Wind Turbine Payback in St. Louis County, MO
Wind turbine payback in St. Louis 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. Louis County, MO averages 4.11 m/s (9.2 mph). A 10 kW turbine there would make about 7,143 kWh a year, worth $1,020 at MO's 14.28¢/kWh. Against an installed cost of about $100,000, that is a payback of 98 years, and the turbine is built to last about 20.
What to do in St. Louis County
A home turbine is not worth buying for savings in St. Louis County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.11 m/s here. Per kW, solar panels would make about 1,218 kWh a year here against the turbine's 714, so get a solar quote first.
What would have to change
- Power would have to cost 70¢/kWh, 4.9 times what MO pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.11. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MO
St. Louis County is the 1,990th 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. Louis County
March is the strongest month here, at 4.78 m/s and about 940 kWh. July is the weakest, 3.11 m/s and 250 kWh, so the best month makes 3.8 times the worst. November to March brings in 56% of the year's output in St. Louis County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.72 m/s | 908 kWh | $130 |
| February | 4.75 m/s | 837 kWh | $120 |
| March | 4.78 m/s | 940 kWh | $134 |
| April | 4.78 m/s | 910 kWh | $130 |
| May | 4.00 m/s | 558 kWh | $80 |
| June | 3.50 m/s | 355 kWh | $51 |
| July | 3.11 m/s | 250 kWh | $36 |
| August | 3.13 m/s | 255 kWh | $36 |
| September | 3.49 m/s | 352 kWh | $50 |
| October | 4.13 m/s | 617 kWh | $88 |
| November | 4.45 m/s | 744 kWh | $106 |
| December | 4.49 m/s | 790 kWh | $113 |
What a taller tower would buy
Measured at 10 m the wind in St. Louis County averages 2.8 m/s; at 50 m it is 4.91 m/s. That gives a shear exponent of 0.349, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,596 to 11,933 kWh a year, 160% 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 | 3.57 m/s | 4,596 kWh | over 100 years |
| 30 m | 4.11 m/s | 7,133 kWh | 98 years |
| 40 m | 4.54 m/s | 9,593 kWh | 73 years |
| 50 m | 4.91 m/s | 11,933 kWh | 59 years |
Counties around St. Louis County
5 of the 6 closest counties are windier at turbine height; the windiest, St. Charles County, averages 5.06 m/s.
- St. Louis city, MO: 5.05 m/s, 12,873 kWh, payback 54 years (11 mi)
- St. Charles County, MO: 5.06 m/s, 12,941 kWh, payback 54 years (16 mi)
- Jefferson County, MO: 4.11 m/s, 7,143 kWh, payback 98 years (27 mi)
- Monroe County, IL: 5.05 m/s, 12,873 kWh, payback 40 years (29 mi)
- St. Clair County, IL: 5.05 m/s, 12,873 kWh, payback 40 years (30 mi)
- Jersey County, IL: 5.06 m/s, 12,941 kWh, payback 40 years (31 mi)
Sun versus wind in St. Louis County
St. Louis County gets 4.17 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,218 kWh a year; one kW of the turbine above makes 714. Kilowatt for kilowatt, panels make 1.7 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.