Wind Turbine Payback in Bullitt County, KY
Wind turbine payback in Bullitt 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 Bullitt County, KY averages 4.63 m/s (10.4 mph). A 10 kW turbine there would make about 10,132 kWh a year, worth $1,439 at KY's 14.2¢/kWh. Against an installed cost of about $100,000, that is a payback of 70 years, and the turbine is built to last about 20.
What to do in Bullitt County
A home turbine is not worth buying for savings in Bullitt County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.63 m/s here. Per kW, solar panels would make about 1,212 kWh a year here against the turbine's 1,013, so get a solar quote first.
What would have to change
- Power would have to cost 49¢/kWh, 3.5 times what KY pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.63. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of KY
Bullitt County is the 1,671st 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 Bullitt County
January is the strongest month here, at 5.41 m/s and about 1,309 kWh. August is the weakest, 3.42 m/s and 343 kWh, so the best month makes 3.8 times the worst. November to March brings in 56% of the year's output in Bullitt County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.41 m/s | 1,309 kWh | $186 |
| February | 5.40 m/s | 1,177 kWh | $167 |
| March | 5.41 m/s | 1,309 kWh | $186 |
| April | 5.47 m/s | 1,302 kWh | $185 |
| May | 4.51 m/s | 798 kWh | $113 |
| June | 3.86 m/s | 483 kWh | $69 |
| July | 3.42 m/s | 343 kWh | $49 |
| August | 3.42 m/s | 343 kWh | $49 |
| September | 3.89 m/s | 496 kWh | $70 |
| October | 4.63 m/s | 860 kWh | $122 |
| November | 5.01 m/s | 1,035 kWh | $147 |
| December | 5.14 m/s | 1,144 kWh | $162 |
What a taller tower would buy
Measured at 10 m the wind in Bullitt County averages 3.35 m/s; at 50 m it is 5.38 m/s. That gives a shear exponent of 0.294, typical of ordinary open country. Going from 20 m to 50 m takes output from 7,140 to 15,176 kWh a year, 113% 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 | 4.11 m/s | 7,140 kWh | 99 years |
| 30 m | 4.63 m/s | 10,131 kWh | 70 years |
| 40 m | 5.04 m/s | 12,794 kWh | 55 years |
| 50 m | 5.38 m/s | 15,176 kWh | 46 years |
Counties around Bullitt County
None of the 6 closest counties is windier than Bullitt County.
- Jefferson County, KY: 4.63 m/s, 10,132 kWh, payback 70 years (15 mi)
- Nelson County, KY: 4.63 m/s, 10,132 kWh, payback 70 years (17 mi)
- Spencer County, KY: 4.63 m/s, 10,132 kWh, payback 70 years (21 mi)
- Hardin County, KY: 4.2 m/s, 7,623 kWh, payback 92 years (24 mi)
- Harrison County, IN: 3.63 m/s, 4,862 kWh, payback over 100 years (26 mi)
- Floyd County, IN: 4.61 m/s, 10,008 kWh, payback 59 years (27 mi)
Sun versus wind in Bullitt County
Bullitt County gets 4.15 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,212 kWh a year; one kW of the turbine above makes 1,013. Kilowatt for kilowatt, panels make 1.2 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.