scholarly journals Power and Wind Shear Implications of Large Wind Turbine Scenarios in the US Central Plains

Energies ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 4269 ◽  
Author(s):  
Rebecca J. Barthelmie ◽  
Tristan J. Shepherd ◽  
Jeanie A. Aird ◽  
Sara C. Pryor
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Shear ◽  
International Energy Agency ◽  
Fatigue Loading ◽  
Vertical Shear ◽  
Central Plains ◽  
Energy Agency ◽  
Wind Speeds

Continued growth of wind turbine physical dimensions is examined in terms of the implications for wind speed, power and shear across the rotor plane. High-resolution simulations with the Weather Research and Forecasting model are used to generate statistics of wind speed profiles for scenarios of current and future wind turbines. The nine-month simulations, focused on the eastern Central Plains, show that the power scales broadly as expected with the increase in rotor diameter (D) and wind speeds at hub-height (H). Increasing wind turbine dimensions from current values (approximately H = 100 m, D = 100 m) to those of the new International Energy Agency reference wind turbine (H = 150 m, D = 240 m), the power across the rotor plane increases 7.1 times. The mean domain-wide wind shear exponent (α) decreases from 0.21 (H = 100 m, D = 100 m) to 0.19 for the largest wind turbine scenario considered (H = 168 m, D = 248 m) and the frequency of extreme positive shear (α > 0.2) declines from 48% to 38% of 10-min periods. Thus, deployment of larger wind turbines potentially yields considerable net benefits for both the wind resource and reductions in fatigue loading related to vertical shear.

SHAPING OF AN AUTONOMOUS POWER SYSTEM FOR GUARANTEED POWER SUPPLY WITH THE PREDOMINANCE WIND ENERGY

2018 ◽  
pp. 28-50
Author(s):  
S. G. Ignatiev ◽  
S. V. Kiseleva
Keyword(s):  
Energy Storage ◽  
Wind Speed ◽  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Energy Demand ◽  
Diesel Generator ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Optimization of the autonomous wind-diesel plants composition and of their power for guaranteed energy supply, despite the long history of research, the diversity of approaches and methods, is an urgent problem. In this paper, a detailed analysis of the wind energy characteristics is proposed to shape an autonomous power system for a guaranteed power supply with predominance wind energy. The analysis was carried out on the basis of wind speed measurements in the south of the European part of Russia during 8 months at different heights with a discreteness of 10 minutes. As a result, we have obtained a sequence of average daily wind speeds and the sequences constructed by arbitrary variations in the distribution of average daily wind speeds in this interval. These sequences have been used to calculate energy balances in systems (wind turbines + diesel generator + consumer with constant and limited daily energy demand) and (wind turbines + diesel generator + consumer with constant and limited daily energy demand + energy storage). In order to maximize the use of wind energy, the wind turbine integrally for the period in question is assumed to produce the required amount of energy. For the generality of consideration, we have introduced the relative values of the required energy, relative energy produced by the wind turbine and the diesel generator and relative storage capacity by normalizing them to the swept area of the wind wheel. The paper shows the effect of the average wind speed over the period on the energy characteristics of the system (wind turbine + diesel generator + consumer). It was found that the wind turbine energy produced, wind turbine energy used by the consumer, fuel consumption, and fuel economy depend (close to cubic dependence) upon the specified average wind speed. It was found that, for the same system with a limited amount of required energy and high average wind speed over the period, the wind turbines with lower generator power and smaller wind wheel radius use wind energy more efficiently than the wind turbines with higher generator power and larger wind wheel radius at less average wind speed. For the system (wind turbine + diesel generator + energy storage + consumer) with increasing average speed for a given amount of energy required, which in general is covered by the energy production of wind turbines for the period, the maximum size capacity of the storage device decreases. With decreasing the energy storage capacity, the influence of the random nature of the change in wind speed decreases, and at some values of the relative capacity, it can be neglected.

Importance of Shear in Site Assessment of Wind Turbine Fatigue Loads

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
René M. M. Slot ◽  
Lasse Svenningsen ◽  
John D. Sørensen ◽  
Morten L. Thøgersen
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Structural Reliability ◽  
Turbine Blades ◽  
Structural Response ◽  
Fatigue Loading ◽  
Worst Case ◽  
Shear Model ◽  
Wind Climate

