Hasil untuk "Renewable energy sources"

Irwan Andi Lukman, Rusli Andi M., Ansar Muhammad Chaeroel et al.

The issue of climate change has become a global concern, prompting extensive research across various disciplines, including government science. This study presents a bibliometric analysis of role of public institutions in climate change research, examining trends in publication, influential authors, leading institutions, and critical themes within this field. CiteSpace and Biblioshiny were used to analyse 1436 publications published between 2005 and 2025 using the Scopus database. The results indicate an increasing trend in publications over the last decade, highlighting the growing interest in integrating climate change mitigation and adaptation strategies within public policy and governance frameworks. Key themes identified include environmental policy, adaptive management, and sustainable development, with the United States, China, and Australia emerging as the most active countries in this research area. This study provides a comprehensive overview of the current research landscape and identifies future research directions for strengthening the role of public institutions in addressing climate change challenges, especially for the local government.

Bobok I.I., Kobozieva A.A.

In the context of the rapid development of information technologies, their implementation in the process of functioning of critical infrastructure, in particular energy, of any state is extreme-ly relevant. At the same time, the continuity and quality of functioning of any automated system in the digital space critically depends on ensuring the integrity of the information used. The ef-fectiveness of digital content integrity expertise methods is determined by their theoretical foun-dations. Existing theoretical approaches do not allow obtaining a final solution to this problem. The aim of this work is to develop a general approach to the analysis of the state of information systems, based on the theory of matrices, for its use in the examination of the integrity of digital content. The objective was achieved by investigating the perturbation properties of singular val-ues and singular vectors of the image (or video frame) matrix as a result of perturbation for orig-inal and non-original contents. The most important results of the work are: substantiation for non-original content of the destruction of the monotony of the trend of the function of depend-ence of the disturbance of the singular number on its number, which takes place for original content; substantiation of the fundamental possibility of estimating the magnitude of the perturb-ing effect. The significance of the obtained results lies in their subsequent use for the develop-ment of universal methods for examining the integrity of digital images, video, in particular ste-ganoanalytical methods, which make it possible not only to identify the fact of integrity viola-tion, but also to assess the magnitude of the perturbing effect, which is extremely important in steganoanalysis, where this value characterizes the throughput of a hidden communication channel.

Ahmad Raza, Majed Alharthi, Moonis Shakeel et al.

The BRICS nations are now undergoing rapid economic growth, which has led to apprehensions over the increase in CO2 emissions and energy consumption. The research tries to identify heterogeneity in carbon dioxide emissions, energy use, and GDP growth paths among BRICS nations and further explores using a technique of cointegration between the long-run relationship of these variables. The study employs secondary data obtained from World Development Indicators and panel data analysis to examine the interplay of the variables over the period 2009–2022. The analysis utilizes some of the following variables, that is, CO2 emissions per capita in metric tons, GDP per capita, and energy consumption per capita in oil equivalent. The techniques that will be utilized include those associated with the literature review (text analytics techniques) and other panel data models used for the data analysis, such as Pooled Ordinary Least Squares (OLS), Breusch-Pagan Lagrange Multiplier (BP) test, Random Effects Model (REM), Fixed Effects Model (FEM), and Hausman test. The study also applies the first-generation and second-generation panel unit root tests to determine data stationarity, cross-sectional dependency, serial correlation, heteroscedasticity, Pedroni cointegration tests, and the Dumitrescu-Hurlin Granger causality test to check causality. The findings are that there is no heterogeneity in the dispersion of CO2 emissions, energy consumption, and GDP growth across the BRICS countries. The cointegration tests further reveal the long-run relationship between these variables. This study finally looks for interlinkages between CO2 emissions, economic growth, and energy consumption for BRICS countries. Using an approach with panel data analysis, it contributes to ongoing policy debates on sustainable development and offers guidelines to policymakers in terms of reaching an expedient balance between economic growth and the preservation of the environment.

