Wind Turbine Payback in Coffee County, AL
Wind turbine payback in Coffee 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 Coffee County, AL averages 3.1 m/s (6.9 mph). A 10 kW turbine there would make about 2,906 kWh a year, worth $480 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 Coffee County
A home turbine is not worth buying for savings in Coffee County unless your spot is far windier than the county average, 7.5 m/s at the hub against 3.1 m/s here. Per kW, solar panels would make about 1,387 kWh a year here against the turbine's 291, so get a solar quote first.
What would have to change
- Power would have to cost 172¢/kWh, 10.4 times what AL pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 3.1. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of AL
Coffee County is the 3,000th 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 Coffee County
March is the strongest month here, at 3.52 m/s and about 373 kWh. July is the weakest, 2.45 m/s and 106 kWh, so the best month makes 3.5 times the worst. November to March brings in 55% of the year's output in Coffee County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.45 m/s | 349 kWh | $58 |
| February | 3.47 m/s | 323 kWh | $53 |
| March | 3.52 m/s | 373 kWh | $62 |
| April | 3.44 m/s | 336 kWh | $55 |
| May | 3.01 m/s | 224 kWh | $37 |
| June | 2.58 m/s | 124 kWh | $20 |
| July | 2.45 m/s | 106 kWh | $18 |
| August | 2.50 m/s | 114 kWh | $19 |
| September | 2.94 m/s | 199 kWh | $33 |
| October | 3.21 m/s | 277 kWh | $46 |
| November | 3.38 m/s | 318 kWh | $53 |
| December | 3.35 m/s | 319 kWh | $53 |
What a taller tower would buy
Measured at 10 m the wind in Coffee County averages 1.87 m/s; at 50 m it is 3.93 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 1,512 to 6,231 kWh a year, 312% 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 | 2.58 m/s | 1,512 kWh | over 100 years |
| 30 m | 3.11 m/s | 2,924 kWh | over 100 years |
| 40 m | 3.55 m/s | 4,513 kWh | over 100 years |
| 50 m | 3.93 m/s | 6,231 kWh | 97 years |
Counties around Coffee County
4 of the 6 closest counties are windier at turbine height; the windiest, Geneva County, averages 4.39 m/s.
- Dale County, AL: 3.29 m/s, 3,541 kWh, payback over 100 years (22 mi)
- Geneva County, AL: 4.39 m/s, 8,690 kWh, payback 70 years (24 mi)
- Pike County, AL: 3.04 m/s, 2,721 kWh, payback over 100 years (28 mi)
- Covington County, AL: 3.69 m/s, 5,121 kWh, payback over 100 years (29 mi)
- Crenshaw County, AL: 3.1 m/s, 2,906 kWh, payback over 100 years (30 mi)
- Holmes County, FL: 4.39 m/s, 8,690 kWh, payback 75 years (39 mi)
Sun versus wind in Coffee County
Coffee County gets 4.75 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,387 kWh a year; one kW of the turbine above makes 291. Kilowatt for kilowatt, panels make 4.8 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.