Wind turbines are subjected to fatigue loading during their entire lifetime due to the fluctuating excitation from the wind. To predict the fatigue damage, the design standard IEC 61400-1 describes how to parametrize an on-site specific wind climate using the wind speed, turbulence, wind shear, air density, and flow inclination. In this framework, shear is currently modeled by its mean value, accounting for neither its natural variance nor its wind speed dependence. This very simple model may lead to inaccurate fatigue assessment of wind turbine components, whose structural response is nonlinear with shear. Here we show how this is the case for flapwise bending of blades, where the current shear model leads to inaccurate and in worst case nonconservative fatigue assessments. Based on an optimization study, we suggest modeling shear as a wind speed dependent 60% quantile. Using measurements from almost one hundred sites, we document that the suggested model leads to accurate and consistent fatigue assessments of wind turbine blades, without compromising other main components such as the tower and the shaft. The proposed shear model is intended as a replacement to the mean shear, and should be used alongside the current IEC models for the remaining climate parameters. Given the large number of investigated sites, a basis for evaluating the uncertainty related to using a simplified statistical wind climate is provided. This can be used in further research when assessing the structural reliability of wind turbines by a probabilistic or semiprobabilistic approach.

scholarly journals Analysis of the Patent of a Protective Cover for Vertical-Axis Wind Turbines (VAWTs): Simulations of Wind Flow

2020 ◽  
Vol 12 (18) ◽  
pp. 7818
Author(s):  
Jose Alberto Moleón Baca ◽  
Antonio Jesús Expósito González ◽  
Candido Gutiérrez Montes
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
High Speed ◽  
Experimental Tests ◽  
Weather Conditions ◽  
Vertical Axis ◽  
Good Alternative ◽  
Wind Speeds ◽  
Vertical Axis Wind Turbines

This paper presents a numerical and experimental analysis of the patent of a device to be used in vertical-axis wind turbines (VAWTs) under extreme wind conditions. The device consists of two hemispheres interconnected by a set of conveniently implemented variable section ducts through which the wind circulates to the blades. Furthermore, the design of the cross-section of the ducts allows the control of the wind speed inside the device. These ducts are intended to work as diffusers or nozzles, depending on the needs of the installation site. Simulations were performed for the case of high-speed external wind, for which the ducts act as diffusers to reduce wind speed and maintain a well-functioning internal turbine. Four different patent designs were analyzed, focusing on turbine performance and generated power. The results indicate that the patent allows the generation of electric power for a greater range of wind speeds than with a normal wind turbine. The results support that this patent may be a good alternative for wind power generation in geographic areas with extreme weather conditions or with maintained or strong gusty wind. Experimental tests were carried out on the movement of the blades using the available model. Finally, the power curve of the model of this wind turbine was obtained.

scholarly journals Results from a wake-steering experiment at a commercial wind plant: investigating the wind speed dependence of wake-steering performance

2021 ◽  
Vol 6 (6) ◽  
pp. 1427-1453
Author(s):  
Eric Simley ◽  
Paul Fleming ◽  
Nicolas Girard ◽  
Lucas Alloin ◽  
Emma Godefroy ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Direction ◽  
Wind Farm ◽  
Poor Performance ◽  
Power Production ◽  
Wind Rose ◽  
Wind Speeds ◽  
Variability Model

Abstract. Wake steering is a wind farm control strategy in which upstream wind turbines are misaligned with the wind to redirect their wakes away from downstream turbines, thereby increasing the net wind plant power production and reducing fatigue loads generated by wake turbulence. In this paper, we present results from a wake-steering experiment at a commercial wind plant involving two wind turbines spaced 3.7 rotor diameters apart. During the 3-month experiment period, we estimate that wake steering reduced wake losses by 5.6 % for the wind direction sector investigated. After applying a long-term correction based on the site wind rose, the reduction in wake losses increases to 9.3 %. As a function of wind speed, we find large energy improvements near cut-in wind speed, where wake steering can prevent the downstream wind turbine from shutting down. Yet for wind speeds between 6–8 m/s, we observe little change in performance with wake steering. However, wake steering was found to improve energy production significantly for below-rated wind speeds from 8–12 m/s. By measuring the relationship between yaw misalignment and power production using a nacelle lidar, we attribute much of the improvement in wake-steering performance at higher wind speeds to a significant reduction in the power loss of the upstream turbine as wind speed increases. Additionally, we find higher wind direction variability at lower wind speeds, which contributes to poor performance in the 6–8 m/s wind speed bin because of slow yaw controller dynamics. Further, we compare the measured performance of wake steering to predictions using the FLORIS (FLOw Redirection and Induction in Steady State) wind farm control tool coupled with a wind direction variability model. Although the achieved yaw offsets at the upstream wind turbine fall short of the intended yaw offsets, we find that they are predicted well by the wind direction variability model. When incorporating the expected yaw offsets, estimates of the energy improvement from wake steering using FLORIS closely match the experimental results.

