Cut-in Wind Speed Research Articles

On the use of fractal geometry to boost galloping-based wind energy harvesting

In this study, we introduce fractal bluff bodies to galloping energy harvesters (GEH) to improve the performance of wind energy harvesting. Three basic sectional shapes are proposed for GEH, from which four fractal bluff bodies are developed. An aero-electro-mechanical model with distributed parameters is established to elucidate the underlying mechanism. Then numerical simulations and wind tunnel tests are conducted based on a fabricated prototype. Compared with the conventional galloping energy harvester with a cuboid bluff body (GEH-CB), the GEH with a fractal bluff body (GEH-FB) owns a lower cut-in wind speed and can generate higher voltages. The galloping critical wind speed for GEH-FB is reduced by 0.4 m/s. Furthermore, the output voltage can increase by 51.97 % at the wind speed of 5 m/s. Especially, compared to the GEH-CB, the GEH-FB demonstrates a great advantage in terms of power density, being approximately 164.1 % higher. Three-dimensional computational fluid dynamics (3D-CFD) shows that the wake vortex area and the space between the adjacent vortices both increase, which explains the aerodynamic mechanism of a large aerodynamic force and a performance enhancement in wind galloping energy harvesting. Finally, some practical application tests exhibit the effectiveness of the proposed fractal galloping harvesters.

Performance enhancement of galloping wind energy harvesting via bio-inspired V-shaped blade

ABSTRACT Galloping wind energy harvesting has promising applications in future distributed self-powered low-power devices. A novel V-shaped blade is figured out from Palm leaf galloping. The enhancement of galloping oscillation from the bio-inspired V-shaped blade is evaluated. The galloping wind energy harvester (WEH) with a V-shaped blade is developed by electro-mechanical modeling, finite element simulation, ground vibration tests, and wind tunnel tests. It is found that the structural damping, effective electro-mechanical coupling coefficient, and V-shape included angle have big effects on the harvesting performance. The cut-in wind speed of WEH is below 3 m/s. With an included angle of 115° and a wind speed of 6.5 m/s, the output voltage is 4.48 V and the power density is 90.00 μW/cm3. The V-shaped blade harvester exhibits a 151.69% increase in output voltage and a 575.00% increase in power density compared to the traditional brick blade (square cross-section) harvester. Tests indicate that the output frequency remains stable at the structural resonant despite increasing wind speed. This study provides insights into enhancing galloping oscillation and wind energy harvesting efficiency by optimizing the aerodynamic shape of vortex shedding bluffs.

Numerical modeling and analysis of multistage gear transmission system in wind turbine gearbox under load uncertainty

A multistage gear transmission system (MGTS) is widely used in wind turbine gearboxes. Its dynamic responses are closely related to stochastic aerodynamic torque that has a wide interval range between cut-in and cut-out wind speeds. However, most of the dynamic models of MGTS lack attention to dynamic responses caused by uncertainties of multiple parameters under varied input torque. In this study, a dynamic modeling method in conjunction with interval uncertain analysis of MGTS caused by multiple load-related parameters due to varied input torques is proposed. A comprehensive dynamic model of MGTS is developed considering time-varying gear mesh transmission error, load-related gear mesh stiffness and bearing stiffness as well as flexible shafts. The reasonability of simulation is validated, and then the effects of multiple load-related parameters on uncertain dynamic responses are discussed in-depth. Results show that both gear mesh stiffness and bearing stiffness are enlarged with increasing input torque to cause uncertain dynamic responses. These uncertainties would propagate along the flexible shaft and be suppressed by system rigidity. The dominant transverse vibration modes of shafts are sensitive to bearing stiffness, thus, uncertain bearing stiffness has remarkable effects on dynamic responses than gear mesh stiffness.

