COLORADO ANEMOMETER LOAN PROGRAM
 

PROGRAM INFORMATION

Frequently Asked Questions
Colorado Wind Resource Maps
ALP Sites and Data
Small Wind Electric Systems: A Colorado Consumer's Guide
Small Wind Applications Guide Video
Professional Anemometry
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APPLICATION INFORMATION

Program Goals
Selection Criteria
Lessee Responsibilities
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Tower Safety
Data Plug Replacement
Ideal Sites
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WIND TURBINE RESOURCES

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PLATTEVILLE - 6/18/2009 to 4/8/2011

LOCATION DETAILS
Latitude:
N 40° 10.514’ or N 40 ° 10’ 31"
Longitude:
W 104° 47.367’or W 104° 47’22"
Township:
3 N
Range:
66 W
Section:
33
Elevation (ft.):
4,915
Datum:
WGS 84
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 ft)
Vane Offset (deg):
+180°
Direction Basis:
Magnetic North
Mag. Declination:
9° 5' E, changing by 8' W/yr
Wind Explorer S/N:
0749
Site No.:
0440

 

CSU ALP Install Team (from left): Nick Wagner, Todd MacDonald, Doug Hopper, Derrick Benallie, Daniel Fink, Eric Rasbach, Nathan Davis, and Mike Kostrzewa (taking picture).

DATA DETAILS

June 18, 2009 to April 8, 2011:

The anemometer tower was installed on June 18, 2009 and removed on April 28, 2011. However, the last data plug reached its capacity on April 8, 2011. The site was located in a sagebrush-covered field in Weld County about 2.2 miles south of Platteville and about 1.4 miles east of U.S. Highway 85. The terrain is flat in all directions, with a very slight 3-4 foot uphill on the north side of the tower site. The winds are expected to be strong from the west and northwest.

All data is collected using an NRG #40 Calibrated Anemometer and NRG #200 Wind Vane mounted on a tilt-up tower located at a height of 20m. The certification for the anemometer is as follows:

NRG #40C Calibrated Anemometer
Model No.
1900
Serial No.
179500109725
Calibration Date
5/4/2009 2:37:34 p.m.
Slope
0.759 m/s per Hz
Offset
0.34 m/s

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

Highest
2 sec
Gust
mph

Gust
Date/Time
Platteville_0440_2009_0618_0818.A09 Platteville_0440_2009_0618_0818.txt
50
7/4/09 14:17
Platteville_0440_2009_0818_1030.A09 Platteville_0440_2009_0818_1030.txt
49
9/30/09 20:14
Platteville_0440_2009_1030_0126.A09 Platteville_0440_2009_1030_0126.txt
43
12/13/09 12:26
Platteville_0440_2009_1030_0414.A09 Platteville_0440_2009_1030_0414.txt
73
4/13/10 14:33
Platteville_0440_2010_0414_0823.A10 Platteville_0440_2010_0414_0823.txt
65
5/24/10 13:41
Platteville_0440_2010_0823_0428.A10 Platteville_0440_2010_0823_0428.txt
58
4/3/11 6:23

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 1.49. For this data an offset of +180° 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 5 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:

Final Wind Resource Summary

Highlights of the final wind resource assessment at this site are shown below:

Data Properties
Variable
Data Set Starts:
6/18/2009 12:40 MST
Height above ground (m)
20
Data Set Ends:
4/8/2011 4:20
Mean 10 min avg. wind speed (mph)
8.180
Data Set Duration:
22 months
Median 10 min avg. wind speed (mph)
6.860
Length of Time Step:
10 minutes
Min 10 min avg. wind speed (mph)
0.760
Elevation (ft.):
4,915
Max 10 min avg. wind speed (mph)
49.36
Mean air density (kg/m³):
1.060
Mean power density (W/m²)
78
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
686
Power Density at 50m:
120 W/m²
Energy pattern factor
3.026
Wind Power Class:
1 (Poor)
Weibull k
1.407
Wind Shear Coefficients
Weibull c (mph)
8.973
Power Law Exponent:
0.126
1-hr autocorrelation coefficient
0.736
Surface Roughness:
0.01 m
Diurnal pattern strength
0.275
Roughness Class:
0.78
Hour of peak wind speed
17
Roughness Description:
Rough pasture
Mean turbulence intensity
0.2483
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 the surface roughness for a rough pasture. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
5.8995
Total data elements
284,541
Suspect/missing elements
1,956
Data completeness (%)
99.3

 

Probability Distribution Function at 20m: Frequency (%) vs. Wind Speed (mph)

 

Vertical Wind Shear, Height (m) vs Mean Wind Speed (mph)

 

 

Wind Frequency Rose at 20 meters

 

Wind Energy Rose at 20 meters

 

Seasonal Wind Speed Profile, Monthly Mean Wind Speed (mph) at 20 m vs. Month

 

Daily Wind Speed Profile, Hourly Mean Wind Speed (mph) at 20 m vs. Hour of the Day

 

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. 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 8.18 51.4 1.4 0.7 6,400 9.8
Bergey Excel-S
6.7
10
20 8.18 32.9 0.5 0.8 7,100 8.1
Bergey XL.1
2.5
1
20 8.18 14.5 1.7 0.1 1,000 11.4
Southwest Skystream 3.7
3.7
1.8
20 8.18 49.1 0.0 0.2 1,900 12.0
Southwest Whisper 500
4.5
3
20 8.18 51.4 1.5 0.4 3,300 12.6
Northern Power NW 100/21
21
100
37 8.84 45.1 0.0 8.8 77,100 8.8
Vestas V47 - 660 kW
47
660
65 9.49 43.4 0.1 71 621,700 10.8
GE 1.5s
70.5
1,500
80.5 9.75 50.2 1.5 139.4 1,221,200 9.3
Vestas V80 - 2.0 MW
80
2,000
100 10.02 49.1 0.7 241.8 2,118,300 12.1
GE 2.5xl
100
2,500
110 10.14 41.3 1.9 342.3 2,998,300 13.7

IMPORTANT: No turbine losses are included in the power, energy, and capacity factor values in the table. Typically, turbine losses can be 5-20% to account for maintenance downtime, icing/soiling and losses from other turbines in a wind farm. Users wanting to be conservative in the performance projections should multiply the power, energy, and capacity values by (1- % losses) to account for these losses.


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