Wind Turbine Payback in Delaware County, IA
Wind turbine payback in Delaware 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 Delaware County, IA averages 6.06 m/s (13.6 mph). A 10 kW turbine there would make about 20,149 kWh a year, worth $2,932 at IA's 14.55¢/kWh. Against an installed cost of about $100,000, that is a payback of 34 years, and the turbine is built to last about 20.
What to do in Delaware County
A home turbine is not worth buying for savings in Delaware County unless your spot is far windier than the county average, 8.1 m/s at the hub against 6.06 m/s here. Per kW, solar panels would make about 1,156 kWh a year here against the turbine's 2,015, so get a solar quote first.
What would have to change
- Power would have to cost 25¢/kWh, 1.7 times what IA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 6.06. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IA
Delaware County is the 747th 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 Delaware County
April is the strongest month here, at 6.92 m/s and about 2,177 kWh. August is the weakest, 4.77 m/s and 934 kWh, so the best month makes 2.3 times the worst. November to March brings in 48% of the year's output in Delaware County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.53 m/s | 2,007 kWh | $292 |
| February | 6.62 m/s | 1,863 kWh | $271 |
| March | 6.63 m/s | 2,068 kWh | $301 |
| April | 6.92 m/s | 2,177 kWh | $317 |
| May | 6.20 m/s | 1,800 kWh | $262 |
| June | 5.44 m/s | 1,285 kWh | $187 |
| July | 4.78 m/s | 939 kWh | $137 |
| August | 4.77 m/s | 934 kWh | $136 |
| September | 5.68 m/s | 1,428 kWh | $208 |
| October | 6.37 m/s | 1,907 kWh | $277 |
| November | 6.50 m/s | 1,926 kWh | $280 |
| December | 6.28 m/s | 1,851 kWh | $269 |
What a taller tower would buy
Measured at 10 m the wind in Delaware County averages 4.73 m/s; at 50 m it is 6.8 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 16,240 to 25,602 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 | 5.53 m/s | 16,240 kWh | 42 years |
| 30 m | 6.06 m/s | 20,138 kWh | 34 years |
| 40 m | 6.47 m/s | 23,153 kWh | 30 years |
| 50 m | 6.8 m/s | 25,602 kWh | 27 years |
Counties around Delaware County
4 of the 6 closest counties are windier at turbine height; the windiest, Fayette County, averages 6.18 m/s.
- Buchanan County, IA: 6.11 m/s, 20,520 kWh, payback 34 years (24 mi)
- Dubuque County, IA: 5.97 m/s, 19,482 kWh, payback 35 years (25 mi)
- Clayton County, IA: 6.07 m/s, 20,223 kWh, payback 34 years (26 mi)
- Jones County, IA: 6.01 m/s, 19,778 kWh, payback 35 years (27 mi)
- Linn County, IA: 6.07 m/s, 20,223 kWh, payback 34 years (30 mi)
- Fayette County, IA: 6.18 m/s, 21,039 kWh, payback 33 years (36 mi)
Sun versus wind in Delaware County
Delaware County gets 3.96 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,156 kWh a year; one kW of the turbine above makes 2,015. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.7 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.