Wind Turbine Payback in Pettis County, MO
Wind turbine payback in Pettis 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 Pettis County, MO averages 4.81 m/s (10.8 mph). A 10 kW turbine there would make about 11,276 kWh a year, worth $1,610 at MO's 14.28¢/kWh. Against an installed cost of about $100,000, that is a payback of 62 years, and the turbine is built to last about 20.
What to do in Pettis County
A home turbine is not worth buying for savings in Pettis County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.81 m/s here. Per kW, solar panels would make about 1,247 kWh a year here against the turbine's 1,128, so get a solar quote first.
What would have to change
- Power would have to cost 44¢/kWh, 3.1 times what MO pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.81. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MO
Pettis County is the 1,557th 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 Pettis County
March is the strongest month here, at 5.54 m/s and about 1,384 kWh. July is the weakest, 3.73 m/s and 450 kWh, so the best month makes 3.1 times the worst. November to March brings in 53% of the year's output in Pettis County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.33 m/s | 1,259 kWh | $180 |
| February | 5.38 m/s | 1,166 kWh | $167 |
| March | 5.54 m/s | 1,384 kWh | $198 |
| April | 5.57 m/s | 1,360 kWh | $194 |
| May | 4.73 m/s | 915 kWh | $131 |
| June | 4.29 m/s | 666 kWh | $95 |
| July | 3.73 m/s | 450 kWh | $64 |
| August | 3.79 m/s | 473 kWh | $68 |
| September | 4.15 m/s | 605 kWh | $86 |
| October | 4.87 m/s | 991 kWh | $142 |
| November | 5.19 m/s | 1,135 kWh | $162 |
| December | 5.13 m/s | 1,137 kWh | $162 |
What a taller tower would buy
Measured at 10 m the wind in Pettis County averages 3.44 m/s; at 50 m it is 5.62 m/s. That gives a shear exponent of 0.305, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 7,896 to 16,907 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 | 4.25 m/s | 7,896 kWh | 89 years |
| 30 m | 4.81 m/s | 11,271 kWh | 62 years |
| 40 m | 5.25 m/s | 14,258 kWh | 49 years |
| 50 m | 5.62 m/s | 16,907 kWh | 41 years |
Counties around Pettis County
4 of the 6 closest counties are windier at turbine height; the windiest, Saline County, averages 5.74 m/s.
- Cooper County, MO: 5.43 m/s, 15,534 kWh, payback 45 years (27 mi)
- Johnson County, MO: 5.42 m/s, 15,462 kWh, payback 45 years (28 mi)
- Saline County, MO: 5.74 m/s, 17,785 kWh, payback 39 years (29 mi)
- Benton County, MO: 4.81 m/s, 11,276 kWh, payback 62 years (29 mi)
- Morgan County, MO: 4.81 m/s, 11,276 kWh, payback 62 years (31 mi)
- Henry County, MO: 5.42 m/s, 15,462 kWh, payback 45 years (36 mi)
Sun versus wind in Pettis County
Pettis County gets 4.27 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,247 kWh a year; one kW of the turbine above makes 1,128. Kilowatt for kilowatt, panels make 1.1 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.