Search Results (620)

Accurate short-term forecasting of photovoltaic power generation is vital for the operational stability of isolated energy systems, especially in regions with increasing renewable energy penetration. This study presents a novel AI-based forecasting framework applied to the island of Cyprus. Using machine learning methods, particularly regression trees, the proposed approach evaluates the impact of key environmental variables on PV performance, with an emphasis on atmospheric dust transport and air composition variability. A distinguishing feature of this work is the integration of cross-continental dust events and diverse atmospheric parameters into a structured forecasting model. A new clustering methodology is introduced to classify these inputs and analyze their correlation with PV output, enabling improved feature selection for model training. Importantly, all input parameters are sourced from publicly accessible, internet-based platforms, facilitating wide reproducibility and operational application. The obtained results demonstrate that incorporating dust deposition and air composition features significantly enhances forecasting accuracy, particularly during severe dust episodes. This research not only fills a notable gap in the PV forecasting literature but also provides a scalable model for other dust-prone regions transitioning to high levels of solar energy integration. Full article

This work presents a novel approach to investigating epitaxial GaAsN layers and GaAsN-based p-i-n solar cell structures using light-assisted scanning capacitance microscopy (SCM) and spectroscopy. Due to the technological challenges in growing high-quality GaAsN with controlled nitrogen incorporation, the epitaxial layers often exhibit inhomogeneity in their opto-electrical properties. By combining localized cross-section SCM measurements with wavelength-tunable optical excitation (800–1600 nm), we resolved carrier concentration profiles, internal electric fields, and deep-level transitions across the device structure at a nanoscale resolution. A comparative analysis between electrochemical capacitance–voltage (EC-V) profiling and photoluminescence spectroscopy confirmed multiple localized transitions, attributed to compositional fluctuations and nitrogen-induced defects within GaAsN. The SCM method revealed spatial variations in energy states, including discrete nitrogen-rich regions and gradual variations in the nitrogen content throughout the layer depth, which are not recognizable using standard characterization methods. Our results demonstrate the unique capability of the photo-scanning capacitance microscopy and spectroscopy technique to provide spatially resolved insights into complex dilute nitride structures, offering a universal and accessible tool for semiconductor structures and optoelectronic devices evaluation. Full article

The National Institute of Earth Physics (NIEP) in Romania has upgraded its seismic monitoring stations into multifunctional platforms equipped with advanced devices for measuring gas emissions, magnetic fields, telluric fields, solar radiation, and more. This enhancement enabled the integration of a seismic forecasting system designed to extend the alert time of the existing warning system, which previously relied solely on seismic data. The implementation of an Operational Earthquake Forecast (OEF) aims to expand NIEP’s existing Rapid Earthquake Early Warning System (REWS) which currently provides a warning time of 25–30 s before an earthquake originating in the Vrancea region reaches Bucharest. The AFROS project (PCE119/4.01.2021) introduced fundamental research essential to the development of the OEF system. As a result, real-time analyses of radon and CO₂ emissions are now publicly available at afros.infp.ro, dategeofizice. The primary monitored area is Vrancea, known for producing the most destructive earthquakes in Romania, with impacts extending to neighboring countries such as Bulgaria, Ukraine, and Moldova. The structure and methodology of the monitoring network are adaptable to other seismic regions, depending on their specific characteristics. All collected data are stored in an open-access database available in real time, geobs.infp.ro. The monitoring methods include threshold-based event detection and seismic data analysis. Each method involves specific technical nuances that distinguish this monitoring network as a novel approach in the field. In conclusion, experimental results indicate that the Gutenberg-Richter law, combined with gas emission measurements (radon and CO₂), can be used for real-time earthquake forecasting. This approach provides warning times ranging from several hours to a few days, with results made publicly accessible. Another key finding from several years of real-time monitoring is that the value of fundamental research lies in its practical application through cost-effective and easily implementable solutions—including equipment, maintenance, monitoring, and data analysis software. Full article

Urban morphology critically shapes environmental performance, yet few studies integrate multiple sustainability targets within a unified modeling framework for its design optimization. This study proposes a data-driven, multi-scale approach that combines parametric simulation, artificial neural network-based multi-task learning (MTL), SHAP interpretability, and NSGA-II optimization to assess and optimize urban form across 18 districts in Hong Kong. Four key sustainability targets—photovoltaic generation (PVG), accumulated urban heat island intensity (AUHII), indoor overheating degree (IOD), and carbon emission intensity (CEI)—were jointly predicted using an artificial neural network-based MTL model. The prediction results outperform single-task models, achieving R² values of 0.710 (PVG), 0.559 (AUHII), 0.819 (IOD), and 0.405 (CEI), respectively. SHAP analysis identifies building height, density, and orientation as the most important design factors, revealing trade-offs between solar access, thermal stress, and emissions. Urban form design strategies are informed by the multi-objective optimization, with the optimal solution featuring a building height of 72.11 m, building centroid distance of 109.92 m, and east-facing orientation (183°). The optimal configuration yields the highest PVG (55.26 kWh/m²), lowest CEI (359.76 kg/m²/y), and relatively acceptable AUHII (294.13 °C·y) and IOD (92.74 °C·h). This study offers a balanced path toward carbon reduction, thermal resilience, and renewable energy utilization in compact cities for either new town planning or existing district renovation. Full article

