COLORADO ANEMOMETER LOAN PROGRAM
 

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RAMAH - 12/22/2010 to 12/20/2011

LOCATION DETAILS
Latitude:
N 39° 9.761’ or N 39° 9’ 45.66"
Longitude:
W 104° 13.721’ or W 104° 13’ 43.26"
Survey Meridian:
Colorado, Sixth Principal Meridian
Township:
10 S
Range:
61 W
Section:
21
Elevation:
6,474 feet (1,973.3 m)
Datum:
WGS 84
Tower Type:
NRG Tilt-Up
Tower Height
30 m (98.4 feet)
Vane Offset (deg):
+170°
Direction Basis:
Magnetic North
Mag. Declination:
8° 32' E, changing by 7' W/yr
Wind Explorer S/N:
0925
Site No.:
3900

 CSU ALP Install Team (from left): Rich Crawford, Eric Rasbach, Jake Renquist, Chris Hertneky, Hunter Vassau, Mike Kostrzewa, and Jacqueline Hess

DATA DETAILS

December 22, 2010 to December 20, 2011:

The anemometer tower was installed on December 22, 2010 and removed on December 20, 2011. The site was located on a ranch about 8.3 miles NSW and 8.8 miles N of Ramah. The tower was located on a flat spot on the top of a hill. The wind was expected to blow from the N and S at the site.

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 30m. The certification for the anemometer is as follows:

NRG #40C Calibrated Anemometer
Model No.
1900
Serial No.
179500142909
Calibration Date
2/9/2010 3:38:28 p.m.
Slope
0.758 m/s per Hz
Offset
0.35 m/s

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
m/s
Gust
Date/Time
Ramah_3900_2010_1222_0201.A10 Ramah_3900_2010_1222_0201.txt
26
1/22/2011 10:51
Ramah_3900_2010_0201_0311.A11 Ramah_3900_2010_0201_0311.txt
26
2/20/2011 11:36
Ramah_3900_2011_0311_0513.A11 Ramah_3900_2011_0311_0513.txt
31
4/3/2011 3:44
Ramah_3900_2011_0513_0818.A11 Ramah_3900_2011_0513_0818.txt
31
6/28/2011 19:14
Ramah_3900_2011_0818_1109.A11 Ramah_3900_2011_0818_1109.txt
32
10/6/2011 11:56
Ramah_3900_2011_1109_1220.A11 Ramah_3900_2011_1109_1220.txt
29
11/21/2011 18:03

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.

Note: An NRG #110S temperature sensor with a radiation shield was added to the data logger on 2/1/2010 at 12:20 p.m.

Using this data, an analysis of the wind resource report was developed using Windographer 1.50. For this data an offset of +170° 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 m/s and the temperature was below 0°C for 6 hours or more was deleted.
  2. Any wind direction data where the wind direction varied by less than 3 degrees and the temperature was below 0°C over 6 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 to date at this site are shown below:

Data Properties
Variable
Data Set Starts:
12/22/2010 16:50 MST
Height above ground (m)
30
Data Set Ends
12/20/2011 11:10
10-min. mean wind speed (m/s)
7.138
Data Set Duration:
12 months
10-min median wind speed (m/s)
6.770
Length of Time Step:
10 minutes
10-min min. wind speed (m/s)
0.287
Elevation:
6,474 feet (1,973.3 m)
10-min max wind speed (m/s)
23.470
Mean air density (kg/m³):
0.984
10-min standard deviation (m/s)
3.488
Wind Power Coefficients
Weibull k
2.149
Power Density at 50m:
384 W/m²
Weibull c (m/s)
8.056
Wind Power Class:
3 (Fair)
Mean power density (W/m²)
320
Wind Shear Coefficients
Mean energy content (kWh/m²/yr)
2,800
Power Law Exponent:
0.121
Mean turbulence intensity
0.1314
Surface Roughness:
0.01 m
Energy pattern factor
1.784
Roughness Class:
0.78
1-hr autocorrelation coefficient
0.813
Roughness Description:
Rough Pasture
Diurnal pattern strength
0.069
The wind power density and wind power class at 50m are projections of the data from 30m. 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
19
Total data elements
208,952
Missing/suspect data elements
8,600
Data recovery rate (%)
95.9

 

Vertical Wind Shear, Height (m) vs Mean Wind Speed (m/s)

 

Wind Energy Rose at 30 meters

 

Wind Frequency Rose at 30 meters

 

Daily Wind Speed Profile at 30m, Hourly Mean Wind Speed (m/s) vs. Hour of the Day

 

Seasonal Wind Speed Profile at 30m, Monthly Mean Wind Speed (m/s) vs. Month

 

Probability Distribution Function at 30m: Frequency (%) vs. Wind Speed (m/s)

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
m/s
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
30
7.14 12.5 8.4 2.7 23,300 35.4
Bergey Excel-S
6.7
10
30
7.14 5.5 4.7 2.9 25,500 29.1
Bergey XL.1
2.5
1.0
30
7.14 1.6 11.8 0.4 3,500 39.8
Southwest Skystream 3.7
3.7
1.8
30
7.14 10.8 0.0 0.7 5,900 37.4
Southwest Whisper 500
4.5
3.0
30
7.14 12.5 10.3 1.2 10,900 41.4
Northern Power NW 100/21
21
100
37
7.32 10.1 0.0 29.4 258,000 29.4
Vestas V47 - 660 kW
47
660
65
7.84 10.1 0.9 226.7 1,985,800 34.3
GE 1.5s
70.5
1,500
80.5
8.04 13.5 8.3 478.2 4,188,700 31.9
Vestas V80 - 2.0 MW
80
2,000
100
8.26 12.7 4.1 744.6 6,523,100 37.2
GE 2.5xl
100
2,500
110
8.35 9.0 9.8 1033.3 9,051,300 41.3

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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