Energy harvesting from transverse galloping using a two-degree-of-freedom flow energy harvester

Abstract A two degree-of-freedom (2-DOF) galloping piezoelectric energy harvesting system where both oscillators are excited by the incoming flow is studied in this paper. A coupled lumped-parameter model is developed to simulate the electro-fluid-structural coupling behaviour assuming a quasi-steady aerodynamic flow field. The differential equations governing the dynamics of the lumped system are converted into nonlinear algebraic equations employing the harmonic balance method (HBM) and then solved using Newton’s method. The approximate analytical solutions are compared to the solutions obtained by numerical integration, and the results agree, both qualitatively and quantitatively. The solutions were subsequently used to investigate the effects of the bluff body dimension, mechanical, electrical, aerodynamic, and electromechanical parameters on the performance of the harvester and to illustrate how to optimise some of these parameters to reduce the cut-in wind speed and maximise the power output of the energy harvester. It will be shown that the energy harvesting performance could be significantly improved by introducing piezoelectric transducers on both oscillators and including both masses in the incoming flow. A comparative study between the proposed 2-DOF flow energy harvesting system, a single-degree-of-freedom (SDOF) galloping piezoelectric energy harvester (GPEH), and other configurations of 2-DOF GPEH shows that the present 2-DOF GPEH generates the largest power peak.

Magnetic transfer piezoelectric wind energy harvester with dual vibration mode conversion

Wind-induced vibration piezoelectric energy harvesters have garnered significant interest in recent years as a means to power autonomous wireless sensor systems. A magnetic transfer piezoelectric wind energy harvester (MT-PWEH) is proposed and its durability, power generation performance and environmental adaptability are improved utilizing dual mode conversion. This MT-PWEH incorporated a downstream rectangular baffle, which facilitated the transition of the hollow cylinder from a traditional single vortex-induced vibration to a coupled vibration involving both vortex-induced vibration and galloping (i.e., the first vibration mode conversion). Besides, the vibration direction of the hollow cylinder was perpendicular to the vibration direction of the transducer, which achieved the purpose of limiting the amplitude (i.e., the second vibration mode conversion). The feasibility of MT-PWEH was confirmed through theoretical analysis, CFD simulation, fabrication and experiments. The experimental results demonstrated that the working characteristics of MT-PWEH were significantly affected by position and size of the baffle. Specifically, the ratio of the maximum cut-in wind speed of 12.5 m/s to the minimum cut-in wind speed of 1.2 m/s reached 10.4. Additionally, a maximum power output of 0.78 mW was recorded at 10 m/s with an optimal load resistance of 800 kΩ and 10 LEDs were drove successfully.

Enhancing energy harvesting through hybrid bluff body at a predefined angle of attack coupling vortex-induced vibration and galloping

This paper introduces a novel approach to enhance energy harvesting efficiency by coupling vortex-induced vibration and galloping through the use of a D-shaped hybrid bluff body with a predefined angle of attack. By adjusting the angle of attack, the aerodynamic interaction with the bluff body is improved, significantly increasing the vibration amplitude. Wind tunnel experiments are conducted to explore the effects of the predefined angle of attack and the rectangular height of the bluff body cross-section on the energy harvester's efficiency. The analysis identifies several optimal configurations that utilize the coupled vortex-induced vibration and galloping to enhance energy harvesting at low wind speeds while maintaining significant vibration amplitudes at high wind speeds. The proposed structure could achieve an RMS output voltage of 38.76 V, representing a 153.5% improvement compared to the traditional galloping piezoelectric energy harvesters. Additionally, the cut-in wind speed is reduced by 37.5%, allowing vibrations to begin at a low wind speed of 1.5 m/s, exhibiting a superior wind energy harvesting efficiency. Two-dimensional computational fluid dynamics simulations are employed to explain the underlying mechanisms of fluid-structure interaction, demonstrating the characteristics of the flow field, vortex shedding, and the transition in vibration modes.