Shreya Dave, Venkat Ram Reddy Minampati, Parth Prajapati

The abundant solar energy source provides an immense scope to create ample opportunities to produce affordable and clean energy. To utilise this energy optimally, the Ministry of New and Renewable Energy, Government of India, has launched the ‘Rooftop Solar Programme’ in 2014, aiming to achieve an installed capacity of 40 gigawatts by 2022, further extended till 2026. The present study identifies the interests and apprehensions of the respondents to install rooftop solar (RTS) panels; it analyses respondents’ perception of RTS panels and sustainable lifestyle and evaluates the government’s role in encouraging people to adopt sustainable lifestyle practices. The data are collected by applying the snowball sampling method through a structured questionnaire circulated in the 5 zones of Ahmedabad city. The citizens’ perception is collected through a 5-point Likert scale. It is found in the study that the main advantage of installing RTS panels is a reduction in electricity costs, and the main challenge is the regular maintenance of the panels. A total of 44.8% of respondents installed RTS panels as they felt that this would help them to contribute to preserving the environment. The study also reveals that the lengthy payback period of the panels (28.6% respondents) and lack of knowledge about net-metering (27% respondents) are the factors that prevent nonusers from installing the panels. The study concludes that adopting RTS panels results from awareness campaigns, government subsidies, and word of mouth. The study also concludes that both citizens and the government need each other’s cooperation to carry out a greater behaviour change programme.

Wenqiang Xie, Mingming Shi, Yuying He et al.

Compared to the AC counterpart, the DC shore power system provides a significant advantage of efficient power supply from renewable sources to ships and onshore loads. Super-capacitors serve as key energy storage units in such a system to buffer the power fluctuations and collect the regenerative energy. However, the ultra-wide voltage range of super-capacitors imposes a significant challenge in the topology selection and efficiency optimization of the interfacing isolated bidirectional DC–DC converter. To tackle this challenge, this paper analyzes and compares two promising converter topologies, which are a configurable modular two-level dual-active bridge (CM-2L-DAB) and a three-level dual-active bridge (3L-DAB). To facilitate an ultra-wide voltage range, extended phase-shift (EPS) modulation in conjunction with the topology reconfiguration is analyzed for the CM-2L-DAB, while a hybrid modulation scheme is proposed for the 3L-DAB. A unified design approach is provided for both topologies, which also yields to the power loss modeling. On this basis, the CM-2L-DAB and 3L-DAB are thoroughly compared in terms of the modulation schemes, current stress, soft-switching operation, power conversion efficiency, material usage, closed-loop control scheme, and reliability. A prominent conclusion can be drawn that the CM-2L-DAB provides a higher efficiency than the 3L-DAB over the whole voltage range, but it relies on additional relays to reconfigure its topology which results in lower reliability and dynamic performance than the 3L-DAB.

Abderrahim Zemmit, Yacine Benchenina, Mohammed Moustafa Bouzaki et al.

In this study, we engineered an advanced electrolyzer utilizing Matlab Simscape. Our primary objective is to Green hydrogen production has emerged as a cornerstone for achieving sustainable energy transitions. Electrolyzer systems play a pivotal role in converting renewable energy into hydrogen, yet their performance is heavily influenced by the design, operation, and integration with renewable energy sources. This study presents an advanced modeling and simulation framework for electrolyzers, emphasizing the optimization of green hydrogen production under dynamic operational conditions. The proposed model incorporates key factors such as temperature, pressure, and electrical input variability to accurately predict electrolyzer performance. By integrating renewable energy sources, such as photovoltaic (PV) systems, and employing novel optimization techniques, this study demonstrates significant improvements in efficiency and hydrogen yield. Comprehensive validation is performed using real-world data, highlighting the model's applicability for large-scale deployment. This research provides a robust foundation for developing cost-effective, efficient, and sustainable green hydrogen production systems, addressing critical challenges in renewable energy integration and contributing to the global energy transition.

Wan-Ling Tseng, Cheng-Wei Lin, Yi-Chi Wang et al.

