Wind Turbine Payback in Madison County, IL
Wind turbine payback in Madison 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 Madison County, IL averages 5.57 m/s (12.5 mph). A 10 kW turbine there would make about 16,544 kWh a year, worth $3,181 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 31 years, and the turbine is built to last about 20.
What to do in Madison County
A home turbine is not worth buying for savings in Madison County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.57 m/s here. Per kW, solar panels would make about 1,221 kWh a year here against the turbine's 1,654, so get a solar quote first.
What would have to change
- Power would have to cost 30¢/kWh, 1.6 times what IL pays now.
- Or the average wind at the hub would have to be 6.8 m/s instead of 5.57. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Madison County is the 1,180th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in IL is Cook County at 6.73 m/s, payback 21 years.
Month by month in Madison County
April is the strongest month here, at 6.54 m/s and about 1,948 kWh. July is the weakest, 4.17 m/s and 633 kWh, so the best month makes 3.1 times the worst. November to March brings in 53% of the year's output in Madison County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.28 m/s | 1,853 kWh | $356 |
| February | 6.25 m/s | 1,654 kWh | $318 |
| March | 6.36 m/s | 1,903 kWh | $366 |
| April | 6.54 m/s | 1,948 kWh | $375 |
| May | 5.54 m/s | 1,389 kWh | $267 |
| June | 4.80 m/s | 919 kWh | $177 |
| July | 4.17 m/s | 633 kWh | $122 |
| August | 4.20 m/s | 646 kWh | $124 |
| September | 4.71 m/s | 873 kWh | $168 |
| October | 5.78 m/s | 1,537 kWh | $296 |
| November | 6.21 m/s | 1,750 kWh | $337 |
| December | 6.10 m/s | 1,736 kWh | $334 |
What a taller tower would buy
Measured at 10 m the wind in Madison County averages 4.25 m/s; at 50 m it is 6.32 m/s. That gives a shear exponent of 0.247, typical of ordinary open country. Going from 20 m to 50 m takes output from 12,805 to 22,077 kWh a year, 72% 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 | 5.04 m/s | 12,805 kWh | 41 years |
| 30 m | 5.57 m/s | 16,550 kWh | 31 years |
| 40 m | 5.98 m/s | 19,564 kWh | 27 years |
| 50 m | 6.32 m/s | 22,077 kWh | 24 years |
Counties around Madison County
3 of the 6 closest counties are windier at turbine height; the windiest, Macoupin County, averages 5.84 m/s.
- St. Louis city, MO: 5.05 m/s, 12,873 kWh, payback 54 years (23 mi)
- St. Clair County, IL: 5.05 m/s, 12,873 kWh, payback 40 years (25 mi)
- Bond County, IL: 5.8 m/s, 18,226 kWh, payback 29 years (25 mi)
- Clinton County, IL: 5.65 m/s, 17,126 kWh, payback 30 years (30 mi)
- Jersey County, IL: 5.06 m/s, 12,941 kWh, payback 40 years (30 mi)
- Macoupin County, IL: 5.84 m/s, 18,521 kWh, payback 28 years (30 mi)
Sun versus wind in Madison County
Madison County gets 4.18 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,221 kWh a year; one kW of the turbine above makes 1,654. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.4 times. 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.