COLORADO ANEMOMETER LOAN PROGRAM
 

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AURORA - 04/09/2003 through 06/28/2004

LOCATION DETAILS
Latitude:
N 39.57198°
Longitude:
W 104.3059°
Township:
5 S
Range:
62 W
Section:
35
Elevation (ft.):
5,715
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 ft)
Vane Offset (deg):
+20°
Direction Basis:
Unknown
Site Number:
0666
Wind Explorer S/N:
0666

DATA DETAILS

April 9, 2003 through June 28, 2004:

The anemometer tower was installed on April 9, 2003. The site was approximately 10.4 miles southwest of the town of Byers and I-70. The tower is located in a cultivated field next to bluffs along the West Bijou Creek. Tall vegetation and/or buildings are not present in the area. Hence, the site has good exposure to the wind in all directions. The bluffs could create significant amounts of turbulence in the wind, which could affect measurements of easterly or southerly winds at the site.

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

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 an offset of +20° to the wind vane data. This corrected data and wind resource summary report are available here:

The file includes suspect data and when that data occurs, there is also a flag field that indicates these suspect data values. For a version of this wind data with blanks, you can download here.

CSU was chosen as the contractor for the program on September 14, 2007. Using the raw data from all data plugs for this site, an analysis of the wind resource was developed using Windographer 1.21. No data quality 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:

Wind Resource Summary

Highlights of the wind resource at this site for the entire data collection period are shown below:

Data Properties
Variable
Data Set Starts:
4/9/2003 0:00
Height above ground (m)
20
Data Set Ends:
6/29/2004 0:00
Mean wind speed (mph)
12.58
Data Set Duration:
15 months
Median wind speed (mph)
11.63
Length of Time Step:
10 minutes
Min wind speed (mph)
0
Elevation (ft.):
5,715
Max wind speed (mph)
59.38
Calm threshold (mph):
0
Mean power density (W/m²)
186
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
1,629
Power Density at 50m:
263 W/m²
Energy pattern factor
2.026
Wind Power Class:
2 (Marginal)
Weibull k
1.956
Wind Shear Coefficients
Weibull c (mph)
14.19
Power Law Exponent:
0.14
1-hr autocorrelation coefficient
0.773
Surface Roughness:
0.01 m
Diurnal pattern strength
0.045
Roughness Class:
0.780
Hour of peak wind speed
21
Roughness Description:
Rough Pasture
Mean turbulence intensity
0.182
Note: The wind power density and wind power class at 50m are projections of the data from 20m. A surface roughness of 0.01 meters was assumed for this projection. This is equal to that of a rough pasture. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
6.73
Coefficient of variation (%)
53.5
Frequency of calms (%)
0.039
Possible records
64,368
Valid records
63,730
Suspect records
638
Data completeness (%)
99.0

 

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
12.58
21.12
2.86
1.40
12,200
18.6
Bergey Excel-S
6.7
10
20
12.58
9.35
1.66
1.52
13,200
15.2
Bergey XL.1
2.5
1
20
12.58
2.87
4.21
0.21
1,900
21.2
Southwest Skystream 3.7
3.7
1.8
20
12.58
17.97
0
0.40
3,500
21.9
Southwest Whisper 500
4.5
3
20
12.58
21.0
3.54
0.70
6,100
23.2
Northern Power NW 100/20
20
100
25
12.97
30.4
0
13.2
115,900
13.2
Vestas V47 - 660 kW
47
660
65
14.83
14.61
0.77
141
1,233,000
21.3
GE 1.5s
70.5
1,500
80.5
15.28
19.22
4.27
288
2,521,800
19.2
Vestas V80 - 2.0 MW
80
2,000
100
15.75
18.09
2.50
476
4,169,900
23.8
GE 2.5xl
100
2,500
110
15.96
13.33
5.11
671
5,880,200
26.9

 

 

 


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