Wind Turbine Payback in St. Francois County, MO
Wind turbine payback in St. Francois 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 St. Francois County, MO averages 3.59 m/s (8 mph). A 10 kW turbine there would make about 4,694 kWh a year, worth $670 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 St. Francois County
A home turbine is not worth buying for savings in St. Francois County unless your spot is far windier than the county average, 8.2 m/s at the hub against 3.59 m/s here. Per kW, solar panels would make about 1,241 kWh a year here against the turbine's 469, so get a solar quote first.
What would have to change
- Power would have to cost 107¢/kWh, 7.5 times what MO pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 3.59. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MO
St. Francois County is the 2,419th 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 St. Francois County
March is the strongest month here, at 4.18 m/s and about 640 kWh. July is the weakest, 2.75 m/s and 162 kWh, so the best month makes 4.0 times the worst. November to March brings in 57% of the year's output in St. Francois County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.13 m/s | 615 kWh | $88 |
| February | 4.19 m/s | 582 kWh | $83 |
| March | 4.18 m/s | 640 kWh | $91 |
| April | 4.16 m/s | 609 kWh | $87 |
| May | 3.49 m/s | 363 kWh | $52 |
| June | 3.07 m/s | 231 kWh | $33 |
| July | 2.75 m/s | 162 kWh | $23 |
| August | 2.78 m/s | 169 kWh | $24 |
| September | 3.07 m/s | 231 kWh | $33 |
| October | 3.57 m/s | 393 kWh | $56 |
| November | 3.86 m/s | 486 kWh | $69 |
| December | 3.91 m/s | 522 kWh | $75 |
What a taller tower would buy
Measured at 10 m the wind in St. Francois County averages 2.24 m/s; at 50 m it is 4.47 m/s. That gives a shear exponent of 0.429, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,652 to 9,160 kWh a year, 245% 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 | 3.02 m/s | 2,652 kWh | over 100 years |
| 30 m | 3.59 m/s | 4,696 kWh | over 100 years |
| 40 m | 4.06 m/s | 6,893 kWh | over 100 years |
| 50 m | 4.47 m/s | 9,160 kWh | 77 years |
Counties around St. Francois County
3 of the 6 closest counties are windier at turbine height; the windiest, Monroe County, averages 5.05 m/s.
- Iron County, MO: 3.41 m/s, 3,980 kWh, payback over 100 years (18 mi)
- Ste. Genevieve County, MO: 4.69 m/s, 10,508 kWh, payback 67 years (18 mi)
- Madison County, MO: 3.41 m/s, 3,980 kWh, payback over 100 years (24 mi)
- Washington County, MO: 3.59 m/s, 4,694 kWh, payback over 100 years (25 mi)
- Jefferson County, MO: 4.11 m/s, 7,143 kWh, payback 98 years (31 mi)
- Monroe County, IL: 5.05 m/s, 12,873 kWh, payback 40 years (36 mi)
Sun versus wind in St. Francois County
St. Francois County gets 4.25 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,241 kWh a year; one kW of the turbine above makes 469. Kilowatt for kilowatt, panels make 2.6 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.