Wind Turbine Payback in Mills County, TX
Wind turbine payback in Mills 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 Mills County, TX averages 5.87 m/s (13.1 mph). A 10 kW turbine there would make about 18,742 kWh a year, worth $3,004 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 Mills County
A home turbine is not worth buying for savings in Mills County unless your spot is far windier than the county average, 7.6 m/s at the hub against 5.87 m/s here. Per kW, solar panels would make about 1,451 kWh a year here against the turbine's 1,874, so get a solar quote first.
What would have to change
- Power would have to cost 27¢/kWh, 1.7 times what TX pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 5.87. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Mills County is the 1,026th 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 Mills County
April is the strongest month here, at 6.79 m/s and about 2,098 kWh. September is the weakest, 4.93 m/s and 993 kWh, so the best month makes 2.1 times the worst. November to March brings in 47% of the year's output in Mills County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.08 m/s | 1,723 kWh | $276 |
| February | 6.31 m/s | 1,688 kWh | $271 |
| March | 6.52 m/s | 2,002 kWh | $321 |
| April | 6.79 m/s | 2,098 kWh | $336 |
| May | 6.17 m/s | 1,779 kWh | $285 |
| June | 5.71 m/s | 1,446 kWh | $232 |
| July | 5.16 m/s | 1,159 kWh | $186 |
| August | 4.89 m/s | 1,001 kWh | $160 |
| September | 4.93 m/s | 993 kWh | $159 |
| October | 5.75 m/s | 1,517 kWh | $243 |
| November | 6.09 m/s | 1,673 kWh | $268 |
| December | 6.05 m/s | 1,706 kWh | $273 |
What a taller tower would buy
Measured at 10 m the wind in Mills County averages 4.55 m/s; at 50 m it is 6.6 m/s. That gives a shear exponent of 0.231, typical of ordinary open country. Going from 20 m to 50 m takes output from 14,898 to 24,142 kWh a year, 62% 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 | 5.34 m/s | 14,898 kWh | 42 years |
| 30 m | 5.87 m/s | 18,708 kWh | 33 years |
| 40 m | 6.27 m/s | 21,695 kWh | 29 years |
| 50 m | 6.6 m/s | 24,142 kWh | 26 years |
Counties around Mills County
2 of the 6 closest counties are windier at turbine height; the windiest, Brown County, averages 6.05 m/s.
- San Saba County, TX: 5.82 m/s, 18,374 kWh, payback 34 years (27 mi)
- Lampasas County, TX: 5.75 m/s, 17,859 kWh, payback 35 years (29 mi)
- Brown County, TX: 6.05 m/s, 20,075 kWh, payback 31 years (30 mi)
- Comanche County, TX: 6.05 m/s, 20,075 kWh, payback 31 years (32 mi)
- Hamilton County, TX: 5.82 m/s, 18,374 kWh, payback 34 years (32 mi)
- Coryell County, TX: 5.69 m/s, 17,419 kWh, payback 36 years (48 mi)
Sun versus wind in Mills County
Mills County gets 4.97 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,451 kWh a year; one kW of the turbine above makes 1,874. 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.