The transition to renewable energy sources, such as offshore wind farms, is essential in mitigating climate change. Taiwan has set ambitious targets to harness wind energy from the Taiwan Strait, but offshore wind farm installations are highly dependent on weather conditions, particularly wind speeds. This study examines the relationship between the El Niño-Southern Oscillation (ENSO) and offshore wind farm installation by assessing weather windows—periods with wind speeds below 12 m per second at a height of 100 m for at least 12 h. Our analysis shows that during La Niña years, the number of feasible weather windows decreases by up to 40 %, particularly between October and June, compared to neutral and El Niño years. This decrease can be as high as fourfold in December, significantly impacting installation schedules. Seasonal variations are also notable, with wind speeds exceeding 12 m s−1 in winter 66.4 % of the time, compared to 29.4 % in spring, making spring and summer the most favorable periods for installation. However, even during these favorable seasons, La Niña years can bring higher wind speeds, necessitating careful planning. These results underscore the importance of integrating ENSO forecasts into project planning to avoid installation delays and optimize installation timelines. By leveraging seasonal and interannual climate variability predictions, decision-makers can improve the resilience of offshore wind farm projects and ensure efficient energy transition strategies.

Driss Mouloua, Nitul S Rajput, Michael Lejeune et al.

The exaltation of the photodegradation performance of dichalcogenide MoS2 grown on top of silver nanoparticles (Ag‐NPs) is reported on. The fabricated MoS2 nanosheets nucleate vertically from Ag‐NPs seeds, enabling the growth of both metallic and semiconductor phases 1T/2H‐MoS2. Findings reveal remarkable enhancement of the Raman scattering and an exceptional broadband optical absorption attributed to plasmonic effects induced by the presence of both metallic 1T‐MoS2 and Ag‐NPS at 2H‐MoS2 interfaces. To leverage this effect, photodegradation tests are conducted to remove methyl orange pollutant. Notably, results reveal a significant increase in photodegradation efficiency and rate constant, reaching up to 120% and 550% over pristine 2H‐MoS2, respectively. This finding underscores the role of Ag‐NPs and 1T‐MoS2 tandem to unlock the superior photodegradation properties of vertically aligned 2H‐MoS2 toward methyl orange, paving the way for the development of dichalcogenide‐based hybrid photocatalyst for wastewater treatment and environmental remediation.

Grzegorz Hołdyński, Zbigniew Skibko, Andrzej Borusiewicz

The phenomenon of voltage asymmetry is common in electricity networks and is the cause of many unfavourable phenomena occurring, such as an increase in power and energy losses, as well as the abnormal operation of certain loads. Voltage asymmetry can be caused by several different factors, which include the design of the transmission line (e.g., routing of conductors in relation to each other and the earth), the parameters of consumer circuits (e.g., unequal loading of individual phases), or the design of network equipment (e.g., generators or transformers). An asymmetrical condition also occurs during system disturbances such as single-phase short circuits or lightning. One of the many factors impinging on voltage asymmetry in the electrical network is also the effect of load, but in the case of medium voltage power networks, this effect is neglected in the literature. This paper presents and evaluates the influence of the power consumed by consumers on the values of zero-voltage asymmetry factor indices in medium voltage compensated power networks with the neutral point earthed by an inductance (Petersen coil) operating with wind and photovoltaic power plants.

Obed Nkuriyingoma, Obed Nkuriyingoma, Engin Özdemir et al.

Due to the inadequacy of distribution networks in developing countries, especially in small residential areas, there are frequent interruptions in the electrical energy provided by the grid. This problem negatively affects the life quality and productivity of the people living in these regions. This problem can be overcome by integrating BESS-supported renewable energy sources into the distribution system. These distributed energy resources contribute significantly to providing energy directly to consumers. On a small scale, such a system is supported by the grid, when possible, to ensure energy supply continuity. This study presents a techno-economic analysis, using PV*SOL simulation software, of a grid-connected solar PV system with BESS that is used to supply a small residential community in Rwanda, Muhanga district, Shyogwe sector. The consumers were a group of one hundred households around a wetland valley. The energy generated from the solar PV system was used to supply home appliances and a water pumping system for agricultural activities. The simulation results showed that the annual energy requirement is 82.34 MWh with a peak load of 30.4 kW. The simulation results also revealed that a PV system, with an installed capacity of 57.33 kWp integrated with a BESS of 89.2 kWh storage capacity, can supply the load with own power consumption of 68.65%, a level of self-sufficiency of 64.38%, and a performance ratio of 86.05% when the desired ratio is set to 110% with a year as the reference period. The financial analysis demonstrated a return on assets of 9.14% and an amortization period of 9.65 years. These results indicate that the proposed method is technically and economically feasible for use in addressing the issue of electrical power outages in developing countries.

