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HOMER Pro 3.9

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Wind Resource

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To access the Wind Resource page, select the Resources tab and click the Wind icon.

You can use the Wind Resource page to describe the available wind resource. HOMER uses this data to calculate the output of the wind turbine in each time step. This page provides access to the following tabs:

Parameters: Variables related to altitude

Variation with Height: Parameters describing wind shear and the wind velocity's vertical profile

Advanced Parameters: Parameters controlling variation of the wind over time

You can download monthly average wind resource data from the HOMER Energy website, or see the Finding data to run HOMER section of the help.

Baseline Data

The baseline data is a one-year time series representing the average wind speed, expressed in meters per second, for each time step of the year. HOMER displays the monthly averages calculated from the baseline data in the wind resource table and graph.

You can create baseline data by downloading data from the HOMER Energy website, entering monthly average manually and using HOMER to synthesize time series data, or by importing time series data from a file.

To synthesize data, you must enter or download twelve average wind speed values: one for each month of the year. To download the monthly averages for synthesized wind data, be sure to first select your location on the Home Page. Then click "Download from Internet..." to download the averages from the HOMER website. Wind resource data comes with the anemometer height at which the wind speed was measured. Downloading a wind resource automatically sets this input to the correct value. Some regions have wind resource data available that includes values for the four advanced parameters. If that is the case, these four parameters are also set when you download the wind resource. You can also edit the four advanced parameters manually.

To input data manually, enter each month's average wind speed (m/s) in the table. As you enter values in the table, HOMER synthesizes time series data with the statistical characteristics you have specified. For more information, see the synthetic wind data section of the help.

Scaled Data for Simulation

HOMER uses scaled data for calculations. To create scaled data, HOMER multiplies each of the baseline data values by a common factor that results in an annual average value equal to the value that you specify in Scaled Annual Average.


To determine the value of this factor, HOMER divides the Scaled Annual Average by the baseline annual average. The scaled data retains the shape and statistical characteristics of the baseline data, but may differ in magnitude. The default value for the Scaled Annual Average is the baseline annual average. When the two values are equal, the scaled data and baseline are identical. HOMER interprets a scaled annual average of zero to mean that there is no wind resource.

Two reasons to use a scaled annual average that is different from the baseline annual average are for unit conversion and sensitivity analysis.

An example of using the Scaled Annual Average for unit conversion is to convert data from an imported file that contains wind speed expressed in kilometers per hour. If the baseline annual average is 20 km/hr, if you enter 5.56 in Scaled Annual Average, the scaled data is equivalent to the baseline data, but expressed in m/s rather than km/hr: 1 m/s = 3.6 km/hr; 5.56 m/s = 20 km/hr.

Note: To the right of the Scaled Annual Averages input is a sensitivity button (shots_sensitivity-button) that allows you to do a sensitivity analysis on that variable. For more information, see Why Would I Do a Sensitivity Analysis?

Importing Wind Speed Data

To import a file, you must prepare a text file that contains the wind speed in each time step for a complete year.

Tip: You can import data with any time step down to one minute. HOMER detects the time step when you import the data file. For example, if the data file contains 8760 lines, HOMER assumes it contains hourly data. If the data file contains 52,560 lines, HOMER assumes it contains 10-minute data.

The data file must contain a single value on each line, where each line corresponds to one time step. Each value in the file represents the average wind speed (in m/s) for that time step. The first time step starts at midnight on January 1st. The following is a sample input file.


When you import data from a text file, HOMER makes a copy of the data set and integrates it with the HOMER (.homer) file. After the data is part of the HOMER file, HOMER no longer refers to the original text file. If you modify data in the original file, you must import the modified file in order for the modification to be included in the HOMER file. After you import a data file, HOMER calculates twelve monthly average wind speed values and displays them in the table and graph. HOMER also displays the name of the imported data file in the title of the graph. HOMER calculates the four advanced parameters from the imported data and displays them (read-only) in the text boxes.

If you click the Enter monthly averages radio button after importing data from a file, HOMER discards the data from the imported file and synthesizes new data based on the twelve monthly average wind speed values and four advanced parameters it calculated from the imported data. You can edit synthesized data by changing values in the monthly wind speed table. To edit values from an imported file, you must edit the file directly and then import the modified file, as described above.

See also

How HOMER Calculates Wind Turbine Power Output

Generating Synthetic Wind Data

Finding Data to Run HOMER

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