Advances in Meteorology

Volume 2018, Article ID 2716868, 10 pages

https://doi.org/10.1155/2018/2716868

## Analysis of Wind Data, Calculation of Energy Yield Potential, and Micrositing Application with WAsP

Department of Computer Engineering, Faculty of Engineering, Karadeniz Technical University, 61080 Trabzon, Turkey

Correspondence should be addressed to Fatih Topaloğlu; moc.liamtoh@320ulgolapot_f

Received 7 February 2018; Revised 5 April 2018; Accepted 24 April 2018; Published 30 May 2018

Academic Editor: Ismail Gultepe

Copyright © 2018 Fatih Topaloğlu and Hüseyin Pehlivan. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

#### Abstract

The parameters required for building a wind power plant have been calculated using the fuzzy logic method by means of Wind Atlas Analysis and Application Program (WAsP) in this study. Overall objectives of the program include analysis of raw data, evaluation of wind and climate, construction of a wind atlas, and estimation of wind power potential. With the analysis performed in the application, the average wind velocity, average power density, energy potential from micrositing, capacity factor, unit cost price, and period of redemption have been calculated, which are needed by the project developer during the decision-making stage and intended to be used as the input unit in the fuzzy logic-based system designed. It is aimed at processing the parameters calculated by the designed fuzzy logic-based decision-making system at the rule base and generating a compatibility factor that will allow for making the final decision in building wind power plants.

#### 1. Introduction

Various methods are being used for the determination of wind power potentials. One of the most important of these is WAsP (Wind Atlas Analysis and Application Program), which is made in the Denmark Riso National Laboratory and used to generate the wind atlas of the European continent (EWA) [1].

WAsP is being used for the determination of regional wind atlas statistics and energy yield potential by using the wind speed and direction information as well as the obstacles around the wind observation station, land surface roughness, and land topographical characteristics.

Fuzzy logic is a multiple-logic system that is developed against the binary-logic system and assigns membership grades to variables used in everyday life and determines the proportions at which events occur. Everything is right or wrong in two-valued logic. In fuzzy logic, everything, including truth, is only a matter of degree.

Wind is formed by heating and cooling different surfaces at different speeds on the earth from the sunrise until sunset. Kinetic energy of the air in motion is called as wind power. Since the humans are being concerned with the environment, the interest in utilisation of renewable power is increasing. Wind power among the renewable energy is being used widely [2]. Due to the fact that Turkey is a country with three sides surrounded by sea, it is in a very important position in terms of wind power potential. The calculated wind power potential of Turkey is around 88000 MW, and a great majority of this potential is located in Aegean, South Mediterranean, and Marmara regions [3].

In this study, analysis of wind measurement data obtained at 10 m height and 10-minute interval has been carried out with WAsP, and the wind speed, average power density, form parameter, scale parameter, dominant wind direction, and the Hellmann coefficient have been calculated in accordance with the Weibull distribution. While planning to install the wind turbines to the plant, the required regional wind atlas has been generated. Meteorological data from weather stations outside urban areas are sometimes used, where wind measurements are not available [4, 5].

In this micrositing study, a wind plant with 12 MW in the region has been planned to be established, and the use of a 2 MW V80-type turbine belonging to the VESTAS company available in the WAsP library has been planned for this establishment. Annual energy generation values of the turbines have been calculated as a result of the micrositing study performed in this way.

The capacity factor, which is the most important parameter during the definition of wind energy potential of one region, is identified as the proportion of energy generated by a wind power plant to the energy that has to be generated at nominal power [6]. With the calculations made, the capacity factor of the region and the annual generation value of the plant in kWh and the amortization period have been found.

#### 2. WAsP Model

WAsP has been used during the analysis of wind data and energy generation potential. WAsP is a computer program developed in the Denmark Riso National Meteorology Laboratory which is performing analysis with the assumption that wind speed data comply with the Weibull distribution with 2 parameters.

##### 2.1. Basic Information Used by WAsP

WAsP carries out some analyses by assessing four various basic data in its submodels. Hourly wind data, roughness data of the region, obstacle data in the near vicinity, and topographical data of the region are the basic information used by the program. For the wind farm location, it is also necessary to enter data such as the power curve, thrust coefficient curve, turbine hub height, and turbine rotor diameter in the program [7].

