Wind Turbine Payback in Overton County, TN
Wind turbine payback in Overton 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 Overton County, TN averages 3.41 m/s (7.6 mph). A 10 kW turbine there would make about 3,980 kWh a year, worth $549 at TN's 13.8¢/kWh. Against an installed cost of about $100,000, that is a payback of over 100 years, and the turbine is built to last about 20.
What to do in Overton County
A home turbine is not worth buying for savings in Overton County unless your spot is far windier than the county average, 8.4 m/s at the hub against 3.41 m/s here. Per kW, solar panels would make about 1,226 kWh a year here against the turbine's 398, so get a solar quote first.
What would have to change
- Power would have to cost 126¢/kWh, 9.1 times what TN pays now.
- Or the average wind at the hub would have to be 8.4 m/s instead of 3.41. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TN
Overton County is the 2,607th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in TN is Lake County at 5.54 m/s, payback 44 years.
Month by month in Overton County
March is the strongest month here, at 4.05 m/s and about 578 kWh. August is the weakest, 2.56 m/s and 126 kWh, so the best month makes 4.6 times the worst. November to March brings in 59% of the year's output in Overton County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.97 m/s | 544 kWh | $75 |
| February | 4.11 m/s | 548 kWh | $76 |
| March | 4.05 m/s | 578 kWh | $80 |
| April | 3.99 m/s | 536 kWh | $74 |
| May | 3.28 m/s | 299 kWh | $41 |
| June | 2.84 m/s | 176 kWh | $24 |
| July | 2.58 m/s | 129 kWh | $18 |
| August | 2.56 m/s | 126 kWh | $17 |
| September | 2.88 m/s | 185 kWh | $26 |
| October | 3.36 m/s | 321 kWh | $44 |
| November | 3.63 m/s | 399 kWh | $55 |
| December | 3.80 m/s | 476 kWh | $66 |
What a taller tower would buy
Measured at 10 m the wind in Overton County averages 2.12 m/s; at 50 m it is 4.26 m/s. That gives a shear exponent of 0.434, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,211 to 7,953 kWh a year, 260% 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 | 2.86 m/s | 2,211 kWh | over 100 years |
| 30 m | 3.41 m/s | 3,991 kWh | over 100 years |
| 40 m | 3.87 m/s | 5,927 kWh | over 100 years |
| 50 m | 4.26 m/s | 7,953 kWh | 91 years |
Counties around Overton County
3 of the 6 closest counties are windier at turbine height; the windiest, Clay County, averages 3.62 m/s.
- Putnam County, TN: 3.44 m/s, 4,094 kWh, payback over 100 years (18 mi)
- Pickett County, TN: 3.41 m/s, 3,980 kWh, payback over 100 years (19 mi)
- Fentress County, TN: 3.41 m/s, 3,980 kWh, payback over 100 years (19 mi)
- Clay County, TN: 3.62 m/s, 4,820 kWh, payback over 100 years (20 mi)
- Jackson County, TN: 3.62 m/s, 4,820 kWh, payback over 100 years (22 mi)
- Clinton County, KY: 3.41 m/s, 3,980 kWh, payback over 100 years (28 mi)
Sun versus wind in Overton County
Overton County gets 4.2 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,226 kWh a year; one kW of the turbine above makes 398. Kilowatt for kilowatt, panels make 3.1 times as much here as the turbine. 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.