ALP No. 71 - Branson

LOCATION DETAILS
Latitude:	N 37° 9.549’ or N 37° 9’ 33"
Longitude:	W 103° 46.722 ’ or W 106° 46’43"
Township:	33 S
Range:	57 W
Section:	22
Elevation (ft.):	5,690
Datum:	WGS 84
Tower Type:	NRG Tilt-Up
Tower Height (ft.):	98
Tower Height (m):	30
Vane Offset (deg):	+354°
Direction Basis:	Magnetic North
Mag. Declination:	8° 17' E, changing by 7' W/yr
Wind Explorer S/N:	0662
Site No.:	3703

CSU ALP Install Team (from left): Derrick Benallie, Jake Renquist, Eric Rasbach, Nick Wagner, Mike Kostrzewa, Doug Hopper, and Daniel Fink.

DATA DETAILS

July 21, 2009 through October 10, 2009:

The anemometer tower was installed on July 21, 2009. The site is located just south of U. S. Highway 160 in Las Animas County east of Trinidad and about 11.4 miles NE of Branson. The site is flat in all directions with no obstructions within at least 1/2 mile.

All data is collected using an NRG #40 anemometer and NRG #200 Wind Vane mounted on a tilt-up tower located at a height of 30m. 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
Branson_3703_2009_0721_1010.A09	Branson_3703_2009_0721_1010.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 +354° was applied to the wind vane data. For this report, a data quality analysis was performed on the data. This data was filtered two ways:

Any wind speed data where the wind speed was less than 1 mph for 3 hours or more was deleted.
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 summary report, the combined data files (with and without the data quality analysis), and the Windographer files (with and without the data quality analysis) are given below:

Interim Wind Resource Summary

Highlights of the wind resource to date at this site are shown below:

Data Properties		Variable
Data Set Starts:	7/21/2009 11:30 MST	Height above ground (m)	30
Data Set Ends:	10/10/2009 12:50	Mean wind speed (mph)	13.893
Data Set Duration:	81 days	Median wind speed (mph)	12.810
Length of Time Step:	10 minutes	Min wind speed (mph)	0.78
Elevation (ft.):	5,690	Max wind speed (mph)	46.28
Calm threshold (mph):	0	Mean power density (W/m²)	258
Wind Power Coefficients		Mean energy content (kWh/m²/yr)	2,256
Power Density at 50m:	348 W/m²	Energy pattern factor	2.079
Wind Power Class:	3 (Fair)	Weibull k	1.804
Wind Shear Coefficients		Weibull c (mph)	15.595
Power Law Exponent:	0.121	1-hr autocorrelation coefficient	0.784
Surface Roughness:	0.01 m	Diurnal pattern strength	0.262
Roughness Class:	0.780	Hour of peak wind speed	20
Roughness Description:	Rough Pasture	Mean turbulence intensity	0.1898
Note: 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 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.		Standard deviation (mph)	7.884
		Frequency of calms (%)	0
		Total data elements	35,016
		Suspect/missing elements	768
		Data completeness (%)	97.9

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