Energy Output Of Wind Turbine Research Articles

Modeling ship-wind turbine dynamics for optimal energy generation and navigation

This paper deals with modeling the dynamics of the ship-wind turbine system in order to optimize power generation and ensure safe navigation. The focus is on developing mathematical models describing the interaction of wind forces, turbine performance and ship dynamics. Numerical simulations are used to investigate the effects of varying wind conditions, turbine design and navigation parameters on energy efficiency. Control strategies are also developed to maximize the energy output of wind turbines while maintaining stability and safety of ship navigation. Model validation is performed through comparative analysis with experimental data or cases from existing wind-assisted ship propulsion systems. The aim of the study is to provide valuable practical recommendations for the implementation of wind energy technologies in maritime operations, contributing to sustainable development and environmental standards in shipping.

Nacelle and tower effect on a stand-alone wind turbine energy output—A discussion on field measurements of a small wind turbine

Nowadays, small wind turbines (i.e., those less than 100 kW) have unique advantages in remote and underdeveloped areas with low and distributed electricity demand. With this consideration, expert committees are established for small wind turbine under various international scientific communities such as International Electrotechnical Committee and International Energy Agency. The major research question is the wake effect from the nacelle and tower, which significantly affect the turbine performance because it is relatively large compared with megawatt turbine. To answer this question, a four-month field test campaign was conducted by using anemometers to measure the incoming and wake flow of a 33 kW horizontal axis wind turbine in a remote area in Gansu, China. The results show that nacelle and tower significantly affect the turbulent kinetic energy, flow angles and velocity deficit. Particularly, the distributing range of flow angles of wake is increased significantly and the horizontal flow angle has an asymmetric bimodal probability distribution. Furthermore, the spectral analysis reveals a strong interaction between the tower and nacelle as well as blade-generated structures. This interaction leads to distortion at low-frequency of the power spectrum, and then a frequency band with relatively stable energy is generated. Overall, this study is expected to provide guidance for small wind turbine development in rural area.

Adaptive bidirectional dynamic response control of offshore wind turbines with time‐varying structural properties

Wind, wave and seismic loading induced excessive vibration of offshore wind turbines (OWTs) impairs the wind turbine energy output and escalates its fatigue damage. The present study proposes a three-dimensional adaptive pendulum tuned mass damper (3D-APTMD) to control the bidirectional dynamic responses of monopile OWTs exposed to combined wind, wave, seismic loading, and time-varying structural properties. In terms of the proposed adaptive tuning algorithm, the natural frequency and damping property of the 3D-APTMD are tuned in real time to match the wind turbine time-varying dominant frequency caused by environmental and/or structural property variations. Performance of the developed adaptive damper is examined on a monopile 5-MW (megawatt) baseline wind turbine subjected to representative wind, wave, and seismic loading. Time-varying stiffness of the tower and foundation is introduced to simulate damage evolution during service life. A three-dimensional pendulum tuned mass damper (3D-PTMD) and dual linear TMDs (2TMD) are used for comparison. Research results show that when damage occurs, 3D-PTMD and 2TMD become partially off-tuned and less effective. In comparison, the 3D-APTMD which is tuned in real time maintains its effectiveness. It can improve the reduction effect by around 25% and 30% when compared with the 3D-PTMD and 2TMD, respectively. Therefore, the proposed 3D-APTMD is promising for real application to protect OWTs, high-rise buildings, chimneys, and other types of slender structures suffering from excessive bidirectional vibration, and environmental, operational, and/or structural property variations.

High-resolution numerical simulation of the performance of vertical axis wind turbines in urban area: Part I, wind turbines on the side of single building

In urban areas, vertical axis wind turbines have been installed on both sides of the road and rooftop. Compared with rooftop, vertical axis wind turbines mounted on the side of a building have a larger swept area with longer blades, and the effect of tip vortices can be reduced at the same time. Around the building, there are several high wind speed regions that can provide more wind energy. In this paper, a high-resolution numerical method composed of overset grid and adaptive mesh refinement techniques is adopted to verify the feasibility of vertical axis wind turbines mounted on the side of the building. Firstly, the complex flow field around the building is simplified into the flow field around the cylindrical building. Five typical flow regions with different flow conditions are determined: windward zone, crosswind zone, tailwind zone, recirculation zone and leeward zone. Secondly, wind turbines are installed evenly around the building. The simulation results show that the energy output of wind turbines in tailwind zone can be increased by 120% compared with the reference value. Thirdly, multiple wind turbines are coupled with the building. In order to get the optimal arrangement, power outputs of four arrangements are compared for the best choice. The results indicate that the arrangement with six wind turbines in crosswind zone and tailwind zone can achieve the best performance. Through changing the rotational directions, the forward blades of wind turbines can be close to the wall, and the energy output of all the wind turbines around the building can be improved.