A bioinspired triboelectric wireless anemometer with low cut-in wind speed for meteorological UAVs

Currently, unmanned aerial vehicles (UAVs) play a pivotal role in meteorological wind speed measurements. Nevertheless, existing anemometers exhibit notable issues, including excessive weight, high cost and high cut-in wind speed. This investigation introduces a biomimetic owl wing airfoil wind speed sensor utilizing the principles of the triboelectric nanogenerator (BOW-TENG) designed for UAV applications. Inspired by owl wings, an airfoil configuration with superior aerodynamic characteristics is ascertained, subsequently fabricating it into an impeller, and a wind speed sensor with low weight, low cost and low cut-in wind speed is developed. Experimental results affirm the BOW-TENG’s precision in depicting wind speed across the range of 1.6–10.7 m/s, featuring a sensitivity of 21.893 Hz/(m·s−1), a goodness of fit R2 of 0.9995, and a remarkable resolution of 0.057 m/s. The sensor weighs only 30 g. Furthermore, a cost-effective triboelectric signal processing system is devised for integrating the BOW-TENG into the UAV, as well as the optimal positioning for BOW-TENG on the UAV is identified through simulations. The relative wind direction can be calculated from signals of the BOW-TENGs on the four arms of the UAV. Ultimately, application experiments demonstrate the feasibility of employing BOW-TENG for wireless wind speed transmission from UAVs. This work incorporates bionics and proposes a practical application of triboelectric sensors for UAVs, as well as a solution for developing wind speed sensors in the field of meteorological UAV detection.

Commercial Small-Scale Horizontal and Vertical Wind Turbines: A Comprehensive Review of Geometry, Materials, Costs and Performance

The effective exploitation of renewable energy sources is one of the most effective solutions to counter the energy, environmental and economic problems associated with the use of fossil fuels. Small-scale wind turbines (converting wind energy into electric energy with a power output lower than 50 kW) have received tremendous attention over the past few decades thanks to their reduced environmental impact, high efficiency, low maintenance cost, high reliability, wide wind operation range, self-starting capability at low wind speed, limited installation space, reduced dependence on grid-connected power and long transmission lines, low capital costs, as well as the possibility to be installed in some urban settings. However, there are significant challenges and drawbacks associated with this technology from many different perspectives, including the significant discrepancy between theoretical performance data provided by the manufacturers and real field operation, that need to be investigated in greater depth in order to enable a more widespread deployment of small-scale wind turbines. In this review, a complete and updated list of more than 200 commercially available small-scale horizontal and vertical wind turbine models is provided and analysed, detailing the corresponding characteristics in terms of the number and material of blades, start-up wind speed, cut-in wind speed, cut-out wind speed, survival wind speed, maximum power, noise level, rotor diameter, turbine length, tower height, and specific capital cost. In addition, several scientific papers focusing on the experimental assessment of field performance of commercially available small-scale horizontal and vertical wind turbines have been reviewed and the corresponding measured data have been compared with the rated performance derived from the manufacturers’ datasheets in order to underline the discrepancies. This review represents an opportunity for the scientific community to have a clear and up-to-date picture of small-scale horizontal as well as vertical wind turbines on the market today, with a precise summary of their geometric, performance, and economic characteristics, which can enable a more accurate and informed choice of the wind turbine to be used depending on the application. It also describes the differences between theoretical and in-situ performance, emphasizing the need for further experimental research and highlighting the direction in which future studies should be directed for more efficient design and use of building-integrated small-scale wind turbines.

Lessons learned from 10 years of wind tunnel tests on small wind turbines designed by students

This article discusses results from an international contest, open for university student teams (bachelor and master), involving the design, construction, and testing of small wind turbines in a large wind tunnel. The wind tunnel has an outlet of 2.85 x 2.85 m allowing a maximum rotor swept area of 2 m2 without significant tunnel effects. Both horizontal and vertical axis wind turbines are part of the competition. The turbines are evaluated by an external jury of industry experts based on criteria such as Annual Energy Production, cut-in wind speed, innovations, design, and sustainability. Although the contest has been initiated in 2013 with an educational focus, it has also evolved into a valuable database for scientific purposes by providing a decade worth of performance measurements for roughly 9-10 various turbine concepts each year. The collected data may serve as a unique validation resource for assessing the accuracy of design codes in modelling diverse turbine concepts thanks to detailed design reports with model descriptions accompanying each turbine (such turbine descriptions are often considered confidential for field measurements). The paper aims to explore the scientific value of this database by comparing calculations with measurements, offering explanations where possible, and reporting intriguing findings on unconventional concepts’ performance. Even though not all observations could be explained fully they provide food for thought. Recommendations are provided for both students to enhance their designs and for contest organizers to elevate the scientific value of the measurements in future contests.

