Wind Turbine Payback in Johnson County, TX
Wind turbine payback in Johnson 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 Johnson County, TX averages 5.79 m/s (13 mph). A 10 kW turbine there would make about 18,153 kWh a year, worth $2,910 at TX's 16.03¢/kWh. Against an installed cost of about $100,000, that is a payback of 34 years, and the turbine is built to last about 20.
What to do in Johnson County
A home turbine is not worth buying for savings in Johnson County unless your spot is far windier than the county average, 7.6 m/s at the hub against 5.79 m/s here. Per kW, solar panels would make about 1,413 kWh a year here against the turbine's 1,815, so get a solar quote first.
What would have to change
- Power would have to cost 28¢/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 5.79. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TX
Johnson County is the 1,080th 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 Johnson County
April is the strongest month here, at 6.78 m/s and about 2,091 kWh. August is the weakest, 4.65 m/s and 872 kWh, so the best month makes 2.4 times the worst. November to March brings in 49% of the year's output in Johnson County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.12 m/s | 1,750 kWh | $281 |
| February | 6.30 m/s | 1,682 kWh | $270 |
| March | 6.54 m/s | 2,012 kWh | $323 |
| April | 6.78 m/s | 2,091 kWh | $335 |
| May | 6.04 m/s | 1,700 kWh | $273 |
| June | 5.51 m/s | 1,324 kWh | $212 |
| July | 4.96 m/s | 1,043 kWh | $167 |
| August | 4.65 m/s | 872 kWh | $140 |
| September | 4.75 m/s | 894 kWh | $143 |
| October | 5.63 m/s | 1,445 kWh | $232 |
| November | 6.11 m/s | 1,689 kWh | $271 |
| December | 6.07 m/s | 1,717 kWh | $275 |
What a taller tower would buy
Measured at 10 m the wind in Johnson County averages 4.46 m/s; at 50 m it is 6.53 m/s. That gives a shear exponent of 0.237, typical of ordinary open country. Going from 20 m to 50 m takes output from 14,294 to 23,628 kWh a year, 65% 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 | 5.26 m/s | 14,294 kWh | 44 years |
| 30 m | 5.79 m/s | 18,119 kWh | 34 years |
| 40 m | 6.19 m/s | 21,140 kWh | 30 years |
| 50 m | 6.53 m/s | 23,628 kWh | 26 years |
Counties around Johnson County
2 of the 6 closest counties are windier at turbine height; the windiest, Hood County, averages 5.91 m/s.
- Somervell County, TX: 5.75 m/s, 17,859 kWh, payback 35 years (26 mi)
- Hood County, TX: 5.91 m/s, 19,038 kWh, payback 33 years (27 mi)
- Tarrant County, TX: 5.82 m/s, 18,374 kWh, payback 34 years (27 mi)
- Hill County, TX: 5.62 m/s, 16,907 kWh, payback 37 years (31 mi)
- Ellis County, TX: 5.68 m/s, 17,345 kWh, payback 36 years (33 mi)
- Bosque County, TX: 5.75 m/s, 17,859 kWh, payback 35 years (37 mi)
Sun versus wind in Johnson County
Johnson County gets 4.84 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,413 kWh a year; one kW of the turbine above makes 1,815. 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.