Wind Turbine Payback in Franklin County, MO
Wind turbine payback in Franklin 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 Franklin County, MO averages 3.63 m/s (8.1 mph). A 10 kW turbine there would make about 4,862 kWh a year, worth $694 at MO's 14.28¢/kWh. Against an installed cost of about $100,000, that is a payback of over 100 years, and the turbine is built to last about 20.
What to do in Franklin County
A home turbine is not worth buying for savings in Franklin County unless your spot is far windier than the county average, 8.2 m/s at the hub against 3.63 m/s here. Per kW, solar panels would make about 1,235 kWh a year here against the turbine's 486, so get a solar quote first.
What would have to change
- Power would have to cost 103¢/kWh, 7.2 times what MO pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 3.63. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MO
Franklin County is the 2,354th 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 Franklin County
March is the strongest month here, at 4.22 m/s and about 657 kWh. July is the weakest, 2.81 m/s and 175 kWh, so the best month makes 3.8 times the worst. November to March brings in 56% of the year's output in Franklin County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.14 m/s | 620 kWh | $89 |
| February | 4.20 m/s | 583 kWh | $83 |
| March | 4.22 m/s | 657 kWh | $94 |
| April | 4.19 m/s | 621 kWh | $89 |
| May | 3.53 m/s | 376 kWh | $54 |
| June | 3.13 m/s | 247 kWh | $35 |
| July | 2.81 m/s | 175 kWh | $25 |
| August | 2.82 m/s | 179 kWh | $26 |
| September | 3.13 m/s | 247 kWh | $35 |
| October | 3.65 m/s | 419 kWh | $60 |
| November | 3.89 m/s | 496 kWh | $71 |
| December | 3.92 m/s | 526 kWh | $75 |
What a taller tower would buy
Measured at 10 m the wind in Franklin County averages 2.3 m/s; at 50 m it is 4.49 m/s. That gives a shear exponent of 0.416, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,803 to 9,279 kWh a year, 231% 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 | 3.07 m/s | 2,803 kWh | over 100 years |
| 30 m | 3.63 m/s | 4,864 kWh | over 100 years |
| 40 m | 4.09 m/s | 7,048 kWh | 99 years |
| 50 m | 4.49 m/s | 9,279 kWh | 76 years |
Counties around Franklin County
3 of the 6 closest counties are windier at turbine height; the windiest, St. Charles County, averages 5.06 m/s.
- Gasconade County, MO: 3.63 m/s, 4,862 kWh, payback over 100 years (24 mi)
- Warren County, MO: 4.55 m/s, 9,641 kWh, payback 73 years (25 mi)
- Jefferson County, MO: 4.11 m/s, 7,143 kWh, payback 98 years (31 mi)
- St. Charles County, MO: 5.06 m/s, 12,941 kWh, payback 54 years (33 mi)
- Crawford County, MO: 3.44 m/s, 4,094 kWh, payback over 100 years (34 mi)
- Washington County, MO: 3.59 m/s, 4,694 kWh, payback over 100 years (34 mi)
Sun versus wind in Franklin County
Franklin County gets 4.23 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,235 kWh a year; one kW of the turbine above makes 486. Kilowatt for kilowatt, panels make 2.5 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.