Wind Turbine Payback in Bibb County, AL
Wind turbine payback in Bibb 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 Bibb County, AL averages 3.13 m/s (7 mph). A 10 kW turbine there would make about 3,002 kWh a year, worth $496 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 Bibb County
A home turbine is not worth buying for savings in Bibb County unless your spot is far windier than the county average, 7.5 m/s at the hub against 3.13 m/s here. Per kW, solar panels would make about 1,317 kWh a year here against the turbine's 300, so get a solar quote first.
What would have to change
- Power would have to cost 167¢/kWh, 10.1 times what AL pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 3.13. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of AL
Bibb County is the 2,968th 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 Bibb County
March is the strongest month here, at 3.62 m/s and about 408 kWh. July is the weakest, 2.36 m/s and 92 kWh, so the best month makes 4.4 times the worst. November to March brings in 56% of the year's output in Bibb County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.50 m/s | 367 kWh | $61 |
| February | 3.60 m/s | 363 kWh | $60 |
| March | 3.62 m/s | 408 kWh | $67 |
| April | 3.55 m/s | 373 kWh | $62 |
| May | 3.00 m/s | 221 kWh | $36 |
| June | 2.55 m/s | 120 kWh | $20 |
| July | 2.36 m/s | 92 kWh | $15 |
| August | 2.47 m/s | 110 kWh | $18 |
| September | 2.93 m/s | 197 kWh | $33 |
| October | 3.20 m/s | 276 kWh | $46 |
| November | 3.40 m/s | 325 kWh | $54 |
| December | 3.41 m/s | 338 kWh | $56 |
What a taller tower would buy
Measured at 10 m the wind in Bibb County averages 1.88 m/s; at 50 m it is 3.96 m/s. That gives a shear exponent of 0.463, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,545 to 6,378 kWh a year, 313% 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 | 2.59 m/s | 1,545 kWh | over 100 years |
| 30 m | 3.13 m/s | 2,989 kWh | over 100 years |
| 40 m | 3.57 m/s | 4,617 kWh | over 100 years |
| 50 m | 3.96 m/s | 6,378 kWh | 95 years |
Counties around Bibb County
2 of the 6 closest counties are windier at turbine height; the windiest, Shelby County, averages 3.14 m/s.
- Chilton County, AL: 3.13 m/s, 3,002 kWh, payback over 100 years (26 mi)
- Perry County, AL: 3.05 m/s, 2,751 kWh, payback over 100 years (28 mi)
- Tuscaloosa County, AL: 2.99 m/s, 2,571 kWh, payback over 100 years (30 mi)
- Shelby County, AL: 3.14 m/s, 3,034 kWh, payback over 100 years (32 mi)
- Hale County, AL: 2.97 m/s, 2,513 kWh, payback over 100 years (34 mi)
- Jefferson County, AL: 3.14 m/s, 3,034 kWh, payback over 100 years (39 mi)
Sun versus wind in Bibb County
Bibb County gets 4.51 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,317 kWh a year; one kW of the turbine above makes 300. Kilowatt for kilowatt, panels make 4.4 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.