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Multivariate time series energy forecasting using a hybrid neural-SVM ensemble model: A data-driven approach for energy management in Bangladesh 使用混合神经-支持向量机集成模型的多元时间序列能源预测:孟加拉国能源管理的数据驱动方法
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2026-01-10 DOI: 10.1016/j.nexus.2026.100641
Mohammad Mynul Islam Mahin, Md Jawad Bin Rouf, Shah Murtoza Morshed, Sheak Salman, Md Shihab Shakur, Mohammad Morshed, Md. Parvez
Energy forecasting of generation, demand, sources, and prices over short-time horizons is necessary for optimization of energy management. Given the increased use of developing technologies and reliance on renewable energy sources, strategic planning, management, and operational decision-making depend on accuracy and reliability of forecasting system. Complex interconnections reside among energy features in modern day power systems. Developing nations such as Bangladesh encounter challenges, including insufficient advanced tools for power planning and policy development. Previous studies have often focused on forecasting a single energy variable, like load or demand, with little attention on multiple energy parameters, and the interrelations among them. This study introduces a Hybrid Neural-SVM Ensemble (HNSE) model to simultaneously forecast day-ahead daily total energy generation, non-renewable energy generation, fuel cost, and evening peak demand of national grid of Bangladesh. Utilizing the Power Grid Company of Bangladesh’s (PGCB) data, HNSE went through processing and hyperparameter optimization. Performance evaluation based on five statistical indices demonstrated the model's predictive capabilities, with a coefficient of determination (R2) of 0.9744, and a mean squared error (MSE) of 0.0291. Additionally, the study utilizes the Kernel-based Changepoint Detection (KernelCPD) algorithm to detect structural shifts in residuals, and two explainable artificial intelligence (XAI) methods, Local Interpretable Model-Agnostic Explanations (LIME) and SHapley Additive exPlanations (SHAP), for feature contribution analysis to provide local and global interpretability. The aim is to offer actionable guidance for policymakers and stakeholders in mitigating current energy crises in Bangladesh through strategic decision-making and support the development of sustainable energy policies in emerging economies.
短期内的发电、需求、来源和价格预测是优化能源管理的必要条件。鉴于越来越多地使用发展中的技术和对可再生能源的依赖,战略规划、管理和业务决策取决于预测系统的准确性和可靠性。在现代电力系统中,复杂的互连存在于能源特征中。孟加拉国等发展中国家面临着挑战,包括缺乏先进的电力规划和政策制定工具。以往的研究往往侧重于预测单一的能源变量,如负荷或需求,很少关注多个能源参数及其相互关系。本文引入混合神经-支持向量机集成(HNSE)模型,对孟加拉国国家电网日前日总发电量、不可再生能源发电量、燃料成本和晚高峰需求进行同步预测。利用孟加拉国电网公司(PGCB)的数据,HNSE进行了处理和超参数优化。基于5个统计指标的绩效评价表明,模型具有较好的预测能力,决定系数(R2)为0.9744,均方误差(MSE)为0.0291。此外,该研究利用基于核的变化点检测(KernelCPD)算法检测残差的结构变化,并利用两种可解释的人工智能(XAI)方法,局部可解释模型不可知解释(LIME)和SHapley加性解释(SHAP)进行特征贡献分析,以提供局部和全局可解释性。其目的是为决策者和利益相关者提供可操作的指导,通过战略决策缓解孟加拉国当前的能源危机,并支持新兴经济体制定可持续能源政策。
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引用次数: 0
Obtaining the efficiency limits of axial hydrokinetic turbines 获得轴向水动力涡轮的效率极限
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2026-01-08 DOI: 10.1016/j.nexus.2026.100635
Víctor Manuel Fernández Pacheco , Ahmed Gharib Yosry , Rodolfo Espina Valdés , Alexandre Presas Batlló , Eduardo Álvarez Álvarez , Eduardo Blanco Marigorta
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.
