COLORADO ANEMOMETER LOAN PROGRAM
 

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COALMONT - 5/3/2008 through 1/5/2010

LOCATION DETAILS
Latitude:
N 40° 33.461’ or N 40° 33’ 27"
Longitude:
W 106° 26.260’ or W 106° 26’ 15"
Township:
7 N
Range:
81 W
Section:
24
Elevation (ft.):
8,348
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 ft)
Vane Offset (deg):
+280°
Direction Basis:
Magnetic North
Mag. Declination:
10° 8' E, changing by 8' W/yr
Wind Explorer S/N:
0666
Site No.:
4006

DATA DETAILS

May 3, 2008 to January 5, 2010:

The anemometer tower was installed on May 3, 2008. The site is located about one mile SW of Coalmont. The location is a flat pasture on high ground near the edge of a small overlook to the north and a higher knoll to the west of 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 feds into an NRG Wind Explorer data logger. All data plugs were sent to the Colorado ALP at Colorado State University for analysis. The data plug files and text versions of these files are given below.

Raw Wind Data Files
NRG Data Plug Files
Txt Files

Highest
2 sec
Gust
mph

Gust
Date/Time
(Corrected)
55

5/21/08 13:45

Coalmont_4006_2008_0601_0716.A08 Coalmont_4006_2008_0601_0716.txt
68
6/11/08 14:21
Coalmont_4006_2008_0716_0912.A08 Coalmont_4006_2008_0716_0912.txt
58
8/13/08 16:15
Coalmont_4006_2008_0912_1107.A08 Coalmont_4006_2008_0912_1107.txt
62
10/10/08 10:54
Coalmont_4006_2008_1107_0109.A08 Coalmont_4006_2008_1107_0109.txt
73
11/13/08 19:34
Coalmont_4006_2008_0109_0314.A09 Coalmont_4006_2008_0109_0314.txt
70
2/2/09 1:28
Coalmont_4006_2009_0426_0723.A09 Coalmont_4006_2009_0426_0723.txt
61
5/12/09 13:18
Coalmont_4006_2009_0723_0105.A09 Coalmont_4006_2009_0723_0105.txt
64
9/30/09 7:57

Note: The date on all data files is off by one day. The tower was installed on 5/3/2008, but the datalogger was mistakenly set to 5/2/2008. The dates have been changed in the files listed below but not in the raw data files.

Also, note that there is a gap in the data from March 14, 2009 at 4:00 p.m. through April 26, 2009 at 6:00 a.m. due to a loose battery connection.

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.

Using this data, an analysis of the wind resource report was developed using Windographer 1.45. For this data an offset of +280° was applied to the wind vane data. For this report, a data 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 mph for 2 hours or more was deleted.
  2. Any wind direction data where the wind direction varied by less than 3 degrees over 6 hours was deleted

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

Final Wind Resource Summary

The anemometer tower was removed from the site on January 5, 2010. Highlights of the wind resource at this site for the entire monitoring period are shown below:

Data Properties
Variable
Data Set Starts:
5/2/2008 14:50 MST
Height above ground (m)
20
Data Set Ends:
1/5/2010 15:00
Mean 10 min avg. wind speed (mph)
12.055
Data Set Duration:
20 months
Median 10 min avg. wind speed (mph)
11.400
Length of Time Step:
15 minutes
Min 10 min avg. wind speed (mph)
0.405
Elevation (ft.):
8,348
Max 10 min avg. wind speed (mph)
76.25
Mean air density (kg/m³):
0.953
Mean power density (W/m²)
178
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
1,555
Power Density at 50m:
268 W/m²
Energy pattern factor
2.381
Wind Power Class:
2 (Marginal)
Weibull k
1.594
Wind Shear Coefficients
Weibull c (mph)
13.418
Power Law Exponent:
0.126
1-hr autocorrelation coefficient
0.772
Surface Roughness:
0.01 m
Diurnal pattern strength
0.268
Roughness Class:
0.780
Hour of peak wind speed
14
Roughness Description:
Rough Pasture
Mean turbulence intensity
0.208
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)
7.602
Frequency of calms (%)
0
Total data elements
352,516
Suspect/missing elements
72,222
Data completeness (%)
79.5

 

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 18%. 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
12.06
32.58
3.01
1.3
11,600
17.6
Bergey Excel-S
6.7
10
20
12.06
20.25
1.48
1.4
12,400
14.1
Bergey XL.1
2.5
1
20
12.06
8.77
4.29
0.2
1,700
19.8
Southwest Skystream 3.7
3.7
1.8
20
12.06
29.80
0
0.4
3,100
19.6
Southwest Whisper 500
4.5
3
20
12.06
32.52
3.6
0.6
5,600
21.3
Northern Power NW 100/21
20.7
100
37
13.03
27.45
0
16.5
144,700
16.5
Vestas V47 - 660 kW
47
660
65
13.98
27.46
0.54
127.1
1,113,800
19.3
GE 1.5s
70.5
1,500
80.5
14.37
31.82
3.79
261.6
2,292,000
17.4
Vestas V80 - 2.0 MW
80
2,000
100
14.76
30.80
1.94
422.9
3,704,800
21.1
GE 2.5xl
100
2,500
110
14.94
25.36
4.65
594.7
5,209,900
23.8

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Colorado State University, Fort Collins, CO 80523 USA (970) 491-7709
Last updated: June 2009
Email questions & comments to: michael@engr.colostate.edu
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