Wind Turbine Payback in Vermilion County, IL
Wind turbine payback in Vermilion 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 Vermilion County, IL averages 5.9 m/s (13.2 mph). A 10 kW turbine there would make about 18,964 kWh a year, worth $3,647 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 Vermilion County
A home turbine is not worth buying for savings in Vermilion County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.9 m/s here. Per kW, solar panels would make about 1,165 kWh a year here against the turbine's 1,896, 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 5.9. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Vermilion County is the 988th 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 Vermilion County
April is the strongest month here, at 6.92 m/s and about 2,175 kWh. July is the weakest, 4.43 m/s and 759 kWh, so the best month makes 2.9 times the worst. November to March brings in 51% of the year's output in Vermilion County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.61 m/s | 2,056 kWh | $395 |
| February | 6.56 m/s | 1,832 kWh | $352 |
| March | 6.62 m/s | 2,061 kWh | $396 |
| April | 6.92 m/s | 2,175 kWh | $418 |
| May | 5.97 m/s | 1,654 kWh | $318 |
| June | 5.15 m/s | 1,116 kWh | $215 |
| July | 4.43 m/s | 759 kWh | $146 |
| August | 4.47 m/s | 777 kWh | $149 |
| September | 5.06 m/s | 1,065 kWh | $205 |
| October | 6.12 m/s | 1,749 kWh | $336 |
| November | 6.57 m/s | 1,968 kWh | $378 |
| December | 6.41 m/s | 1,934 kWh | $372 |
What a taller tower would buy
Measured at 10 m the wind in Vermilion County averages 4.57 m/s; at 50 m it is 6.64 m/s. That gives a shear exponent of 0.232, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,094 to 24,436 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 | 15,094 kWh | 35 years |
| 30 m | 5.9 m/s | 18,949 kWh | 27 years |
| 40 m | 6.3 m/s | 21,966 kWh | 24 years |
| 50 m | 6.64 m/s | 24,436 kWh | 21 years |
Counties around Vermilion County
3 of the 6 closest counties are windier at turbine height; the windiest, Champaign County, averages 6 m/s.
- Warren County, IN: 5.99 m/s, 19,630 kWh, payback 30 years (22 mi)
- Champaign County, IL: 6 m/s, 19,704 kWh, payback 26 years (25 mi)
- Fountain County, IN: 5.9 m/s, 18,964 kWh, payback 31 years (26 mi)
- Vermillion County, IN: 5.9 m/s, 18,964 kWh, payback 31 years (27 mi)
- Edgar County, IL: 5.76 m/s, 17,932 kWh, payback 29 years (35 mi)
- Benton County, IN: 5.99 m/s, 19,630 kWh, payback 30 years (36 mi)
Sun versus wind in Vermilion County
Vermilion County gets 3.99 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,165 kWh a year; one kW of the turbine above makes 1,896. 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.