Urban thermal environments, characterized by the interplay between indoor and outdoor conditions, pose growing challenges in high-density coastal cities. This study proposes a multi-scale, integrative framework that couples a satellite-derived land surface temperature (LST) analysis with microscale building performance simulations to holistically evaluate the high-density urban thermal environment in subtropical climates. The results reveal that compact, high-density morphologies reduce outdoor heat stress (UTCI) through self-shading but lead to significantly higher cooling loads, energy use intensity (EUI), and poorer daylight autonomy (DA) due to restricted ventilation and limited sky exposure. In contrast, more open, vegetation-rich forms improve ventilation and reduce indoor energy demand, yet exhibit higher UTCI values in exposed areas and increased lighting energy use in poorly oriented spaces. This study also proposes actionable design strategies, including optimal building spacing (≥15 m), façade orientation (30–60° offset from west), SVF regulation (0.4–0.6), and the integration of vertical greenery to balance solar access, ventilation, and shading. These findings offer evidence-based guidance for embedding morphological performance metrics into planning policies and building design codes. This work advances the integration of outdoor and indoor performance evaluation and supports climate-adaptive urban form design through quantitative, policy-relevant insights. Full article

This study addresses the influence of clouds and aerosols on solar radiation and energy over Greece from September 2004 to August 2024. By leveraging Earth Observation data and radiative transfer models, the largest to date time series was constructed, in order to investigate the fluctuations in global horizontal irradiance, its rate of change, and the natural and anthropogenic factors that drive them. By incorporating simulation tools and appropriate calibration, the solar potential per region and the rate of change of the produced photovoltaic energy for 1 kWp were also quantified, highlighting the climatic effects on the production of solar energy. Additionally, two energy planning scenarios were explored: the first regarding the energy adequacy that each region can achieve, if a surface equal to 1% of its total area is covered with photovoltaics; and the latter estimating the necessary area covered with photovoltaics to fully meet each region’s energy demand. Finally, to ensure a solid and holistic approach, the research converted energy data into economic gains and avoided CO₂ emissions. The study is innovative, particularly for the Greek standards, in terms of the volume and type of information it provides. It is able to offer stakeholders and decision and policymakers, both in Greece and worldwide thanks to the use of open access data, invaluable insights regarding the impact of climate change on photovoltaic energy production, the optimization of photovoltaic installations and investments and the resulting financial and environmental benefits from proper and methodical energy planning. Full article

Many communities in the Brazilian Amazon region remain without reliable access to electricity due to geographical barriers and the high cost of connecting to the national grid. This study aims to evaluate the techno-economic feasibility of implementing battery storage systems in an existing isolated solar–diesel microgrid located in Tunui-Cachoeira, in the district of São Gabriel da Cachoeira (AM). The analysis uses an energy balance methodology, implemented through the HOMER Pro simulation platform, to assess three scenarios: (i) without batteries, (ii) with lithium-ion batteries, and (iii) with lead–acid batteries. Technical and economic indicators such as net present cost (NPC), levelized cost of energy (LCOE), diesel consumption, and renewable fraction were compared. The results indicate that incorporating lead–acid batteries yields the lowest LCOE (1.99 R$/kWh) and the highest renewable fraction (96.8%). This demonstrates that adding energy storage systems significantly enhances the performance and cost-effectiveness of microgrids, offering a viable path to electrify remote and hard-to-reach communities in the Amazon. Full article

Photocatalytic CO₂ conversion is one of the ideal approaches to address both topics of solar energy shortage and carbon neutrality. Cobalt(II) centers coordinated with bipyridines have been designed and evaluated as catalysts for CO₂ conversion under light irradiation. Herein, we report a series of pyridine-based cobalt complexes with alkyl substituents as molecular photocatalysts, aiming to elucidate the effects of alkyl type and substitution position on catalytic performance through spectroscopic and electrochemical measurements. The substitution of the hydrogen at 4,4′-positions on the bipyridine ring with a methyl group, a tert-butyl group, and a nonyl group led to a decrease in the conversion rate of CO₂ by 13.2%, 29.6%, and 98%, respectively. The methyl substituents at the 5, 5′-positions of the bipyridine ring resulted in a 71.1% decrease in the CO₂ conversion rate. The usage of either 6, 6′-Me₂-2,2′-bipy, 2,4-bipy, or 3,3′-bipy resulted in no detectable activity for CO₂ conversion in the current system. Both photo- and electrochemical analyses have been employed to reveal the relationship between changing ligands and photocatalytic performance on the molecular scale. These results demonstrate that bulky ligands significantly hinder CO₂ reduction by cobalt complexes due to steric interference with coordination and active-site accessibility. This study demonstrates that the substituent effect of ligands on photocatalytic reactions for CO₂ conversion provides valuable insight into a deeper understanding of molecular catalysis. Full article