##### 2.2. General Purposes of WAsP

It is possible to group them under four main titles of general purpose of WAsP so as to analyze the raw data, generate the wind atlas, and assess the wind climate and wind energy potential.

WAsP is performing the time-series analysis by adjusting the raw meteorological data including wind direction and speed data. Weibull parameters are being calculated with the performed analysis [7]. Wind speed histograms may be converted into wind atlas series. Histograms may be generated by the data analysis method or may be directly made with standard climatologic tables [7].

It is possible to carry out wind climate assessment in any region by using the wind atlas generated by WAsP or by using the data series or data from other reliable sources. Wind climate is being assessed with Weibull parameters and regional distribution of the wind [7]. WAsP also calculates the total energy to be obtained from wind. Program may also provide annual average energy to be obtained from a wind turbine and an energy curve of the subject turbine.

#### 3. Submodels Used at the Application

WAsP uses some submodels while determining the wind potential. These submodels are obstacle screening, orographic, and roughness exchange models.

##### 3.1. Roughness Exchange Model

The logarithmic wind profile is only applicable where the surface is homogeneous. Pressure changes as per the average surface tensions and surface conditions of surface wind speed until where the gradient force is equal to the fraction force. For the roughness length values belonging to two different surfaces, the following equation may be written for the increase of the limit layer height values:where is the boundary layer height value, is the surface condition distance, and are the roughness coefficients (constant: 0.9).

The wind profile is deformed below the level , and the constant value is 0.9. If we accept the neutral wind profile at height , the difference in the surface friction speed may be modelled empirically, and this can be shown as follows:where is the friction speed at the considered point and is the surface friction speed.

In this equation, friction speed at the point taken into consideration is the surface friction speed.

##### 3.2. Shelter Model

The wind profile is deformed at close distances and at lower parts of the flow of wind coming from the turbine. For this, these objects creating an obstacle effect should be separately studied. Generally, there should be a distance of two objects’ height on the upper wind part of the obstacle and five objects’ height on the lower wind part of the obstacle. Since the meteorological stations are being impacted by the obstacles in the vicinity, this model corrects the fault caused by the obstacle on the data.

The results of wind tunnel studies on simple two-dimensional objects have the following equation:where is the open area/total area, is the height of the obstacle, is the height of the anemometer, and is the under wind region distance.

In this equation, is expressed as follows:where is the height of the anemometer, is the height of the obstacle, is the under wind region distance, and is the roughness coefficient.

If there are more than one object, they have been assessed with sectors formed with angles of 30°.

##### 3.3. Orographic Model

In this model, on the measured wind, data faults of local impacts caused by the topographical structure are being corrected [8]. For the remedial of these impacts, a horizontal scale of 20–30 km shall be taken into account. Primarily, potential current deformations caused by the land topography shall be calculated. The speed perturbation iswhere is the potential and is the three-dimensional speed deformation vector.

For a given radius , for the potential flow at polar coordinates, the following equation shall be written:where is the random coefficient, , is the level Bessel function, is the radius, is the azimuth, is the height, and s , which is zero.

For the specific problems, coefficients shall be calculated from surface kinematical limit conditions:where , is the level Bessel function; s *i*, which is zero; and is the radius.

Functions are as Fourier–Bessel series. coefficients may be defined independently. The model forms the gray data on the contour lines on the topographical map. Sensitivity of the model depends on the density of contours.

#### 4. Wind Atlas Analysis and Program Application

In order to make the wind power more competitive against other power generation methods, bigger wind turbines are being designed and established on the clusters especially on the overseas regions called as the wind plant [9].

To be able to establish a wind power plant, both meteorological and financial parameters are needed. This also shows that one wind plant establishment actually requires to think and use more than one discipline at the same time. For this reason, during the analysis, WAsP has been used which has been already used for the preparation of the European Wind Atlas and Turkish Wind Atlas.

This study is aimed at finding out the average wind speed, average power density, energy yield potential obtained as a result of micrositing, capacity factor, amortization period, and unit cost price required for the establishment of the wind power plant as a result of the performed analysis. These obtained values are being planned to be used to generate a compliance factor for the establishment of the wind power plant by scaling in the rule basis prepared in the fuzzy logic method. In Figure 1, Matlab/Simulink design of the inspection system is seen, which is planned to be used as an input unit of obtained parameters.