J. Quick, J. Quick, R. N. King et al.

<p>Wake steering is an emerging wind power plant control strategy where upstream turbines are intentionally yawed out of perpendicular alignment with the incoming wind, thereby “steering” wakes away from downstream turbines. However, trade-offs between the gains in power production and fatigue loads induced by this control strategy are the subject of continuing investigation. In this study, we present a multifidelity multiobjective optimization approach for exploring the Pareto front of trade-offs between power and loading during wake steering. A large eddy simulation is used as the high-fidelity model, where an actuator line representation is used to model wind turbine blades and a rainflow-counting algorithm is used to compute damage equivalent loads. A coarser simulation with a simpler loads model is employed as a supplementary low-fidelity model. Multifidelity Bayesian optimization is performed to iteratively learn both a surrogate of the low-fidelity model and an additive discrepancy function, which maps the low-fidelity model to the high-fidelity model. Each optimization uses the expected hypervolume improvement acquisition function, weighted by the total cost of a proposed model evaluation in the multifidelity case. The multifidelity approach is able to capture the logit function shape of the Pareto frontier at a computational cost only 30 % that of the single-fidelity approach. Additionally, we provide physical insights into the vortical structures in the wake that contribute to the Pareto front shape.</p>

Sampath Suranjan Salins, Shiva Kumar, S.V. Kota Reddy et al.

Current work mainly deals with the design and construction of a centrifugal humidifier where the humidification and cooling are due to the soaking of the packing and the dispersion of the water from packing due to the centrifugal effect. Celdek pad 7090 is used as humidifying media, and water is used as a working substance. Experiments are performed by varying the water flow rate (WFR), air velocity (AV) and rotational packing speed. Performance parameters such as a difference in dry bulb temperature (DBT), difference in relative humidity (RH), saturation efficiency, coefficient of performance (COP) and evaporation rate (ER) are evaluated. Results showed that a water flow rate of 0.6 litres per minute (L/min), rotor speed of 150 rpm and air flow rate of 5 m/s gave the maximum performance. The current unit gave a maximum cooling efficiency, COP and ER equal to 79.23%, 5.24 and 0.90 g/s, respectively. Stationary and dynamic packing conditions are assessed where it is observed that the performance of dynamic packing is higher than that of the static case at all operating ranges. Celdek packing with dynamic conditions can be suitably applied to handle huge cooling loads, which encourages sustainable energy sources and reduces environmental pollution by limiting greenhouse gas emissions.

Carlos García-Santacruz, Luis Galván, Juan M. Carrasco et al.

Energy storage systems are expected to play a fundamental part in the integration of increasing renewable energy sources into the electric system. They are already used in power plants for different purposes, such as absorbing the effect of intermittent energy sources or providing ancillary services. For this reason, it is imperative to research managing and sizing methods that make power plants with storage viable and profitable projects. In this paper, a managing method is presented, where particle swarm optimisation is used to reach maximum profits. This method is compared to expert systems, proving that the former achieves better results, while respecting similar rules. The paper further presents a sizing method which uses the previous one to make the power plant as profitable as possible. Finally, both methods are tested through simulations to show their potential.

Jinheng Li, Dongxia Chen, Lu Chang et al.

