PROGRAM INFORMATION

Sheep Mountain (Usry Ranch)

9/9/2008 through 5/21/2010

DATA DETAILS

September 9, 2008 through May 21, 2010:

This tower is the sole 50m anemometer tower owned by the Governor's Energy Office. It is intended for community wind projects. The anemometer tower was installed on September 9, 2008 and removed on May 21, 2010.

Data was collected using four (4) NRG #40 Anemometers and two (2) NRG #200P Wind Vanes, as follows:

• Anemometers
  1. 30 meters heading 225° on an NRG 43" offset standard boom
  2. 40 meters heading 225° on an NRG 43" offset standard boom
  3. 49.53 meters heading 225° on an NRG 43" offset standard boom
  4. 49.53 meters heading 135° on an NRG 43" offset standard boom
• Wind Vanes
  1. 38 meters heading 0° on an NRG 43" offset standard boom with the null point facing away from the tower
  2. 48.53 meters heading 0° on an NRG 43" offset standard boom with the null point facing away from the tower

There was also a temperature sensor at a height of 2.5 meters on a 6" boom, a voltmeter in the data logger box, and relative humidity at a height of 2 meters under the data logger box.

All sensors fed into an NRG Symphonie data logger. The certifications for the anemometers are as follows:

The data logger generated wind reports for each day. Using the Symphonie Data Retriever software, each day's data was complied into one large data file. A zipped file that contains all of the NRG data files and a text version of the aggregate data for all days are given below .

It is important to note that these are the raw files without any compensation for offset.

From this data, an analysis of the wind resource report was developed for entire data collection period using Windographer 1.45. No offset was applied to the wind vane data as none was needed. Since the data set contains data for two or more wind speed sensors at different heights above the ground, Windographer considered the wind shear relationship between different wind speed sensors to synthesize missing data for those wind speed sensors. A best fit using the power law profile was chosen to synthesize the data. Once the wind shear relation was chosen, a daily influence on the wind shear profile was considered so that in each time step where the wind speed is known at one height but not at a different height, Windographer estimated the unknown wind speed based on the best-fit wind shear profile for the appropriate hour of the day.

Using this data, an analysis of the wind resource report was developed using Windographer 1.45. For this report, a data quality analysis was performed on the data. This data was filtered two ways:

1. Any wind speed data (from any anemometer) where the wind speed was less than 1 m/s at a temperature less than 2°C for 4 hours or more was deleted.
2. Any wind direction data (from any wind vane) where the wind direction varied by less than 2 degrees at a temperature less than 2°C for 4 hours or more was deleted.

Windographer was then used to add in synthetic data to these intervals with suspect data. The summary report, the combined data files (with and without the data quality analysis), and the Windographer files (with and without the data quality analysis) are given below:

• Sheep_Mountain_Usry_Ranch_5440_2008_0910_2010_0521_Summary_Report.pdf
• Sheep_Mountain_Usry_Ranch_5440_2008_0910_2010_0521_without_data_validation.windog
• Sheep_Mountain_Usry_Ranch_5440_2008_0910_2010_0521_without_data_validation.txt
• Sheep_Mountain_Usry_Ranch_5440_2008_0910_2010_0521_with_data_validation.windog
• Sheep_Mountain_Usry_Ranch_5440_2008_0910_2010_0521_with_data_validation.txt

Final Wind Resource Summary

The anemometer tower was removed from the site on May 21, 2010. Highlights of the wind resource at this site for the entire monitoring period are shown below:

Windographer was used to match up the wind at this site with the performance curves of some common turbines of various sizes and various heights. The table below shows the results. For the larger turbines, the tower height was increased to account for the larger turbine blades - the wind resource was extrapolated to these higher heights. Keep in mind that the larger and the higher the turbine, the better the wind and the greater the output. But of course, as the tower heights and turbine sizes increase so does the cost.

IMPORTANT: No turbine losses are included in the power, energy, and capacity factor values in the table. Typically, turbine losses can be 5-20% to account for maintenance downtime, icing/soiling and losses from other turbines in a wind farm. Users wanting to be conservative in the performance projections should multiply the power, energy, and capacity values by (1- % losses) to account for these losses.

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