Alternative Moment Method for wind energy potential and turbine energy output estimation

Abstract An accurate analysis of wind characteristics is a critical factor for wind farm energy output estimation. Therefore, it is necessary to develop an effective and efficient method to asses wind energy resource. The main objective of the present paper is to introduce a novel method to estimate Weibull distribution parameters. This method is called Alternative Moment Method (AMM). AMM method is expressed in an analytical form and doesn’t need iterative procedure. The efficiency and accuracy of the introduced method is compared with commonly used parameter estimation methods. Result of the graphical comparison showed that AMM method is better than Justus Moment Method (JMM) and Novel Energy Pattern Factor Method (NEPFM). While mean error of AMM was 3.53 × 10−7%, JMM and NEPFM was 0.63% and 0.0031% respectively. AMM method is validated by comparing wind turbine energy output estimation accuracy for 144 cases. AMM mean energy output estimation error for 750 kW and 1600 kW wind turbine was 0.039% and 0.043%, respectively. Moreover, data from 16 weather station distributed around Spain is used to evaluate the power density estimation capability of developed method. Result showed that mean absolute error of AMM and MLH was 3.47% and 10.59%, respectively.

Impact of Atmospheric Parameters on Power Generation of Wind Turbine

Economic growth of any country depends on access to reliable energy. Wind energy is fast gaining importance among non-conventional sources, which is a function of parameters like topography of the terrain, weather conditions etc. The present work explores the potential of a 225 MW turbine located in a mountainous site in Maharashtra, India. Values of wind velocity, air temperature, density and power generation were recorded for one complete year. Analysis was done using power curves. The results show that the energy output of wind turbine is based on power curves of a specific site. The conceptual features such as energy per rated power, efficiency of wind turbine and average energy per hour are calculated. It is useful for the investor to access the wind turbine pay-back period and adopt of new optimizing technique.

J0530301 ビル風利用風力発電モデルの発電特性と実装可能性評価

The aim of this study is to design and propose the size and layout of buildings which provide the better wind speed distribution for the higher power generation of wind turbine. A building model whose layout is like nozzle is proposed to obtain the acceleration of wind blowing through buildings due to contracted flow between buildings. In addition, the effect of the angle between two buildings on the power generation performance of the proposed building model is also investigated. For the feasibility check of installing the building model in some cities actually, the power energy output of wind turbine is investigated by considering the meteorological data such as wind speed and direction distribution for Fukushima city and Tsu city as an example. As a result, the proposed building models which have the angle between two buildings like nozzle of 90, 135 and 180 degree can provide the wind acceleration at the back of buildings for the wind blowing from the main wind direction and the angle of 135 degree is found to be the optimum building layout. In the case of installing the proposed building model in Fukushima city and Tsu city, the wind power energy output in winter is higher while that in summer is lower irrespective of the buildings angle. The interaction between the change in frequency distribution of wind speed direction through the year and the location of open tip of building model decides the power generation characteristics of the proposed building model.

Use of Bayesian networks classifiers for long-term mean wind turbine energy output estimation at a potential wind energy conversion site

Due to the interannual variability of wind speed a feasibility analysis for the installation of a Wind Energy Conversion System at a particular site requires estimation of the long-term mean wind turbine energy output. A method is proposed in this paper which, based on probabilistic Bayesian networks (BNs), enables estimation of the long-term mean wind speed histogram for a site where few measurements of the wind resource are available. For this purpose, the proposed method allows the use of multiple reference stations with a long history of wind speed and wind direction measurements. That is to say, the model that is proposed in this paper is able to involve and make use of regional information about the wind resource. With the estimated long-term wind speed histogram and the power curve of a wind turbine it is possible to use the method of bins to determine the long-term mean energy output for that wind turbine. The intelligent system employed, the knowledgebase of which is a joint probability function of all the model variables, uses efficient calculation techniques for conditional probabilities to perform the reasoning. This enables automatic model learning and inference to be performed efficiently based on the available evidence. The proposed model is applied in this paper to wind speeds and wind directions recorded at four weather stations located in the Canary Islands (Spain). Ten years of mean hourly wind speed and direction data are available for these stations. One of the conclusions reached is that the BN with three reference stations gave fewer errors between the real and estimated long-term mean wind turbine energy output than when using two measure–correlate–predict algorithms which were evaluated and which use a linear regression between the candidate station and one reference station.

