COLORADO ANEMOMETER LOAN PROGRAM
 

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YAMPA - 7/17/2008 through 7/24/2009

LOCATION DETAILS
Latitude:
N 40° 9.201’ or N 40° 9’ 12"
Longitude:
W 106° 52.367’ or W 106° 52’ 22"
Township:
2 N
Range:
85 W
Section:
12
Elevation (ft.):
8,287
Tower Type:
NRG Tilt-Up
Tower Height:
20 m (65.6 ft)
Vane Offset (deg):
+185°
Direction Basis:
Magnetic North
Mag. Declination:
10° 17' E, changing by 8' W/yr
Wind Explorer S/N:
0750
Site No.:
1112

DATA DETAILS

July 17, 2008 through July 24, 2009:

The anemometer tower was installed on June 17, 2008. The site is located about 2 miles east of Yampa on the top of a hill in an east-west canyon with some scrub vegetation. Strong westerly winds and thermal winds up and down the canyon are expected at the site.

All data is 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 feeds into an NRG Wind Explorer data logger. All data plugs are 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
60
7/25/08 17:11
Yampa_1112_2008_0925_1206.A08 Yampa_1112_2008_0925_1206.txt
60
10/09/08 23:27
Yampa_1112_2008_1206_0314.A08 Yampa_1112_2008_1206_0314.txt
54
3/4/09 12:20
Yampa_1112_2009_0314_0519.A09 Yampa_1112_2009_0314_0519.txt
57
5/12/09 17:50
Yampa_1112_2009_0519_0724.A09 Yampa_1112_2009_0519_0724.txt
52
7/20/09 14:02

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 +185° 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 2 hours or more was deleted.
  2. Any wind direction data where the wind direction varied by less than 3 degrees over 12 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

The anemometer tower was removed from the site on July 24, 2009. Highlights of the wind resource at this site for the entire monitoring period are shown below:

Data Properties
Variable
Data Set Starts:
7/17/2008 15:00 MST
Height above ground (m)
20
Data Set Ends:
7/24/2009 13:10
Mean 10 min avg. wind speed (mph)
8.308
Data Set Duration:
12 months
Median 10 min avg. wind speed (mph)
7.90
Length of Time Step:
10 minutes
Min 10 min avg. wind speed (mph)
0.471
Elevation (ft.):
8,287
Max 10 min avg. wind speed (mph)
39.1
Mean air density (kg/m³):
0.954
Mean power density (W/m²)
53
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
466
Power Density at 50m:
87 W/m²
Energy pattern factor
2.175
Wind Power Class:
1 (Poor)
Weibull k
1.782
Wind Shear Coefficients
Weibull c (mph)
9.330
Power Law Exponent:
0.177
1-hr autocorrelation coefficient
0.633
Surface Roughness:
0.1 m
Diurnal pattern strength
0.182
Roughness Class:
2.00
Hour of peak wind speed
16
Roughness Description:
Few trees
Mean turbulence intensity
0.276
Note: The wind power density and wind power class at 50m are projections of the data from 20m. A surface roughness of 0.1 meters was assumed for this projection.. This is the surface roughness for an area with a few trees. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
4.804
Frequency of calms (%)
0
Total data elements
160,677
Suspect/missing elements
6,035
Data completeness (%)
96.2

 

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 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
8.31
44.78
0.28
0.4
3,700
5.6
Bergey Excel-S
6.7
10
20
8.31
25.40
0.07
0.5
4,200
4.8
Bergey XL.1
2.5
1
20
8.31
11.06
0.4
0.1
600
6.9
Southwest Skystream 3.7
3.7
1.8
20
8.31
39.86
0
0.1
1,200
7.7
Southwest Whisper 500
4.5
3
20
8.31
44.35
0.32
0.2
2,100
8.1
Northern Power NW 100/20
20
100
25
8.31
39.86
0
5.1
44,500
5.1
Vestas V47 - 660 kW
47
660
65
9.80
35.01
0.01
44.4
389,000
6.7
GE 1.5s
70.5
1,500
80.5
10.1
34.19
0.02
92.5
810,000
6.2
Vestas V80 - 2.0 MW
80
2,000
100
10.41
39.90
0.12
160.0
1,401,400
8.0
GE 2.5xl
100
2,500
110
10.55
31.58
0.55
230.5
2,019,100
9.2

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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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