Wind Turbine Payback in Benton County, TN
Wind turbine payback in Benton 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 Benton County, TN averages 3.61 m/s (8.1 mph). A 10 kW turbine there would make about 4,778 kWh a year, worth $659 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 Benton County
A home turbine is not worth buying for savings in Benton County unless your spot is far windier than the county average, 8.4 m/s at the hub against 3.61 m/s here. Per kW, solar panels would make about 1,250 kWh a year here against the turbine's 478, so get a solar quote first.
What would have to change
- Power would have to cost 105¢/kWh, 7.6 times what TN pays now.
- Or the average wind at the hub would have to be 8.4 m/s instead of 3.61. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of TN
Benton County is the 2,382nd 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 Benton County
March is the strongest month here, at 4.26 m/s and about 675 kWh. July is the weakest, 2.74 m/s and 161 kWh, so the best month makes 4.2 times the worst. November to March brings in 57% of the year's output in Benton County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.12 m/s | 612 kWh | $84 |
| February | 4.24 m/s | 600 kWh | $83 |
| March | 4.26 m/s | 675 kWh | $93 |
| April | 4.26 m/s | 653 kWh | $90 |
| May | 3.52 m/s | 373 kWh | $51 |
| June | 2.99 m/s | 211 kWh | $29 |
| July | 2.74 m/s | 161 kWh | $22 |
| August | 2.80 m/s | 174 kWh | $24 |
| September | 3.13 m/s | 248 kWh | $34 |
| October | 3.55 m/s | 385 kWh | $53 |
| November | 3.84 m/s | 475 kWh | $66 |
| December | 3.92 m/s | 524 kWh | $72 |
What a taller tower would buy
Measured at 10 m the wind in Benton County averages 2.33 m/s; at 50 m it is 4.42 m/s. That gives a shear exponent of 0.398, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,811 to 8,865 kWh a year, 215% 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 | 3.07 m/s | 2,811 kWh | over 100 years |
| 30 m | 3.61 m/s | 4,765 kWh | over 100 years |
| 40 m | 4.04 m/s | 6,802 kWh | over 100 years |
| 50 m | 4.42 m/s | 8,865 kWh | 82 years |
Counties around Benton County
4 of the 6 closest counties are windier at turbine height; the windiest, Carroll County, averages 5.09 m/s.
- Humphreys County, TN: 3.51 m/s, 4,368 kWh, payback over 100 years (16 mi)
- Henry County, TN: 4.17 m/s, 7,461 kWh, payback 97 years (22 mi)
- Carroll County, TN: 5.09 m/s, 13,146 kWh, payback 55 years (23 mi)
- Houston County, TN: 3.99 m/s, 6,527 kWh, payback over 100 years (25 mi)
- Perry County, TN: 3.28 m/s, 3,506 kWh, payback over 100 years (30 mi)
- Stewart County, TN: 3.99 m/s, 6,527 kWh, payback over 100 years (30 mi)
Sun versus wind in Benton County
Benton 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 478. Kilowatt for kilowatt, panels make 2.6 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.