Pub Date : 2026-01-08DOI: 10.1016/j.nexus.2026.100634
Claudinei de Moura Altea, Jurandir Itizo Yanagihara
<div><div>Brazil’s electricity sector is undergoing a profound transformation as the share of intermittent renewables, such as wind and solar, continues to grow. While the country benefits from abundant renewable resources and a historically hydro-dominated grid, this configuration is increasingly challenged by seasonal water variability, rising curtailments, and the need to phase out fossil-based backup generation. Addressing these challenges requires the deployment of long-duration energy storage technologies that can provide reliability, flexibility, and resilience at the system level.</div><div>For the first time in the Brazilian context, this study proposes a long-term optimization framework to assess the role of Pumped Hydro Storage (PHS) and Hydrogen (H₂) in enabling a cost-effective and sustainable expansion of Brazil’s power system. The framework simultaneously co-optimizes PHS siting—based on a geospatial inventory of 337 potential sites—together with modular H₂ deployment, renewable expansion, and hydrogen exports within a unified objective function. The model spans a 25-year planning horizon (2026–2050) with monthly resolution, explicitly integrating hydrological cycles and water-dependent dispatch, which is crucial for a hydro-dominated system like Brazil’s. It captures renewable expansion, storage deployment, hydrogen exports, and fossil imports. Decision variables include renewable capacity additions, the siting and adoption of PHS plants, and modular deployment of H₂ electrolysis and re-electrification units. The formulation incorporates round-trip efficiencies, investment and operating costs, CO₂ emissions with a carbon price, and penalties for curtailment, thereby ensuring an integrated assessment of technical, economic, and environmental trade-offs.</div><div>The results highlight distinct but complementary contributions of PHS and H₂. PHS consistently delivers higher round-trip efficiency and cost-effectiveness, confirming its role as a mature and reliable backbone for renewable integration. Hydrogen, in turn, provides strategic systemic flexibility, particularly under high-renewable penetration, enabling surplus absorption and export opportunities. In the optimal configuration (Scenario 7), the model deploys 101 PHS plants and 75 H₂ modules, and the system transitions from a negative net balance in the baseline to a positive economic outcome. While the baseline operates in a net cost position, the optimized configuration not only fully offsets this deficit but also generates additional revenues equivalent to 28 % of the original system costs, underscoring the economic superiority of the PHS–H₂ hybrid solution. Complementarily, the Fossil-Free scenario, which enforces the complete elimination of fossil-based imports in the final five years of the horizon, demonstrates the system’s ability to sustain a fully renewable and storage-backed operation, while maintaining overall system costs reduction within 4 % of the optimal config
{"title":"Optimizing pumped hydro and hydrogen storage for water-dependent renewable systems","authors":"Claudinei de Moura Altea, Jurandir Itizo Yanagihara","doi":"10.1016/j.nexus.2026.100634","DOIUrl":"10.1016/j.nexus.2026.100634","url":null,"abstract":"<div><div>Brazil’s electricity sector is undergoing a profound transformation as the share of intermittent renewables, such as wind and solar, continues to grow. While the country benefits from abundant renewable resources and a historically hydro-dominated grid, this configuration is increasingly challenged by seasonal water variability, rising curtailments, and the need to phase out fossil-based backup generation. Addressing these challenges requires the deployment of long-duration energy storage technologies that can provide reliability, flexibility, and resilience at the system level.</div><div>For the first time in the Brazilian context, this study proposes a long-term optimization framework to assess the role of Pumped Hydro Storage (PHS) and Hydrogen (H₂) in enabling a cost-effective and sustainable expansion of Brazil’s power system. The framework simultaneously co-optimizes PHS siting—based on a geospatial inventory of 337 potential sites—together with modular H₂ deployment, renewable expansion, and hydrogen exports within a unified objective function. The model spans a 25-year planning horizon (2026–2050) with monthly resolution, explicitly integrating hydrological cycles and water-dependent dispatch, which is crucial for a hydro-dominated system like Brazil’s. It captures renewable expansion, storage deployment, hydrogen exports, and fossil imports. Decision variables include renewable capacity additions, the siting and adoption of PHS plants, and modular deployment of H₂ electrolysis and re-electrification units. The formulation incorporates round-trip efficiencies, investment and operating costs, CO₂ emissions with a carbon price, and penalties for curtailment, thereby ensuring an integrated assessment of technical, economic, and environmental trade-offs.</div><div>The results highlight distinct but complementary contributions of PHS and H₂. PHS consistently delivers higher round-trip efficiency and cost-effectiveness, confirming its role as a mature and reliable backbone for renewable integration. Hydrogen, in turn, provides strategic systemic flexibility, particularly under high-renewable penetration, enabling surplus absorption and export opportunities. In the optimal configuration (Scenario 7), the model deploys 101 PHS plants and 75 H₂ modules, and the system transitions from a negative net balance in the baseline to a positive economic outcome. While the baseline operates in a net cost position, the optimized configuration not only fully offsets this deficit but also generates additional revenues equivalent to 28 % of the original system costs, underscoring the economic superiority of the PHS–H₂ hybrid solution. Complementarily, the Fossil-Free scenario, which enforces the complete elimination of fossil-based imports in the final five years of the horizon, demonstrates the system’s ability to sustain a fully renewable and storage-backed operation, while maintaining overall system costs reduction within 4 % of the optimal config","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100634"},"PeriodicalIF":9.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145977275","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 : 2026-01-08DOI: 10.1016/j.nexus.2026.100632