对于开阔地设置的水动力涡轮,在没有流量限制的情况下,Betz极限表示可能的最大功率系数。涡轮机的效率是根据这个值来评估的,假设它们连接到电网,因此以最大功率持续运行。然而,在岛模型运行(与主电源断开)中,涡轮机在空载和最大功率系数之间的点上运行,这是与贝茨极限不同的效率限制。在目前的研究中,已经发现了一个函数定义功率效率限制取决于叶尖速比,轴向涡轮机在一个开放的通道没有堵塞。数学推导使用了在一个开放通道内的驱动器盘理论,并辅以涡轮机械的欧拉方程。该方法假定流动简化,包括稳定、一维、不可压缩和无湍流条件。此外,还提出了实系数曲线与极限系数曲线之间的两个无量纲参数。这些参数能够更好地定义在整个叶尖速比范围内的实际效率和极限之间的差异,以及改进的潜力。对数值模拟的水轮机和文献基准的三种不同的水轮机进行了功能和参数计算。
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引用次数: 0
Water-energy nexus: Integrating hydrochemical characterization and life cycle assessment for a holistic profile of agricultural groundwater sustainability 水-能源关系:综合水化学特征和生命周期评估,以实现农业地下水可持续性的整体概况
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2025-12-09 DOI: 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.
特别是在微观层面上,水质评估与抽取基础设施的环境影响(EI)之间的脱节严重阻碍了可持续地下水管理。本研究通过为马来西亚Labu Kubong的一个农业抽水井开发一个整体的可持续性概况,应用了一种新型的微连接透镜来弥合这一差距。目标概述如下:(i)利用Piper, Gibbs, Wilcox和美国盐度实验室(USSL)图表表征水化学特性并评估地下水对水稻灌溉的适用性;(ii)利用从摇篮到闸门的生命周期评估(LCA),找出主要的环境热点,包括原材料和能源消耗;(iii)利用蒙特卡罗不确定性分析验证LCA的可靠性;(iv)将水化学和LCA结果综合成一个整体的可持续性资产负债表(HSBS)。Piper图结果显示为钙-镁-碳酸氢盐型水,Gibbs图确定岩石风化为主要的地球化学过程。根据Wilcox图和USSL图,地下水被划分为优秀灌溉(C2-S1级)。与直觉相反,LCA显示,主要的EI不是来自运营能源消耗(1.65%),而是来自地下水开采基础设施中原材料的隐含足迹。原材料生产,特别是聚对苯二甲酸乙二醇酯(61.6%)、潜水泵用铜(14.8%)、砾石填料(4.51%)、钢(3.5%)、电缆用铜线(2.05%)、聚氯乙烯(1.12%)和高密度聚乙烯(0.0062%)是主要贡献者。这种集成的微联系模式提供了HSBS,突出了一个重要的悖论,即地下水固有的适合水稻田农业和不适合饮用,因为铁(1.71 mg/L)、锰(0.173 mg/L)和砷(0.04 mg/L)的浓度升高,与提取基础设施产生的显著外在EI同时发生。HSBS为决策者提供了综合管理决策的重要工具,能够平衡考虑可用性、操作风险和生命周期影响,以支持真正可持续的地下水管理。
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引用次数: 0
Evaluating year-round solar energy harvesting in semi-transparent PV-integrated greenhouses with roof and wall installation in an even-span design 评估半透明光伏集成温室全年太阳能收集,屋顶和墙壁采用均匀跨设计
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2025-12-09 DOI: 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.
