WIND

The use of wind as an energy source has its roots in antiquity. At one time, wind was the major source of power for pumping water, grinding grain and transporting goods by sailing ships. Present day applications of wind power include water pumping and the generation of electricity.

In 1994, wind turbines generated approximately 4 billion kWh of electricity worldwide -- enough power for about half a million Texas households. While utility-scale electricity generation from wind is in its infancy in Texas, the industry is already experiencing vigorous activity. In 1993, the Lower Colorado River Authority contracted to purchase competitively priced electricity from Kenetech's 50 MW wind plant in the Delaware Mountains. Royalty payments from this project to the General Land Office (the leaseholder of the site) will provide a new source of funding for the Permanent School Fund. Several of the state's large investor owned utilities, including Texas Utilities and Central and South West Services, have also recently committed to wind power projects.

Characterization of the Resource

Vast areas with high wind power potential exist in Texas. Figures 6 and 7 on the facing page show average annual wind power for the United States and Texas. Wind power is categorized according to Wind Power Class. Wind class 1 (light blue) denotes very light winds; higher numbers indicate stronger winds. In the United States, wind farms are presently built on tracts with winds of class 5 (orange) and higher. Technology currently being developed should make class 4 (yellow) wind regimes viable. Eventually, even class 3 (green) wind regimes are expected to be capable of supporting utility-scale ventures.

FIG. 6. U.S. Wind Power Potential. 
While the strongest winds are located along ridgetops in mountainous areas, the Great Plains from Texas to North Dakota contain the preponderance of the nation's wind power potential.

 

 

TEXAS WIND POWER POTENTIAL
WIND POWER CLASS		WIND CHARACTERISTICS 50 METERS ABOVE GROUND*
		POWER (W/m2)	SPEED (mph)	COMMERCIAL VIABILITY
1	1- 1+	0 - 100 100 - 200	0 - 9.8 9.8 - 12.5	VERY POOR
2	2- 2+	200 - 250 250 - 300	12.5 - 13.5 13.5 - 14.3	POOR
3	3- 3+	300 - 350 350 - 400	14.3 - 15.0 15.0 - 15.7	MARGINAL
4	4- 4+	400 - 450 450 - 500	15.7 - 16.3 16.3 - 16.8	GOOD
5	5- 5+	500 - 550 550 - 600	16.8 - 17.4 17.4 - 17.9	VERY GOOD
6	6- 6+	600 - 700 700 - 800	17.9 - 18.8 18.8 - 19.7	EXCELLENT

* Fifty meters (164 feet) is a common tower height for large wind turbines.

 

 

FIGURE 7. Texas Wind Power Potential.
The prevailing wind environment throughout Texas is characterized by wind power class (defined in the legend above).

 

 

The U.S. map was assembled by the Pacific Northwest Laboratory (PNL) from available measured wind data. In many areas there were no measured data. To address this shortcoming, PNL scientists partitioned the country into thousands of uniformly sized pieces and to each piece assigned a constant value for wind class. This is what gives the map its jagged, "pixelized" appearence.

The Alternative Energy Institute (AEI) at West Texas A&M University constructed the improved resolution Texas wind map as a refinement of the PNL map. It incorporates additional ground exposure information. A hilltop, for example, will experience stronger winds than the base of a valley. The AEI used elevation and prevailing wind data to compute exposure and reclassify wind power throughout the state.

While helpful, this technique is not a precise tool. Some areas on the map may, with improved data, turn out to be windier than indicated, while others may be worse. Overall, the reclassified map simply identifies promising regions in which to focus future assessment activities and development; the true potential of a specific site can only be determined from long-term, quality measurements.

The Texas map identifies three major areas with good wind power potential: the Great Plains, the Gulf Coast, and specific ridgetops and mountain passes throughout the Trans-Pecos. The electric generation potential of the windy areas of Texas is summarized in Table 3, below. These values reflect exclusions for various technical and environmental constraints. The table points out that Texas contains enough class 4 resource to produce all of the electricity currently consumed in the state. Even when utilizing only class 5 and 6 lands, wind power could generate a significant portion of the state's electricity.

Potential Value of Resource in Texas

Wind is a highly variable resource, but with proper understanding it can be readily incorporated into an electric utility's generation mix. This fact has already been recognized by Texas wind developers and electric utilities active in the state's nascent industry. The Panhandle, mountainous parts of West Texas, and perhaps even the lower Gulf Coast, contain areas with winds presently suitable for electric power generation. The number of commercially attractive sites will only expand as development costs continue to drop and wind turbine technology improves.