Wind Turbine Payback in Johnston County, OK
Wind turbine payback in Johnston 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 Johnston County, OK averages 6.07 m/s (13.6 mph). A 10 kW turbine there would make about 20,223 kWh a year, worth $2,793 at OK's 13.81¢/kWh. Against an installed cost of about $100,000, that is a payback of 36 years, and the turbine is built to last about 20.
What to do in Johnston County
A home turbine is not worth buying for savings in Johnston County unless your spot is far windier than the county average, 8.4 m/s at the hub against 6.07 m/s here. Per kW, solar panels would make about 1,349 kWh a year here against the turbine's 2,022, so get a solar quote first.
What would have to change
- Power would have to cost 25¢/kWh, 1.8 times what OK pays now.
- Or the average wind at the hub would have to be 8.4 m/s instead of 6.07. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of OK
Johnston County is the 717th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in OK is Cimarron County at 6.82 m/s, payback 28 years.
Month by month in Johnston County
April is the strongest month here, at 7.06 m/s and about 2,259 kWh. August is the weakest, 4.89 m/s and 1,000 kWh, so the best month makes 2.3 times the worst. November to March brings in 48% of the year's output in Johnston County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.40 m/s | 1,928 kWh | $266 |
| February | 6.56 m/s | 1,832 kWh | $253 |
| March | 6.87 m/s | 2,221 kWh | $307 |
| April | 7.06 m/s | 2,259 kWh | $312 |
| May | 6.28 m/s | 1,850 kWh | $255 |
| June | 5.68 m/s | 1,429 kWh | $197 |
| July | 4.96 m/s | 1,040 kWh | $144 |
| August | 4.89 m/s | 1,000 kWh | $138 |
| September | 5.17 m/s | 1,126 kWh | $156 |
| October | 6.11 m/s | 1,743 kWh | $241 |
| November | 6.56 m/s | 1,957 kWh | $270 |
| December | 6.32 m/s | 1,878 kWh | $259 |
What a taller tower would buy
Measured at 10 m the wind in Johnston County averages 4.7 m/s; at 50 m it is 6.83 m/s. That gives a shear exponent of 0.232, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,196 to 25,819 kWh a year, 59% 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 | 5.52 m/s | 16,196 kWh | 45 years |
| 30 m | 6.07 m/s | 20,198 kWh | 36 years |
| 40 m | 6.49 m/s | 23,300 kWh | 31 years |
| 50 m | 6.83 m/s | 25,819 kWh | 28 years |
Counties around Johnston County
None of the 6 closest counties is windier than Johnston County.
- Marshall County, OK: 5.95 m/s, 19,334 kWh, payback 38 years (21 mi)
- Murray County, OK: 6.07 m/s, 20,223 kWh, payback 36 years (27 mi)
- Coal County, OK: 5.49 m/s, 15,965 kWh, payback 45 years (28 mi)
- Pontotoc County, OK: 6.07 m/s, 20,223 kWh, payback 36 years (28 mi)
- Bryan County, OK: 5.29 m/s, 14,538 kWh, payback 50 years (33 mi)
- Atoka County, OK: 5.49 m/s, 15,965 kWh, payback 45 years (36 mi)
Sun versus wind in Johnston County
Johnston County gets 4.62 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,349 kWh a year; one kW of the turbine above makes 2,022. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 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.