Recently, increasing numbers of oil and gas reservoirs have been discovered in the Wenchang Depression, western Pearl River Mouth Basin, South China Sea, revealing prospects for hydrocarbon exploration. The Enping Formation (E 3 e) is a key target layer for the development of source rocks. However, previous work has only focused on lacustrine swamp source rocks of E 3 e in the Wenchang A Sag, without a systematic study of shallow lacustrine source rocks. In this study, the quality of E 3 e shallow lacustrine source rocks is reevaluated, and the hydrocarbon generation and expulsion characteristics are analyzed using relevant geological data and constructing a conceptual model. The results show that the E 3 e 2 source rocks have greater thickness (50–600 m) and similar organic matter abundance (0.5–2.5%) compared with the E 3 e 1 source rocks (50–500 m and 0.5–2.5%). On the whole, the E 3 e source rocks were deposited in the continental environment and are dominated by Type II and Type III kerogen. Meanwhile, the E 3 e source rocks of the Wenchang A Sag are in the stage of mature to over mature, while those of the Wenchang B Sag are in the stage of low mature. Vertically, the hydrocarbon generation potential of the E 3 e 2 source rocks is greater than E 3 e 1 . Also, the cumulative hydrocarbon production of steep slope in the Wenchang A Sag is larger than that in the Wenchang B Sag. In addition, the corresponding vitrinite reflectances of hydrocarbon expulsion threshold and peak are 0.72 and 0.96%, respectively. Horizontally, four hydrocarbon generation and expulsion centers were mainly concentrated in different subsags of the Wenchang A and B Sags for E 3 e. The maximum values of hydrocarbon generation and expulsion intensity for E 3 e 1 are 1500 × 10 4 t/km 2 and 1000 × 10 4 t/km 2 , respectively, while those for E 3 e 2 are 1800 × 10 4 t/km 2 and 1200 × 10 4 t/km 2 , respectively, with the expulsion efficiency of 75%.

Horia Andrei, Cristian Andrei Badea, Paul Andrei et al.

Wastewater treatment plants and power generation constitute inseparable parts of present society. So the growth of wastewater treatment plants is accompanied by an increase in the energy consumption, and a sustainable development implies the use of renewable energy sources on a large scale in the power generation. A case study of the synergy between wastewater treatment plants and photovoltaic systems, aiming to improve the energetic, environmental and economic impacts, is presented. Based on data acquisition, the energy consumption analysis of wastewater treatment plant reveals that the highest demand is during April, and the lowest is during November. The placement of photovoltaic modules is designed to maximize the use of free space on the technological area of wastewater treatment plant in order to obtain a power output as high as possible. The peak consumption of wastewater treatment plant occurs in April, however the peak production of the photovoltaic is in July, so electrochemical batteries can partly compensate for this mismatch. The impact of the photovoltaic system connectivity on power grid is assessed by means of the matching-index method and the storage battery significantly improves this parameter. Carbon credit and energy payback time are used to assess the environmental impact. The results prove that the photovoltaic system mitigates 12,118 tons of carbon and, respectively, the embedded energy is compensated by production in 8 ½ years. The economic impact of the photovoltaic system is analyzed by the levelized cost of energy, and the results show that the price of energy from the photovoltaic source is below the current market price of energy.

Jiale Fan, Xiaoyang Tong

The gas-fired generation has recently become an important power source for power systems. The increasing integration of gas-fired units (GFUs) brings a problem of location allocation strategy for power system planners. This paper proposes a bi-level maximum-minimum optimal placement model of GFUs to improve the static voltage stability in the transmission network. In the first stage, the locations of installed GFUs are optimized to improve the static voltage stability margin. The optimal installed capacity of GFUs is determined to minimize the operation costs and power losses in the second stage. The proposed mixed-integer nonlinear programming (MINLP) model is solved by second-order cone programming relaxations. Numerical results in the IEEE 118-bus test system demonstrate the effectiveness of the proposed method and the static voltage stability can be improved.

Shafayet Ahmed, Ingrid Arocho

Timber has been considered as a promising building material because of its structural rigidity, environmental sustainability, and renewability nature. In Europe and Australia, timber materials have been used for many different types of construction such as residential, commercial, education, and industrial. However, in the U.S., the familiarity of timber products is gaining momentum. The construction practitioners are still reluctant to consider mass timber as a mainstream building material. A limited number of case study projects make it difficult for industry personnel to evaluate the actual construction feasibility of mass timber. As a result, a significant knowledge gap has been created that hindering the progress of mass timber material in the U.S. construction industry. To help solve the problem, this study aims to identify the existing awareness level among the U.S. building constructors regarding mass timber building materials. It further determines some of the major construction-related difficulties of mass timber buildings and recommendations overcome those difficulties to increase the acceptance of this material. The study performed a semi-structured questionnaire survey to carry out statistical analysis regarding mass timber building material. Analysis of descriptive statistics suggested that the level of awareness and involvement by the U.S. construction practitioners in mass timber building is still significantly low as 55% of the participants indicated no experience on mass timber building construction projects. Qualitative data analysis suggested that lack of experience in timber construction, poor coordination among the project parties, design-related difficulties, and high cost of mass timber panels are the biggest construction-related barriers to adopt this product. To overcome the existing difficulties, the study proposed an increasing number of timber building projects and manufacturing plants, effective early collaboration among the project parties, developing skilled workers, and a nation-wide promotion by the owners and the architects. The outcomes of this study will be helpful for the industry practitioners and the owners to adopt mass timber as a mainstream building material. The study will further increase the acceptance of this material in the U.S. construction industry.

