Wind Turbine Payback in Jefferson County, AL
Wind turbine payback in Jefferson 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 Jefferson County, AL averages 3.14 m/s (7 mph). A 10 kW turbine there would make about 3,034 kWh a year, worth $501 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 Jefferson County
A home turbine is not worth buying for savings in Jefferson County unless your spot is far windier than the county average, 7.5 m/s at the hub against 3.14 m/s here. Per kW, solar panels would make about 1,308 kWh a year here against the turbine's 303, so get a solar quote first.
What would have to change
- Power would have to cost 165¢/kWh, 10.0 times what AL pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 3.14. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of AL
Jefferson County is the 2,952nd 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 Jefferson County
March is the strongest month here, at 3.65 m/s and about 420 kWh. July is the weakest, 2.36 m/s and 92 kWh, so the best month makes 4.6 times the worst. November to March brings in 56% of the year's output in Jefferson County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.50 m/s | 368 kWh | $61 |
| February | 3.62 m/s | 369 kWh | $61 |
| March | 3.65 m/s | 420 kWh | $69 |
| April | 3.62 m/s | 396 kWh | $65 |
| May | 3.04 m/s | 232 kWh | $38 |
| June | 2.61 m/s | 130 kWh | $21 |
| July | 2.36 m/s | 92 kWh | $15 |
| August | 2.44 m/s | 105 kWh | $17 |
| September | 2.88 m/s | 187 kWh | $31 |
| October | 3.19 m/s | 272 kWh | $45 |
| November | 3.39 m/s | 321 kWh | $53 |
| December | 3.41 m/s | 337 kWh | $56 |
What a taller tower would buy
Measured at 10 m the wind in Jefferson County averages 1.89 m/s; at 50 m it is 3.97 m/s. That gives a shear exponent of 0.461, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,570 to 6,428 kWh a year, 309% 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 | 2.6 m/s | 1,570 kWh | over 100 years |
| 30 m | 3.14 m/s | 3,025 kWh | over 100 years |
| 40 m | 3.58 m/s | 4,661 kWh | over 100 years |
| 50 m | 3.97 m/s | 6,428 kWh | 94 years |
Counties around Jefferson County
4 of the 6 closest counties are windier at turbine height; the windiest, Blount County, averages 3.23 m/s.
- Shelby County, AL: 3.14 m/s, 3,034 kWh, payback over 100 years (24 mi)
- Walker County, AL: 3.15 m/s, 3,067 kWh, payback over 100 years (28 mi)
- Blount County, AL: 3.23 m/s, 3,333 kWh, payback over 100 years (35 mi)
- St. Clair County, AL: 3.21 m/s, 3,265 kWh, payback over 100 years (36 mi)
- Bibb County, AL: 3.13 m/s, 3,002 kWh, payback over 100 years (39 mi)
- Cullman County, AL: 3.23 m/s, 3,333 kWh, payback over 100 years (40 mi)
Sun versus wind in Jefferson County
Jefferson County gets 4.48 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,308 kWh a year; one kW of the turbine above makes 303. Kilowatt for kilowatt, panels make 4.3 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.