scholarly journals Results from a Wake Steering Experiment at a Commercial Wind Plant: Investigating the Wind Speed Dependence of Wake Steering Performance

2021 ◽  
Author(s):  
Eric Simley ◽  
Paul Fleming ◽  
Nicolas Girard ◽  
Lucas Alloin ◽  
Emma Godefroy ◽  
...  
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Direction ◽  
Wind Farm ◽  
Poor Performance ◽  
Power Production ◽  
Wind Rose ◽  
Wind Speeds ◽  
Variability Model

Abstract. Wake steering is a wind farm control strategy in which upstream wind turbines are misaligned with the wind to redirect their wakes away from downstream turbines, thereby increasing the net wind plant power production and reducing fatigue loads generated by wake turbulence. In this paper, we present results from a wake steering experiment at a commercial wind plant involving two wind turbines spaced 3.7 rotor diameters apart. During the three-month experiment period, we estimate that wake steering reduced wake losses by 5.7 % for the wind direction sector investigated. After applying a long-term correction based on the site wind rose, the reduction in wake losses increases to 9.8 %. As a function of wind speed, we find large energy improvements near cut-in wind speed, where wake steering can prevent the downstream wind turbine from shutting down. Yet for wind speeds between 6–8 m/s, we observe little change in performance with wake steering. However, wake steering was found to improve energy production significantly for below-rated wind speeds from 8–12 m/s. By measuring the relationship between yaw misalignment and power production using a nacelle lidar, we attribute much of the improvement in wake steering performance at higher wind speeds to a significant reduction in the power loss of the upstream turbine as wind speed increases. Additionally, we find higher wind direction variability at lower wind speeds, which contributes to poor performance in the 6–8 m/s wind speed bin because of slow yaw controller dynamics. Further, we compare the measured performance of wake steering to predictions using the FLORIS (FLOw Redirection and Induction in Steady State) wind farm control tool coupled with a wind direction variability model. Although the achieved yaw offsets at the upstream wind turbine fall short of the intended yaw offsets, we find that they are predicted well by the wind direction variability model. When incorporating the predicted achieved yaw offsets, estimates of the energy improvement from wake steering using FLORIS closely match the experimental results.

scholarly journals Dynamic Modeling of Wind Turbines Based on Estimated Wind Speed under Turbulent Conditions

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 1907 ◽  
Author(s):  
Ahmed G. Abo-Khalil ◽  
Saeed Alyami ◽  
Khairy Sayed ◽  
Ayman Alhejji
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Shear ◽  
Large Scale ◽  
Estimation Error ◽  
Turbine Rotor ◽  
Average Wind Speed ◽  
Rotating Speed ◽  
Tower Shadow

Large-scale wind turbines with a large blade radius rotates under fluctuating conditions depending on the blade position. The wind speed is maximum in the highest point when the blade in the upward position and minimum in the lowest point when the blade in the downward position. The spatial distribution of wind speed, which is known as the wind shear, leads to periodic fluctuations in the turbine rotor, which causes fluctuations in the generator output voltage and power. In addition, the turbine torque is affected by other factors such as tower shadow and turbine inertia. The space between the blade and tower, the tower diameter, and the blade diameter are very critical design factors that should be considered to reduce the output power fluctuations of a wind turbine generator. To model realistic characteristics while considering the critical factors of a wind turbine system, a wind turbine model is implemented using a squirrel-cage induction motor. Since the wind speed is the most important factor in modeling the aerodynamics of wind turbine, an accurate measurement or estimation is essential to have a valid model. This paper estimates the average wind speed, instead of measuring, from the generator power and rotating speed and models the turbine’s aerodynamics, including tower shadow and wind shear components, without having to measure the wind speed at any height. The proposed algorithm overcomes the errors of measuring wind speed in single or multiple locations by estimating the wind speed with estimation error less than 2%.

scholarly journals Evaluation of the Effect of Blades Number on the Performance of Pico Wind Turbines

2021 ◽  
Vol 8 (1) ◽  
pp. 29-39
Author(s):  
Yasir Abood ◽  
Tariq A. Ismail ◽  
Omar A. Abdulrazzaq ◽  
Haider S. Hussein
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Electrical Power ◽  
Internal Resistance ◽  
Power Coefficient ◽  
Sharp Reduction ◽  
Wind Speeds ◽  
Air Blower

