Wind Turbine Payback in Gillespie County, TX
Wind turbine payback in Gillespie 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 Gillespie County, TX averages 5.89 m/s (13.2 mph). A 10 kW turbine there would make about 18,890 kWh a year, worth $3,028 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 Gillespie County
A home turbine is not worth buying for savings in Gillespie County unless your spot is far windier than the county average, 7.6 m/s at the hub against 5.89 m/s here. Per kW, solar panels would make about 1,437 kWh a year here against the turbine's 1,889, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/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 5.89. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Gillespie County is the 1,001st 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 Gillespie County
April is the strongest month here, at 6.69 m/s and about 2,041 kWh. September is the weakest, 4.88 m/s and 962 kWh, so the best month makes 2.1 times the worst. November to March brings in 47% of the year's output in Gillespie County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.14 m/s | 1,763 kWh | $283 |
| February | 6.34 m/s | 1,704 kWh | $273 |
| March | 6.53 m/s | 2,009 kWh | $322 |
| April | 6.69 m/s | 2,041 kWh | $327 |
| May | 6.25 m/s | 1,830 kWh | $293 |
| June | 5.74 m/s | 1,462 kWh | $234 |
| July | 5.29 m/s | 1,232 kWh | $197 |
| August | 5.00 m/s | 1,065 kWh | $171 |
| September | 4.88 m/s | 962 kWh | $154 |
| October | 5.70 m/s | 1,483 kWh | $238 |
| November | 6.09 m/s | 1,673 kWh | $268 |
| December | 6.14 m/s | 1,763 kWh | $283 |
What a taller tower would buy
Measured at 10 m the wind in Gillespie County averages 4.6 m/s; at 50 m it is 6.61 m/s. That gives a shear exponent of 0.225, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,166 to 24,216 kWh a year, 60% 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 | 5.38 m/s | 15,166 kWh | 41 years |
| 30 m | 5.89 m/s | 18,907 kWh | 33 years |
| 40 m | 6.29 m/s | 21,827 kWh | 29 years |
| 50 m | 6.61 m/s | 24,216 kWh | 26 years |
Counties around Gillespie County
3 of the 6 closest counties are windier at turbine height; the windiest, Mason County, averages 6.08 m/s.
- Kendall County, TX: 5.75 m/s, 17,859 kWh, payback 35 years (30 mi)
- Llano County, TX: 5.89 m/s, 18,890 kWh, payback 33 years (31 mi)
- Kerr County, TX: 5.9 m/s, 18,964 kWh, payback 33 years (31 mi)
- Mason County, TX: 6.08 m/s, 20,297 kWh, payback 31 years (32 mi)
- Blanco County, TX: 5.69 m/s, 17,419 kWh, payback 36 years (33 mi)
- Bandera County, TX: 5.9 m/s, 18,964 kWh, payback 33 years (43 mi)
Sun versus wind in Gillespie County
Gillespie County gets 4.92 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,437 kWh a year; one kW of the turbine above makes 1,889. 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.