SWRF wind resource file creation

How do I create a custom SWRF file from Met tower wind speed and measurement data.
I have custom wind speed and measurement data from a western site where it was measured from a cell tower at 35m and 50m heights. How can I edit or create a custom file.

Also can this file be used for the P50/P90 analysis?

SAM's utility scale wind model is designed to use wind resource data from NREL's Western Wind Dataset (see www.nrel.gov/wind/integrationdatasets/western/methodology.html ). When you use SAM to download data from the database, SAM stores the data in a .swrf file.

A .swrf file stores one year's worth of hourly wind speed, direction, and temperature resource data at four heights above the ground: 10, 20, 50, and 100 meters. It also stores hourly atmospheric pressure data, and information in the header describing the geographic coordinates and elevation above the ground.

The first row in the file is for the hour ending at 1 am on January 1. The 8,760 hours represented by the data do not account for leap years.

These files are not designed to store measured data. However, with some effort, you can create your own .swrf file by modifying an existing file, for example, the "elko nv_2005.swrf" file in the default climate folder, "c:\SAM\2011.12.2\exelib\climate_files\" by default.

SAM uses the power law to extrapolate wind speed data from the measured height to the hub height, so it is important that the wind speed data at each height in the weather file represents your measured data. In your case, you could use your 50 m data in the 50 m column of the .swrf file. Because the .swrf file does not store 35 m data, you would need to use the power law to adjust your 35 m data to 20 m. You would also need to use the power law calculate values for the 10 m and 100 m columns.

If you do not expect to use the resource data to model turbine hub heights above 50 m or below 20 m, you could ignore the data in the 100 m and 10 m columns.

If you do not have temperature data, you can ignore those columns or use monthly average values. The impact of temperature on turbine output is relatively small.

The P50/P90 analysis option in SAM is not currently set up to work with the wind resource database.

Best regards,
Paul.

Dear,

I tried to open one of the exsting wind data (.swrf format like elko nv_2005.swrf)to adapt it our proper wind data but the format is not appropriate: There is no column wher I have just to put my data (like under Excel)in place of the existing one. The files that I have (own wind datat) are under .txt, .dat or . txt that I can also convert to excel format but not to .swrf format.

Could you please provide an advice about how to solve this issue?

Regards
Chakir

The .swrf file format is a text format with tab delimited columns of wind resource data, and a few rows of header data at the top of the file. You can open the file with either a text editor, or with a spreadsheet program (import it as a tab-delimited file).

Best regards,
Paul.

Just to be sure:
Are those meters you have been speaking about, the height over the terrain or the altitude over the sea level?

Best regards,
Juan Peña

Dear Juan,

The elevation above sea level is in Line 7 of the header "Elevation" and is in meters.

The height above the ground, also in meters, is indicated in the column heading for the wind speed, wind direction, and temperature data elements. For example the column heading "Speed 200m (m/s)" for the wind speed data at 200 meters above the ground.

Best regards,
Paul.