COLORADO ANEMOMETER LOAN PROGRAM
 

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GEORGETOWN - 7/24/2009 to 10/30/2009

LOCATION DETAILS
Latitude:
N 39° 44.015’ or N 39° 44’1"
Longitude:
W 105° 41.358’ or W 105° 41’ 21"
Township:
4 S
Range:
74 W
Section:
4
Elevation (ft.):
8,430
Datum:
WGS 84
Tower Type:
NRG Tilt-Up
Tower Height (ft.):
66
Tower Height (m):
20
Vane Offset (deg):
+147°
Direction Basis:
Magnetic North
Mag. Declination:
9° 30' E, changing by 8' W/yr
Wind Explorer S/N:
0925
Site No.:
0539

 CSU ALP Install Team (from left): Nate Davis, Todd MacDonald, Eric Rasbach, Derrick Benallie, Nick Wagner, Jake Renquist, and Mike Kostrzewa (taking picture).

 

DATA DETAILS

July 24, 2009 to October 30, 2009:

The anemometer tower was installed on July 24, 2009. The site is just below and on the north end of Georgetown Reservoir in Clear Creek County. It is easily seen from I-70. The site is in a valley so that winds are expected from the south down the valley.

All data is collected using an NRG #40 anemometer and NRG #200 Wind Vane mounted on a tilt-up tower located at a height of 20m.

This equipment feeds into an NRG Wind Explorer data logger. All data plugs will be 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
Georgetown_0539_2009_0724_0912.A09 Georgetown_0539_2009_0724_0912.txt
Georgetown_0539_2009_0912_1030.A09 Georgetown_0539_2009_0912_1030.txt

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 +147° was applied to the wind vane data. 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 mph for 3 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 the validation analysis), and the Windographer files (with and without the validation analysis) are given below:

Highlights of the wind resource to date at this site are shown below:

Data Properties
Variable
Data Set Starts:
7/24/2009 10:50 MST
Height above ground (m)
20
Data Set Ends:
10/30/2009 10:40
Mean wind speed (mph)
8.725
Data Set Duration:
3.2 months
Median wind speed (mph)
7.890
Length of Time Step:
10 minutes
Min wind speed (mph)
0.780
Elevation (ft.):
8,430
Max wind speed (mph)
44.89
Calm threshold (mph):
0
Mean power density (W/m²)
81
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
711
Power Density at 50m:
105 W/m²
Energy pattern factor
2.880
Wind Power Class:
1 (Poor)
Weibull k
1.326
Wind Shear Coefficients
Weibull c (mph)
9.461
Power Law Exponent:
0.116
1-hr autocorrelation coefficient
0.674
Surface Roughness:
0.005 m
Diurnal pattern strength
0.389
Roughness Class:
0.64
Hour of peak wind speed
14
Roughness Description:
Lawn grass
Mean turbulence intensity
0.3337
Note: The wind power density and wind power class at 50m are projections of the data from 20m. A surface roughness of 0.005 meters was assumed for this projection. This is the surface roughness for surface bewteen a smooth lawn and a snow surface. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
6.3368
Frequency of calms (%)
0
Total data elements
42,333
Suspect/missing elements
357
Data completeness (%)
99.2

 

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
8.72
46.89
0.8
0.7
5,900
9.00
Bergey Excel-S
6.7
10
20
8.72
33.89
0.27
0.7
6,300
7.20
Bergey XL.1
2.5
1
20
8.72
21.15
1.13
0.1
900
10.30
Southwest Skystream 3.7
3.7
1.8
20
8.72
43.49
0
0.2
1,700
11.00
Southwest Whisper 500
4.5
3
20
8.72
46.89
0.91
0.4
3,100
11.70
Northern Power NW 100/21
21
100
37
9.37
41.11
0
9.0
78,900
9.00
Vestas V47 - 660 kW
47
660
65
10.0
41.46
0.05
64.2
562,100
9.70
GE 1.5s
70.5
1,500
80.5
10.25
46.58
0.81
121.7
1,066,400
8.10
Vestas V80 - 2.0 MW
80
2,000
100
10.51
45.45
0.29
216.4
1,895,700
10.80
GE 2.5xl
100
2,500
110
10.63
39.72
1.11
308.8
2,705,500
12.40

 


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Last updated: June 2009
Email questions & comments to: michael@engr.colostate.edu
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