Jaruwan Chaiyanupong, Tawit Chitsomboon

Flows through a vertical axis wind turbine (VAWT) are very complex due to their inherent unsteadiness caused by large variations of the angle of attacks as the turbine is rotating and changing its azimuth angles simultaneously. In addition, a turbine must go through a wide range of operating conditions especially the change in blade speed ratio (BSR). Accurate prediction of flows over VAWT using Reynolds-Averaged Navier-Stokes (RANS) model needs a well-tested turbulence model as well as a careful grid control around the airfoil. This paper aimed to compare various turbulence models and seek the most accurate one. Furthermore, grid convergence was studied using the Roache method to determine the sufficient number of grid elements around the blade section. The three-dimensional grid was generated by extrution from the two-dimensional grid along with the appropriate y+ controlling. Comparisons were made among the three turbulence models that are widely used namely: the RNG model, the shear stress transport k-ω model (SST) and the Menter’s shear stress transport k-ω model (transition SST). Results obtained clearly showed that turbulence models significantly affected computational accuracy. The SST turbulence model showed best agreement with reported experimental data at BSR lower than 2.35, while the transition SST model showed better results when BSR is higher than 2.35. In addition, grid extruding technique with y+ control could reduce total grid requirement while maintaining acceptable prediction accuracy. Article History: Received April 15th 2018; Received in revised form June 16th 2018; Accepted September 17th 2018; Available online How to Cite This Article: Chaiyanupong,J and Chitsomboon, T. (2018) Effects of Turbulence Models and Grid Densities on Computational Accuracy of Flows Over a Vertical Axis Wind Turbine. Int. Journal of Renewable Energy Development, 7(3), 213-222. http://dx.doi.org/10.14710/ijred.7.3.213-222

Gulten Izmirlioglu, Ali Demirci

Bio-ethanol is one of the energy sources that can be produced by renewable sources. Waste potato mash was chosen as a renewable carbon source for ethanol fermentation because it is relatively inexpensive compared with other feedstock considered as food sources. However, a pretreatment process is needed: specifically, liquefaction and saccharification processes are needed to convert starch of potato into fermentable sugars before ethanol fermentation. In this study, hydrolysis of waste potato mash and growth parameters of the ethanol fermentation were optimized to obtain maximum ethanol production. In order to obtain maximum glucose conversions, the relationship among parameters of the liquefaction and saccharification process was investigated by a response surface method. The optimum combination of temperature, dose of enzyme (α-amylase) and amount of waste potato mash was 95 °C, 1 mL of enzyme (18.8 mg protein/mL) and 4.04 g dry-weight/100 mL DI water, with a 68.86% loss in dry weight for liquefaction. For saccharification, temperature, dose of enzyme and saccharification time were optimized and optimum condition was determined as 60 °C-72 h-0.8 mL (300 Unit/mL) of amyloglucosidase combination, yielded 34.9 g/L glucose. After optimization of hydrolysis of the waste potato mash, ethanol fermentation was studied. Effects of pH and inoculum size were evaluated to obtain maximum ethanol. Results showed that pH of 5.5 and 3% inolculum size were optimum pH and inoculum size, respectively for maximum ethanol concentration and production rate. The maximum bio-ethanol production rate was obtained at the optimum conditions of 30.99 g/L ethanol. Since yeast extract is not the most economical nitrogen source, four animal-based substitutes (poultry meal, hull and fines mix, feather meal, and meat and bone meal) were evaluated to determine an economical alternative nitrogen source to yeast extract. Poultry meal and feather meal were able to produce 35 g/L and 32.9 g/L ethanol, respectively, which is higher than yeast extract (30.8 g/L). In conclusion, waste potato mash was found as a promising carbon source for ethanol fermentation with alternate nitrogen sources.