Wind Turbine Payback in Fayette County, IL
Wind turbine payback in Fayette 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 Fayette County, IL averages 5.82 m/s (13 mph). A 10 kW turbine there would make about 18,374 kWh a year, worth $3,533 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 28 years, and the turbine is built to last about 20.
What to do in Fayette County
A home turbine is not worth buying for savings in Fayette County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.82 m/s here. Per kW, solar panels would make about 1,200 kWh a year here against the turbine's 1,837, so get a solar quote first.
What would have to change
- Power would have to cost 27¢/kWh, 1.4 times what IL pays now.
- Or the average wind at the hub would have to be 6.8 m/s instead of 5.82. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Fayette County is the 1,048th 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 Fayette County
April is the strongest month here, at 6.87 m/s and about 2,147 kWh. July is the weakest, 4.30 m/s and 696 kWh, so the best month makes 3.1 times the worst. November to March brings in 52% of the year's output in Fayette County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.55 m/s | 2,021 kWh | $389 |
| February | 6.51 m/s | 1,800 kWh | $346 |
| March | 6.64 m/s | 2,076 kWh | $399 |
| April | 6.87 m/s | 2,147 kWh | $413 |
| May | 5.84 m/s | 1,576 kWh | $303 |
| June | 5.03 m/s | 1,047 kWh | $201 |
| July | 4.30 m/s | 696 kWh | $134 |
| August | 4.36 m/s | 722 kWh | $139 |
| September | 4.88 m/s | 964 kWh | $185 |
| October | 6.04 m/s | 1,698 kWh | $327 |
| November | 6.51 m/s | 1,929 kWh | $371 |
| December | 6.33 m/s | 1,882 kWh | $362 |
What a taller tower would buy
Measured at 10 m the wind in Fayette County averages 4.48 m/s; at 50 m it is 6.57 m/s. That gives a shear exponent of 0.238, typical of ordinary open country. Going from 20 m to 50 m takes output from 14,486 to 23,922 kWh a year, 65% 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 | 5.28 m/s | 14,486 kWh | 36 years |
| 30 m | 5.82 m/s | 18,358 kWh | 28 years |
| 40 m | 6.23 m/s | 21,411 kWh | 24 years |
| 50 m | 6.57 m/s | 23,922 kWh | 22 years |
Counties around Fayette County
1 of the 6 closest counties is windier at turbine height; the windiest, Shelby County, averages 5.95 m/s.
- Effingham County, IL: 5.82 m/s, 18,374 kWh, payback 28 years (23 mi)
- Bond County, IL: 5.8 m/s, 18,226 kWh, payback 29 years (24 mi)
- Marion County, IL: 5.71 m/s, 17,565 kWh, payback 30 years (25 mi)
- Shelby County, IL: 5.95 m/s, 19,334 kWh, payback 27 years (29 mi)
- Montgomery County, IL: 5.8 m/s, 18,226 kWh, payback 29 years (29 mi)
- Clay County, IL: 5.71 m/s, 17,565 kWh, payback 30 years (34 mi)
Sun versus wind in Fayette County
Fayette County gets 4.11 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,200 kWh a year; one kW of the turbine above makes 1,837. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 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.