JULESBURG - 4/21/2003 through 7/9/2004
LOCATION DETAILS |
Latitude: |
N 40° 55.183’ or N 40° 55’ 11" |
Longitude: |
W 102° 15.3833’ or W 102° 15’ 23" |
Township: |
11 N |
Range: |
44 W |
Section: |
21 |
Elevation (ft.): |
3,790 |
Tower Type: |
NRG Tilt-Up |
Tower Height: |
20m (65.6 ft) |
Vane Offset (deg): |
+9° |
Direction Basis: |
Unknown |
Site Number: |
0665 |
Wind Explorer S/N: |
0665 |
DATA DETAILS
April 21, 2003 through July 9, 2004:
The anemometer tower was installed on April 9, 2003. The site was located 4.8 miles southeast of the town of Julesburg and 2.2 miles southeast of I-76. The tower was located in a pasture that is situated on a plateau above the South Platte River. The vegetation around the area was predominately grass. A rural residence with a shelter belt of trees is located a quarter of a mile to the east. Overall, the site has good exposure to the wind.
All data was 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 fed into an NRG Wind Explorer data logger. All data plugs were sent into the Governor's Energy Office and then to the University of North Dakota for analysis. All data plug files and text versions of these files are given below.
Raw Wind Data Files |
NRG Data_Plug Files |
Txt Files |
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Note that not all data plug files were available from UND for this site. 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.
For this data, UND applied an offset of +9° to the wind vane data. This corrected data and wind resource summary report are available here:
CSU was chosen as the contractor for the program on September 14, 2007. From the UND data, an analysis of the wind resource was developed using Windographer 1.13. For this data, an offset of +9° was applied to the wind vane data. No data quality analysis was performed for this data other than what was available from the flag data fields included in the data. The suspect data was first removed from the collected data. Windographer was then used to add in synthetic data to these intervals with suspect data. The Windographer files (with blanks for the suspect data and with the blanks filled with synthetic data) are given below:
Complete Wind Resource Summary
The anemometer tower was removed from the site on July 9, 2004. Highlights of the wind resource at this site for the entire data collection period using the Windographer for the data adjusted for data quality and offset by +9° are shown below:
Data Properties |
Variable |
Data Set Starts: |
4/21/2003 13:30 |
Height above ground (m) |
20m |
Data Set Ends: |
7/9/2004 08:20 |
Mean wind speed (mph) |
14.66 |
Data Set Duration: |
15 months |
Median wind speed (mph) |
14.11 |
Length of Time Step: |
10 minutes |
Min wind speed (mph) |
0.00 |
Elevation (ft.): |
3,790 |
Max wind speed (mph) |
57.68 |
Calm threshold (mph): |
0 |
Mean power density (W/m²) |
263 |
Wind Power Coefficients |
Mean energy content (kWh/m²/yr) |
2,302 |
Power Density at 50m: |
372 W/m² |
Energy pattern factor |
1.703 |
Wind Power Class: |
3 (Fair) |
Weibull k |
2.273 |
Wind Shear Coefficients |
Weibull c (mph) |
16.55 |
Power Law Exponent: |
0.126 |
1-hr autocorrelation coefficient |
0.829 |
Surface Roughness: |
0.01 m |
Diurnal pattern strength |
0.066 |
Roughness Class: |
0.780 |
Hour of peak wind speed |
18 |
Roughness Description: |
Rough Pasture |
Mean turbulence intensity |
0.145 |
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 equal to that of a rough pasture. This value was then used this to calculate the roughness class and the power law exponent shown above.
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Standard deviation (mph) |
6.81 |
Coefficient of variation (%) |
46.4 |
Frequency of calms (%) |
0.26 |
Possible records |
64,049 |
Valid records |
63,322 |
Missing records |
727 |
Data recovery rate (%) |
98.9 |
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 |
20 |
14.66 |
12.27 |
5.37 |
2.08 |
18,200 |
27.7 |
Bergey Excel-S |
6.7 |
10 |
20 |
14.66 |
4.93 |
2.71 |
2.22 |
19,400 |
22.2 |
Bergey XL.1 |
2.5 |
1 |
20 |
14.66 |
1.52 |
7.47 |
0.31 |
2,700 |
30.9 |
Southwest Skystream 3.7 |
3.7 |
1.8 |
20 |
14.66 |
10.93 |
0 |
0.57 |
5,000 |
31.7 |
Southwest Whisper 500 |
4.5 |
3 |
20 |
14.66 |
12.24 |
6.59 |
0.99 |
8,600 |
32.9 |
Northern Power NW 100/20 |
20 |
100 |
25 |
15.13 |
20.02 |
0 |
20.1 |
176,100 |
20.1 |
Vestas V47 - 660 kW |
47 |
660 |
65 |
17.3 |
7.78 |
0.84 |
205 |
1,798,100 |
31.1 |
GE 1.5s |
70.5 |
1,500 |
80.5 |
17.82 |
10.95 |
7.38 |
437 |
3,830,000 |
29.1 |
Vestas V80 - 2.0 MW |
80 |
2,000 |
100 |
18.37 |
10.36 |
3.87 |
684 |
5,993,600 |
34.2 |
GE 2.5xl |
100 |
2,500 |
110 |
18.62 |
6.98 |
9.20 |
955 |
8,369,200 |
38.2 |
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