Kabbir Ali , Mohamed I Hassan Ali
This research analyzes the performance and economic viability of a solar-assisted air gap membrane distillation (AGMD) system, comparing a conventional single long-channel module with an optimized multi-short-channel configuration. A computational fluid dynamics (CFD) model, validated against published literature data (<5% error), was developed to evaluate the effects of Reynolds number, solar irradiance, air gap thickness, and concentration ratio (CR) on thermal and mass transfer characteristics. The multi-short-channel design consistently outperformed the single-channel module, achieving up to 26% higher permeate flux and marginally improved thermal efficiency due to reduced temperature polarization, enhanced flow uniformity, and sustained high membrane surface temperatures. Parametric analysis revealed that thinner air gaps and lower flow rates favored higher flux, whereas thicker gaps improved thermal efficiency, indicating a trade-off between productivity and energy utilization. Integration with a concentrator photovoltaic (CPV) solar absorber further elevated feedwater temperatures, with higher CR values significantly boosting system output. Economic analysis demonstrated that the multi-short-channel configuration reduced freshwater production costs by up to ∼25% compared to the single-channel design, reaching as low as (5–18) $/m³ under optimal solar and hydraulic conditions. These findings highlight the potential of advanced channel geometries and solar-thermal integration to deliver cost-effective, energy-efficient desalination solutions, particularly for remote and off-grid regions.
{"title":"Advancing solar-assisted air gap membrane distillation through multi-short-channel module innovation","authors":"Kabbir Ali , Mohamed I Hassan Ali","doi":"10.1016/j.nexus.2026.100632","DOIUrl":"10.1016/j.nexus.2026.100632","url":null,"abstract":"<div><div>This research analyzes the performance and economic viability of a solar-assisted air gap membrane distillation (AGMD) system, comparing a conventional single long-channel module with an optimized multi-short-channel configuration. A computational fluid dynamics (CFD) model, validated against published literature data (<5% error), was developed to evaluate the effects of Reynolds number, solar irradiance, air gap thickness, and concentration ratio (CR) on thermal and mass transfer characteristics. The multi-short-channel design consistently outperformed the single-channel module, achieving up to 26% higher permeate flux and marginally improved thermal efficiency due to reduced temperature polarization, enhanced flow uniformity, and sustained high membrane surface temperatures. Parametric analysis revealed that thinner air gaps and lower flow rates favored higher flux, whereas thicker gaps improved thermal efficiency, indicating a trade-off between productivity and energy utilization. Integration with a concentrator photovoltaic (CPV) solar absorber further elevated feedwater temperatures, with higher CR values significantly boosting system output. Economic analysis demonstrated that the multi-short-channel configuration reduced freshwater production costs by up to ∼25% compared to the single-channel design, reaching as low as (5–18) $/m³ under optimal solar and hydraulic conditions. These findings highlight the potential of advanced channel geometries and solar-thermal integration to deliver cost-effective, energy-efficient desalination solutions, particularly for remote and off-grid regions.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100632"},"PeriodicalIF":9.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145927132","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}
For a hydrokinetic turbine in an open field setting, in the absence of flow restrictions, Betz’s limit represents the maximum power coefficient possible. The efficiency of turbines is evaluated against this value, under the assumption that they are connected to the grid, and therefore continuously operating at their maximum power. However, in island model operation (disconnected to the mains) the turbines operate at points between the no load and the maximum power coefficient, being the efficiency limits different from the Betz’s limit. In the present study, a function has been found defining the power efficiency limits depending on the tip speed ratio, for axial turbines in an open channel without blockage. Mathematical deduction uses the actuator disk theory within an open channel, complemented by the Euler equation for turbomachinery. The approach assumes flow simplifications, including steady, one-dimensional, incompressible, and turbulent-free conditions. Furthermore, two dimensionless parameters have been proposed relating the real coefficient curve with the limit one. These parameters enable a better definition -in the whole range of tip speed ratios- of the difference between the actual efficiency and the limits, as well as the potential for improvement. Function and parameters have been calculated for a numerically simulated turbine and three different turbines from a literature benchmark.
