Pub Date : 2026-03-01Epub Date: 2026-01-10DOI: 10.1016/j.nexus.2026.100642
Hassan Hajabdollahi, Mohsen Abooli Pour, Mohammad Shafiey Dehaj
A comprehensive energy, exergy, economic, and exergoeconomic analyses was performed on a geothermal-based cogeneration system designed for the simultaneous production of hydrogen, oxygen, and freshwater. The system comprises three principal subsystems: a dual-pressure organic Rankine cycle for power generation, a reverse osmosis desalination unit for freshwater production, and a proton exchange membrane electrolyzer for hydrogen and oxygen generation. The system optimization was carried out using a non-dominated sorting genetic algorithm with the objective of minimizing the total exergy destruction cost rate while maximizing freshwater output. The results indicate that the organic Rankine cycle is responsible for the largest share of exergy destruction, accounting for approximately 61 % of the total, whereas the proton exchange membrane electrolyzer contributes about 65 % of the total exergy destruction cost rate. From an exergoeconomic perspective, the high-pressure turbine demonstrated the highest exergoeconomic factor, implying that its exergy destruction is relatively low compared to its associated investment cost. The overall exergy efficiency of the system and the corresponding payback period were estimated to be 23.81 % and 7.04 years, respectively, confirming the technical feasibility and economic viability of the proposed configuration.
{"title":"Cogeneration system utilizing geothermal energy: Energy, exergy, economic and environmental analyses and multi-objective optimization","authors":"Hassan Hajabdollahi, Mohsen Abooli Pour, Mohammad Shafiey Dehaj","doi":"10.1016/j.nexus.2026.100642","DOIUrl":"10.1016/j.nexus.2026.100642","url":null,"abstract":"<div><div>A comprehensive energy, exergy, economic, and exergoeconomic analyses was performed on a geothermal-based cogeneration system designed for the simultaneous production of hydrogen, oxygen, and freshwater. The system comprises three principal subsystems: a dual-pressure organic Rankine cycle for power generation, a reverse osmosis desalination unit for freshwater production, and a proton exchange membrane electrolyzer for hydrogen and oxygen generation. The system optimization was carried out using a non-dominated sorting genetic algorithm with the objective of minimizing the total exergy destruction cost rate while maximizing freshwater output. The results indicate that the organic Rankine cycle is responsible for the largest share of exergy destruction, accounting for approximately 61 % of the total, whereas the proton exchange membrane electrolyzer contributes about 65 % of the total exergy destruction cost rate. From an exergoeconomic perspective, the high-pressure turbine demonstrated the highest exergoeconomic factor, implying that its exergy destruction is relatively low compared to its associated investment cost. The overall exergy efficiency of the system and the corresponding payback period were estimated to be 23.81 % and 7.04 years, respectively, confirming the technical feasibility and economic viability of the proposed configuration.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100642"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-08DOI: 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":"2026-03-01","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 : 2026-03-01Epub Date: 2025-12-07DOI: 10.1016/j.nexus.2025.100610
Mohammed E.B. Abdalla , Osama Ayadi , Aseel Al Omari , Bilal Rinchi , Jawad T. Al-Bakri
Agrivoltaics (AV), the co-location of solar photovoltaic energy generation and agricultural farming, directly addresses the water-energy-food nexus and associated security challenges. Maximizing land efficiency is a long-standing practice, and AV presents an untapped opportunity to optimize land use in countries struggling with water, energy, or food security. Despite its promise, AV potential remains unexplored in countries that could benefit the most, particularly those in the Middle East & North Africa (MENA) region. While AV suitability has been studied in many countries, no region-wide, quantitative assessment exists for the MENA region, despite its acute resource constraints. This study is the first to quantify AV suitability across the MENA region, expressed as a proportion of national agricultural land, using a Geographic Information System (GIS)-based weighted overlay analysis. The method integrated openly available datasets on solar irradiance, land cover, slope, and agricultural land distribution, providing a consistent-resolution assessment at regional and national scales. Results show that in the absence of solar radiation limitations, AV-suitable areas almost perfectly overlap with agriculturally suitable areas, yielding ranges of 74–100% under a conservative scenario and 94–100% under an optimistic scenario. Results from a control set of countries (UK, JPN, ECU, SWZ) exhibited substantially lower overlap supporting these findings. These findings highlight the immense AV potential in the MENA region and demonstrate the scalability of this open-dataset approach, providing a foundation that encourages detailed crop-specific studies and pilot projects at localized scales.