In this paper, the influence of blades number on the performance of pico wind turbine was investigated by using a small-motorized axial DC fan with a rated power of 4W. Fixed streaming air blower was used as a source of wind. Varying in wind speed was accomplished by changing the distance from the blower. A resistor equals to the turbine internal resistance was utilized as a load to collect the electrical power across the load at various wind speeds and for fans of different blades (1, 2, and 5). Values of the cut-in and cut-out speeds were extracted from the power plot. Rated power was recorded, as well. The results have shown that the rated power generated by turbine has decreased due to the reduction of blades number (i.e., reduction in solidity) from 2.6W for a 5-bladed turbine to 0.665W for a 2-bladed turbine and to 0.13W for a 1-bladed turbine. Moreover, the cut-in speed (initial electrical generating speed) has increased from 4.9m/s for 5-bladed to 8m/s for 2-bladed, then to 19.15m/s for 1-bladed. These results are explained by the balancing problems during rotation (polar asymmetrical rotor), and it is seen that the reduction of blades has made a sharp reduction in power coefficient.

ANALISA PERFORMA TURBIN ANGIN SUMBU HORISONTAL BERSUDU AIRFOIL MELALUI VARIASI JUMLAH SUDU

ROTOR ◽  
2018 ◽  
Vol 11 (2) ◽  
pp. 18
Author(s):  
Wabang A Jhon ◽  
Abanat D.J Jufra ◽  
Hattu Edwin
Keyword(s):  
Wind Speed ◽  
Kinetic Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Mechanical Energy ◽  
Coefficient Of Performance ◽  
Research Activity ◽  
Average Wind Speed ◽  
Wind Speeds ◽  
Average Wind

Indonesia is an area that has the potential for sufficient wind resources to be utilized for kinetic energy into other energy such as mechanical energy and electrical energy through its generators (generators). The way to utilize wind kinetic energy into other energy is through a device called a wind turbine. Wind turbines have been around since ancient times, and are called airfoil angled wind turbines. This airfoil wind turbine is designed only for areas with average wind speeds above 6m / s. While in Indonesia not all regions have the same wind speed. In certain seasons, the average wind speed is below 6 m / s. This has become a major problem in regions that have average wind speeds below 6 m / s. Seeing this condition, there is a need for scientific research to obtain wind turbines that can be used in areas with average wind speeds below 5m / s. For this reason, the research I want to do is get a wind turbine that can be used as a power plant in areas that have wind speeds below 6m / s. This research was conducted on the basis of scientific theory in fluid mechanics regarding the sweeping area of wind turbines and the performance of variations in the number of blades in the wind. In addition, the research in several scientific journals was used as the basis of this research This research method is an experimental method, in the form of testing a wind turbine axis prototype horizontal and airfoil axis. The details of the research activity are the design and manufacture of laboratory scale horizontal airfoil axis turbines. Next, testing with a fan as a source of wind. The fan used has three variations of speed, all of which are used to determine the lowest average wind speed that can be applied. The results of the research are where wind turbines with the greatest torque and power and the Coefficient of Performance (CP) with the highest value will be used as a result to be applied to the community. Based on experimental data, it can be concluded that the greatest torque and power occur in turbines with 4 blades with details at speed 1, the largest torque and power are 0.201 Nm and 4.5 W; at speed 2, the biggest torque and power are 0.25 Nm and 7.21 W; at speed 3, the biggest torque and power are 0.28 Nm and 8.35 W Keywords: wind turbine, airfoil, nozzle, diffuser

scholarly journals Pengaruh Jumlah Bilah dan Sudut Pasang terhadap Daya Turbin Angin Poros Vertikal Tipe H-Darrieus Termodifikasi sebagai Energi Alternatif Pembangkit Tenaga Listrik Skala Rumah Tangga

2019 ◽  
Vol 12 (2) ◽  
pp. 92
Author(s):  
Susilo Susilo ◽  
Bambang Widodo ◽  
Eva Magdalena Silalahi ◽  
Atmadi Priyono
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Output Power ◽  
Wind Turbines ◽  
Output Voltage ◽  
Turbine Rotor ◽  
Wind Speeds ◽  
Blade Shape ◽  
Low Wind Speeds ◽  
Wind Turbine Rotor