{"title":"Obtaining the efficiency limits of axial hydrokinetic turbines","authors":"Víctor Manuel Fernández Pacheco , Ahmed Gharib Yosry , Rodolfo Espina Valdés , Alexandre Presas Batlló , Eduardo Álvarez Álvarez , Eduardo Blanco Marigorta","doi":"10.1016/j.nexus.2026.100635","DOIUrl":"10.1016/j.nexus.2026.100635","url":null,"abstract":"<div><div>For a hydrokinetic turbine in an open field setting, in the absence of flow restrictions, Betz’s limit represents the maximum power coefficient possible. The efficiency of turbines is evaluated against this value, under the assumption that they are connected to the grid, and therefore continuously operating at their maximum power. However, in island model operation (disconnected to the mains) the turbines operate at points between the no load and the maximum power coefficient, being the efficiency limits different from the Betz’s limit. In the present study, a function has been found defining the power efficiency limits depending on the tip speed ratio, for axial turbines in an open channel without blockage. Mathematical deduction uses the actuator disk theory within an open channel, complemented by the Euler equation for turbomachinery. The approach assumes flow simplifications, including steady, one-dimensional, incompressible, and turbulent-free conditions. Furthermore, two dimensionless parameters have been proposed relating the real coefficient curve with the limit one. These parameters enable a better definition -in the whole range of tip speed ratios- of the difference between the actual efficiency and the limits, as well as the potential for improvement. Function and parameters have been calculated for a numerically simulated turbine and three different turbines from a literature benchmark.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100635"},"PeriodicalIF":9.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077984","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 : 2026-01-08DOI: 10.1016/j.nexus.2026.100633
Dipak Kumar Gupta , Arti Bhatia , Amit Kumar , Tapas Kumar Das , Bidisha Chakrabarti , Ranjan Bhattacharyya
The conventional rice-wheat cropping system of the northern-Indo-Gangetic Plains is tillage, energy, and water-intensive leading to greenhouse gases emission (GHG) and soil-carbon loss. Practices such as direct seeding, zero-tillage, and residue-retention are promoted for sustainable-farming and environmental-benefit, however the impact on the net-carbon footprint (NCF) has been less evaluated. Measurement of GHG emission and soil organic carbon was carried out for three consecutive years in a long-term experiment in rice–wheat system. Six treatment combination of zero-till direct-seeded rice (ZTDSR), transplanted-puddled rice, zero-tilled wheat (ZTW), conventionally-tilled wheat (CTW), summer-fallow, zero-tilled green-gram (ZTGG), rice-residue retention (RS), rice residue burning (RRB), and green-gram residue (GGR) were field experimented. The zero tillage (ZT) and crop residue retention significantly reduced energy input and net carbon footprint (NCF) of rice wheat system through energy saving, water saving and net positive ecosystem carbon balance (NECB). The CH4, N2O and CO2 emissions from the field burning of rice residue were 2.56±0.52 g kg−1, 0.3 ± 0.05 g kg−1 and 1035±0.82 g kg−1, respectively. The NCF differed significantly (p < 0.001) among the treatments, and ZT-systems with and without residue retention, had 64–78% lower NCF than conventional-system due to lower methane emission with significantly higher net ecosystem carbon balance (NECB). Residue retention in ZT-treatments reduced NCF by 7–39% varying with type of residue and frequency of application. The triple ZT treatment of ZTDSR+GGR–ZTW+RS–ZTGG significantly reduced GHG emissions (on-farm+off-farm) by 52.6%, energy input by 23.5%, carbon intensity by 64.1%, and NECB by 105% compared to conventional rice-wheat-fallow system. Higher Dehydrogenase activity in the triple ZT-treatments indicated better microbial activity and soil health. Additionally, this approach of triple ZT based rice-wheat-green gram system can yield up to 11 carbon credits per hectare annually, providing additional income for smallholder farmers of the region. However, policymakers need to invest in strengthening agricultural extension services to provide farmers with the necessary knowledge, training, and technical support to adopt these practices and participate in carbon markets.
