Wind Turbine Payback in Minnehaha County, SD
Wind turbine payback in Minnehaha 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 Minnehaha County, SD averages 6.46 m/s (14.5 mph). A 10 kW turbine there would make about 23,112 kWh a year, worth $3,370 at SD's 14.58¢/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 Minnehaha County
A home turbine is not worth buying for savings in Minnehaha 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 1,200 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 SD 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 SD
Minnehaha County is the 239th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in SD is Todd County at 6.77 m/s, payback 27 years.
Month by month in Minnehaha County
April is the strongest month here, at 7.30 m/s and about 2,396 kWh. August is the weakest, 5.50 m/s and 1,364 kWh, so the best month makes 1.8 times the worst. November to March brings in 43% of the year's output in Minnehaha County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.45 m/s | 1,954 kWh | $285 |
| February | 6.51 m/s | 1,801 kWh | $263 |
| March | 6.89 m/s | 2,227 kWh | $325 |
| April | 7.30 m/s | 2,396 kWh | $349 |
| May | 6.79 m/s | 2,167 kWh | $316 |
| June | 6.15 m/s | 1,711 kWh | $249 |
| July | 5.52 m/s | 1,375 kWh | $200 |
| August | 5.50 m/s | 1,364 kWh | $199 |
| September | 6.55 m/s | 1,951 kWh | $284 |
| October | 6.84 m/s | 2,200 kWh | $321 |
| November | 6.61 m/s | 1,989 kWh | $290 |
| December | 6.36 m/s | 1,898 kWh | $277 |
What a taller tower would buy
Measured at 10 m the wind in Minnehaha County averages 5.12 m/s; at 50 m it is 7.19 m/s. That gives a shear exponent of 0.211, typical of ordinary open country. Going from 20 m to 50 m takes output from 19,156 to 28,390 kWh a year, 48% 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 | 5.93 m/s | 19,156 kWh | 36 years |
| 30 m | 6.46 m/s | 23,078 kWh | 30 years |
| 40 m | 6.86 m/s | 26,032 kWh | 26 years |
| 50 m | 7.19 m/s | 28,390 kWh | 24 years |
Counties around Minnehaha County
2 of the 6 closest counties are windier at turbine height; the windiest, Moody County, averages 6.61 m/s.
- Moody County, SD: 6.61 m/s, 24,216 kWh, payback 28 years (25 mi)
- Rock County, MN: 6.46 m/s, 23,112 kWh, payback 26 years (27 mi)
- Lincoln County, SD: 6.46 m/s, 23,112 kWh, payback 30 years (27 mi)
- McCook County, SD: 6.45 m/s, 23,038 kWh, payback 30 years (28 mi)
- Lake County, SD: 6.61 m/s, 24,216 kWh, payback 28 years (30 mi)
- Turner County, SD: 6.46 m/s, 23,112 kWh, payback 30 years (31 mi)
Sun versus wind in Minnehaha County
Minnehaha County gets 4.11 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,200 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.