Wind Turbine Payback in Coosa County, AL
Wind turbine payback in Coosa 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 Coosa 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 Coosa County
A home turbine is not worth buying for savings in Coosa 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 1,346 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
Coosa 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 Coosa County
March is the strongest month here, at 3.71 m/s and about 441 kWh. July is the weakest, 2.46 m/s and 107 kWh, so the best month makes 4.1 times the worst. November to March brings in 56% of the year's output in Coosa County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.60 m/s | 403 kWh | $67 |
| February | 3.69 m/s | 393 kWh | $65 |
| March | 3.71 m/s | 441 kWh | $73 |
| April | 3.64 m/s | 401 kWh | $66 |
| May | 3.10 m/s | 247 kWh | $41 |
| June | 2.63 m/s | 135 kWh | $22 |
| July | 2.46 m/s | 107 kWh | $18 |
| August | 2.54 m/s | 121 kWh | $20 |
| September | 3.01 m/s | 217 kWh | $36 |
| October | 3.30 m/s | 304 kWh | $50 |
| November | 3.52 m/s | 361 kWh | $60 |
| December | 3.52 m/s | 373 kWh | $62 |
What a taller tower would buy
Measured at 10 m the wind in Coosa County averages 1.97 m/s; at 50 m it is 4.05 m/s. That gives a shear exponent of 0.448, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,765 to 6,831 kWh a year, 287% 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 | 1,765 kWh | over 100 years |
| 30 m | 3.22 m/s | 3,304 kWh | over 100 years |
| 40 m | 3.66 m/s | 5,011 kWh | over 100 years |
| 50 m | 4.05 m/s | 6,831 kWh | 89 years |
Counties around Coosa County
1 of the 6 closest counties is windier at turbine height; the windiest, Elmore County, averages 3.88 m/s.
- Elmore County, AL: 3.88 m/s, 5,989 kWh, payback over 100 years (24 mi)
- Tallapoosa County, AL: 3.11 m/s, 2,938 kWh, payback over 100 years (26 mi)
- Chilton County, AL: 3.13 m/s, 3,002 kWh, payback over 100 years (29 mi)
- Talladega County, AL: 3.21 m/s, 3,265 kWh, payback over 100 years (31 mi)
- Clay County, AL: 3.16 m/s, 3,099 kWh, payback over 100 years (32 mi)
- Shelby County, AL: 3.14 m/s, 3,034 kWh, payback over 100 years (33 mi)
Sun versus wind in Coosa County
Coosa County gets 4.61 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,346 kWh a year; one kW of the turbine above makes 330. Kilowatt for kilowatt, panels make 4.1 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.