印度恒河平原北部传统的水稻-小麦种植系统是耕作、能源和水密集型的，导致温室气体排放（GHG）和土壤碳损失。为了可持续农业和环境效益，诸如直接播种、免耕和剩余物保留等做法得到了推广，但对净碳足迹（NCF）的影响却很少得到评估。在水稻-小麦系统长期试验中，连续3年进行了温室气体排放和土壤有机碳的测定。采用免耕直播稻（ZTDSR）、移栽水煮稻、免耕小麦（ZTW）、常规耕作小麦（CTW）、夏休、免耕绿克（ZTGG）、稻渣保留（RS）、稻渣焚烧（RRB）和绿克渣（GGR） 6种处理组合进行田间试验。免耕（ZT）和残茬保留通过节能、节水和生态系统净正碳平衡（NECB）显著降低了稻麦系统的能量投入和净碳足迹（NCF）。稻田秸秆焚烧产生的CH4、N2O和CO2排放量分别为2.56±0.52 g kg - 1、0.3±0.05 g kg - 1和1035±0.82 g kg - 1。不同处理间的NCF差异显著（p < 0.001），有和没有残留物保留的zt系统的NCF比常规系统低64-78%，这是由于甲烷排放量较低，生态系统净碳平衡（NECB）显著较高。zt处理的残茬保留率随残茬类型和施用频率的不同，可使NCF降低7 ~ 39%。ZTDSR+ GGR-ZTW + RS-ZTGG三重ZT处理与常规稻麦休耕系统相比，温室气体（农场+农场）排放量显著降低52.6%，能源投入显著降低23.5%，碳强度显著降低64.1%，NECB显著降低105%。三联zt处理的脱氢酶活性越高，土壤微生物活性越好，土壤健康状况越好。此外，这种基于三重ZT的水稻-小麦-绿克系统每年每公顷可产生高达11个碳信用额，为该地区的小农提供额外收入。然而，政策制定者需要投资于加强农业推广服务，为农民提供必要的知识、培训和技术支持，以采用这些做法并参与碳市场。
{"title":"Reducing carbon footprint and acquiring carbon credits in intensively cultivated rice wheat system by tillage and residue management","authors":"Dipak Kumar Gupta , Arti Bhatia , Amit Kumar , Tapas Kumar Das , Bidisha Chakrabarti , Ranjan Bhattacharyya","doi":"10.1016/j.nexus.2026.100633","DOIUrl":"10.1016/j.nexus.2026.100633","url":null,"abstract":"<div><div>The conventional rice-wheat cropping system of the northern-Indo-Gangetic Plains is tillage, energy, and water-intensive leading to greenhouse gases emission (GHG) and soil-carbon loss. Practices such as direct seeding, zero-tillage, and residue-retention are promoted for sustainable-farming and environmental-benefit, however the impact on the net-carbon footprint (NCF) has been less evaluated. Measurement of GHG emission and soil organic carbon was carried out for three consecutive years in a long-term experiment in rice–wheat system. Six treatment combination of zero-till direct-seeded rice (ZTDSR), transplanted-puddled rice, zero-tilled wheat (ZTW), conventionally-tilled wheat (CTW), summer-fallow, zero-tilled green-gram (ZTGG), rice-residue retention (RS), rice residue burning (RRB), and green-gram residue (GGR) were field experimented. The zero tillage (ZT) and crop residue retention significantly reduced energy input and net carbon footprint (NCF) of rice wheat system through energy saving, water saving and net positive ecosystem carbon balance (NECB). The CH<sub>4</sub>, N<sub>2</sub>O and CO<sub>2</sub> emissions from the field burning of rice residue were 2.56±0.52 g kg<sup>−1</sup>, 0.3 ± 0.05 g kg<sup>−1</sup> and 1035±0.82 g kg<sup>−1</sup>, respectively. The NCF differed significantly (<em>p</em> < 0.001) among the treatments, and ZT-systems with and without residue retention, had 64–78% lower NCF than conventional-system due to lower methane emission with significantly higher net ecosystem carbon balance (NECB). Residue retention in ZT-treatments reduced NCF by 7–39% varying with type of residue and frequency of application. The triple ZT treatment of ZTDSR+GGR–ZTW+RS–ZTGG significantly reduced GHG emissions (on-farm+off-farm) by 52.6%, energy input by 23.5%, carbon intensity by 64.1%, and NECB by 105% compared to conventional rice-wheat-fallow system. Higher Dehydrogenase activity in the triple ZT-treatments indicated better microbial activity and soil health. Additionally, this approach of triple ZT based rice-wheat-green gram system can yield up to 11 carbon credits per hectare annually, providing additional income for smallholder farmers of the region. However, policymakers need to invest in strengthening agricultural extension services to provide farmers with the necessary knowledge, training, and technical support to adopt these practices and participate in carbon markets.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100633"},"PeriodicalIF":9.5,"publicationDate":"2026-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037987","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 : 2025-12-11DOI: 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":"2025-12-11","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}
Recent advances in agrivoltaic systems (AVSs) have revived interest in understanding the effects of not only light intensity but also different light spectra on plants and overall land productivity, with research showing plant carbon assimilation being more efficient under red light, while the more energetic blue light would be more effective for producing solar electricity. AVSs are highly efficient in harvesting solar radiation for the co-generation of food and solar electricity, thus resulting in higher land productivity, compared to single-use alternatives, i.e., agriculture or utility-scale solar. This is particularly advantageous in arid and semi-arid areas with abundant sun and limited land and water. The question