{"title":"A pathway to food and energy security: Agrivoltaic potential in the MENA region","authors":"Mohammed E.B. Abdalla , Osama Ayadi , Aseel Al Omari , Bilal Rinchi , Jawad T. Al-Bakri","doi":"10.1016/j.nexus.2025.100610","DOIUrl":"10.1016/j.nexus.2025.100610","url":null,"abstract":"<div><div>Agrivoltaics (AV), the co-location of solar photovoltaic energy generation and agricultural farming, directly addresses the water-energy-food nexus and associated security challenges. Maximizing land efficiency is a long-standing practice, and AV presents an untapped opportunity to optimize land use in countries struggling with water, energy, or food security. Despite its promise, AV potential remains unexplored in countries that could benefit the most, particularly those in the Middle East & North Africa (MENA) region. While AV suitability has been studied in many countries, no region-wide, quantitative assessment exists for the MENA region, despite its acute resource constraints. This study is the first to quantify AV suitability across the MENA region, expressed as a proportion of national agricultural land, using a Geographic Information System (GIS)-based weighted overlay analysis. The method integrated openly available datasets on solar irradiance, land cover, slope, and agricultural land distribution, providing a consistent-resolution assessment at regional and national scales. Results show that in the absence of solar radiation limitations, AV-suitable areas almost perfectly overlap with agriculturally suitable areas, yielding ranges of 74–100% under a conservative scenario and 94–100% under an optimistic scenario. Results from a control set of countries (UK, JPN, ECU, SWZ) exhibited substantially lower overlap supporting these findings. These findings highlight the immense AV potential in the MENA region and demonstrate the scalability of this open-dataset approach, providing a foundation that encourages detailed crop-specific studies and pilot projects at localized scales.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100610"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145798688","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":"2026-03-01","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}
The Ecological Footprint (EF) is a vital metric for assessing the evolution of global sustainability, but its underlying factors are complex and interwoven. This study employs bibliometric analysis to map the vast academic landscape exploring how socioeconomic and institutional factors may influence the EF. By analyzing 929 publications from 1992–2025 using VOS Viewer and RStudio software, we visualize the evolution of key themes, major contributing countries, leading authors, and core journals. Results show that while research on economic drivers like GDP and energy use is prevalent, the role of institutional factors, such as governance quality and political stability, is increasingly recognized as fundamental yet requires greater attention. The findings provide a clear roadmap for academic scholars, highlighting the need to integrate institutional analyses with traditional economic models to better understand and mitigate ecological degradation.
{"title":"Ecological Footprint under the lens: A bibliometric coupling analysis of institutional and socioeconomic factors","authors":"Stefania Pinzon , Ernesto Rodríguez-Crespo , Brayan Tillaguango , Nuria E. Laguna-Molina","doi":"10.1016/j.nexus.2026.100643","DOIUrl":"10.1016/j.nexus.2026.100643","url":null,"abstract":"<div><div>The Ecological Footprint (EF) is a vital metric for assessing the evolution of global sustainability, but its underlying factors are complex and interwoven. This study employs bibliometric analysis to map the vast academic landscape exploring how socioeconomic and institutional factors may influence the EF. By analyzing 929 publications from 1992–2025 using VOS Viewer and RStudio software, we visualize the evolution of key themes, major contributing countries, leading authors, and core journals. Results show that while research on economic drivers like GDP and energy use is prevalent, the role of institutional factors, such as governance quality and political stability, is increasingly recognized as fundamental yet requires greater attention. The findings provide a clear roadmap for academic scholars, highlighting the need to integrate institutional analyses with traditional economic models to better understand and mitigate ecological degradation.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100643"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146037984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-09DOI: 10.1016/j.nexus.2026.100648
Anwur Alenezi , Yousef Alabaiadly
The principle of thermoelectric cooling (TEC) has been extensively investigated owing to its advantages in atmospheric water harvesting (AWH). Key advantages of this technology include direct energy conversion, low weight, and minimal maintenance requirements. This study reviews the TEC applications in AWH, focusing on device materials, design strategies, performance metrics, and existing limitations. A detailed bibliometric analysis was conducted on 202 peer-reviewed studies on TEC-AWH, sourced from Google Scholar and filtered for relevance, language, and scientific rigor (2000–2025). The temporal evolution of research output was mapped, and dominant thematic clusters were identified through keyword co-occurrence analysis. The review also highlights emerging frontiers, such as bio-inspired surfaces and AI-driven control and offers a strategic perspective for future research and innovation. Bismuth Telluride (Bi₂Te₃) remains the most widely utilized thermoelectric semiconductor material in TEC applications, owing to its high thermoelectric efficiency, stability, and availability. This makes Bi₂Te₃ a preferred candidate for integration into various energy conversion and cooling systems. Notably, bio-inspired and nature-mimicking surfaces have demonstrated a 20–40% improvement in water collection efficiency compared with flat or conventional hydrophobic coatings. Case studies further indicate that solar-TEC hybrid systems can generate 2–4 L/day in off-grid settings, significantly reducing dependence on bottled water and long-distance transportation. While TEC-AWH is not yet ready for large-scale deployment, it is on the cusp of transformative innovation. The integration of materials science, sustainable design principles, and artificial intelligence presents a unique opportunity to redefine global water sourcing.
