Wind Turbine Payback in Zavala County, TX
Wind turbine payback in Zavala County
No. The turbine wears out before it pays for itself.
At 30 m, the height a home turbine tower usually reaches, the wind in Zavala County, TX averages 5.32 m/s (11.9 mph). A 10 kW turbine there would make about 14,750 kWh a year, worth $2,364 at TX's 16.03¢/kWh. Against an installed cost of about $100,000, that is a payback of 42 years, and the turbine is built to last about 20.
What to do in Zavala County
A home turbine is not worth buying for savings in Zavala County unless your spot is far windier than the county average, 7.6 m/s at the hub against 5.32 m/s here. Per kW, solar panels would make about 1,457 kWh a year here against the turbine's 1,475, so get a solar quote first.
What would have to change
- Power would have to cost 34¢/kWh, 2.1 times what TX pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 5.32. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Zavala County is the 1,321st windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in TX is Dallam County at 6.82 m/s, payback 24 years.
Month by month in Zavala County
May is the strongest month here, at 5.88 m/s and about 1,598 kWh. September is the weakest, 4.84 m/s and 942 kWh, so the best month makes 1.7 times the worst. November to March brings in 37% of the year's output in Zavala County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.88 m/s | 998 kWh | $160 |
| February | 5.21 m/s | 1,073 kWh | $172 |
| March | 5.67 m/s | 1,465 kWh | $235 |
| April | 5.94 m/s | 1,585 kWh | $254 |
| May | 5.88 m/s | 1,598 kWh | $256 |
| June | 5.77 m/s | 1,482 kWh | $238 |
| July | 5.52 m/s | 1,377 kWh | $221 |
| August | 5.17 m/s | 1,162 kWh | $186 |
| September | 4.84 m/s | 942 kWh | $151 |
| October | 5.14 m/s | 1,146 kWh | $184 |
| November | 5.03 m/s | 1,044 kWh | $167 |
| December | 4.82 m/s | 963 kWh | $154 |
What a taller tower would buy
Measured at 10 m the wind in Zavala County averages 4.15 m/s; at 50 m it is 5.97 m/s. That gives a shear exponent of 0.226, typical of ordinary open country. Going from 20 m to 50 m takes output from 11,559 to 19,482 kWh a year, 69% more, before counting the extra cost of the taller tower. Why tower height decides it explains the shear behind these numbers.
| Hub height | Average wind | Output | Payback |
|---|---|---|---|
| 20 m | 4.85 m/s | 11,559 kWh | 54 years |
| 30 m | 5.32 m/s | 14,743 kWh | 42 years |
| 40 m | 5.68 m/s | 17,319 kWh | 36 years |
| 50 m | 5.97 m/s | 19,482 kWh | 32 years |
Counties around Zavala County
4 of the 6 closest counties are windier at turbine height; the windiest, Kinney County, averages 5.78 m/s.
- Dimmit County, TX: 5.36 m/s, 15,034 kWh, payback 42 years (30 mi)
- Uvalde County, TX: 5.61 m/s, 16,834 kWh, payback 37 years (34 mi)
- Maverick County, TX: 5.24 m/s, 14,186 kWh, payback 44 years (35 mi)
- Frio County, TX: 5.29 m/s, 14,538 kWh, payback 43 years (39 mi)
- Medina County, TX: 5.43 m/s, 15,534 kWh, payback 40 years (52 mi)
- Kinney County, TX: 5.78 m/s, 18,079 kWh, payback 35 years (52 mi)
Sun versus wind in Zavala County
Zavala County gets 4.99 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,457 kWh a year; one kW of the turbine above makes 1,475. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.0 times. Panel output assumes an 80% system performance ratio. Wind or solar runs the same comparison for every county.
How this is worked out
Wind is NASA's Power climate record, the 2001-2025 average at 10 m and 50 m for the county's centre, carried to 30 m with this county's own measured wind shear and spread into hours with a Rayleigh distribution. The turbine is a generic 10 kW, 7 m rotor machine with 10% losses. Cost is $10,000 per kW installed with no tax credit, because the federal one ended in 2025. One county-centre number cannot see your hilltop or your tree line, so treat it as the starting point for a site survey, not a substitute. The full method and its weak spots are in how the numbers are made.