becomes: how much light and what particular spectra of light are more efficient for food and for energy conversion, and how can any light treatment impact water, soil, microclimate and plant productivity? This study explores the potentials of spectrally selective PV panels by testing the performance of field grown processing tomato with the focus on red and blue light treatments. The study evaluates crop productivity and water savings by monitoring microclimate, soil, and plant responses under two specific wavelength patterns (red and blue filters) compared to the full unfiltered light spectrum (control). The red and blue treatments, applied on processing tomatoes in Yolo County (California), yielded 67 % and 58 % of the control, respectively. However, changes in the microclimate — particularly the reduction in solar radiation —resulted in a significant decrease in evapotranspiration. Consequently, the potential water use efficiency (WUE) for the blue and red light treatments compared to the control was improved by 10 % and 13 %, respectively. Overall, our study suggests that benefits from renewable energy and reduced water usage could offset yield reductions, making spectrally selective AVSs a potentially viable and sustainable land-use option, especially in water-scarce regions.
{"title":"Effects of red and blue light treatment on water, microclimate, soil and tomato crops in California","authors":"Majdi Abou Najm , Andre Daccache , Matteo Camporese , Mohamed Emami","doi":"10.1016/j.nexus.2025.100609","DOIUrl":"10.1016/j.nexus.2025.100609","url":null,"abstract":"<div><div>Recent advances in agrivoltaic systems (AVSs) have revived interest in understanding the effects of not only light intensity but also different light spectra on plants and overall land productivity, with research showing plant carbon assimilation being more efficient under red light, while the more energetic blue light would be more effective for producing solar electricity. AVSs are highly efficient in harvesting solar radiation for the co-generation of food and solar electricity, thus resulting in higher land productivity, compared to single-use alternatives, i.e., agriculture or utility-scale solar. This is particularly advantageous in arid and semi-arid areas with abundant sun and limited land and water. The question becomes: how much light and what particular spectra of light are more efficient for food and for energy conversion, and how can any light treatment impact water, soil, microclimate and plant productivity? This study explores the potentials of spectrally selective PV panels by testing the performance of field grown processing tomato with the focus on red and blue light treatments. The study evaluates crop productivity and water savings by monitoring microclimate, soil, and plant responses under two specific wavelength patterns (red and blue filters) compared to the full unfiltered light spectrum (control). The red and blue treatments, applied on processing tomatoes in Yolo County (California), yielded 67 % and 58 % of the control, respectively. However, changes in the microclimate — particularly the reduction in solar radiation —resulted in a significant decrease in evapotranspiration. Consequently, the potential water use efficiency (WUE) for the blue and red light treatments compared to the control was improved by 10 % and 13 %, respectively. Overall, our study suggests that benefits from renewable energy and reduced water usage could offset yield reductions, making spectrally selective AVSs a potentially viable and sustainable land-use option, especially in water-scarce regions.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100609"},"PeriodicalIF":9.5,"publicationDate":"2025-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145799045","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.2025.100626
Giuseppe Mancuso, Dilia Carolina Duran Lugo, Emanuele Spizzirri, Attilio Toscano, Francesca Valenti
