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ESTES PARK - 9/16/2008 to 7/22/2009

LOCATION DETAILS
Latitude:
N 40° 22.318’ or N 40° 22’ 19"
Longitude:
W 105° 29.908’ or W 105° 29’ 54"
Township:
5 N
Range:
72 W
Section:
Not avail.
Elevation (ft.):
7,577
Tower Type:
Existing light pole
Sensor Height (ft.):
60
Sensor Height (m):
18.3
Vane Offset (deg):
+319°
Direction Basis:
Magnetic North
Mag. Declination:
9° 35' E, changing by 8' W/yr
Wind Explorer S/N:
1175
Site No.:
4005

DATA DETAILS

September 16 , 2008 to July 22, 2009:

An anemometer and wind vane were installed at the top of a 60 foot light pole above the softball fields in the Town of Estes Park on September 16, 2008. The site is located near the fairgrounds. Prospect Mountain lies about 1.3 miles west and should provide a large obstruction for wind in the town. Winds should funnel down from about Longs Peak and Rocky Mountain National Park and down the valley from the west side of town. Lake Estes is about 0.2 miles north of the site.

All data is collected using an NRG #40 Anemometer and NRG #200 Wind Vane. The wind vane is mounted on a 43 inch boom to clear it from the obstructions caused by the lights on the pole. 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
Estes_Park_4005_2008_0916_1107.A08
Estes_Park_4005_2008_1107_0108.A08 Estes_Park_4005_2008_1107_0108.txt
Estes_Park_4005_2009_0108_0306.A09 Estes_Park_4005_2009_0108_0306.txt
Estes_Park_4005_2009_0306_0514.A09 Estes_Park_4005_2009_0306_0514.txt
Estes_Park_4005_2009_0514_0722.A09 Estes_Park_4005_2009_0514_0722.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 +319° 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 5 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:
9/16/2008 11:10 MST
Height above ground (m)
18.3
Data Set Ends:
7/22/2009 9:40
Mean wind speed (mph)
10.70
Data Set Duration:
10 months
Median wind speed (mph)
10.00
Length of Time Step:
10 minutes
Min wind speed (mph)
0.071
Elevation (ft.):
7,577
Max wind speed (mph)
49.30
Calm threshold (mph):
0
Mean power density (W/m²)
165
Wind Power Coefficients
Mean energy content (kWh/m²/yr)
1,442
Power Density at 50m:
229 W/m²
Energy pattern factor
3.086
Wind Power Class:
2 (Marginal)
Weibull k
1.170
Wind Shear Coefficients
Weibull c (mph)
11.252
Power Law Exponent:
0.123
1-hr autocorrelation coefficient
0.829
Surface Roughness:
0.008 m
Diurnal pattern strength
0.310
Roughness Class:
0.740
Hour of peak wind speed
13
Roughness Description:
Lawn grass
Mean turbulence intensity
0.294
Note: The wind power density and wind power class at 50m are projections of the data from 20m. A surface roughness of 0.008 meters was assumed for this projection. This is equal to that of lawn grass. This value was then used this to calculate the roughness class and the power law exponent shown above.
Standard deviation (mph)
8.226
Frequency of calms (%)
0
Total data elements
133,461
Suspect/missing elements
2,796
Data completeness (%)
97.9

 

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
18.3
10.7
39.18
3.91
1.2
10,700
16.2
Bergey Excel-S
6.7
10
18.3
10.7
31.15
2.08
1.3
11,500
13.2
Bergey XL.1
2.5
1
18.3
10.7
23.58
5.22
0.2
1,600
18.2
Southwest Skystream 3.7
3.7
1.8
18.3
10.7
37.27
0
0.3
2,800
17.8
Southwest Whisper 500
4.5
3
18.3
10.7
39.18
4.63
0.6
5,100
19.5
Northern Power NW 100/20
20
100
18.3
10.7
37.27
0
13.0
114,200
13.0
Vestas V47 - 660 kW
47
660
65
12.77
34.63
0.65
122.4
1,072,600
18.6
GE 1.5s
70.5
1,500
80.5
13.16
34.29
1.34
275.8
2,415,900
18.4
Vestas V80 - 2.0 MW
80
2,000
100
13.57
36.88
3.07
409.2
3,584,400
20.5
GE 2.5xl
100
2,500
110
13.75
33.76
6.61
570.2
4,995,000
22.8

 

For Larimer County Residents:

County zoning codes limit the height of any structure to 40 feet. Using the surface roughness and power law exponent given above, Windographer was used to project the wind speed at 40 feet (12.2m). At this height, the average wind speed is 10.14 mph and the wind power density is 140 W per square meter of wind swept area. For residents looking to install small scale wind turbines, the table below provides the expected performance of typical home-scale wind turbines at 40 feet:

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
12.2
10.14
40.52
3.09
1.1
9,500
14.4
Bergey Excel-S
6.7
10
12.2
10.14
32.06
1.5
1.2
10,200
11.6
Bergey XL.1
2.5
1
12.2
10.14
23.84
4.03
0.2
1,400
16.2
Southwest Skystream 3.7
3.7
1.8
12.2
10.14
38.4
0
0.3
2,500
16.1
Southwest Whisper 500
4.5
3
12.2
10.14
40.52
3.61
0.5
4,600
17.6

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