Wind Turbine Payback in Grayson County, KY
Wind turbine payback in Grayson 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 Grayson County, KY averages 4.2 m/s (9.4 mph). A 10 kW turbine there would make about 7,623 kWh a year, worth $1,083 at KY's 14.2¢/kWh. Against an installed cost of about $100,000, that is a payback of 92 years, and the turbine is built to last about 20.
What to do in Grayson County
A home turbine is not worth buying for savings in Grayson County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.2 m/s here. Per kW, solar panels would make about 1,215 kWh a year here against the turbine's 762, so get a solar quote first.
What would have to change
- Power would have to cost 66¢/kWh, 4.6 times what KY pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.2. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of KY
Grayson County is the 1,951st windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in KY is Fulton County at 5.54 m/s, payback 43 years.
Month by month in Grayson County
March is the strongest month here, at 4.98 m/s and about 1,051 kWh. August is the weakest, 3.13 m/s and 255 kWh, so the best month makes 4.1 times the worst. November to March brings in 57% of the year's output in Grayson County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.88 m/s | 998 kWh | $142 |
| February | 4.94 m/s | 932 kWh | $132 |
| March | 4.98 m/s | 1,051 kWh | $149 |
| April | 4.99 m/s | 1,026 kWh | $146 |
| May | 4.09 m/s | 596 kWh | $85 |
| June | 3.49 m/s | 354 kWh | $50 |
| July | 3.14 m/s | 257 kWh | $36 |
| August | 3.13 m/s | 255 kWh | $36 |
| September | 3.52 m/s | 362 kWh | $51 |
| October | 4.13 m/s | 615 kWh | $87 |
| November | 4.49 m/s | 764 kWh | $108 |
| December | 4.62 m/s | 855 kWh | $121 |
What a taller tower would buy
Measured at 10 m the wind in Grayson County averages 2.93 m/s; at 50 m it is 4.96 m/s. That gives a shear exponent of 0.327, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 5,059 to 12,266 kWh a year, 142% 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 | 3.68 m/s | 5,059 kWh | over 100 years |
| 30 m | 4.2 m/s | 7,607 kWh | 93 years |
| 40 m | 4.61 m/s | 10,014 kWh | 70 years |
| 50 m | 4.96 m/s | 12,266 kWh | 57 years |
Counties around Grayson County
4 of the 6 closest counties are windier at turbine height; the windiest, Edmonson County, averages 4.47 m/s.
- Edmonson County, KY: 4.47 m/s, 9,160 kWh, payback 77 years (17 mi)
- Breckinridge County, KY: 3.63 m/s, 4,862 kWh, payback over 100 years (23 mi)
- Butler County, KY: 4.38 m/s, 8,632 kWh, payback 82 years (25 mi)
- Hardin County, KY: 4.2 m/s, 7,623 kWh, payback 92 years (27 mi)
- Ohio County, KY: 4.35 m/s, 8,460 kWh, payback 83 years (27 mi)
- Hart County, KY: 4.45 m/s, 9,041 kWh, payback 78 years (28 mi)
Sun versus wind in Grayson County
Grayson County gets 4.16 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,215 kWh a year; one kW of the turbine above makes 762. Kilowatt for kilowatt, panels make 1.6 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.