PROGRAM INFORMATION

KERSEY (70 Ranch) - 8/10/2010 to 8/10/2011

CSU ALP Install Team (from left): Daniel Fink, John Purcell, Mark Goudreault, Jake Renquist, Eric Rasbach, and Mike Kostrzewa (taking picture).

DATA DETAILS

August 10, 2010 to August 10, 2011:

The anemometer tower was installed on August 10, 2010 and removed exactly one year later on August 10, 2011. The site was located in a field about 4.8 miles north of U.S. Highway 34 and 8.6 miles due east of Kersey on the 70 Ranch. The terrain was generally flat or slightly rolling in all directions, but the exact site was on a slight rise above all of the terrain within about 1,000 feet of the site. A power transmission line lies about 1/4 mile east of the site.

Data was collected using three (3) NRG #40C Calibrated Anemometers and one (1) NRG #200P Wind Vane, as follows:

• Anemometers
  1. 33.8 m (111 feet) on an NRG 60" standard boom
  2. 33.8 m (111 feet) on an NRG 60" standard boom
  3. 20.0 m (65.6 feet) on an NRG 60" standard boom
• Wind Vane
  1. 34.7 m (114 feet) heading 166° on an NRG 13" Z-mast with the null point facing toward the tower

There was also a temperature sensor at a height of 1.8 m (6 feet) on a 6" boom.

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 the wind direction data included in these files has already been adjusted for offset at the data logger.

Using this data, an analysis of the wind resource report was developed using Windographer 1.49. For this report, a validation analysis was performed on the data. This data was filtered two ways:

1. Any wind speed data where the wind speed was less than 1 m/s for 3 hours or more when the temperature was less than 2°C was deleted.
2. Any wind direction data where the wind direction varied by less than 3 degrees over 3 hours when the temperature was less than 2°C was deleted.

Windographer was then used to add in synthetic data to these intervals with suspect data. During the period considered, there were no intervals of suspect data, so no synthetic data were added.

The final 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:

• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_Summary_Report.pdf
• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_without_data_validation.windog
• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_without_data_validation.txt
• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_with_data_validation.windog
• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_with_data_validation.txt

However, when the tower was removed, the crew noticed that one of the three cups on the 20m anemometer was damaged. The cup could have been damaged by the guy wires as the tower was lowered because the anemometer was directly in alignment with the lifting guys. But the cup could have also been damaged before lowering the tower - it's a little hard to notice this type of damage from 20 m below.

So we looked at the data so see if there was any indication of prior damage. The 20 m anemometer throughout the entire data collection period has recorded significantly reduced wind speed than the 34 m anemometers, but starting on June 11, 2011 at 18:00, the sensor looked to have longer periods of low or no wind speed. This affected the power law exponent because it is a curve-fit with the 20m and 34m wind speed data. The graph below shows how the power law exponent varied over the entire data collection period:

The change in the power law exponent occurs in early June, perhaps as early as June 8 but certainly by June 11. For this reason, we prepared another wind resource assessment after removing the 20m wind speed data from 18:00 on June 11 through the remaining two months of the data collection period. The revised final summary report, the combined data file (with the data quality analysis), and the Windographer file (with the data quality analysis) with the bad data removed are given below:

• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_Summary_Report_WO_bad_data.pdf
• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_with_data_validation_bad WS20 data removed.windog
• Kersey_70_Ranch_0404_2010_0810_to_2011_0810_with_data_validation_bad WS20 data removed.txt

The tables and graphs below show the results both with and without this data removed.

But even with this consideration, the final result is that the wind at this site is a Class 1 wind at 34m and would likely still be a Class 1 wind at 50m.

Final Wind Resource Summary

The anemometer tower was removed from the site on August 10, 2011. 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.

WITHOUT BAD DATA

WITH BAD DATA INCLUDED

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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