Wind Turbine Payback in Zapata County, TX
Wind turbine payback in Zapata 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 Zapata County, TX averages 5.93 m/s (13.3 mph). A 10 kW turbine there would make about 19,186 kWh a year, worth $3,075 at TX's 16.03¢/kWh. Against an installed cost of about $100,000, that is a payback of 33 years, and the turbine is built to last about 20.
What to do in Zapata County
A home turbine is not worth buying for savings in Zapata County unless your spot is far windier than the county average, 7.6 m/s at the hub against 5.93 m/s here. Per kW, solar panels would make about 1,510 kWh a year here against the turbine's 1,919, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/kWh, 1.6 times what TX pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 5.93. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Zapata County is the 950th 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 Zapata County
May is the strongest month here, at 6.74 m/s and about 2,137 kWh. September is the weakest, 5.13 m/s and 1,104 kWh, so the best month makes 1.9 times the worst. November to March brings in 35% of the year's output in Zapata County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.27 m/s | 1,221 kWh | $196 |
| February | 5.54 m/s | 1,251 kWh | $201 |
| March | 6.24 m/s | 1,826 kWh | $293 |
| April | 6.60 m/s | 1,986 kWh | $318 |
| May | 6.74 m/s | 2,137 kWh | $343 |
| June | 6.68 m/s | 2,035 kWh | $326 |
| July | 6.69 m/s | 2,109 kWh | $338 |
| August | 6.10 m/s | 1,735 kWh | $278 |
| September | 5.13 m/s | 1,104 kWh | $177 |
| October | 5.53 m/s | 1,380 kWh | $221 |
| November | 5.40 m/s | 1,260 kWh | $202 |
| December | 5.18 m/s | 1,167 kWh | $187 |
What a taller tower would buy
Measured at 10 m the wind in Zapata County averages 4.76 m/s; at 50 m it is 6.56 m/s. That gives a shear exponent of 0.199, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,796 to 23,849 kWh a year, 51% 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 | 5.47 m/s | 15,796 kWh | 40 years |
| 30 m | 5.93 m/s | 19,156 kWh | 33 years |
| 40 m | 6.28 m/s | 21,744 kWh | 29 years |
| 50 m | 6.56 m/s | 23,849 kWh | 26 years |
Counties around Zapata County
5 of the 6 closest counties are windier at turbine height; the windiest, Starr County, averages 6.05 m/s.
- Jim Hogg County, TX: 6.03 m/s, 19,926 kWh, payback 31 years (27 mi)
- Starr County, TX: 6.05 m/s, 20,075 kWh, payback 31 years (42 mi)
- Webb County, TX: 5.68 m/s, 17,345 kWh, payback 36 years (54 mi)
- Brooks County, TX: 5.96 m/s, 19,408 kWh, payback 32 years (60 mi)
- Duval County, TX: 5.98 m/s, 19,556 kWh, payback 32 years (63 mi)
- Hidalgo County, TX: 6.05 m/s, 20,075 kWh, payback 31 years (74 mi)
Sun versus wind in Zapata County
Zapata County gets 5.17 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,510 kWh a year; one kW of the turbine above makes 1,919. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.3 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.