As the global demand for sustainable energy solutions grows, Constructed Wetlands (CWs) are gaining recognition not only for their effectiveness in wastewater treatment but also for their untapped potential as bioenergy sources. This study explores the viability of CW-derived plant biomass for biogas production, evaluating how plant species, maturity stages, and storage durations can influence methane yield. Using biomass from a free water surface wetland in Italy, four plant species, e.g., Phragmites australis, Typha latifolia, Carex spp., and Iris pseudacorus, were analyzed through Biomethane Potential (BMP) tests at three storage intervals: i) immediate – t(0), ii) three months after harvesting – t(1), and iii) six months – t(2) after harvesting, respectively. Results indicate that biogas yield peaked at t(1) for all species, with Iris pseudacorus showing consistent performance over time, and low carbon-to-nitrogen (C/N) ratios correlating with higher methane output. While plant maturity and storage significantly affected volatile solids and gas production, not all decreases in solids translated to higher methane yields. These findings indicate that CW biomass holds potential as a renewable feedstock for biogas production, though further optimization and scale-up studies are needed to confirm its practical applicability. By aligning with the Water-Energy-Food Nexus and Nature-based Solutions (NbS), the research promotes integrated approaches to enhance resource recovery, reduce waste, and support climate resilience.
{"title":"Optimizing plant biomass from constructed wetlands for biogas production within the water-energy-food nexus","authors":"Giuseppe Mancuso, Dilia Carolina Duran Lugo, Emanuele Spizzirri, Attilio Toscano, Francesca Valenti","doi":"10.1016/j.nexus.2025.100626","DOIUrl":"10.1016/j.nexus.2025.100626","url":null,"abstract":"<div><div>As the global demand for sustainable energy solutions grows, Constructed Wetlands (CWs) are gaining recognition not only for their effectiveness in wastewater treatment but also for their untapped potential as bioenergy sources. This study explores the viability of CW-derived plant biomass for biogas production, evaluating how plant species, maturity stages, and storage durations can influence methane yield. Using biomass from a free water surface wetland in Italy, four plant species, e.g., <em>Phragmites australis, Typha latifolia, Carex</em> spp., and <em>Iris pseudacorus</em>, were analyzed through Biomethane Potential (BMP) tests at three storage intervals: i) immediate – t(0), ii) three months after harvesting – t(1), and iii) six months – t(2) after harvesting, respectively. Results indicate that biogas yield peaked at t(1) for all species, with <em>Iris pseudacorus</em> showing consistent performance over time, and low carbon-to-nitrogen (C/N) ratios correlating with higher methane output. While plant maturity and storage significantly affected volatile solids and gas production, not all decreases in solids translated to higher methane yields. These findings indicate that CW biomass holds potential as a renewable feedstock for biogas production, though further optimization and scale-up studies are needed to confirm its practical applicability. By aligning with the Water-Energy-Food Nexus and Nature-based Solutions (NbS), the research promotes integrated approaches to enhance resource recovery, reduce waste, and support climate resilience.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100626"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747036","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.2025.100612
Idiano D'Adamo , Simone Di Leo , Massimo Gastaldi , Anna Chiara Maccallini
The transition to sustainable business models in the catering sector requires the integration of environmental innovation with economic feasibility. Restaurants, as energy-intensive businesses, represent a strategic context for assessing the financial viability of renewable energy technologies. This study evaluates the economic viability of photovoltaic (PV) and battery energy storage (BES) systems in Italy. The analysis evaluates the project under different policy conditions, with and without public incentives (40 % capital deduction on investment costs), and identifies the key factors that influence their profitability. A comprehensive methodology combining financial and sensitivity analysis, scenario analysis, LASSO regression, break-even point and Monte Carlo simulations was applied to assess economic performance and risk. The results show that the PV system is profitable in both contexts, although incentives significantly improve returns: from 425 to 1590 €/kW. Profitability depends mainly on specific production, the cost of purchasing electricity and the percentage of self-consumption. For the BES, profitability only occurs when self-consumption increases by at least 22–25 % with incentives and 30–35 % without them. Overall, the results emphasise that policy support and management strategies to optimise self-consumption are key to ensuring financial profitability. This work enables restaurant owners to identify the variables that most strongly influence the final outcome, helping them mitigate risks and maximise returns, while supporting more informed decisions that contribute to long-term sustainable development.
