Wind Turbine Payback in McLean County, IL
Wind turbine payback in McLean 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 McLean County, IL averages 6.13 m/s (13.7 mph). A 10 kW turbine there would make about 20,668 kWh a year, worth $3,974 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 25 years, and the turbine is built to last about 20.
What to do in McLean County
A home turbine is not worth buying for savings in McLean County unless your spot is far windier than the county average, 6.8 m/s at the hub against 6.13 m/s here. Per kW, solar panels would make about 1,174 kWh a year here against the turbine's 2,067, so get a solar quote first.
What would have to change
- Power would have to cost 24¢/kWh, 1.3 times what IL pays now.
- Or the average wind at the hub would have to be 6.8 m/s instead of 6.13. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
McLean County is the 658th 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 McLean County
April is the strongest month here, at 7.17 m/s and about 2,322 kWh. August is the weakest, 4.61 m/s and 851 kWh, so the best month makes 2.7 times the worst. November to March brings in 51% of the year's output in McLean County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.80 m/s | 2,172 kWh | $418 |
| February | 6.72 m/s | 1,922 kWh | $370 |
| March | 6.81 m/s | 2,183 kWh | $420 |
| April | 7.17 m/s | 2,322 kWh | $447 |
| May | 6.23 m/s | 1,821 kWh | $350 |
| June | 5.38 m/s | 1,246 kWh | $240 |
| July | 4.62 m/s | 855 kWh | $164 |
| August | 4.61 m/s | 851 kWh | $164 |
| September | 5.32 m/s | 1,210 kWh | $233 |
| October | 6.41 m/s | 1,933 kWh | $372 |
| November | 6.86 m/s | 2,139 kWh | $411 |
| December | 6.65 m/s | 2,084 kWh | $401 |
What a taller tower would buy
Measured at 10 m the wind in McLean County averages 4.79 m/s; at 50 m it is 6.87 m/s. That gives a shear exponent of 0.224, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,727 to 26,109 kWh a year, 56% 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 | 5.6 m/s | 16,727 kWh | 31 years |
| 30 m | 6.13 m/s | 20,647 kWh | 25 years |
| 40 m | 6.54 m/s | 23,665 kWh | 22 years |
| 50 m | 6.87 m/s | 26,109 kWh | 20 years |
Counties around McLean County
None of the 6 closest counties is windier than McLean County.
- De Witt County, IL: 6.04 m/s, 20,001 kWh, payback 26 years (22 mi)
- Woodford County, IL: 6.03 m/s, 19,926 kWh, payback 26 years (28 mi)
- Livingston County, IL: 6.04 m/s, 20,001 kWh, payback 26 years (32 mi)
- Ford County, IL: 6.07 m/s, 20,223 kWh, payback 26 years (33 mi)
- Tazewell County, IL: 6.02 m/s, 19,852 kWh, payback 26 years (35 mi)
- Piatt County, IL: 6.04 m/s, 20,001 kWh, payback 26 years (36 mi)
Sun versus wind in McLean County
McLean County gets 4.02 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,174 kWh a year; one kW of the turbine above makes 2,067. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.8 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.