Wind Turbine Payback in Calhoun County, AL
Wind turbine payback in Calhoun 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 Calhoun County, AL averages 3.22 m/s (7.2 mph). A 10 kW turbine there would make about 3,299 kWh a year, worth $545 at AL's 16.51¢/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 Calhoun County
A home turbine is not worth buying for savings in Calhoun County unless your spot is far windier than the county average, 7.5 m/s at the hub against 3.22 m/s here. Per kW, solar panels would make about 1,314 kWh a year here against the turbine's 330, so get a solar quote first.
What would have to change
- Power would have to cost 152¢/kWh, 9.2 times what AL pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 3.22. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of AL
Calhoun County is the 2,857th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in AL is Mobile County at 4.72 m/s, payback 57 years.
Month by month in Calhoun County
March is the strongest month here, at 3.73 m/s and about 448 kWh. July is the weakest, 2.44 m/s and 105 kWh, so the best month makes 4.3 times the worst. November to March brings in 57% of the year's output in Calhoun County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.65 m/s | 422 kWh | $70 |
| February | 3.72 m/s | 402 kWh | $66 |
| March | 3.73 m/s | 448 kWh | $74 |
| April | 3.69 m/s | 422 kWh | $70 |
| May | 3.12 m/s | 252 kWh | $42 |
| June | 2.66 m/s | 141 kWh | $23 |
| July | 2.44 m/s | 105 kWh | $17 |
| August | 2.47 m/s | 110 kWh | $18 |
| September | 2.88 m/s | 186 kWh | $31 |
| October | 3.24 m/s | 286 kWh | $47 |
| November | 3.48 m/s | 349 kWh | $58 |
| December | 3.52 m/s | 374 kWh | $62 |
What a taller tower would buy
Measured at 10 m the wind in Calhoun County averages 1.98 m/s; at 50 m it is 4.03 m/s. That gives a shear exponent of 0.442, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,768 to 6,729 kWh a year, 281% 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 | 2.69 m/s | 1,768 kWh | over 100 years |
| 30 m | 3.22 m/s | 3,284 kWh | over 100 years |
| 40 m | 3.65 m/s | 4,954 kWh | over 100 years |
| 50 m | 4.03 m/s | 6,729 kWh | 90 years |
Counties around Calhoun County
1 of the 6 closest counties is windier at turbine height; the windiest, Etowah County, averages 3.3 m/s.
- Cleburne County, AL: 3.16 m/s, 3,099 kWh, payback over 100 years (19 mi)
- Etowah County, AL: 3.3 m/s, 3,577 kWh, payback over 100 years (23 mi)
- Cherokee County, AL: 3.22 m/s, 3,299 kWh, payback over 100 years (23 mi)
- St. Clair County, AL: 3.21 m/s, 3,265 kWh, payback over 100 years (28 mi)
- Talladega County, AL: 3.21 m/s, 3,265 kWh, payback over 100 years (34 mi)
- Clay County, AL: 3.16 m/s, 3,099 kWh, payback over 100 years (35 mi)
Sun versus wind in Calhoun County
Calhoun County gets 4.5 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,314 kWh a year; one kW of the turbine above makes 330. Kilowatt for kilowatt, panels make 4.0 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.