Wind Turbine Payback in Trimble County, KY
Wind turbine payback in Trimble 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 Trimble County, KY averages 4.61 m/s (10.3 mph). A 10 kW turbine there would make about 10,008 kWh a year, worth $1,421 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 Trimble County
A home turbine is not worth buying for savings in Trimble County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.61 m/s here. Per kW, solar panels would make about 1,183 kWh a year here against the turbine's 1,001, so get a solar quote first.
What would have to change
- Power would have to cost 50¢/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 4.61. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of KY
Trimble County is the 1,685th 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 Trimble County
January is the strongest month here, at 5.41 m/s and about 1,309 kWh. July is the weakest, 3.38 m/s and 328 kWh, so the best month makes 4.0 times the worst. November to March brings in 57% of the year's output in Trimble County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.41 m/s | 1,309 kWh | $186 |
| February | 5.40 m/s | 1,173 kWh | $167 |
| March | 5.38 m/s | 1,288 kWh | $183 |
| April | 5.45 m/s | 1,287 kWh | $183 |
| May | 4.50 m/s | 793 kWh | $113 |
| June | 3.87 m/s | 488 kWh | $69 |
| July | 3.38 m/s | 328 kWh | $47 |
| August | 3.40 m/s | 333 kWh | $47 |
| September | 3.85 m/s | 482 kWh | $68 |
| October | 4.63 m/s | 860 kWh | $122 |
| November | 5.01 m/s | 1,034 kWh | $147 |
| December | 5.12 m/s | 1,134 kWh | $161 |
What a taller tower would buy
Measured at 10 m the wind in Trimble County averages 3.35 m/s; at 50 m it is 5.35 m/s. That gives a shear exponent of 0.291, typical of ordinary open country. Going from 20 m to 50 m takes output from 7,079 to 14,963 kWh a year, 111% 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 | 4.1 m/s | 7,079 kWh | 100 years |
| 30 m | 4.61 m/s | 10,015 kWh | 70 years |
| 40 m | 5.01 m/s | 12,627 kWh | 56 years |
| 50 m | 5.35 m/s | 14,963 kWh | 47 years |
Counties around Trimble County
1 of the 6 closest counties is windier at turbine height; the windiest, Jefferson County, averages 4.82 m/s.
- Jefferson County, IN: 4.82 m/s, 11,341 kWh, payback 52 years (12 mi)
- Carroll County, KY: 3.76 m/s, 5,432 kWh, payback over 100 years (13 mi)
- Oldham County, KY: 4.61 m/s, 10,008 kWh, payback 70 years (16 mi)
- Henry County, KY: 3.76 m/s, 5,432 kWh, payback over 100 years (17 mi)
- Clark County, IN: 4.61 m/s, 10,008 kWh, payback 59 years (22 mi)
- Scott County, IN: 4.61 m/s, 10,008 kWh, payback 59 years (22 mi)
Sun versus wind in Trimble County
Trimble County gets 4.05 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,183 kWh a year; one kW of the turbine above makes 1,001. 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.