Wind Turbine Payback in Grady County, GA
Wind turbine payback in Grady 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 Grady County, GA averages 3.91 m/s (8.7 mph). A 10 kW turbine there would make about 6,134 kWh a year, worth $949 at GA's 15.48¢/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 Grady County
A home turbine is not worth buying for savings in Grady County unless your spot is far windier than the county average, 7.8 m/s at the hub against 3.91 m/s here. Per kW, solar panels would make about 1,396 kWh a year here against the turbine's 613, so get a solar quote first.
What would have to change
- Power would have to cost 82¢/kWh, 5.3 times what GA pays now.
- Or the average wind at the hub would have to be 7.8 m/s instead of 3.91. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of GA
Grady County is the 2,125th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in GA is Glynn County at 5.08 m/s, payback 49 years.
Month by month in Grady County
March is the strongest month here, at 4.39 m/s and about 739 kWh. July is the weakest, 3.10 m/s and 248 kWh, so the best month makes 3.0 times the worst. November to March brings in 54% of the year's output in Grady County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.34 m/s | 715 kWh | $111 |
| February | 4.36 m/s | 653 kWh | $101 |
| March | 4.39 m/s | 739 kWh | $114 |
| April | 4.22 m/s | 634 kWh | $98 |
| May | 3.77 m/s | 465 kWh | $72 |
| June | 3.25 m/s | 281 kWh | $43 |
| July | 3.10 m/s | 248 kWh | $38 |
| August | 3.15 m/s | 261 kWh | $40 |
| September | 3.81 m/s | 466 kWh | $72 |
| October | 4.08 m/s | 594 kWh | $92 |
| November | 4.27 m/s | 660 kWh | $102 |
| December | 4.26 m/s | 674 kWh | $104 |
What a taller tower would buy
Measured at 10 m the wind in Grady County averages 2.71 m/s; at 50 m it is 4.64 m/s. That gives a shear exponent of 0.334, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,005 to 10,195 kWh a year, 155% 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 | 3.42 m/s | 4,005 kWh | over 100 years |
| 30 m | 3.91 m/s | 6,144 kWh | over 100 years |
| 40 m | 4.31 m/s | 8,214 kWh | 79 years |
| 50 m | 4.64 m/s | 10,195 kWh | 63 years |
Counties around Grady County
2 of the 6 closest counties are windier at turbine height; the windiest, Baker County, averages 4.66 m/s.
- Thomas County, GA: 4.32 m/s, 8,289 kWh, payback 78 years (19 mi)
- Decatur County, GA: 3.91 m/s, 6,134 kWh, payback over 100 years (20 mi)
- Mitchell County, GA: 3.91 m/s, 6,134 kWh, payback over 100 years (25 mi)
- Leon County, FL: 3.01 m/s, 2,631 kWh, payback over 100 years (29 mi)
- Gadsden County, FL: 3.01 m/s, 2,631 kWh, payback over 100 years (30 mi)
- Baker County, GA: 4.66 m/s, 10,320 kWh, payback 63 years (33 mi)
Sun versus wind in Grady County
Grady County gets 4.78 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,396 kWh a year; one kW of the turbine above makes 613. Kilowatt for kilowatt, panels make 2.3 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.