鉴于全球对可持续农业实践的推动,半透明光伏(STPV)技术提供了产生可再生能源的双重好处,同时仍然允许植物生长所必需的部分阳光。与局限于屋顶表面的传统光伏装置不同,这项工作研究了在垂直墙面上创新性地使用STPV板,以最大限度地收集太阳能。通过对整个日历年的每小时辐照度进行分析,我们评估了卡塔尔气候条件下不同温室部分(屋顶和墙壁)的太阳能潜力。结果显示,壁挂式STPV装置的贡献很大,与屋顶安装系统相比,它产生了83.77%的年总能量。在这些墙中,东墙(EW)贡献稳定,年平均发电量为0.35 kWh/m²,而南墙(SW)和西墙(WW)也提供了可观的发电量,分别为0.19 kWh/m²和0.22 kWh/m²。相比之下,北屋顶(NR)和北墙(NW)部分显示出最低的能量输出,年平均为0.01 kWh/m²和0.05 kWh/m²,强调了由于其朝向而限制的太阳能接入。敏感性分析进一步表明,面板效率在能源生产中起着至关重要的作用,在20%的效率下,每年的潜在产量将达到18904千瓦时,显著高于本研究中考虑的7%的基准效率。
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引用次数: 0
Optimizing energy efficiency and legionella control in hot water circulation systems: laboratory validation and field assessment in Swedish multifamily buildings 优化能源效率和军团菌控制在热水循环系统:实验室验证和现场评估在瑞典多户建筑
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2025-12-09 DOI: 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.
多户建筑中的热水循环(HWC)系统面临着一个基本的权衡:保持足够的温度来抑制嗜肺军团菌(≥50°C),同时最大限度地减少这些系统仅在瑞典就代表的2.5-4.3太瓦时的年能量损失。本研究采用了一种新颖的双重方法,将实验室控制实验与现实世界验证相结合,以解决这一挑战。我们建造了一个模拟20栋公寓建筑的全尺寸测试平台,以量化在不同流速和温度下的热损失和微生物动力学。此外,还对来自31座多户住宅的56个水样进行了实地验证。结果表明,当优化系统以保持调节所需的回流温度为50°C时,低流量(0.2 m/s)和高流量(0.5 m/s)运行时的热损失几乎相同。决定性因素是泵的能量,大流量作业所需的功率是小流量作业所需功率的3.4倍(108 W对32 W)。这使得低流量策略每年节省约12%的能源,完全归功于减少了泵的电力消耗。60-65°C的周期性热冲击有效降低了嗜肺乳杆菌的浓度,表明不需要连续的高温操作来控制微生物。现场抽样显示,23%的样本检测出军团菌阳性,问题病例与设计缺陷密切相关,如与HWC回路相连的毛巾加热器。这些发现表明,基于风险的策略结合低流量循环(0.2 m/s)、50°C的基线返回温度和周期性热冲击可以显著降低系统能耗,同时保持军团菌的安全。
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引用次数: 0
High-performance electrochemical sensing of tetracycline via functionalised reduced graphene oxide nanocomposites 功能化还原氧化石墨烯纳米复合材料对四环素的高性能电化学传感
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2025-12-11 DOI: 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.
抗生素残留的检测,特别是四环素(TC)的检测,由于其对公众健康和环境安全的潜在风险而至关重要。本研究报告了一种基于还原性氧化石墨烯与翡翠盐和钯纳米粒子功能化(rGO-ES-Pd)的选择性和敏感电化学传感器的开发,用于检测模拟样品、尿液、地表水和废水中的TC。rGO-ES-Pd纳米复合材料通过湿化学方法合成,并滴铸到玻碳电极(GCE)上,以制造rGO-ES-Pd/GCE传感器。为了评估不同聚苯胺氧化状态的影响,我们还制备并测试了另外三种纳米复合材料,即rGO-EB-Pd(祖母绿碱)、rGO-PG-Pd (pernigraniline)和rGO-LE-Pd (leucemeraldine)。采用透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)、粉末x射线衍射(XRD)、电化学阻抗谱(EIS)和循环伏安法(CV)对样品进行了综合表征。在所测试的纳米复合材料中,rGO-ES-Pd/GCE传感器对TC检测表现出最高的电催化活性,在0.1-0.4 V的电位范围内具有ph依赖性的峰值电流响应。该传感器具有较宽的线性检测范围(0.01 ~ 5.0 × 10−6 M)和较低的检测限(1.51 × 10−7 M)。在常见干扰物质布洛芬、红霉素和阿莫西林存在下的选择性研究显示,干扰最小,相对标准偏差(RSD)为3.29%,证实了该传感器的鲁棒性。所建立的电化学方法成功地应用于实际环境(河水、废水)和生物(尿液)样品中TC的检测,具有良好的重现性和长期稳定性。
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引用次数: 0
Quantifying and benchmarking drinking water treatment facilities in 5 geographical regions in New Jersey, USA using energy and carbon intensity metrics 使用能源和碳强度指标对美国新泽西州5个地理区域的饮用水处理设施进行量化和基准测试
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2026-02-03 DOI: 10.1016/j.nexus.2026.100645
Amna A.M. Bashir, William T. Riddell, Jagadish Torlapati
Energy use in drinking water systems varies significantly across utilities due to differences in operating conditions, and system configuration, posing challenges for consistent energy benchmarking. In this study, we present data collection, alignment and benchmarking approach based on a long-term operational data set from a water utility company operated in five geographical regions in New Jersey. The framework enabled quantification and comparison of total energy consumption and water production, across raw water, treatment and finished water facilities. The total energy and carbon intensity metrics were calculated using the aligned dataset supporting the comparative benchmarking approach. Energy and carbon intensities were calculated for all regions combined, by region, and by specific function of drinking water facilities, resulting in overall averages of 0.7 kWh/m³ and 0.24 kg CO2e/m3, respectively. Additionally, this study highlights that factors such as topography, applied treatment technologies and the spatial distribution of water consumers are positively correlated with energy requirements for pumping and treatment.
