Wind Turbine Payback in Polk County, MO
Wind turbine payback in Polk 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 Polk County, MO averages 4.73 m/s (10.6 mph). A 10 kW turbine there would make about 10,762 kWh a year, worth $1,537 at MO's 14.28¢/kWh. Against an installed cost of about $100,000, that is a payback of 65 years, and the turbine is built to last about 20.
What to do in Polk County
A home turbine is not worth buying for savings in Polk County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.73 m/s here. Per kW, solar panels would make about 1,267 kWh a year here against the turbine's 1,076, so get a solar quote first.
What would have to change
- Power would have to cost 46¢/kWh, 3.3 times what MO pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.73. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MO
Polk County is the 1,596th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MO is Atchison County at 6.17 m/s, payback 33 years.
Month by month in Polk County
March is the strongest month here, at 5.47 m/s and about 1,344 kWh. July is the weakest, 3.65 m/s and 421 kWh, so the best month makes 3.2 times the worst. November to March brings in 53% of the year's output in Polk County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.24 m/s | 1,204 kWh | $172 |
| February | 5.34 m/s | 1,144 kWh | $163 |
| March | 5.47 m/s | 1,344 kWh | $192 |
| April | 5.52 m/s | 1,331 kWh | $190 |
| May | 4.71 m/s | 902 kWh | $129 |
| June | 4.20 m/s | 627 kWh | $90 |
| July | 3.65 m/s | 421 kWh | $60 |
| August | 3.72 m/s | 447 kWh | $64 |
| September | 4.06 m/s | 564 kWh | $81 |
| October | 4.77 m/s | 934 kWh | $133 |
| November | 5.10 m/s | 1,087 kWh | $155 |
| December | 5.08 m/s | 1,114 kWh | $159 |
What a taller tower would buy
Measured at 10 m the wind in Polk County averages 3.4 m/s; at 50 m it is 5.52 m/s. That gives a shear exponent of 0.301, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 7,566 to 16,181 kWh a year, 114% 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 | 4.19 m/s | 7,566 kWh | 93 years |
| 30 m | 4.73 m/s | 10,783 kWh | 65 years |
| 40 m | 5.16 m/s | 13,639 kWh | 51 years |
| 50 m | 5.52 m/s | 16,181 kWh | 43 years |
Counties around Polk County
3 of the 6 closest counties are windier at turbine height; the windiest, Cedar County, averages 5.73 m/s.
- Dallas County, MO: 4.73 m/s, 10,762 kWh, payback 65 years (21 mi)
- Hickory County, MO: 3.84 m/s, 5,800 kWh, payback over 100 years (23 mi)
- Greene County, MO: 4.73 m/s, 10,762 kWh, payback 65 years (25 mi)
- Cedar County, MO: 5.73 m/s, 17,712 kWh, payback 40 years (26 mi)
- Dade County, MO: 5.73 m/s, 17,712 kWh, payback 40 years (28 mi)
- St. Clair County, MO: 5.01 m/s, 12,602 kWh, payback 56 years (36 mi)
Sun versus wind in Polk County
Polk County gets 4.34 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,267 kWh a year; one kW of the turbine above makes 1,076. 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.