Wind Turbine Payback in Cumberland County, IL
Wind turbine payback in Cumberland 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 Cumberland 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 Cumberland County
A home turbine is not worth buying for savings in Cumberland 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 1,188 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
Cumberland 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 Cumberland County
April is the strongest month here, at 6.97 m/s and about 2,205 kWh. July is the weakest, 4.44 m/s and 762 kWh, so the best month makes 2.9 times the worst. November to March brings in 52% of the year's output in Cumberland County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.62 m/s | 2,065 kWh | $397 |
| February | 6.59 m/s | 1,845 kWh | $355 |
| March | 6.68 m/s | 2,098 kWh | $403 |
| April | 6.97 m/s | 2,205 kWh | $424 |
| May | 5.96 m/s | 1,646 kWh | $317 |
| June | 5.17 m/s | 1,124 kWh | $216 |
| July | 4.44 m/s | 762 kWh | $147 |
| August | 4.46 m/s | 771 kWh | $148 |
| September | 5.02 m/s | 1,044 kWh | $201 |
| October | 6.13 m/s | 1,753 kWh | $337 |
| November | 6.56 m/s | 1,961 kWh | $377 |
| December | 6.40 m/s | 1,926 kWh | $370 |
What a taller tower would buy
Measured at 10 m the wind in Cumberland County averages 4.58 m/s; at 50 m it is 6.66 m/s. That gives a shear exponent of 0.233, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,174 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 | 5.38 m/s | 15,174 kWh | 34 years |
| 30 m | 5.91 m/s | 19,058 kWh | 27 years |
| 40 m | 6.32 m/s | 22,096 kWh | 24 years |
| 50 m | 6.66 m/s | 24,582 kWh | 21 years |
Counties around Cumberland County
1 of the 6 closest counties is windier at turbine height; the windiest, Shelby County, averages 5.95 m/s.
- Coles County, IL: 5.91 m/s, 19,038 kWh, payback 27 years (17 mi)
- Jasper County, IL: 5.73 m/s, 17,712 kWh, payback 29 years (19 mi)
- Clark County, IL: 5.76 m/s, 17,932 kWh, payback 29 years (24 mi)
- Effingham County, IL: 5.82 m/s, 18,374 kWh, payback 28 years (24 mi)
- Shelby County, IL: 5.95 m/s, 19,334 kWh, payback 27 years (31 mi)
- Crawford County, IL: 5.61 m/s, 16,834 kWh, payback 31 years (32 mi)
Sun versus wind in Cumberland County
Cumberland County gets 4.07 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,188 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.