{"title":"Green restaurants: An economic assessment of solar photovoltaics and energy storage systems","authors":"Idiano D'Adamo , Simone Di Leo , Massimo Gastaldi , Anna Chiara Maccallini","doi":"10.1016/j.nexus.2025.100612","DOIUrl":"10.1016/j.nexus.2025.100612","url":null,"abstract":"<div><div>The transition to sustainable business models in the catering sector requires the integration of environmental innovation with economic feasibility. Restaurants, as energy-intensive businesses, represent a strategic context for assessing the financial viability of renewable energy technologies. This study evaluates the economic viability of photovoltaic (PV) and battery energy storage (BES) systems in Italy. The analysis evaluates the project under different policy conditions, with and without public incentives (40 % capital deduction on investment costs), and identifies the key factors that influence their profitability. A comprehensive methodology combining financial and sensitivity analysis, scenario analysis, LASSO regression, break-even point and Monte Carlo simulations was applied to assess economic performance and risk. The results show that the PV system is profitable in both contexts, although incentives significantly improve returns: from 425 to 1590 €/kW. Profitability depends mainly on specific production, the cost of purchasing electricity and the percentage of self-consumption. For the BES, profitability only occurs when self-consumption increases by at least 22–25 % with incentives and 30–35 % without them. Overall, the results emphasise that policy support and management strategies to optimise self-consumption are key to ensuring financial profitability. This work enables restaurant owners to identify the variables that most strongly influence the final outcome, helping them mitigate risks and maximise returns, while supporting more informed decisions that contribute to long-term sustainable development.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100612"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747037","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.2025.100620
Adnan Ozden
Renewable-electricity-powered hydrogen production via alkaline water electrolysis provides an efficient route to hydrogen economy. Recent advances in catalysts, membranes, and systems have enhanced the technology’s practicality. This work provides a techno-economic assessment of hydrogen production, offering scenarios that needs to be met toward wide-scale industrial implementation. The work explores the cost implications of critical performance metrics and parameters, including current density, cell voltage, Faradaic efficiency (FE), electricity and water prices, catalyst/membrane and system lifetimes, and electrolyzer cost. The study reveals 15 scenarios that could take the technology a step closer to the DOE’s hydrogen cost targets. The analysis reveals that the economically compelling production of hydrogen requires performance enhancements (particularly voltage reductions), along with lower electricity (<3.6 c kWh−1) and water (<3 $ ton−1) prices, longer catalyst/membrane lifetimes (>13,140 hours), electrolyzer costs (<200 kW−1), and catalyst/membrane costs (<5% of total electrolyzer capital). The work discusses the remaining technical and economic challenges, offering research directions toward marketable electrified hydrogen production.
{"title":"Pathways to feasible hydrogen production in alkaline water electrolyzers","authors":"Adnan Ozden","doi":"10.1016/j.nexus.2025.100620","DOIUrl":"10.1016/j.nexus.2025.100620","url":null,"abstract":"<div><div>Renewable-electricity-powered hydrogen production via alkaline water electrolysis provides an efficient route to hydrogen economy. Recent advances in catalysts, membranes, and systems have enhanced the technology’s practicality. This work provides a techno-economic assessment of hydrogen production, offering scenarios that needs to be met toward wide-scale industrial implementation. The work explores the cost implications of critical performance metrics and parameters, including current density, cell voltage, Faradaic efficiency (FE), electricity and water prices, catalyst/membrane and system lifetimes, and electrolyzer cost. The study reveals 15 scenarios that could take the technology a step closer to the DOE’s hydrogen cost targets. The analysis reveals that the economically compelling production of hydrogen requires performance enhancements (particularly voltage reductions), along with lower electricity (<3.6 c kWh<sup>−1</sup>) and water (<3 $ ton<sup>−1</sup>) prices, longer catalyst/membrane lifetimes (>13,140 hours), electrolyzer costs (<200 kW<sup>−1</sup>), and catalyst/membrane costs (<5% of total electrolyzer capital). The work discusses the remaining technical and economic challenges, offering research directions toward marketable electrified hydrogen production.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100620"},"PeriodicalIF":9.5,"publicationDate":"2025-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145747038","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}
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}
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