{"title":"Thermoelectric cooling in atmospheric water harvesting: A critical review of materials, design, and applications","authors":"Anwur Alenezi , Yousef Alabaiadly","doi":"10.1016/j.nexus.2026.100648","DOIUrl":"10.1016/j.nexus.2026.100648","url":null,"abstract":"<div><div>The principle of thermoelectric cooling (TEC) has been extensively investigated owing to its advantages in atmospheric water harvesting (AWH). Key advantages of this technology include direct energy conversion, low weight, and minimal maintenance requirements. This study reviews the TEC applications in AWH, focusing on device materials, design strategies, performance metrics, and existing limitations. A detailed bibliometric analysis was conducted on 202 peer-reviewed studies on TEC-AWH, sourced from Google Scholar and filtered for relevance, language, and scientific rigor (2000–2025). The temporal evolution of research output was mapped, and dominant thematic clusters were identified through keyword co-occurrence analysis. The review also highlights emerging frontiers, such as bio-inspired surfaces and AI-driven control and offers a strategic perspective for future research and innovation. Bismuth Telluride (Bi₂Te₃) remains the most widely utilized thermoelectric semiconductor material in TEC applications, owing to its high thermoelectric efficiency, stability, and availability. This makes Bi₂Te₃ a preferred candidate for integration into various energy conversion and cooling systems. Notably, bio-inspired and nature-mimicking surfaces have demonstrated a 20–40% improvement in water collection efficiency compared with flat or conventional hydrophobic coatings. Case studies further indicate that solar-TEC hybrid systems can generate 2–4 L/day in off-grid settings, significantly reducing dependence on bottled water and long-distance transportation. While TEC-AWH is not yet ready for large-scale deployment, it is on the cusp of transformative innovation. The integration of materials science, sustainable design principles, and artificial intelligence presents a unique opportunity to redefine global water sourcing.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100648"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188430","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}
Effluent treatment plant sludge (ETPS) is a significant byproduct of the pulp and paper industry and has been investigated to assess its thermal degradation behaviour, kinetic parameters, and bioenergy recovery potential. Physicochemical characterisation revealed lower moisture content (4.40 wt.%), a higher volatile content (67.79 wt.%), and a significant ash fraction (19.22 wt.%), rich in catalytically active alkali metals. Thermogravimetric analysis at 10–30 °C/min showed three distinct stages: dehydration (30–150 oC), active devolatilization (150–700 oC), and char stabilisation (>700 oC), with decomposition temperatures shifting higher at elevated heating rates due to kinetic effects. Furthermore, to capture the complex, multi-step reactions, eight iso-conversional kinetic models (KAS, OFW, FM, DAEM, STM, TM, VZM, and AVIC) were employed. The activation energy varied (139–350 kJ/mol) with conversion (0.1–0.8), confirming heterogeneous decomposition behaviour. The apparent average activation energies (185–225 kJ/mol) indicate moderate to high energy requirements influenced by inorganic interactions. Master plot analysis revealed a shift from diffusion-controlled mechanisms at early conversions to nucleation and interfacial reactions at higher conversions. Lastly, thermodynamic analysis indicated that ETPS pyrolysis is endothermic (ΔH > 0), non-spontaneous (ΔG>0), and disorder-promoting (ΔS>0), requiring continuous heat supply. These results demonstrate the technical feasibility of ETPS valorisation through pyrolysis while highlighting the need for process optimisation to overcome ash-related operational challenges.