A continuous bivariate model for wind power density and wind turbine energy output estimations

The wind power probability density function is useful in both the design process of a wind turbine and in the evaluation process of the wind resource available at a potential site. The continuous probability models used in the scientific literature to estimate the wind power density distribution function and wind turbine energy output assume that air density is independent of the wind speed. A constant annual value for air density of 1.225 kg m −3 , corresponding to standard conditions (sea level, 15 °C), is generally used. A bivariate probability model (BPM) is presented in this paper for wind power density and wind turbine energy output estimations. This model takes into account the time variability of air density and wind speed, as well as the correlation existing between both variables. Contingency type bivariate distributions with specified marginal distributions have been used for this purpose. The proposed model is applied in this paper to meteorological data (temperature, pressure, relative humidity, wind speed) recorded over a one year period at a weather station located at the facilities of the Technological Institute of the Canary Islands (Spain). The conclusion reached is that the BPM presented in this paper is more realistic than the univariate probability models (UPMs) normally used in the scientific literature. In the particular case under study, and for all the situations analysed, the BPM has provided values for the annual mean wind power density and annual energy output of a wind turbine that fit the sample data better than the UPMs. However, as a result of the climatological characteristics of the area where the analysis was performed, the results do not differ notably from those obtained through the use of a UPM and the mean air density of the area.

Optimization of a wind-power fuel-cell hybrid system in an autonomous electrical network environment

Stability considerations associated with intermittency prevent high wind energy penetration in small electrical networks. The case of the islands of the Aegean is presented. [Ntziachristos L, Kouridis C, Samaras Z, Pattas K. A wind-power fuel-cell hybrid system study on the non-interconnected Aegean islands grid. Renewable Energy 2005;30(10):1471–1487] proposed a wind turbine(WT)–fuel-cell hybrid as a means to store wind energy and increase penetration in these islands. The effect of network restraints was, however, not included in that study. Simulation results including network restrictions prove that when network restrictions are relatively “strict”, hybridizing a WT using the scheme presented in the same paper will indeed increase the WT's energy output. However, in the case of “lenient” network restrictions, that hybridization scheme will in fact decrease the WT's energy output. Moreover, the system configurations presented that paper could not achieve financial viability at current electricity prices due to high capital costs. Two alternative operating principles for the hybrid system are presented in this study. These operating principles significantly improve the hybrid system's energy performance even under “lenient” network restrictions. In some cases, these operating principles manage to yield hybrid systems that are financially viable assuming current electricity prices.

The wind shear exponent in a Mediterranean island climate

The difficulties in estimating the long term mean wind speed and subsequently wind turbine energy output derive from the fact that more often than not, available data is taken at a level other than machine hub height. The 1/7th power law has been recognised as a handy tool to carry out vertical wind speed extrapolation to the desired hub height. It is also understood that using an exponent of 1/7th could lead to underestimation of the actual long-term mean wind speed aloft. This paper strives to evaluate the power law with respect to wind data taken on a 25 m mast on the central Mediterranean island of Malta. Whilst deriving a site-specific factor affiliated to a typical terrain type, it also strives to determine characteristic variations of the power law exponent over appropriate sampling intervals.

Continuous Variable Speed Wind Turbine: Transmission Concept and Robust Control

This paper presents the theory and design of a novel hybrid mechanical-electrical variable speed wind turbine transmission, and discusses a robust control solution for optimal power output of the wind turbine equipped with such a transmission. The novel, planetary differential transmission would be driven by the variable speed rotor and controlled by a control system to ensure a constant speed of the main generator at a wide range of wind speed variations. Analysis shows that this would lead to an increase in the wind turbine energy output, estimated to be in the range of 15% to 20%, compared to a wind turbine with the same rotor and a fixed transmission. Using robust control design techniques, a single controller is synthesized for efficient operation over the entire anticipated wind speed range. The control system automatically varies the rotor speed to optimize its power output for slow wind speed variation and attenuates high frequency wind gust effects to reduce the resulting fatigue damage. Overall, the new concept provides a cost effective solution for variable speed wind turbine operation. The improved system performance is demonstrated using the results of a numerically simulated dynamic model of the proposed system.

Comparison of generating and transmission systems for an offshore array of vertical-axis wind turbines

Alternative electrical generation and transmission systems for an offshore wind-turbine array are studied and compared. A parametric analysis is carried out to assess the annual wind-turbine energy output as a function of the type of electrical generating system. The operational advantages of various generating systems are identified, complementing the economic studies in dealing with the choice of a generating system for an offshore site. Different transmission alternatives for the integration of generating systems in a cluster are compared. Also, various transmission options (AC and DC) are considered for carrying the generated power to the shore. Different transmission schemes, together with various generating systems studied, produce a number of feasible schemes which are compared economically and operationally.