Bentuk sudu taper linier merupakan bentuk sudu yang paling optimal untuk kecepatan angin yang rendah. Jumlah sudu yang baik untuk kecepatan angin rendah berkisar antara 3-7 buah sudu, namun desain sudu dengan menggunakan airfoil dan profil pada sudut pasang sudu yang bagaimana memberikan daya keluaran dan tegangan keluaran yang optimal. Turbin angin didesain dengan 2 bilah dan 4 bilah dengan sudut pasang yang bisa diatur untuk mendapatkan perbedaan daya optimal masing-masing desain. Pengujian dilakukan di 3 area berbeda untuk mendapatkan gambaran geografis kondisi angin yang berbeda khususnya masalah kecepatan angin di ksiaran 2 m/s - 7 m/s. Pengujian dilakukan dengan luas penampang turbin angin (A) sebesar 3m2 Hasil penelitian menunjukkan bahwa nilai terbaik diperoleh pada kecepatan angin maksimal 4 m/s dan jumlah blade 4  sedangkan untuk nilai terkecil diperoleh pada kecepatan angin 3 m/s dan jumlah blade 2 yaitu. Untuk nilai TSR maksimal pada kecepatan maksimal 4 m/s terjadi pada jumlah blade 4, sedangkan untuk nilai terendah pada kecepatan angin 3 m/s dihasilkan pada jumlah blade 2. Melalui pengukuran berbasis teknologi smart monitoring system, dari penelitian diperoleh semakin tinggi kecepatan angin maka tegangan keluaran semakin tinggi. Semakin tinggi tegangan keluaran, semakin tinggi daya keluaran pada generator. Sudut pasang ? dan jumlah sudu mempengaruhi kecepatan putaran rotor turbin angin. Kecepatan putaran rotor turbin angin berelasi dengan tegangan keluaran generator. pada sudut pasang ? dan jumlah sudu 4, diperoleh daya keluaran yang sebesar 150 watt namun pada kecepatan angin 7 m/s daya turbin yang dihasilkan mencapai 600 watt. Dengan kondisi ini cukup memenuhi untuk alternatif cadangan listrik skala rumah tangga khusunya di pedesaan dan daerah terpencil (rural area). The linear taper blade shape is the most optimal blade shape for low wind speeds. The number of blades that are good for low wind speeds ranges from 3-7 blades, but the blade design uses an airfoil and profile on the blade mounting angle which is how to provide optimal output power and output voltage. Wind turbines are designed with 2 blades and 4 blades with adjustable tide angles to get the difference in the optimal power of each design. Tests were carried out in 3 different areas to obtain a geographical description of different wind conditions, especially the problem of wind speed in the range of 2 m / s - 7 m / s. Tests carried out with a cross section area of  wind turbines (A) of 3m2 The results showed that the best value was obtained at a maximum wind speed of 4 m / s and number 4 blade while the smallest value was obtained at wind speeds of 3 m / s and number 2 blades namely. For the maximum TSR value at a maximum speed of 4 m / s occurs in the number of 4 blades, while for the lowest value at 3 m / s wind speed is produced on the number of blades 2. From the research, the higher the wind speed, the higher the output voltage. The higher the output voltage, the higher the output power at the generator. The ? tide angle and number of blades affect the speed of the wind turbine rotor rotation. The rotational speed of the wind turbine rotor is related to the generator output voltage. at the tide angle ? and number of blades 4, the output power of 150 watts is obtained but with wind speed 7 m/s turbine power 600 watt achieved. With this condition, it is sufficient for alternative household electricity reserves, especially in rural and remote areas (rural areas).

scholarly journals Analysis of the Wind Turbine Selection for the Given Wind Conditions

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7740
Author(s):  
Waldemar Kuczyński ◽  
Katarzyna Wolniewicz ◽  
Henryk Charun
Keyword(s):  
Wind Speed ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Medium Size ◽  
Wind Speeds ◽  
The North ◽  
Wind Measurements ◽  
Hourly Distribution ◽  
The Given

The aim of the current paper is to present an approach to a wind turbine selection based on an annual wind measurements. The proposed approach led to a choice of an optimal device for the given wind conditions. The research was conducted for two potential wind farm locations, situated on the north of Poland. The wind measurements pointed out a suitability of the considered localizations for a wind farm development. Six types of wind turbines were investigated in each localization. The power of the wind turbines were in the range of 2.0 to 2.5 MW and with a medium size of the rotor being in the range of 82 to 100 m. The purpose of the research was to indicate a wind turbine with the lowest sensitivity to the variation of wind speed and simultaneously being most effective energetically. The Weibull density distribution was used in the analyses for three values of a shape coefficients k. The energy efficiency of the considered turbines were also assessed. In terms of the hourly distribution of the particular wind speeds, the most effective wind turbines were those with a nominal power of 2 MW, whereas the least effective were those with the nominal power of 2.3–2.5 MW. The novelty of the proposed approach is to analyze the productivity for many types of wind turbines in order to select the one which is the most effective energy producer. The analyses conducted in the paper allowed to indicate a wind turbine which generates the highest amount of energy independently on the wind speed variation.

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