Wind Turbine Payback in Metcalfe County, KY
Wind turbine payback in Metcalfe 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 Metcalfe County, KY averages 4.28 m/s (9.6 mph). A 10 kW turbine there would make about 8,064 kWh a year, worth $1,145 at KY's 14.2¢/kWh. Against an installed cost of about $100,000, that is a payback of 87 years, and the turbine is built to last about 20.
What to do in Metcalfe County
A home turbine is not worth buying for savings in Metcalfe County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.28 m/s here. Per kW, solar panels would make about 1,226 kWh a year here against the turbine's 806, so get a solar quote first.
What would have to change
- Power would have to cost 62¢/kWh, 4.4 times what KY pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.28. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of KY
Metcalfe County is the 1,903rd 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 Metcalfe County
March is the strongest month here, at 5.11 m/s and about 1,127 kWh. August is the weakest, 3.18 m/s and 268 kWh, so the best month makes 4.2 times the worst. November to March brings in 57% of the year's output in Metcalfe County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.00 m/s | 1,063 kWh | $151 |
| February | 5.09 m/s | 1,009 kWh | $143 |
| March | 5.11 m/s | 1,127 kWh | $160 |
| April | 5.09 m/s | 1,081 kWh | $154 |
| May | 4.15 m/s | 627 kWh | $89 |
| June | 3.57 m/s | 378 kWh | $54 |
| July | 3.23 m/s | 282 kWh | $40 |
| August | 3.18 m/s | 268 kWh | $38 |
| September | 3.56 m/s | 375 kWh | $53 |
| October | 4.20 m/s | 646 kWh | $92 |
| November | 4.58 m/s | 808 kWh | $115 |
| December | 4.75 m/s | 925 kWh | $131 |
What a taller tower would buy
Measured at 10 m the wind in Metcalfe County averages 3.03 m/s; at 50 m it is 5.03 m/s. That gives a shear exponent of 0.315, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 5,472 to 12,737 kWh a year, 133% 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 | 3.77 m/s | 5,472 kWh | over 100 years |
| 30 m | 4.28 m/s | 8,077 kWh | 87 years |
| 40 m | 4.69 m/s | 10,499 kWh | 67 years |
| 50 m | 5.03 m/s | 12,737 kWh | 55 years |
Counties around Metcalfe County
2 of the 6 closest counties are windier at turbine height; the windiest, Green County, averages 4.45 m/s.
- Barren County, KY: 4.28 m/s, 8,064 kWh, payback 87 years (17 mi)
- Monroe County, KY: 3.62 m/s, 4,820 kWh, payback over 100 years (20 mi)
- Cumberland County, KY: 4.28 m/s, 8,064 kWh, payback 87 years (20 mi)
- Green County, KY: 4.45 m/s, 9,041 kWh, payback 78 years (20 mi)
- Adair County, KY: 4 m/s, 6,577 kWh, payback over 100 years (21 mi)
- Hart County, KY: 4.45 m/s, 9,041 kWh, payback 78 years (26 mi)
Sun versus wind in Metcalfe County
Metcalfe County gets 4.2 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,226 kWh a year; one kW of the turbine above makes 806. Kilowatt for kilowatt, panels make 1.5 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.