Wind Turbine Payback in Cerro Gordo County, IA
Wind turbine payback in Cerro Gordo 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 Cerro Gordo County, IA averages 6.33 m/s (14.2 mph). A 10 kW turbine there would make about 22,151 kWh a year, worth $3,223 at IA's 14.55¢/kWh. Against an installed cost of about $100,000, that is a payback of 31 years, and the turbine is built to last about 20.
What to do in Cerro Gordo County
A home turbine is not worth buying for savings in Cerro Gordo County unless your spot is far windier than the county average, 8.1 m/s at the hub against 6.33 m/s here. Per kW, solar panels would make about 1,159 kWh a year here against the turbine's 2,215, so get a solar quote first.
What would have to change
- Power would have to cost 23¢/kWh, 1.6 times what IA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 6.33. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IA
Cerro Gordo County is the 441st windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in IA is Dickinson County at 6.59 m/s, payback 29 years.
Month by month in Cerro Gordo County
April is the strongest month here, at 7.24 m/s and about 2,362 kWh. August is the weakest, 4.97 m/s and 1,047 kWh, so the best month makes 2.3 times the worst. November to March brings in 47% of the year's output in Cerro Gordo County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.80 m/s | 2,175 kWh | $316 |
| February | 6.78 m/s | 1,955 kWh | $284 |
| March | 6.89 m/s | 2,230 kWh | $324 |
| April | 7.24 m/s | 2,362 kWh | $344 |
| May | 6.56 m/s | 2,025 kWh | $295 |
| June | 5.80 m/s | 1,498 kWh | $218 |
| July | 5.00 m/s | 1,067 kWh | $155 |
| August | 4.97 m/s | 1,047 kWh | $152 |
| September | 6.03 m/s | 1,639 kWh | $238 |
| October | 6.58 m/s | 2,037 kWh | $296 |
| November | 6.75 m/s | 2,073 kWh | $302 |
| December | 6.60 m/s | 2,053 kWh | $299 |
What a taller tower would buy
Measured at 10 m the wind in Cerro Gordo County averages 4.97 m/s; at 50 m it is 7.08 m/s. That gives a shear exponent of 0.220, typical of ordinary open country. Going from 20 m to 50 m takes output from 18,134 to 27,613 kWh a year, 52% 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 | 5.79 m/s | 18,134 kWh | 38 years |
| 30 m | 6.33 m/s | 22,132 kWh | 31 years |
| 40 m | 6.74 m/s | 25,172 kWh | 27 years |
| 50 m | 7.08 m/s | 27,613 kWh | 25 years |
Counties around Cerro Gordo County
4 of the 6 closest counties are windier at turbine height; the windiest, Winnebago County, averages 6.47 m/s.
- Worth County, IA: 6.43 m/s, 22,891 kWh, payback 30 years (21 mi)
- Franklin County, IA: 6.32 m/s, 22,077 kWh, payback 31 years (23 mi)
- Floyd County, IA: 6.21 m/s, 21,262 kWh, payback 32 years (23 mi)
- Hancock County, IA: 6.44 m/s, 22,964 kWh, payback 30 years (25 mi)
- Mitchell County, IA: 6.37 m/s, 22,447 kWh, payback 31 years (30 mi)
- Winnebago County, IA: 6.47 m/s, 23,186 kWh, payback 30 years (32 mi)
Sun versus wind in Cerro Gordo County
Cerro Gordo County gets 3.97 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,159 kWh a year; one kW of the turbine above makes 2,215. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.9 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.