Wind Turbine Payback in Boone County, IL
Wind turbine payback in Boone 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 Boone County, IL averages 6.05 m/s (13.5 mph). A 10 kW turbine there would make about 20,075 kWh a year, worth $3,860 at IL's 19.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 26 years, and the turbine is built to last about 20.
What to do in Boone County
A home turbine is not worth buying for savings in Boone County unless your spot is far windier than the county average, 6.8 m/s at the hub against 6.05 m/s here. Per kW, solar panels would make about 1,130 kWh a year here against the turbine's 2,008, so get a solar quote first.
What would have to change
- Power would have to cost 25¢/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 6.05. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IL
Boone County is the 769th 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 Boone County
April is the strongest month here, at 6.91 m/s and about 2,172 kWh. August is the weakest, 4.67 m/s and 881 kWh, so the best month makes 2.5 times the worst. November to March brings in 49% of the year's output in Boone County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.66 m/s | 2,091 kWh | $402 |
| February | 6.71 m/s | 1,913 kWh | $368 |
| March | 6.58 m/s | 2,035 kWh | $391 |
| April | 6.91 m/s | 2,172 kWh | $418 |
| May | 6.09 m/s | 1,727 kWh | $332 |
| June | 5.34 m/s | 1,222 kWh | $235 |
| July | 4.80 m/s | 953 kWh | $183 |
| August | 4.67 m/s | 881 kWh | $169 |
| September | 5.52 m/s | 1,332 kWh | $256 |
| October | 6.34 m/s | 1,890 kWh | $363 |
| November | 6.59 m/s | 1,980 kWh | $381 |
| December | 6.41 m/s | 1,929 kWh | $371 |
What a taller tower would buy
Measured at 10 m the wind in Boone County averages 4.72 m/s; at 50 m it is 6.79 m/s. That gives a shear exponent of 0.226, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,181 to 25,529 kWh a year, 58% 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 | 5.52 m/s | 16,181 kWh | 32 years |
| 30 m | 6.05 m/s | 20,072 kWh | 26 years |
| 40 m | 6.46 m/s | 23,083 kWh | 23 years |
| 50 m | 6.79 m/s | 25,529 kWh | 20 years |
Counties around Boone County
None of the 6 closest counties is windier than Boone County.
- Winnebago County, IL: 5.98 m/s, 19,556 kWh, payback 27 years (17 mi)
- McHenry County, IL: 6.05 m/s, 20,075 kWh, payback 26 years (19 mi)
- Rock County, WI: 5.98 m/s, 19,556 kWh, payback 27 years (27 mi)
- Walworth County, WI: 6.05 m/s, 20,075 kWh, payback 26 years (28 mi)
- DeKalb County, IL: 6.01 m/s, 19,778 kWh, payback 26 years (29 mi)
- Ogle County, IL: 5.97 m/s, 19,482 kWh, payback 27 years (32 mi)
Sun versus wind in Boone County
Boone County gets 3.87 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,130 kWh a year; one kW of the turbine above makes 2,008. 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.