An improved wind farm parametrization for inhomogeneous inflow

Energy losses due to wind farm clustering and wind farm interaction are rarely well represented in the wind farm design process because of the lack of fast models that can accurately account for neighboring wind farm wakes. A recently developed solution is the actuator wind farm (AWF) model, which is a Reynolds-averaged Navier-stokes (RANS) based wind farm parametrization that models a wind farm as a distributed thrust force and applies a global wind farm thrust coefficient controller. We propose an improved version of the AWF model, where each turbine employs a local thrust force controller and uses turbine thrust and power coefficients as input to better handle inhomogeneous inflow conditions. The proposed AWF model shows improved performance compared to the original AWF model in terms of predicted wind turbine power of a downstream wind farm that operates in a partial wake of an upstream wind farm, without significantly increasing the computational effort. However, the annual energy production (AEP) wake losses of a large wind farm cluster are nearly unaffected by using local or global control and input because the largest impact is found near the cut-in wind speed, which does not contribute much to the AEP wake losses.

Biomimetic swallowtail V-shaped attachments for enhanced low-speed wind energy harvesting by a galloping piezoelectric energy harvester

Efficient low wind speed energy harvesting is pivotal in expanding the reach of sustainable wind power to regions with limited wind resources. This paper introduces an innovative approach to enhance wind energy harvesting efficiency in low wind speed environments through the development of a biomimetically inspired design featuring V-shaped attachments on a square bluff body. Drawing inspiration from the swallowtail, these attachments are engineered to manipulate airflow, creating an asymmetrical pressure field that significantly improves the vibration amplitude of the harvesting device. The proposed design is tested in wind tunnel experiments, demonstrating a 32 % reduction in cut-in wind speed and a significant increase in power output at the lowest tested wind speed of 1.7 m/s, compared to traditional designs. Computational fluid dynamics simulations further elucidate the mechanism behind the enhanced energy harvesting, highlighting the role of V-shaped attachments in generating stronger and more stable vortex shedding, crucial for efficient energy harvesting. The proposed attachments not only substantially reduce the cut-in wind speed of galloping but also significantly increase the device's power output, demonstrating the potential of this design for expanding the viability of wind energy in regions with limited wind resources.

Enhancing Power Output of Ducted Wind Turbines through Flow Control

This study focuses on the performance enhancement of a ducted small-scale National Renewable Energy Laboratory (NREL) Phase VI wind turbine, utilizing a Wind Lens diffuser. The investigation is conducted at the critical cut-in wind speed of 5 m/s. The research evaluates the integration of passive flow control devices, including Vortex Generators, Microtab, and Slot, strategically positioned across the Wind Lens to augment the mass flow through the rotor. The results indicate significant amplifications in the turbine output of up to 127%, attributable to airflow manipulation across the diffuser, resulting in increased torque and power output. The study highlights the effectiveness of employed flow control devices in managing turbulence and/or flow separation, thereby enhancing aerodynamics, particularly under low wind conditions. A comprehensive analysis of various parameters such as pressure and flow fields, turbulence, and other relevant metrics is conducted to ascertain their collective influence on rotor aerodynamics. The results demonstrate the potential of these passive flow control devices in advancing small-scale wind turbine technology, especially in regions with low wind potential. Moreover, the design simplicity and cost-effectiveness of these passive flow control devices suggest wider applicability in the renewable energy sector, contributing to the reduction of carbon-intensive energy reliance.

