Wind Turbine Payback in Runnels County, TX
Wind turbine payback in Runnels 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 Runnels County, TX averages 6.15 m/s (13.8 mph). A 10 kW turbine there would make about 20,816 kWh a year, worth $3,337 at TX's 16.03¢/kWh. Against an installed cost of about $100,000, that is a payback of 30 years, and the turbine is built to last about 20.
What to do in Runnels County
A home turbine is not worth buying for savings in Runnels County unless your spot is far windier than the county average, 7.6 m/s at the hub against 6.15 m/s here. Per kW, solar panels would make about 1,486 kWh a year here against the turbine's 2,082, so get a solar quote first.
What would have to change
- Power would have to cost 24¢/kWh, 1.5 times what TX pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 6.15. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Runnels County is the 638th 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 Runnels County
April is the strongest month here, at 7.07 m/s and about 2,264 kWh. August is the weakest, 5.21 m/s and 1,187 kWh, so the best month makes 1.9 times the worst. November to March brings in 45% of the year's output in Runnels County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.25 m/s | 1,832 kWh | $294 |
| February | 6.47 m/s | 1,781 kWh | $285 |
| March | 6.73 m/s | 2,133 kWh | $342 |
| April | 7.07 m/s | 2,264 kWh | $363 |
| May | 6.50 m/s | 1,988 kWh | $319 |
| June | 6.14 m/s | 1,708 kWh | $274 |
| July | 5.46 m/s | 1,337 kWh | $214 |
| August | 5.21 m/s | 1,187 kWh | $190 |
| September | 5.32 m/s | 1,210 kWh | $194 |
| October | 6.08 m/s | 1,725 kWh | $277 |
| November | 6.32 m/s | 1,816 kWh | $291 |
| December | 6.22 m/s | 1,815 kWh | $291 |
What a taller tower would buy
Measured at 10 m the wind in Runnels County averages 4.79 m/s; at 50 m it is 6.9 m/s. That gives a shear exponent of 0.227, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,793 to 26,325 kWh a year, 57% 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 | 5.6 m/s | 16,793 kWh | 37 years |
| 30 m | 6.14 m/s | 20,776 kWh | 30 years |
| 40 m | 6.56 m/s | 23,843 kWh | 26 years |
| 50 m | 6.9 m/s | 26,325 kWh | 24 years |
Counties around Runnels County
4 of the 6 closest counties are windier at turbine height; the windiest, Taylor County, averages 6.38 m/s.
- Taylor County, TX: 6.38 m/s, 22,521 kWh, payback 28 years (32 mi)
- Concho County, TX: 6.07 m/s, 20,223 kWh, payback 31 years (37 mi)
- Coleman County, TX: 6.11 m/s, 20,520 kWh, payback 30 years (38 mi)
- Coke County, TX: 6.25 m/s, 21,558 kWh, payback 29 years (38 mi)
- Nolan County, TX: 6.33 m/s, 22,151 kWh, payback 28 years (41 mi)
- Tom Green County, TX: 6.28 m/s, 21,781 kWh, payback 29 years (42 mi)
Sun versus wind in Runnels County
Runnels County gets 5.09 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,486 kWh a year; one kW of the turbine above makes 2,082. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.4 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.