Wind Turbine Payback in Christian County, IL
Wind turbine payback in Christian 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 Christian County, IL averages 5.91 m/s (13.2 mph). A 10 kW turbine there would make about 19,038 kWh a year, worth $3,661 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 Christian County
A home turbine is not worth buying for savings in Christian County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.91 m/s here. Per kW, solar panels would make about 1,200 kWh a year here against the turbine's 1,904, 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 5.91. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Christian County is the 978th 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 Christian County
April is the strongest month here, at 6.94 m/s and about 2,187 kWh. July is the weakest, 4.42 m/s and 752 kWh, so the best month makes 2.9 times the worst. November to March brings in 52% of the year's output in Christian County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.62 m/s | 2,063 kWh | $397 |
| February | 6.55 m/s | 1,823 kWh | $351 |
| March | 6.66 m/s | 2,085 kWh | $401 |
| April | 6.94 m/s | 2,187 kWh | $421 |
| May | 5.94 m/s | 1,633 kWh | $314 |
| June | 5.16 m/s | 1,118 kWh | $215 |
| July | 4.42 m/s | 752 kWh | $145 |
| August | 4.45 m/s | 766 kWh | $147 |
| September | 5.00 m/s | 1,033 kWh | $199 |
| October | 6.17 m/s | 1,779 kWh | $342 |
| November | 6.64 m/s | 2,007 kWh | $386 |
| December | 6.46 m/s | 1,963 kWh | $377 |
What a taller tower would buy
Measured at 10 m the wind in Christian County averages 4.57 m/s; at 50 m it is 6.66 m/s. That gives a shear exponent of 0.234, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,139 to 24,582 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 | 5.37 m/s | 15,139 kWh | 34 years |
| 30 m | 5.91 m/s | 19,035 kWh | 27 years |
| 40 m | 6.32 m/s | 22,086 kWh | 24 years |
| 50 m | 6.66 m/s | 24,582 kWh | 21 years |
Counties around Christian County
4 of the 6 closest counties are windier at turbine height; the windiest, Macon County, averages 6.04 m/s.
- Montgomery County, IL: 5.8 m/s, 18,226 kWh, payback 29 years (24 mi)
- Sangamon County, IL: 5.95 m/s, 19,334 kWh, payback 27 years (25 mi)
- Macon County, IL: 6.04 m/s, 20,001 kWh, payback 26 years (28 mi)
- Shelby County, IL: 5.95 m/s, 19,334 kWh, payback 27 years (28 mi)
- Moultrie County, IL: 5.95 m/s, 19,334 kWh, payback 27 years (35 mi)
- Macoupin County, IL: 5.84 m/s, 18,521 kWh, payback 28 years (40 mi)
Sun versus wind in Christian County
Christian 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 1,904. 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.