Wind-Induced Response Analysis and Fatigue Life Prediction of a Hybrid Wind Turbine Tower Combining an Upper Steel Tube with a Lower Steel Truss

Based on the WindPACT-3MW wind turbine tower commonly used in wind power engineering, a finite element model (FEM) of a hybrid wind turbine tower combining an upper steel tube with a lower steel truss is designed and established. On this basis, a static optimization analysis, wind-induced vibration analysis, and fatigue life analysis of the hybrid tower structure are performed. The results show that under the same design parameters, the overall stiffness and static bearing capacity of the tower structure can be significantly improved by using subdivided truss webs, increasing the truss height as much as possible and increasing the width of the truss base appropriately. Under normal operation conditions, the response of the tower structure in the along-wind direction is significantly greater than the response in the crosswind direction, indicating that the aerodynamic thrust generated by the rotation of the blades is the main factor causing the wind-induced vibration of the tower structure. For the tower structure analyzed in this study, when considering the entire range of wind speeds from the cut-in wind speed to the cut-out wind speed, the fatigue life of the structure is 38.5 years.

Aerodynamic characterization of a H-Darrieus wind turbine with a Drag-Disturbed Flow device installation

This study examines the impact of the Drag-Disturbed Flow device on the startup and operation of HDWT (H-Darrieus wind turbine). The device plays a crucial role in enhancing the startup performance of the HDWT and improving the overall wind energy utilization. This work presents a study where two-dimensional computational fluid dynamics (CFD) evaluations are performed on various D-DF (Drag-Disturbed) devices. The HDWT utilizes the NACA0018 airfoil type, while the D-DF device employs triangular, oval, and NACA0018 airfoil structures. The text explains the installation process and operational principles of the D-DF device. It also verifies the device's meshing and accuracy. Furthermore, this study conducts 2-D simulations to analyze the impact of various D-DF devices on the moment and wind energy consumption coefficients of the HDWT. Additionally, the process by which D-DF devices enhance the performance of the HDWT is explained by an analysis of the vortex cloud diagram. The results indicate that the HDWTs equipped with D-DF devices experience significant performance improvements during the wind turbine startup phase. Specifically, the Drag blade effectively enhances the moment coefficient of the HDWTs at low tip speed ratios by an average of approximately 41.74 %. Additionally, once the HDWTs are started and operating at high tip speed ratios, all D-DF devices, except for the DF-Tri, can be utilized within the λ = 1.2–2 range to enhance the torque coefficient of the HDWT by an average of about 7.53 %. This study aims to improve the operating performance of the current HDWT, lower the wind turbine cut-in wind speed, and enhance the wind energy consumption of the turbine.

Design Methodology of Wind Turbine Rotor Models Based on Aerodynamic Thrust and Torque Equivalence

Limited by scaling effects, the physical model tests of FOWTs (floating offshore wind turbines) cannot simulate the aerodynamic loads on rotors correctly. To solve this problem, the real-time hybrid model tests in wind tunnels were developed and provided a feasible solution for the aerodynamic simulation. To perform the wind tunnel tests, the design of aerodynamic equivalent rotor models is most critical. In this study, an innovative methodology of aerodynamic equivalent design for the wind turbine rotors is developed based on GA (genetic algorithm). The NREL (National Renewable Energy Laboratory) 5 MW and DTU (Technical University of Denmark) 10 MW rotors are employed for the case studies to validate the proposed methodology. According to the results, the model-scale aerodynamic thrust performance can be accurately matched with the prototype in the entire region between cut-in and cut-out wind speeds, which allows the rotor model to provide correct thrust at different wind speeds. The variance of the aerodynamic torque with the wind speeds for the developed model is also in good agreement with the prototype, which could be beneficial for the design of the model-scale active pitch control strategy. Moreover, the applicability of the fitness functions of GA is discussed.