Due to the dynamic increase in the number of prosumer electrical installations in Poland, one may observe many negative effects of their development, including the deterioration of energy quality parameters and the reliability of the existing distribution network. The installation of solar panels in Polish homes was mainly motivated by economic reasons. One of the most important problems of the distribution network is the increase in voltage. The aim of this work was to develop a practical method for determining the maximum voltage changes caused by the connection of photovoltaic installations. To accomplish this, a representative low-voltage overhead line, typical of those found in Poland, was modeled using the NEPLAN software. More than 100 distinct simulations were conducted, exploring various locations and power capacities of photovoltaic installations and utilizing authentic annual profiles for both electrical loads and photovoltaic generation. From the analysis of the data obtained, relationships that enable the determination of voltage changes induced by photovoltaic connections at any node within the low-voltage circuit were established. The computational results derived from this simplified model demonstrate sufficient accuracy for practical applications, and the required input data is accessible to distribution system operators. Full article

Solar exposure and shading critically influence outdoor thermal comfort in residential areas, yet quantitative links between spatial morphology and microclimate remain insufficiently explored in cold-region cities. This study proposes a novel morphological indicator, the Insolation Shadow Ratio (ISR), to quantify sunlight–shade dynamics and investigates its correlation with outdoor thermal comfort (UTCI) in Xi’an, China. Combining field observations, microclimate simulations, and statistical analysis, we quantified ISR and UTCI across three representative outdoor spaces in a residential area. Photographic analysis and spatial parameterization were employed to calculate hourly ISR values. Significant correlations were observed between ISR and UTCI values. The measured data showed the strongest correlation at summer solstice at site C (Spearman’s r = 0.883, p < 0.01). GAM analysis of seasonal peak correlation data revealed that an optimal UTCI comfort range of 9 °C to 26 °C, corresponding to ISR thresholds of 0.0202–0.8384, achieved the highest autumn correlation at site C (r = 0.686, p < 0.01), while effectively balancing shade cooling effects and solar accessibility. The ISR framework provides a quantifiable tool for designers to optimize outdoor thermal environments and, when enhanced by parametric modeling tools, enables them to proactively optimize thermal performance during early-stage residential planning, offering a data-driven pathway for climate-resilient outdoor space design. Full article

Within the context of global warming, the frequent occurrence of extreme weather may lead to problems, such as a sharp decrease in new energy output, insufficient system backups, and an increase in the amount of energy consumed by users, resulting in large-scale power shortages within the grid for a short period of time. With the increase in the numbers of electric vehicles (EVs) and microgrids (MGs), which are resilient resources, the ability of a system to participate in demand response (DR) is further improved, which may make up for short-term power shortages. In this paper, we first propose a charging and discharging model for EVs during the onset of a cold wave, and then perform load forecasting for EVs during cold wave weather based on user behavioral characteristics. Secondly, in order to accurately portray the flexible regulation capability of microgrids with massively flexible resource access, this paper adopts the convex packet fitting expression based on MGFOR to characterize the flexible regulation capability of MGs. Then, the Conditional Value at Risk (CVaR) is used to quantify the uncertainty of wind and solar power generation, and a two-layer model with the objective of minimizing the operation cost in the upper layer and maximizing the rate of new energy consumption in the lower layer is proposed and solved using Karush–Kuhn–Tucker (KKT) conditions. Finally, the proposed method is verified through examples to ensure the economic operation of the system and improve the new energy consumption rate of the system. Full article

Decentralized solar water disinfection systems (DSODIS) in continuous flow systems are alternatives for large-scale improved water access in rural contexts. However, DSODIS in rural Ghana are limited. An exploratory sequential mixed-methods design was used to explore the enablers of and barriers to, as well as reported barrier perceptions to, the effective implementation of DSODIS in the Sawla-Tuna-Kalba (STK) District of Ghana. The qualitative data (26 respondents) were analyzed thematically, and the quantitative data (1155 household heads) were subjected to Poisson regression analyses. Enablers were categorized into themes such as willingness to pay for DSODIS, household and community participation, and willingness to use water from DSODIS. Similarly, the barriers include environmental barriers, technological barriers, economic barriers, and political and legal barriers. Household characteristics such as main water source and income, age group, education, marital status, household size, being born in the community, and years living in the community are statistically associated with reported barrier perceptions. Households with unimproved water sources and high income (IRR = 1.432, p = 0.000) and improved water sources and high income (IRR = 1.295, p = 0.000) are 43% and 30% more likely, respectively, to report more barrier perceptions compared with households with unimproved water sources and low income. Females (IRR = 1.070, p = 0.032) are marginally more likely to report more barrier perceptions compared with males. The model output also indicates that household heads with higher educational attainment (IRR = 1.152, p = 0.001) are 15% more likely to report more barrier perceptions compared with those with no formal education. These findings provide valuable information for policymakers and stakeholders aiming to provide quality water in rural Ghana where centralized systems cannot be installed. Full article

