Wind Turbine Payback in Adams County, IL
Wind turbine payback in Adams 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 Adams County, IL averages 5.85 m/s (13.1 mph). A 10 kW turbine there would make about 18,595 kWh a year, worth $3,576 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 28 years, and the turbine is built to last about 20.
What to do in Adams County
A home turbine is not worth buying for savings in Adams County unless your spot is far windier than the county average, 6.8 m/s at the hub against 5.85 m/s here. Per kW, solar panels would make about 1,215 kWh a year here against the turbine's 1,860, so get a solar quote first.
What would have to change
- Power would have to cost 27¢/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 5.85. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Adams County is the 1,036th 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 Adams County
April is the strongest month here, at 6.75 m/s and about 2,074 kWh. August is the weakest, 4.53 m/s and 810 kWh, so the best month makes 2.6 times the worst. November to March brings in 50% of the year's output in Adams County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.44 m/s | 1,950 kWh | $375 |
| February | 6.39 m/s | 1,731 kWh | $333 |
| March | 6.57 m/s | 2,033 kWh | $391 |
| April | 6.75 m/s | 2,074 kWh | $399 |
| May | 5.84 m/s | 1,576 kWh | $303 |
| June | 5.24 m/s | 1,167 kWh | $224 |
| July | 4.56 m/s | 823 kWh | $158 |
| August | 4.53 m/s | 810 kWh | $156 |
| September | 5.16 m/s | 1,121 kWh | $216 |
| October | 6.11 m/s | 1,743 kWh | $335 |
| November | 6.47 m/s | 1,908 kWh | $367 |
| December | 6.26 m/s | 1,838 kWh | $353 |
What a taller tower would buy
Measured at 10 m the wind in Adams County averages 4.52 m/s; at 50 m it is 6.6 m/s. That gives a shear exponent of 0.235, typical of ordinary open country. Going from 20 m to 50 m takes output from 14,760 to 24,142 kWh a year, 64% 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 | 5.32 m/s | 14,760 kWh | 35 years |
| 30 m | 5.85 m/s | 18,620 kWh | 28 years |
| 40 m | 6.26 m/s | 21,653 kWh | 24 years |
| 50 m | 6.6 m/s | 24,142 kWh | 22 years |
Counties around Adams County
1 of the 6 closest counties is windier at turbine height; the windiest, Hancock County, averages 5.96 m/s.
- Brown County, IL: 5.85 m/s, 18,595 kWh, payback 28 years (24 mi)
- Marion County, MO: 5.77 m/s, 18,006 kWh, payback 39 years (26 mi)
- Hancock County, IL: 5.96 m/s, 19,408 kWh, payback 27 years (29 mi)
- Lewis County, MO: 5.77 m/s, 18,006 kWh, payback 39 years (29 mi)
- Pike County, IL: 5.67 m/s, 17,272 kWh, payback 30 years (30 mi)
- Schuyler County, IL: 5.85 m/s, 18,595 kWh, payback 28 years (33 mi)
Sun versus wind in Adams County
Adams County gets 4.16 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,215 kWh a year; one kW of the turbine above makes 1,860. 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.