Using 2-bladed Savonius rotor to harvest highway wind energy at airport: A case study

ABSTRACTThe Savonius wind turbine (SWT) is a famous type of vertical axis wind turbine (VAWT) that accepts wind from all directions, particularly suitable for various applications including the design of small-scale wind turbines. This study evaluates the potential installation of a simple 2-bladed SWT on Queen Alya’ airport highway, Amman, Jordan. The strategic objective of this work was to design and install the SWT prototype at different sites along the airport road to define the most efficient location for capturing wind energy. The SWT rotor was fabricated via galvanized steel sheets. The self-starting ability of the rotor was examined by determining the torque coefficient at different angles of attack. The field tests were carried out by employing the turbine at three different locations along a six-lane highway (including the left, right, and middle sides of the highway). It was found that the proposed turbine has a cut-in wind speed of 2.5 m/s. Furthermore, the torque coefficient values indicated that the proposed rotor has a strong self-starting capacity. Field studies also revealed that the rotational speed of the turbine differs at various positions of the wind turbine. In addition, the results highlighted the significance of wind directions relative to vehicle directions for generating wind power on highways. The established Savonius rotor exhibited a maximum coefficient of performance of 0.25 with operational TSRs up to 0.7. Overall, a maximum enhanced rotational speed of about 53% was attained by positioning the turbine in the middle of six-way-lane highways.

Assessing long-term future climate change impacts on extreme low wind events for offshore wind turbines in the UK exclusive economic zone

The impacts of climate change must be considered while planning offshore wind turbines (OWT), as it will result in more frequent and severe weather extremes. To ensure the dependability and affordability of wind energy, it is necessary to address extreme low wind speed events (LWE). This study aims to assess the reliability of wind power in the future by analyzing the rise of low wind durations and intensities in two future periods, 2021–2040 and 2061–2080, compared to the historical period of 1981–2000. The research compares the results for four main regions in the UK EEZ: East, South, West, and North. We examine different cut-in thresholds of 3 m/s, 4 m/s, 5 m/s, and 6 m/s in the UK exclusive economic zone (EEZ). The seasonal variations in LWE durations <4 m/s demonstrate that summer and autumn have an increase in most of the LWE durations occurrence in the 2061–2080 period in all regions compared to the historical period. Using five days running mean wind speed, the return time for 6 m/s cut-in wind speed shows that OWT will be vulnerable to frequent extreme LWE in most areas, with most sites experiencing a return period of up to 20 years. According to the return year region median and the Risk Ratio (RR) calculations, it is suggested that the South region exhibits a diminished risk of experiencing more frequent instances of wind speeds surpassing the cut-in threshold, specifically when utilizing cut-in thresholds of 5 m/s and 6 m/s, during the period spanning 2021–2040, as compared to the historical period. Furthermore, when employing 6-, 7-, and 8-day running means, the analysis reveals that the return period for wind speeds of 4 m/s in the Western region remains consistently recommended throughout the 2021–2040 period. In contrast, utilizing a 6-day time window for assessing the return period of 4 m/s wind speeds indicates a notable escalation in risk across all regions during the 2061–2080 period.

The impacts of atmospheric icing on performance and behavior of a controlled large-scale wind turbine