由于运行条件和系统配置的差异,饮用水系统的能源使用在不同的公用事业中差异很大,这对一致的能源基准提出了挑战。在本研究中,我们基于一家在新泽西州五个地理区域运营的水务公司的长期运营数据集,提出了数据收集、校准和基准方法。该框架能够量化和比较总能源消耗和水产量,包括原水、处理和成品水设施。总能源和碳强度指标是使用支持比较基准方法的对齐数据集计算的。按地区和饮用水设施的特定功能计算了所有地区的能源和碳强度,得出的总体平均值分别为0.7 kWh/m³和0.24 kg CO2e/m3。此外,该研究还强调了地形、应用处理技术和水消费者的空间分布等因素与抽水和处理的能源需求呈正相关。
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引用次数: 0
Advancements in large floodplain inundation mapping: Integrated computational modeling and remote sensing techniques 大漫滩淹没制图的进展:综合计算模型和遥感技术
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2026-02-09 DOI: 10.1016/j.nexus.2026.100650
Ali R. Alruzuq , Joann Mossa
The devastating impacts of flooding can be mitigated by strengthening the integration between hydrodynamic modeling and remote sensing, thereby improving floodplain management and the accuracy of inundation mapping. However, the relationship between river discharge and floodplain response remains insufficiently quantified in many large river systems, limiting reliable estimation of inundation extent, flood volumes, and floodplain connectivity. This study evaluates the hydraulic behavior of the Lower Apalachicola River and its associated floodplain within the Wewahitchka-Sumatra reaches using a two-dimensional HEC-RAS modeling framework. A high-resolution LiDAR-Sonar integrated digital elevation model (DEM) and terrain surfaces generated using the Relative Elevation Model (REM) approach were implemented to simulate floodplain inundation depth and extent under representative low-flow (175.3 m³/s) and high-flow (4360.8 m³/s) conditions observed during the 2015-2016 flood event. The REM centerline method was applied to smooth channel elevations, resulting in systematically deeper channel representation relative to the LiDAR-Sonar DEM. Model performance was evaluated using inundation extents derived from Landsat-8, MODIS, and Sentinel-1 satellite imagery. Results indicate that differences in inundation extent between DEM-based and REM-based simulations increase with flow magnitude, with areal differences of 9.93% and 4.02% under low- and high-flow conditions, respectively. DEM-based HEC-RAS simulations consistently produced larger flood extents than REM-based simulations, primarily due to differences in the representation of main-channel elevation. Maximum flood-water depth differences of 0.78 m and 0.76 m were observed for DEM and REM simulations under low- and high-flow conditions, respectively. Overall, the findings confirm the robustness of the HEC-RAS 2D framework for simulating floodplain inundation in large, low-gradient river systems and demonstrate the value of integrating high-resolution topographic data with complementary modeling approaches. The proposed framework offers a transferable methodology for floodplain management, restoration assessment, and improved understanding of river-floodplain connectivity under varying hydrologic conditions.
