , Jeeja Jacob , K.H. Tan , Paul Thomas","doi":"10.1016/j.nexus.2025.100625","DOIUrl":"10.1016/j.nexus.2025.100625","url":null,"abstract":"<div><div>MXenes, a class of two-dimensional materials, exhibit exceptional electrical conductivity, catalytic activity, and rapid charge-discharge characteristics, making them highly promising for energy-related applications, such as supercapacitors, batteries, water splitting, and fuel cell catalysis. Despite extensive research on the physicochemical properties and laboratory-scale synthesis of MXenes, a critical gap remains in understanding the feasibility and economic viability of commercial-scale MXene production. This study addresses this gap by systematically evaluating precursor materials, synthesis routes, scalability constraints, and environmental impacts associated with the manufacturing of MXenes. Through a comparative analysis of synthesis parameters and process economics, critical factors influencing consistent large-scale production were identified. The results demonstrate that optimized acid etching and post-processing methods can achieve high yield and reproducible MXene synthesis, effectively addressing significant scalability challenges. Compared with previous laboratory-focused studies, these findings provide more substantial evidence that industrial-scale MXene production can be both technically feasible and economically viable. The accompanying economic assessment further indicates cost-effectiveness, while market analysis reveals increasing demand across the energy, environmental, and electronic sectors. By integrating insights from technical optimization, cost modeling, and market trends, this work establishes a practical framework for advancing the industrialization of MXene. Overall, the study bridges the gap between laboratory research and real-world application, offering actionable guidance for achieving scalable, sustainable, and commercially competitive MXene manufacturing.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100625"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927130","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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