Wind Turbine Payback in Edgar County, IL
Wind turbine payback in Edgar 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 Edgar County, IL averages 5.76 m/s (12.9 mph). A 10 kW turbine there would make about 17,932 kWh a year, worth $3,448 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 29 years, and the turbine is built to last about 20.
What to do in Edgar County
A home turbine is not worth buying for savings in Edgar County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.76 m/s here. Per kW, solar panels would make about 1,180 kWh a year here against the turbine's 1,793, so get a solar quote first.
What would have to change
- Power would have to cost 28¢/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 5.76. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Edgar County is the 1,103rd 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 Edgar County
April is the strongest month here, at 6.78 m/s and about 2,094 kWh. July is the weakest, 4.29 m/s and 692 kWh, so the best month makes 3.0 times the worst. November to March brings in 52% of the year's output in Edgar County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.48 m/s | 1,977 kWh | $380 |
| February | 6.45 m/s | 1,765 kWh | $339 |
| March | 6.53 m/s | 2,004 kWh | $385 |
| April | 6.78 m/s | 2,094 kWh | $403 |
| May | 5.79 m/s | 1,543 kWh | $297 |
| June | 5.01 m/s | 1,037 kWh | $199 |
| July | 4.29 m/s | 692 kWh | $133 |
| August | 4.33 m/s | 709 kWh | $136 |
| September | 4.91 m/s | 978 kWh | $188 |
| October | 5.95 m/s | 1,643 kWh | $316 |
| November | 6.38 m/s | 1,854 kWh | $357 |
| December | 6.25 m/s | 1,832 kWh | $352 |
What a taller tower would buy
Measured at 10 m the wind in Edgar County averages 4.43 m/s; at 50 m it is 6.5 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 14,091 to 23,407 kWh a year, 66% 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 | 5.23 m/s | 14,091 kWh | 37 years |
| 30 m | 5.76 m/s | 17,902 kWh | 29 years |
| 40 m | 6.16 m/s | 20,919 kWh | 25 years |
| 50 m | 6.5 m/s | 23,407 kWh | 22 years |
Counties around Edgar County
4 of the 6 closest counties are windier at turbine height; the windiest, Douglas County, averages 6 m/s.
- Vermillion County, IN: 5.9 m/s, 18,964 kWh, payback 31 years (19 mi)
- Clark County, IL: 5.76 m/s, 17,932 kWh, payback 29 years (24 mi)
- Vigo County, IN: 5.76 m/s, 17,932 kWh, payback 33 years (26 mi)
- Douglas County, IL: 6 m/s, 19,704 kWh, payback 26 years (26 mi)
- Coles County, IL: 5.91 m/s, 19,038 kWh, payback 27 years (28 mi)
- Parke County, IN: 5.9 m/s, 18,964 kWh, payback 31 years (30 mi)
Sun versus wind in Edgar County
Edgar County gets 4.04 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,180 kWh a year; one kW of the turbine above makes 1,793. 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.