COLORADO ANEMOMETER LOAN PROGRAM
 

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CARBONDALE - 8/5/2004 through 7/26/2005

LOCATION DETAILS
Latitude:
N 39° 20.1642’ or N 39° 20’ 10”
Longitude:
W 107° 12.7158’ or W 107° 12’ 43”
Township:
8 S
Range:
88 W
Section:
27
Elevation (ft.):
6,407
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 ft)
Vane Offset (deg):
+121°
Direction Basis:
Unknown
Site Number:
0662
Wind Explorer S/N:
0662

DATA DETAILS

August 5, 2004 through July 26, 2005:

The anemometer tower was installed on July 3, 2003. The site was located approximately 4.1 miles south of the town of Carbondale in a north-south mountain valley. The tower was located in the middle of a meadow roughly 300 feet north of a rural residence. Surrounding the meadow were trees that were between 6 and 30 feet tall.

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
Carbondale_2004_0662_0805_0817.A04 Carbondale_2004_0662_0805_0817.txt
Carbondale_2004_0662_0817_0928.A04 Carbondale_2004_0662_0817_0928.txt
Carbondale_2004_0662_1118_1229.A04 Carbondale_2004_0662_1118_1229.txt
Carbondale_2004_0662_1229_0201.A04 Carbondale_2004_0662_1229_0201.txt
Carbondale_2005_0662_0201_0226.A05 Carbondale_2005_0662_0201_0226.txt
Carbondale_2005_0662_0226_0517.A05 Carbondale_2005_0662_0226_0517.txt
Carbondale_2005_0662_0517_0726.A05 Carbondale_2005_0662_0517_0726.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 an offset of +121° to the wind vane data. 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, an offset of +121° was already applied by UND to the wind vane data. 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:

Complete Wind Resource Summary

The anemometer tower was removed from the site on July 26, 2005. Highlights of the wind resource at this site for the entire data collection period using the Windographer are shown below:

Data Properties
Variable
Data Set Starts:
8/5/2004 09:00
Height above ground (m)
20
Data Set Ends:
7/26/2005 07:00
Mean wind speed (mph)
5.20
Data Set Duration:
12 months
Median wind speed (mph)
4.01
Length of Time Step:
10 minutes
Min wind speed (mph)
0.00
Elevation (ft.):
6,407
Max wind speed (mph)
30.64
Calm threshold (mph):
0
Mean power density (W/m²)
28
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
244
Power Density at 50m:
39 W/m²
Energy pattern factor
4.397
Wind Power Class:
1 (Poor)
Weibull k
1.099
Wind Shear Coefficients
Weibull c (mph)
5.43
Power Law Exponent:
0.126
1-hr autocorrelation coefficient
0.702
Surface Roughness:
0.01 m
Diurnal pattern strength
0.471
Roughness Class:
0.78
Hour of peak wind speed
15
Roughness Description:
Rough pasture
Mean turbulence intensity
0.400
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 terrain of rough pasture. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
4.68
Coefficient of variation (%)
90.1
Frequency of calms (%)
10.92
Possible records
51,108
Valid records
50,058
Missing records
1,050
Data recovery rate (%)
97.9

 

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
5.15
74.49
0.06
0.24
2,100
3.1
Bergey Excel-S
6.7
10
20
5.15
57.32
0
0.26
2,300
2.6
Bergey XL.1
2.5
1
20
5.15
35.04
0.09
0.04
300
3.9
Southwest Skystream 3.7
3.7
1.8
20
5.15
71.27
0
0.08
700
4.2
Southwest Whisper 500
4.5
3
20
5.15
74.49
0.07
0.13
1,100
4.4
Northern Power NW 100/20
20
100
25
5.31
81.44
0
2.06
18,100
2.1
Vestas V47 - 660 kW
47
660
65
6.07
66.66
0
24.7
216,700
3.7
GE 1.5s
70.5
1,500
80.5
6.25
72.55
0.08
45.8
401,000
3.1
Vestas V80 - 2.0 MW
80
2,000
100
6.45
71.27
0.01
88.4
774,200
4.4
GE 2.5xl
100
2,500
110
6.53
64.65
0.13
129
1,128,900
5.2

 


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Last updated: June 2009
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