Icing degrades turbine performance by altering the geometry of blade airfoils, reducing turbine power output, and increasing structural loads. In this study, the impacts of atmospheric icing on the full performance and behavior of a controlled large-scale wind turbine are thoroughly investigated. Using the Mustafa Sahin bladed wind turbine simulation model, the National Renewable Energy Laboratory 5 MW turbine is simulated with and without iced blades. The turbine blades are considered fully covered by light icing at the leading edge, which causes a reduction of up to 9.27% in Cl and an increase of up to 48% in Cd data of blade airfoils. Turbine static performance and behavior are examined at different uniform winds between cut-in and cut-out wind speeds, while the dynamic performance and behavior are estimated under turbulent winds at below (region II) and above (region III) rated regions. Simulation results are presented in terms of various turbine parameters, such as rotor power, thrust, their coefficients, blade pitch angle, rotor speed, etc. Results show that such light icing alters the turbine's aerodynamic characteristics and dynamics, increasing the turbine's cut-in and rated wind speeds, and reducing the thrust and maximum power coefficients by 5.5% and 13.35%, respectively. Under the same uniform winds, due to icing, turbine static performance and behavior are drastically disrupted in below rated region, resulting in reduced rotor speed, turbine efficiency, thrust, and power output by up to 4.77%, 39.7%, 7.63%, and 40%, respectively. In region III, however, thrust increases by up to 15% although the power output, rotor speed, and turbine efficiency do not change considerably. When the dynamic responses are examined under turbulent wind with a mean of 7.9 m/s in region II, mean power and fluctuations reduce by 14.17% and 10.88%, respectively. The mean thrust decreases by 6.86%, while its fluctuations reduce by 11.33%. The mean rotor speed reduces by 3.83%, and its fluctuations decrease by 12.84%. Under turbulent wind with a mean of 15.7 m/s in region III, the mean power and fluctuations decrease by 0.053% and 1.95%, respectively. The mean thrust increases by 11.99% and its fluctuations drop by 0.84%. The mean rotor speed does not change much, but its fluctuations increase by 0.132%. The mean blade pitch angle reduces by 9.39%, while its fluctuations increase by 7.39%.

Wind resource of Ilorin City for vortex-induced wind turbine power generation and off-grid electrification

This study examined the appraisal of wind resources of Ilorin, Nigeria for vortex-induced wind turbine power generation and off-grid electrification. The technical potential of Modern-Era Retrospective Analysis for Research and Application, version 2 (MERRA-2) was employed as a tool to generate an estimated wind resource of Ilorin city, using five different hub-heights (10, 30, 50, 70, and 90 m). A statistical analysis of wind characteristics for 21 years from 2001 to 2021 was carried out using Weibull distribution function. The daytime and night-time wind characteristics were studied to determine prospective and investment hub-height(s). It was observed that the study area is a low wind region with a minimum and maximum mean wind speed of 2.89 m/s at 10 m and 7.68 m/s at 90 m, respectively. Wind turbines with cut-in wind speed of 2, 2.5, and 3 m have operational chances of 98%, 95% and 88%, respectively. Wind power density at 10, 30, and 50 m elevations was classified as poor while at 70 and 90 m elevations, was regarded as marginal and fair, respectively.

Priority of Wind Energy in West Coast of Southern Thailand for Installing the Water Pumping Windmill System with Combining of Entropy Weight Method and TOPSIS

Wind energy potential or quality serve as the primary determinants influencing the decisions of Thai farmers regarding the installation of water-pumping windmills with heights ranging from 9 to 15 m and a cut-in wind speed requirement of 4 m/s, aimed at reducing their fuel costs. To introduce a simplified calculation method as one of their decision-making tools, the combined approach of the entropy weight method with TOPSIS has been introduced to assist them in prioritizing and assessing the wind quality in their respective areas. This study focuses on the western region of Southern Thailand, known for its high agricultural productivity. Initially, only 18 out of the 227 sub-districts with a minimum monthly wind speed exceeding 4 m/s were selected for thorough investigation. Subsequently, the entropy weight method was applied to the monthly wind speed data of these 18 chosen sub-districts to calculate their monthly weight values. These monthly weight values provide a quantifiable characterization of the wind quality in these specific sub-districts, revealing variations in wind quality between seasons, with superior quality during the summer season compared to the rainy season. Following the calculation of monthly weight values, the TOPSIS technique was applied to the wind data in conjunction with these monthly weight values, resulting in the determination of performance scores (Pi) for each of the 18 sub-districts. Pi values were found to vary from 0.0641 to 0.9006. In the final step of the analysis, these 18 sub-districts were ranked based on their respective Pi values, with the implication that sub-districts exhibiting higher Pi values are more suitable for the installation of water-pumping windmills with heights ranging from 9 to 15 m compared to those with lower Pi values.