Wind Turbine Payback in Humboldt County, IA
Wind turbine payback in Humboldt 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 Humboldt County, IA averages 6.46 m/s (14.5 mph). A 10 kW turbine there would make about 23,112 kWh a year, worth $3,363 at IA's 14.55¢/kWh. Against an installed cost of about $100,000, that is a payback of 30 years, and the turbine is built to last about 20.
What to do in Humboldt County
A home turbine is not worth buying for savings in Humboldt County unless your spot is far windier than the county average, 8.1 m/s at the hub against 6.46 m/s here. Per kW, solar panels would make about 1,186 kWh a year here against the turbine's 2,311, so get a solar quote first.
What would have to change
- Power would have to cost 22¢/kWh, 1.5 times what IA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 6.46. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IA
Humboldt County is the 239th 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 Humboldt County
April is the strongest month here, at 7.34 m/s and about 2,418 kWh. August is the weakest, 5.22 m/s and 1,193 kWh, so the best month makes 2.0 times the worst. November to March brings in 46% of the year's output in Humboldt County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.79 m/s | 2,168 kWh | $315 |
| February | 6.80 m/s | 1,963 kWh | $286 |
| March | 6.96 m/s | 2,272 kWh | $331 |
| April | 7.34 m/s | 2,418 kWh | $352 |
| May | 6.69 m/s | 2,107 kWh | $307 |
| June | 5.99 m/s | 1,614 kWh | $235 |
| July | 5.26 m/s | 1,220 kWh | $178 |
| August | 5.22 m/s | 1,193 kWh | $174 |
| September | 6.25 m/s | 1,773 kWh | $258 |
| October | 6.73 m/s | 2,129 kWh | $310 |
| November | 6.83 m/s | 2,125 kWh | $309 |
| December | 6.67 m/s | 2,096 kWh | $305 |
What a taller tower would buy
Measured at 10 m the wind in Humboldt County averages 5.11 m/s; at 50 m it is 7.2 m/s. That gives a shear exponent of 0.213, typical of ordinary open country. Going from 20 m to 50 m takes output from 19,137 to 28,461 kWh a year, 49% 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 | 5.92 m/s | 19,137 kWh | 36 years |
| 30 m | 6.46 m/s | 23,095 kWh | 30 years |
| 40 m | 6.87 m/s | 26,078 kWh | 26 years |
| 50 m | 7.2 m/s | 28,461 kWh | 24 years |
Counties around Humboldt County
None of the 6 closest counties is windier than Humboldt County.
- Wright County, IA: 6.4 m/s, 22,669 kWh, payback 30 years (24 mi)
- Webster County, IA: 6.4 m/s, 22,669 kWh, payback 30 years (24 mi)
- Pocahontas County, IA: 6.4 m/s, 22,669 kWh, payback 30 years (24 mi)
- Kossuth County, IA: 6.46 m/s, 23,112 kWh, payback 30 years (30 mi)
- Hancock County, IA: 6.44 m/s, 22,964 kWh, payback 30 years (31 mi)
- Palo Alto County, IA: 6.46 m/s, 23,112 kWh, payback 30 years (31 mi)
Sun versus wind in Humboldt County
Humboldt County gets 4.06 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,186 kWh a year; one kW of the turbine above makes 2,311. 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.