Wind Turbine Payback in Etowah County, AL
Wind turbine payback in Etowah 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 Etowah County, AL averages 3.3 m/s (7.4 mph). A 10 kW turbine there would make about 3,577 kWh a year, worth $591 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 Etowah County
A home turbine is not worth buying for savings in Etowah County unless your spot is far windier than the county average, 7.5 m/s at the hub against 3.3 m/s here. Per kW, solar panels would make about 1,294 kWh a year here against the turbine's 358, so get a solar quote first.
What would have to change
- Power would have to cost 140¢/kWh, 8.5 times what AL pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 3.3. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of AL
Etowah County is the 2,741st 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 Etowah County
March is the strongest month here, at 3.83 m/s and about 490 kWh. July is the weakest, 2.45 m/s and 106 kWh, so the best month makes 4.6 times the worst. November to March brings in 57% of the year's output in Etowah County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.74 m/s | 452 kWh | $75 |
| February | 3.84 m/s | 445 kWh | $73 |
| March | 3.83 m/s | 490 kWh | $81 |
| April | 3.80 m/s | 462 kWh | $76 |
| May | 3.17 m/s | 267 kWh | $44 |
| June | 2.72 m/s | 151 kWh | $25 |
| July | 2.45 m/s | 106 kWh | $18 |
| August | 2.53 m/s | 120 kWh | $20 |
| September | 2.97 m/s | 207 kWh | $34 |
| October | 3.33 m/s | 312 kWh | $52 |
| November | 3.58 m/s | 381 kWh | $63 |
| December | 3.61 m/s | 405 kWh | $67 |
What a taller tower would buy
Measured at 10 m the wind in Etowah County averages 2.06 m/s; at 50 m it is 4.1 m/s. That gives a shear exponent of 0.428, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,970 to 7,090 kWh a year, 260% 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 | 2.77 m/s | 1,970 kWh | over 100 years |
| 30 m | 3.29 m/s | 3,558 kWh | over 100 years |
| 40 m | 3.73 m/s | 5,282 kWh | over 100 years |
| 50 m | 4.1 m/s | 7,090 kWh | 85 years |
Counties around Etowah County
1 of the 6 closest counties is windier at turbine height; the windiest, Marshall County, averages 3.58 m/s.
- Cherokee County, AL: 3.22 m/s, 3,299 kWh, payback over 100 years (22 mi)
- Calhoun County, AL: 3.22 m/s, 3,299 kWh, payback over 100 years (23 mi)
- Marshall County, AL: 3.58 m/s, 4,653 kWh, payback over 100 years (24 mi)
- St. Clair County, AL: 3.21 m/s, 3,265 kWh, payback over 100 years (28 mi)
- Blount County, AL: 3.23 m/s, 3,333 kWh, payback over 100 years (31 mi)
- DeKalb County, AL: 3.18 m/s, 3,165 kWh, payback over 100 years (31 mi)
Sun versus wind in Etowah County
Etowah County gets 4.43 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,294 kWh a year; one kW of the turbine above makes 358. Kilowatt for kilowatt, panels make 3.6 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.