Wind Turbine Payback in McDonough County, IL
Wind turbine payback in McDonough 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 McDonough County, IL averages 5.94 m/s (13.3 mph). A 10 kW turbine there would make about 19,260 kWh a year, worth $3,704 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 27 years, and the turbine is built to last about 20.
What to do in McDonough County
A home turbine is not worth buying for savings in McDonough County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.94 m/s here. Per kW, solar panels would make about 1,186 kWh a year here against the turbine's 1,926, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/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 5.94. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
McDonough County is the 934th 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 McDonough County
April is the strongest month here, at 6.87 m/s and about 2,147 kWh. August is the weakest, 4.58 m/s and 835 kWh, so the best month makes 2.6 times the worst. November to March brings in 50% of the year's output in McDonough County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.52 m/s | 1,998 kWh | $384 |
| February | 6.47 m/s | 1,780 kWh | $342 |
| March | 6.66 m/s | 2,087 kWh | $401 |
| April | 6.87 m/s | 2,147 kWh | $413 |
| May | 5.97 m/s | 1,652 kWh | $318 |
| June | 5.29 m/s | 1,196 kWh | $230 |
| July | 4.60 m/s | 844 kWh | $162 |
| August | 4.58 m/s | 835 kWh | $161 |
| September | 5.27 m/s | 1,185 kWh | $228 |
| October | 6.21 m/s | 1,809 kWh | $348 |
| November | 6.55 m/s | 1,955 kWh | $376 |
| December | 6.32 m/s | 1,876 kWh | $361 |
What a taller tower would buy
Measured at 10 m the wind in McDonough County averages 4.6 m/s; at 50 m it is 6.69 m/s. That gives a shear exponent of 0.233, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,347 to 24,801 kWh a year, 62% 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 | 5.4 m/s | 15,347 kWh | 34 years |
| 30 m | 5.94 m/s | 19,255 kWh | 27 years |
| 40 m | 6.35 m/s | 22,307 kWh | 23 years |
| 50 m | 6.69 m/s | 24,801 kWh | 21 years |
Counties around McDonough County
3 of the 6 closest counties are windier at turbine height; the windiest, Warren County, averages 6.02 m/s.
- Schuyler County, IL: 5.85 m/s, 18,595 kWh, payback 28 years (21 mi)
- Fulton County, IL: 5.94 m/s, 19,260 kWh, payback 27 years (25 mi)
- Hancock County, IL: 5.96 m/s, 19,408 kWh, payback 27 years (26 mi)
- Warren County, IL: 6.02 m/s, 19,852 kWh, payback 26 years (27 mi)
- Henderson County, IL: 6 m/s, 19,704 kWh, payback 26 years (28 mi)
- Brown County, IL: 5.85 m/s, 18,595 kWh, payback 28 years (34 mi)
Sun versus wind in McDonough County
McDonough County gets 4.06 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,186 kWh a year; one kW of the turbine above makes 1,926. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.6 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.