{"title":"Thermal degradation behaviour and kinetic analysis of effluent treatment plant sludge towards sustainable bioenergy potential","authors":"Gaurav Singh , Ranjeet Kumar Mishra , Neeraj Kumar","doi":"10.1016/j.nexus.2026.100669","DOIUrl":"10.1016/j.nexus.2026.100669","url":null,"abstract":"<div><div>Effluent treatment plant sludge (ETPS) is a significant byproduct of the pulp and paper industry and has been investigated to assess its thermal degradation behaviour, kinetic parameters, and bioenergy recovery potential. Physicochemical characterisation revealed lower moisture content (4.40 wt.%), a higher volatile content (67.79 wt.%), and a significant ash fraction (19.22 wt.%), rich in catalytically active alkali metals. Thermogravimetric analysis at 10–30 °C/min showed three distinct stages: dehydration (30–150 <sup>o</sup>C), active devolatilization (150–700 <sup>o</sup>C), and char stabilisation (>700 <sup>o</sup>C), with decomposition temperatures shifting higher at elevated heating rates due to kinetic effects. Furthermore, to capture the complex, multi-step reactions, eight iso-conversional kinetic models (KAS, OFW, FM, DAEM, STM, TM, VZM, and AVIC) were employed. The activation energy varied (139–350 kJ/mol) with conversion (0.1–0.8), confirming heterogeneous decomposition behaviour. The apparent average activation energies (185–225 kJ/mol) indicate moderate to high energy requirements influenced by inorganic interactions. Master plot analysis revealed a shift from diffusion-controlled mechanisms at early conversions to nucleation and interfacial reactions at higher conversions. Lastly, thermodynamic analysis indicated that ETPS pyrolysis is endothermic (ΔH > 0), non-spontaneous (ΔG>0), and disorder-promoting (ΔS>0), requiring continuous heat supply. These results demonstrate the technical feasibility of ETPS valorisation through pyrolysis while highlighting the need for process optimisation to overcome ash-related operational challenges.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100669"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-02-11DOI: 10.1016/j.nexus.2026.100661
Kevin B. Grell , Sophie S. Parker
“Regenerative agrivoltaics” involves the co-location of regenerative agriculture (RA) and solar development. While RA focuses on promoting environmental quality, such as soil health, biodiversity, and other ecosystem services, agrivoltaics is concerned with the efficiency of dual land-use strategies. Here we describe a novel pilot project of a regenerative agrivoltaics installation in Southern California. We also explore the potential benefits, challenges, and future research opportunities that pertain to regenerative agrivoltaics. Despite recent progress in the development of policies that could support the co-location of solar development and RA, several challenges remain, including increasing the pace and scale of adoption of this land sharing approach, policy and regulatory barriers that prevent its adoption, technical and economic uncertainties, and social and cultural factors. Benefits that could be realized through the deployment of regenerative agrivoltaics include increased land productivity, enhanced soil health and biodiversity, climate change mitigation, and economic diversification. We discuss how agrivoltaics can provide farmers with a new revenue stream, while RA practices can enhance long-term soil fertility and crop yields. We also relate how regenerative agrivoltaics presents a promising opportunity to address growing global food and energy demands. Because this innovative land use combination is so new, further research is needed to fully maximize and quantify its benefits, especially given the potential for synergies and conflicts between solar development and regenerative agriculture.
{"title":"Regenerative agrivoltaics: Challenges and opportunities in Southern California’s Inland Empire region","authors":"Kevin B. Grell , Sophie S. Parker","doi":"10.1016/j.nexus.2026.100661","DOIUrl":"10.1016/j.nexus.2026.100661","url":null,"abstract":"<div><div>“Regenerative agrivoltaics” involves the co-location of regenerative agriculture (RA) and solar development. While RA focuses on promoting environmental quality, such as soil health, biodiversity, and other ecosystem services, agrivoltaics is concerned with the efficiency of dual land-use strategies. Here we describe a novel pilot project of a regenerative agrivoltaics installation in Southern California. We also explore the potential benefits, challenges, and future research opportunities that pertain to regenerative agrivoltaics. Despite recent progress in the development of policies that could support the co-location of solar development and RA, several challenges remain, including increasing the pace and scale of adoption of this land sharing approach, policy and regulatory barriers that prevent its adoption, technical and economic uncertainties, and social and cultural factors. Benefits that could be realized through the deployment of regenerative agrivoltaics include increased land productivity, enhanced soil health and biodiversity, climate change mitigation, and economic diversification. We discuss how agrivoltaics can provide farmers with a new revenue stream, while RA practices can enhance long-term soil fertility and crop yields. We also relate how regenerative agrivoltaics presents a promising opportunity to address growing global food and energy demands. Because this innovative land use combination is so new, further research is needed to fully maximize and quantify its benefits, especially given the potential for synergies and conflicts between solar development and regenerative agriculture.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100661"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2026-01-15DOI: 10.1016/j.nexus.2026.100637