The rising demand for sustainable energy solutions has spurred the development of advanced materials for photovoltaic devices. Among these, transparent conductive oxides (TCOs) play a pivotal role in enhancing device efficiency, particularly in silicon-based solar cells. However, the reliance on indium-based TCOs like ITO raises concerns over cost and material scarcity, prompting the search for more abundant and scalable alternatives. This study focuses on the fabrication and characterization of aluminum-doped zinc oxide (ZnO:Al, AZO) thin films deposited via Atomic Layer Deposition (ALD), targeting their application as transparent conductive oxides in silicon solar cells. The ZnO:Al thin films were synthesized by alternating supercycles of ZnO and Al₂O₃ depositions at 225 °C, allowing precise control of composition and thickness. Structural, optical, and electrical properties were assessed using Scanning Electron Microscopy (SEM), Energy-Dispersive X-ray Spectroscopy (EDS), Transmission Electron Microscopy (TEM), Raman spectroscopy, spectroscopic ellipsometry, and four-point probe measurements. The results confirmed the formation of uniform, crack-free ZnO:Al thin films with a spinel-type ZnAl₂O₄ crystalline structure. Optical analyses revealed high transparency (more than 80%) and tunable refractive indices (1.64 ÷ 1.74); the energy band gap was 2.6 ÷ 3.07 eV, while electrical measurements demonstrated low sheet resistance values, reaching 85 Ω/□ for thicker films. This combination of optical and electrical properties underscores the potential of ALD-grown AZO thin films to meet the stringent demands of next-generation photovoltaics. Integration of Zn:Al thin films into silicon solar cells led to an optimized photovoltaic performance, with the best cell achieving a short-circuit current density of 36.0 mA/cm² and a power conversion efficiency of 15.3%. Overall, this work highlights the technological relevance of ZnO:Al thin films as a sustainable and cost-effective alternative to conventional TCOs, offering pathways toward more accessible and efficient solar energy solutions. Full article

The Trombe Wall (TW) has gained recognition for its simplicity, efficiency, and zero operational costs, making it a key contributor to Sustainable Development Goals (SDGs) 7 and 11 by enhancing energy access and providing sustainable heating solutions. This passive solar technology is particularly beneficial in rural areas, offering cost-effective thermal comfort while minimizing environmental impact. This study evaluates the performance of three TW configurations attached to a room, designed with inclined glazing relative to the vertical air layer and stone layers at the bottom acting as thermal mass, commonly used in rural installations in Peru. Using 2D Computational Fluid Dynamics, the analysis compares an inclined heated wall with guided vanes featuring three or five blades to a configuration without vanes. Results show that the three-blade guided flow configuration achieves the highest temperature rise of 4 °C, with a reference temperature of 20 °C, under an absorber heat flux of 200–400 W/m², albeit with a slightly lower flow rate of 0.17–0.23 kg/s compared to the configuration without guided flow. The maximum thermal efficiency of 57.90% was observed for the three-blade configuration, which is 2.26% higher than the efficiency of the configuration without guided flow, under an absorber heat flux of 400 W/m². The obtained path-lines reveals that the three-blade configuration minimizes flow detachment, nearly eliminates recirculation near the bottom corner of the glazing, and reduces the separation bubble at the top corner of the massive wall near the outlet. These findings highlight the potential of guided vanes to enhance the performance of Trombe Walls in rural settings. Full article

The article aims to analyze the contemporary forms of territorial dispossession that stem from the energy transition, especially those related to free trade corridors and green grabbing in the context of Latin America. To do this, we describe the reconfigurations of contemporary capitalism for territorializing capital in the geopolitical context of Latin America. At the same time, we argue how the territories of Latin America became strategically relevant for the expanded reproduction of capital in contemporary times. We also shed light on the centrality of free trade agreements and the corridors of extractivist dispossession as a turning point in the expansion—relating to the spectrum of hegemonic and imperialist domination of capital—of legal state frameworks for regulating and justifying full access to the neo-extractivist exploitation of Global South territories. Finally, we show that the “energy transition” supports green grabbing—that is, a new model not just of land grabbing, but rather of comprehensive territorial grabbing, since it means the expropriation of subterranean, maritime, wind, solar, and land territory. Full article