通过加强水动力模拟与遥感的结合,可以减轻洪水的破坏性影响,从而改善洪泛区管理和洪水制图的准确性。然而,在许多大型河流系统中,河流流量与洪泛区响应之间的关系仍然没有充分量化,这限制了对淹没程度、洪水量和洪泛区连通性的可靠估计。本研究使用二维HEC-RAS建模框架评估了下阿巴拉契科拉河及其相关的威瓦希奇卡-苏门答腊河段洪泛平原的水力行为。采用高分辨率LiDAR-Sonar集成数字高程模型(DEM)和相对高程模型(REM)方法生成的地形表面,模拟了2015-2016年洪水事件中典型低流量(175.3 m³/s)和高流量(4360.8 m³/s)条件下的漫滩淹没深度和范围。REM中心线方法应用于平滑通道高程,相对于LiDAR-Sonar DEM,系统地获得了更深的通道表示。利用来自Landsat-8、MODIS和Sentinel-1卫星图像的淹没程度来评估模型的性能。结果表明:dem与rem模拟的淹没程度差异随着流量的增大而增大,在小流量和大流量条件下,面积差异分别为9.93%和4.02%;基于dem的HEC-RAS模拟始终比基于rem的模拟产生更大的洪水范围,这主要是由于主河道高程表示的差异。在低流量和高流量条件下,DEM和REM模拟的最大洪水水深差分别为0.78 m和0.76 m。总体而言,研究结果证实了HEC-RAS 2D框架在模拟大型低梯度河流系统洪泛平原淹没方面的鲁棒性,并证明了将高分辨率地形数据与互补建模方法相结合的价值。提出的框架为洪泛区管理、恢复评估和改善对不同水文条件下河流与洪泛区连通性的理解提供了一种可转移的方法。
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引用次数: 0
Impacts of drought on electricity production, fossil carbon emissions, and air pollution in Europe 干旱对欧洲电力生产、化石碳排放和空气污染的影响
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2026-02-09 DOI: 10.1016/j.nexus.2026.100652
Xiangping Hu , Vedant Ballal , Gabriele Martinelli , Geir-Arne Fuglstad , Alessandro Nocente , Roberto Iacono , Bo Huang , Francesco Cherubini
Europe has experienced severe droughts that impacted electricity generation from both renewable and fossil sources. Yet, the response of national electricity systems to drought and the resulting impacts on emissions of CO₂ and air pollutants remain insufficiently understood. This study combines monthly historical electricity generation data (2017–2023) with runoff anomalies, used as a proxy for drought conditions, across 25 European countries. A regression-based counterfactual analysis is applied to quantify the country-level response of electricity systems to drier-than-average conditions. Estimated drought-induced changes in fossil-based generation are subsequently translated into emissions of greenhouse gases and air pollutants using fuel- and country-specific emission factors. We find that electricity generation from hydropower and other renewables is reduced during dry periods, while reliance on fossil fuels and imports increases. Drought induced 141±35 million tonnes of CO₂-equivalent emissions between 2017 and 2023, corresponding to 31 % of the emissions that Europe could release by 2040 under its most ambitious climate goals. Emissions are mainly driven by increased use of natural gas (48 %), coal (22 %), lignite (21 %), and imports (8 %). In France and Portugal, drought-induced emissions account for around 10 % of total fossil-based electricity emissions. The estimated monetized social cost of these emissions is 26 billion USD. Emissions of air pollutants show an average increase of about 2.5 %, though they widely vary across countries. These findings underscore the need for targeted adaptation strategies to reduce the power sector’s vulnerability to drought and to maintain progress toward energy security and decarbonization targets