Amira Nemmour , Khadije El Kadi , Isam Janajreh
Growing volumes of hypersaline reverse osmosis (RO) brine generated by desalination plants pose significant operational and environmental challenges, underscoring the need for energy-efficient treatment pathways that support zero-liquid-discharge objectives. Freeze desalination (FD) and membrane distillation (MD) have individually shown promise, yet existing hybrid FD–MD concepts remain limited by high thermal demands and by process configurations that typically apply FD before MD. This study proposes an enhanced hybrid desalination system for the treatment of RO brine, in which direct contact membrane distillation (DCMD) is performed prior to freeze desalination. The MD-first configuration is designed to maximize water recovery, increase brine concentration toward eutectic conditions, and improve selective salt-hydrate recovery. The DCMD unit is evaluated using a computational fluid dynamics (CFD) model to optimize flux and module performance, while thermodynamic modelling is employed to predict ice and salt crystallization behaviour across different operating conditions. A key innovation of this work is the introduction of a thermal-recovery optimization framework that quantifies and integrates two internal energy-recovery pathways: (i) recovery of cold energy released during ice melting in FD, and (ii) reuse of sensible heat from the MD brine stream. This integrated heat-reuse strategy significantly reduces the specific energy consumption (SEC) of the hybrid process. System performance is assessed across MD reject salinities of 70, 100, and 130 g/L and FD freezing temperatures of −10, −15, and −30 °C. The proposed system achieves an SEC of 403 kWh/m³ of freshwater without heat recovery, which decreases to 299 kWh/m³ with thermal integration. Increasing the FD freezing temperature from −30 °C to −10 °C further reduces SEC to 235 kWh/m³, with an expected trade-off in water recovery (85% to 55%) and salt extraction (∼75% to ∼15%). This integrated approach offers a promising and energy-efficient pathway toward zero liquid discharge in sustainable brine management.
{"title":"A conceptual demonstration of direct contact membrane distillation and freeze desalination hybrid process for reverse osmosis brine treatment","authors":"Amira Nemmour , Khadije El Kadi , Isam Janajreh","doi":"10.1016/j.nexus.2026.100637","DOIUrl":"10.1016/j.nexus.2026.100637","url":null,"abstract":"<div><div>Growing volumes of hypersaline reverse osmosis (RO) brine generated by desalination plants pose significant operational and environmental challenges, underscoring the need for energy-efficient treatment pathways that support zero-liquid-discharge objectives. Freeze desalination (FD) and membrane distillation (MD) have individually shown promise, yet existing hybrid FD–MD concepts remain limited by high thermal demands and by process configurations that typically apply FD before MD. This study proposes an enhanced hybrid desalination system for the treatment of RO brine, in which direct contact membrane distillation (DCMD) is performed prior to freeze desalination. The MD-first configuration is designed to maximize water recovery, increase brine concentration toward eutectic conditions, and improve selective salt-hydrate recovery. The DCMD unit is evaluated using a computational fluid dynamics (CFD) model to optimize flux and module performance, while thermodynamic modelling is employed to predict ice and salt crystallization behaviour across different operating conditions. A key innovation of this work is the introduction of a thermal-recovery optimization framework that quantifies and integrates two internal energy-recovery pathways: (i) recovery of cold energy released during ice melting in FD, and (ii) reuse of sensible heat from the MD brine stream. This integrated heat-reuse strategy significantly reduces the specific energy consumption (SEC) of the hybrid process. System performance is assessed across MD reject salinities of 70, 100, and 130 g/L and FD freezing temperatures of −10, −15, and −30 °C. The proposed system achieves an SEC of 403 kWh/m³ of freshwater without heat recovery, which decreases to 299 kWh/m³ with thermal integration. Increasing the FD freezing temperature from −30 °C to −10 °C further reduces SEC to 235 kWh/m³, with an expected trade-off in water recovery (85% to 55%) and salt extraction (∼75% to ∼15%). This integrated approach offers a promising and energy-efficient pathway toward zero liquid discharge in sustainable brine management.</div></div>","PeriodicalId":93548,"journal":{"name":"Energy nexus","volume":"21 ","pages":"Article 100637"},"PeriodicalIF":9.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-03-01Epub Date: 2025-12-09DOI: 10.1016/j.nexus.2025.100626
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":"2026-03-01","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}
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