Wind Turbine Payback in Williamson County, TX
Wind turbine payback in Williamson 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 Williamson County, TX averages 5.52 m/s (12.3 mph). A 10 kW turbine there would make about 16,181 kWh a year, worth $2,594 at TX's 16.03¢/kWh. Against an installed cost of about $100,000, that is a payback of 39 years, and the turbine is built to last about 20.
What to do in Williamson County
A home turbine is not worth buying for savings in Williamson County unless your spot is far windier than the county average, 7.6 m/s at the hub against 5.52 m/s here. Per kW, solar panels would make about 1,405 kWh a year here against the turbine's 1,618, so get a solar quote first.
What would have to change
- Power would have to cost 31¢/kWh, 1.9 times what TX pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 5.52. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Williamson County is the 1,207th 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 Williamson County
March is the strongest month here, at 6.18 m/s and about 1,787 kWh. September is the weakest, 4.53 m/s and 780 kWh, so the best month makes 2.3 times the worst. November to March brings in 49% of the year's output in Williamson County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.89 m/s | 1,604 kWh | $257 |
| February | 6.09 m/s | 1,564 kWh | $251 |
| March | 6.18 m/s | 1,787 kWh | $286 |
| April | 6.26 m/s | 1,778 kWh | $285 |
| May | 5.81 m/s | 1,554 kWh | $249 |
| June | 5.17 m/s | 1,127 kWh | $181 |
| July | 4.80 m/s | 952 kWh | $153 |
| August | 4.60 m/s | 847 kWh | $136 |
| September | 4.53 m/s | 780 kWh | $125 |
| October | 5.29 m/s | 1,233 kWh | $198 |
| November | 5.76 m/s | 1,471 kWh | $236 |
| December | 5.84 m/s | 1,576 kWh | $253 |
What a taller tower would buy
Measured at 10 m the wind in Williamson County averages 4.25 m/s; at 50 m it is 6.23 m/s. That gives a shear exponent of 0.238, typical of ordinary open country. Going from 20 m to 50 m takes output from 12,597 to 21,410 kWh a year, 70% 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 | 5.01 m/s | 12,597 kWh | 50 years |
| 30 m | 5.52 m/s | 16,158 kWh | 39 years |
| 40 m | 5.91 m/s | 19,021 kWh | 33 years |
| 50 m | 6.23 m/s | 21,410 kWh | 29 years |
Counties around Williamson County
2 of the 6 closest counties are windier at turbine height; the windiest, Burnet County, averages 5.75 m/s.
- Bell County, TX: 5.61 m/s, 16,834 kWh, payback 37 years (28 mi)
- Travis County, TX: 5.43 m/s, 15,534 kWh, payback 40 years (29 mi)
- Burnet County, TX: 5.75 m/s, 17,859 kWh, payback 35 years (37 mi)
- Milam County, TX: 5.43 m/s, 15,534 kWh, payback 40 years (38 mi)
- Bastrop County, TX: 5.43 m/s, 15,534 kWh, payback 40 years (42 mi)
- Lee County, TX: 5.41 m/s, 15,390 kWh, payback 41 years (44 mi)
Sun versus wind in Williamson County
Williamson County gets 4.81 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,405 kWh a year; one kW of the turbine above makes 1,618. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.2 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.