欧洲经历了严重的干旱,影响了可再生能源和化石能源的发电。然而,国家电力系统对干旱的反应及其对二氧化碳和空气污染物排放的影响仍未得到充分了解。这项研究结合了25个欧洲国家的月度历史发电量数据(2017-2023)和径流异常(用作干旱条件的代表)。应用基于回归的反事实分析来量化电力系统对比平均水平更干燥的条件的国家一级反应。根据燃料和国家特定的排放因子,化石发电中估计的干旱引起的变化随后转化为温室气体和空气污染物的排放。我们发现,在干旱时期,水力发电和其他可再生能源发电减少,而对化石燃料和进口的依赖增加。在2017年至2023年期间,干旱导致了1.41±35亿吨二氧化碳当量的排放,相当于欧洲在其最雄心勃勃的气候目标下到2040年可能释放的排放量的31%。排放的主要驱动因素是天然气(48%)、煤炭(22%)、褐煤(21%)和进口(8%)的使用增加。在法国和葡萄牙,干旱引起的排放约占化石能源总排放量的10%。这些排放的货币化社会成本估计为260亿美元。空气污染物的排放量平均增长约2.5%,尽管各国的增幅差别很大。这些发现强调了有针对性的适应战略的必要性,以减少电力部门对干旱的脆弱性,并保持在实现能源安全和脱碳目标方面的进展
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引用次数: 0
Study on degradation mechanisms of proton exchange membrane fuel cell under CO poisoning CO中毒下质子交换膜燃料电池降解机理研究
IF 9.5 Q1 ENERGY & FUELS Pub Date : 2026-03-01 Epub Date: 2026-02-10 DOI: 10.1016/j.nexus.2026.100678
Zhiquan Yao, Zhengkai Tu
Proton exchange membrane fuel cells (PEMFCs) represent a key technology for hydrogen energy utilization, yet their reliance on high-purity hydrogen restricts further advancement. While hydrogen-rich reforming gas can reduce costs, the CO present in such gas poisons the catalyst. A novel treatment method involves creating a mild hydrogen-deficient environment to enable rapid recovery from high-CO poisoning states. This approach utilizes dual-cell cycling to maintain stable operation in CO-containing environments, though research on this method remains limited. This study quantitatively analyzed the effects of CO concentration, back pressure, humidity, and temperature through multifactor experiments. A 100-h endurance test under periodic purging conditions revealed fundamentally different degradation pathways: CO exposure caused irreversible damage—a 14.29% loss in electrochemically active surface area, a 34.4% increase in charge transfer resistance, severe catalyst agglomeration, platinum particle growth reaching 55.6%, and oxidation significantly concentrated at the anode inlet due to CO concentration gradients. In contrast, hydrogen operation induced only minor degradation primarily attributable to cathode flooding. This study identified the dual effects of operating parameters, elucidated two distinct failure mechanisms, and provided critical insights for developing mitigation strategies, enabling PEMFC to operate continuously using impure hydrogen fuel.
质子交换膜燃料电池(pemfc)是氢能利用的关键技术,但其对高纯度氢的依赖限制了其进一步发展。虽然富氢重整气体可以降低成本,但这种气体中的CO会毒害催化剂。一种新的治疗方法包括创造一个轻度缺氢环境,使高co中毒状态快速恢复。该方法利用双电池循环在含co环境中保持稳定运行,尽管对该方法的研究仍然有限。本研究通过多因素实验,定量分析了CO浓度、背压、湿度和温度的影响。在周期性吹吹条件下进行的100 h耐久性试验揭示了截然不同的降解途径:CO暴露造成了不可逆的损伤——电化学活性表面积损失14.29%,电荷转移电阻增加34.4%,催化剂团聚严重,铂颗粒生长达到55.6%,由于CO浓度梯度,氧化在阳极入口处明显集中。相比之下,氢气操作仅引起主要归因于阴极溢油的轻微降解。该研究确定了运行参数的双重影响,阐明了两种不同的失效机制,并为制定缓解策略提供了重要见解,使PEMFC能够使用不纯氢燃料连续运行。
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引用次数: 0
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Energy nexus
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