Wind Turbine Payback in Henry County, TN
Wind turbine payback in Henry 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 Henry County, TN averages 4.17 m/s (9.3 mph). A 10 kW turbine there would make about 7,461 kWh a year, worth $1,030 at TN's 13.8¢/kWh. Against an installed cost of about $100,000, that is a payback of 97 years, and the turbine is built to last about 20.
What to do in Henry County
A home turbine is not worth buying for savings in Henry County unless your spot is far windier than the county average, 8.4 m/s at the hub against 4.17 m/s here. Per kW, solar panels would make about 1,250 kWh a year here against the turbine's 746, so get a solar quote first.
What would have to change
- Power would have to cost 67¢/kWh, 4.9 times what TN pays now.
- Or the average wind at the hub would have to be 8.4 m/s instead of 4.17. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TN
Henry County is the 1,965th 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 Henry County
March is the strongest month here, at 4.92 m/s and about 1,017 kWh. July is the weakest, 3.14 m/s and 258 kWh, so the best month makes 3.9 times the worst. November to March brings in 56% of the year's output in Henry County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.78 m/s | 942 kWh | $130 |
| February | 4.87 m/s | 898 kWh | $124 |
| March | 4.92 m/s | 1,017 kWh | $140 |
| April | 4.95 m/s | 1,003 kWh | $138 |
| May | 4.06 m/s | 586 kWh | $81 |
| June | 3.45 m/s | 339 kWh | $47 |
| July | 3.14 m/s | 258 kWh | $36 |
| August | 3.19 m/s | 270 kWh | $37 |
| September | 3.57 m/s | 380 kWh | $52 |
| October | 4.10 m/s | 601 kWh | $83 |
| November | 4.45 m/s | 744 kWh | $103 |
| December | 4.55 m/s | 821 kWh | $113 |
What a taller tower would buy
Measured at 10 m the wind in Henry County averages 2.9 m/s; at 50 m it is 4.93 m/s. That gives a shear exponent of 0.330, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,920 to 12,065 kWh a year, 145% 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 | 3.64 m/s | 4,920 kWh | over 100 years |
| 30 m | 4.17 m/s | 7,436 kWh | 98 years |
| 40 m | 4.58 m/s | 9,824 kWh | 74 years |
| 50 m | 4.93 m/s | 12,065 kWh | 60 years |
Counties around Henry County
2 of the 6 closest counties are windier at turbine height; the windiest, Weakley County, averages 5.26 m/s.
- Calloway County, KY: 4.17 m/s, 7,461 kWh, payback 94 years (20 mi)
- Benton County, TN: 3.61 m/s, 4,778 kWh, payback over 100 years (22 mi)
- Weakley County, TN: 5.26 m/s, 14,327 kWh, payback 51 years (23 mi)
- Carroll County, TN: 5.09 m/s, 13,146 kWh, payback 55 years (26 mi)
- Stewart County, TN: 3.99 m/s, 6,527 kWh, payback over 100 years (29 mi)
- Houston County, TN: 3.99 m/s, 6,527 kWh, payback over 100 years (33 mi)
Sun versus wind in Henry County
Henry County gets 4.28 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,250 kWh a year; one kW of the turbine above makes 746. Kilowatt for kilowatt, panels make 1.7 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.