COLORADO ANEMOMETER LOAN PROGRAM
 

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EADS - 8/3/2004 through 11/11/2006

LOCATION DETAILS
Latitude:
N 38° 34.4833’ or N 38° 34′ 29″
Longitude:
W 102° 40.124’ or W 102° 40′ 7″
Township:
17 S
Range:
47 W
Section:
15
Elevation (ft.):
4,154
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 ft)
Vane Offset (deg):
Varies
Direction Basis:
Unknown
Site Number:
0924
Wind Explorer S/N:
0924

DATA DETAILS

August 3, 2004 through November 11, 2006:

The anemometer tower was installed on August 3, 2004. The site was located approximately 8.9 miles northeast of the town of Eads. The tower was situated in the middle of pasture. The terrain is flat with no trees or obstructions to the wind. Hence, the site had good exposure to the wind in all directions.

All data was collected using an NRG #40 Anemometer and NRG #200 Wind Vane mounted on a tilt-up tower located on the landowner's property at a height of 20m. This equipment fed into an NRG Wind Explorer data logger. All data plugs were sent into the Governor's Energy Office and then to the University of North Dakota for analysis. All data plug files and text versions of these files are given below.

Raw Wind Data Files
NRG Data_Plug Files
Txt Files
Eads_0924_2005_0223_0314.A05 Eads_0924_2005_0223_0314.txt
Eads_0924_2005_0314_0412.A05 Eads_0924_2005_0314_0412.txt
Eads_0924_2005_0412_0623.A05 Eads_0924_2005_0412_0623.txt
Eads_0924_2005_0623_0817.A05 Eads_0924_2005_0623_0817.txt
Eads_0924_2005_0817_1015.A05 Eads_0924_2005_0817_1015.txt
Eads_0924_2005_1015_0108.A05 Eads_0924_2005_1015_0108.txt
Eads_0924_2006_0108_0215.A06 Eads_0924_2006_0108_0215.txt
Eads_0924_2006_0215_0411.A06 Eads_0924_2006_0215_0411.txt
Eads_0924_2006_0411_0524.A06 Eads_0924_2006_0411_0524.txt
Eads_0924_2006_0524_0731.A06 Eads_0924_2006_0524_0731.txt
Eads_0924_2006_0731_0922.A06 Eads_0924_2006_0731_0922.txt

Note that not all data plug files were available from UND for this site. It is important to note that these are the raw files without any compensation for offset. It is also important to note that the temperature was not recorded during this period.

For this data, UND applied a variety of offsets to the wind vane data, generally between +0° and +10°. However, they noted that the wind direction data was suspect and could not be validated. Thus, the wind direction shoudl be viewed skeptically. The corrected data and wind resource summary report are available here:

CSU was chosen as the contractor for the program on September 14, 2007. From the UND data, an analysis of the wind resource was developed using Windographer 1.13. For this data, the offset was already applied by UND to the wind vane data. No data validation analysis was performed for this data other than what was available from the flag data fields included in the data. The suspect data was first removed from the collected data. Windographer was then used to add in synthetic data to these intervals with suspect data. The Windographer files (with blanks for the suspect data and with the blanks filled with synthetic data) are given below:

Complete Wind Resource Summary

The anemometer tower was removed from the site on November 13, 2006. Highlights of the wind resource at this site for the entire data collection period using the Windographer for the data adjusted for data quality and offset by UND are shown below:

Data Properties
Variable
Data Set Starts:
8/3/2004 00:10
Height above ground (m)
20
Data Set Ends:
11/13/2006 10:40
Mean wind speed (mph)
13.13
Data Set Duration:
27 months
Median wind speed (mph)
12.32
Length of Time Step:
10 minutes
Min wind speed (mph)
0.00
Elevation (ft.):
4,154
Max wind speed (mph)
54.97
Calm threshold (mph):
0
Mean power density (W/m²)
217
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
1,899
Power Density at 50m:
306 W/m²
Energy pattern factor
1.980
Wind Power Class:
3 (Fair)
Weibull k
1.972
Wind Shear Coefficients
Weibull c (mph)
14.80
Power Law Exponent:
0.126
1-hr autocorrelation coefficient
0.832
Surface Roughness:
0.01 m
Diurnal pattern strength
0.138
Roughness Class:
0.78
Hour of peak wind speed
17
Roughness Description:
Few trees
Mean turbulence intensity
0.162
Note: The wind power density and wind power class at 50m are projections of the data from 20m. A surface roughness of 0.1 meters was assumed for this projection. This is equal to terrain with a few trees. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
6.95
Coefficient of variation (%)
52.9
Frequency of calms (%)
0.40
Possible records
119,871
Valid records
107,755
Missing records
12,116
Data recovery rate (%)
89.9

 

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, allowing for losses of about 13%. 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.

Turbine
Rotor
Diameter
meters
Rotor
Power
kW
Hub
Height
meters
Hub
Height
Wind
Speed
mph
Time
At
Zero
Output
percent
Time
At
Rated
Output
percent
Average
Net
Power
Output
kW
Average
Net
Energy
Output
kWh/yr
Average
Net
Capacity
Factor
%
Bergey Excel-R
6.7
7.5
20
13.13
18.01
4.34
1.6
14,000
21.4
Bergey Excel-S
6.7
10
20
13.13
8.55
2.59
1.75
15,400
17.5
Bergey XL.1
2.5
1
20
13.13
2.96
6.3
0.24
2,100
24.2
Southwest Skystream 3.7
3.7
1.8
20
13.13
16.39
0
0.45
3,900
24.9
Southwest Whisper 500
4.5
3
20
13.13
17.96
5.48
0.79
6,900
26.2
Northern Power NW 100/20
20
100
25
13.54
27.25
0
15.5
135,400
15.5
Vestas V47 - 660 kW
47
660
65
15.48
12.79
1.1
160
1,401,100
24.2
GE 1.5s
70.5
1,500
80.5
15.95
16.93
6.34
329
2,881,200
21.9
Vestas V80 - 2.0 MW
80
2,000
100
16.44
15.65
3.72
535
4,685,200
26.7
GE 2.5xl
100
2,500
110
16.67
11.74
7.49
748
6,555,300
29.9

 


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Last updated: June 2009
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