COLORADO ANEMOMETER LOAN PROGRAM
 

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ARAPAHOE FAIRGROUNDS

12/20/2010 to 12/16/2011

LOCATION DETAILS
Latitude:
N 39° 38.102’ or N 39° 38’ 6.13"
Longitude:
W 104° 41.446’ or W 104° 41’ 26.78"
Survey Meridian:
Colorado, Sixth Principal Meridian
Township:
5 S
Range:
65 W
Section:
8
Elevation:
5,858 feet (1,785.5 m)
Datum:
WGS 84
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 feet)
Vane Offset (deg):
+169°
Direction Basis:
True North
Mag. Declination:
8° 49' E, changing by 7' W/yr
Wind Explorer S/N:
0924
Site No.:
9304

 CSU ALP Install Team (from left): Mike Kostrzewa, Hunter Vassau, Jake Renquist, Eric Rasbach, Todd MacDonald, Kevin Gosselin, and Curtis Cole.

DATA DETAILS

December 20, 2010 to December 16, 2011:

The anemometer tower was installed on December 20, 2010 and was removed on December 16, 2011. The site is located about on the grounds of the Arapahoe County Fairgrounds, about 1.5 miles east of the intersection of E-470 and Quincy Avenue in Aurora. The tower was located in a field about 750 feet NW of the fairgrounds offices. The wind was expected to blow from the N and NW at the site.

All data was 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.
179500142908
Calibration Date
2/9/2010 3:28:08 p.m.
Slope
0.755 mph per Hz
Offset
0.38 mph

This equipment feeds 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
ACFG_9304_2010_1220_0201.A10 ACFG_9304_2010_1220_0201.txt
47
1/22/2011 10:00
ACFG_9304_2010_0201_0418.A11 ACFG_9304_2010_0201_0418.txt
61
3/31/2011 10:50
ACFG_9304_2011_0629_0917.A11 ACFG_9304_2011_0629_0917.txt
79
7/8/2011 13:20
43
10/6/2011 12:30
ACFG_9304_2011_1017_1216.A11 ACFG_9304_2011_1017_1216.txt
46
11/12/2011 16:26

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 +169° was applied to the wind vane data to correct to true north. 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 5 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. A summary report, 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:
2/1/2011 2:30 MST
Height above ground (m)
20
Data Set Ends:
12/16/2011 13:30
10-min. mean wind speed (mph)
11.293
Data Set Duration:
12 months
10-min median wind speed (mph)
10.610
Length of Time Step:
10 minutes
10-min min. wind speed (mph)
0.507
Elevation:
5,858 ft (1,785.5 m)
10-min max wind speed (mph)
43.440
Mean air density (kg/m³):
1.028
10-min standard deviation (mph)
6.031
Wind Power Coefficients
Weibull k
1.947
Power Density at 50m:
185 W/m²
Weibull c (mph)
12.726
Wind Power Class:
1 (Poor)
Mean power density (W/m²)
131
Wind Shear Coefficients
Mean energy content (kWh/m²/yr)
1,148
Power Law Exponent:
0.126
Mean turbulence intensity
0.1804
Surface Roughness:
0.01 m
Energy pattern factor
1.980
Roughness Class:
0.78
1-hr autocorrelation coefficient
0.744
Roughness Description:
Rough Pasture
Diurnal pattern strength
0.093
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.
Hour of peak wind speed
20
Total data elements
155,970
Missing data elements
6,209
Data recovery rate (%)
96

 

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

 

Wind Energy Rose at 20 meters

 

Wind Frequency Rose at 20 meters

 

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

 

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

 

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

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
11.29 25.3 2.2 1.3 11,200 17.1
Bergey Excel-S
6.7
10
20
11.29 12.7 0.8 1.4 12,100 13.8
Bergey XL.1
2.5
1
20
11.29 4.5 2.9 0.2 1,700 19.5
Southwest Skystream 3.7
3.7
1.8
20
11.29 23.0 0.0 0.4 3,200 20.5
Southwest Whisper 500
4.5
3
20
11.29 25.3 2.5 0.7 5,700 21.8
Northern Power NW 100/21
21
100
37
12.20 19.9 0.0 17.2 150,500 17.2
Vestas V47 - 660 kW
47
660
65
13.10 19.0 0.2 124 1,086,400 18.8
GE 1.5s
70.5
1,500
80.5
13.46 24.7 2.5 243.2 2,130,200 16.2
Vestas V80 - 2.0 MW
80
2,000
100
13.83 23.4 1.0 418.7 3,668,100 20.9
GE 2.5xl
100
2,500
110
14.00 17.3 3.1 592.7 5,191,900 23.7

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
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