Wind Turbine Payback in Callahan County, TX
Wind turbine payback in Callahan 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 Callahan County, TX averages 6.26 m/s (14 mph). A 10 kW turbine there would make about 21,632 kWh a year, worth $3,468 at TX's 16.03¢/kWh. Against an installed cost of about $100,000, that is a payback of 29 years, and the turbine is built to last about 20.
What to do in Callahan County
A home turbine is not worth buying for savings in Callahan County unless your spot is far windier than the county average, 7.6 m/s at the hub against 6.26 m/s here. Per kW, solar panels would make about 1,489 kWh a year here against the turbine's 2,163, so get a solar quote first.
What would have to change
- Power would have to cost 23¢/kWh, 1.4 times what TX pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 6.26. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Callahan County is the 520th 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 Callahan County
April is the strongest month here, at 7.30 m/s and about 2,396 kWh. August is the weakest, 5.19 m/s and 1,177 kWh, so the best month makes 2.0 times the worst. November to March brings in 46% of the year's output in Callahan County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.41 m/s | 1,930 kWh | $309 |
| February | 6.60 m/s | 1,854 kWh | $297 |
| March | 6.89 m/s | 2,229 kWh | $357 |
| April | 7.30 m/s | 2,396 kWh | $384 |
| May | 6.62 m/s | 2,064 kWh | $331 |
| June | 6.23 m/s | 1,759 kWh | $282 |
| July | 5.50 m/s | 1,360 kWh | $218 |
| August | 5.19 m/s | 1,177 kWh | $189 |
| September | 5.33 m/s | 1,217 kWh | $195 |
| October | 6.21 m/s | 1,806 kWh | $290 |
| November | 6.52 m/s | 1,938 kWh | $311 |
| December | 6.39 m/s | 1,918 kWh | $307 |
What a taller tower would buy
Measured at 10 m the wind in Callahan County averages 4.9 m/s; at 50 m it is 7.02 m/s. That gives a shear exponent of 0.223, typical of ordinary open country. Going from 20 m to 50 m takes output from 17,658 to 27,186 kWh a year, 54% 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 | 5.72 m/s | 17,658 kWh | 35 years |
| 30 m | 6.26 m/s | 21,663 kWh | 29 years |
| 40 m | 6.68 m/s | 24,723 kWh | 25 years |
| 50 m | 7.02 m/s | 27,186 kWh | 23 years |
Counties around Callahan County
2 of the 6 closest counties are windier at turbine height; the windiest, Taylor County, averages 6.38 m/s.
- Coleman County, TX: 6.11 m/s, 20,520 kWh, payback 30 years (26 mi)
- Taylor County, TX: 6.38 m/s, 22,521 kWh, payback 28 years (30 mi)
- Shackelford County, TX: 6.26 m/s, 21,632 kWh, payback 29 years (31 mi)
- Eastland County, TX: 6.13 m/s, 20,668 kWh, payback 30 years (31 mi)
- Brown County, TX: 6.05 m/s, 20,075 kWh, payback 31 years (43 mi)
- Jones County, TX: 6.38 m/s, 22,521 kWh, payback 28 years (43 mi)
Sun versus wind in Callahan County
Callahan County gets 5.1 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,489 kWh a year; one kW of the turbine above makes 2,163. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 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.