Wind Turbine Payback in Lake County, SD
Wind turbine payback in Lake 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 Lake County, SD averages 6.61 m/s (14.8 mph). A 10 kW turbine there would make about 24,216 kWh a year, worth $3,531 at SD's 14.58¢/kWh. Against an installed cost of about $100,000, that is a payback of 28 years, and the turbine is built to last about 20.
What to do in Lake County
A home turbine is not worth buying for savings in Lake County unless your spot is far windier than the county average, 8.1 m/s at the hub against 6.61 m/s here. Per kW, solar panels would make about 1,191 kWh a year here against the turbine's 2,422, so get a solar quote first.
What would have to change
- Power would have to cost 21¢/kWh, 1.4 times what SD pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 6.61. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of SD
Lake County is the 107th 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 Lake County
April is the strongest month here, at 7.41 m/s and about 2,458 kWh. August is the weakest, 5.63 m/s and 1,440 kWh, so the best month makes 1.7 times the worst. November to March brings in 43% of the year's output in Lake County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.62 m/s | 2,066 kWh | $301 |
| February | 6.71 m/s | 1,911 kWh | $279 |
| March | 6.99 m/s | 2,293 kWh | $334 |
| April | 7.41 m/s | 2,458 kWh | $358 |
| May | 6.92 m/s | 2,249 kWh | $328 |
| June | 6.26 m/s | 1,781 kWh | $260 |
| July | 5.63 m/s | 1,440 kWh | $210 |
| August | 5.63 m/s | 1,440 kWh | $210 |
| September | 6.72 m/s | 2,059 kWh | $300 |
| October | 7.04 m/s | 2,320 kWh | $338 |
| November | 6.82 m/s | 2,118 kWh | $309 |
| December | 6.56 m/s | 2,027 kWh | $296 |
What a taller tower would buy
Measured at 10 m the wind in Lake County averages 5.27 m/s; at 50 m it is 7.34 m/s. That gives a shear exponent of 0.206, typical of ordinary open country. Going from 20 m to 50 m takes output from 20,278 to 29,437 kWh a year, 45% 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 | 6.08 m/s | 20,278 kWh | 34 years |
| 30 m | 6.61 m/s | 24,193 kWh | 28 years |
| 40 m | 7.01 m/s | 27,116 kWh | 25 years |
| 50 m | 7.34 m/s | 29,437 kWh | 23 years |
Counties around Lake County
1 of the 6 closest counties is windier at turbine height; the windiest, Brookings County, averages 6.69 m/s.
- Moody County, SD: 6.61 m/s, 24,216 kWh, payback 28 years (22 mi)
- Miner County, SD: 6.49 m/s, 23,333 kWh, payback 29 years (24 mi)
- McCook County, SD: 6.45 m/s, 23,038 kWh, payback 30 years (27 mi)
- Brookings County, SD: 6.69 m/s, 24,801 kWh, payback 28 years (29 mi)
- Kingsbury County, SD: 6.57 m/s, 23,922 kWh, payback 29 years (30 mi)
- Minnehaha County, SD: 6.46 m/s, 23,112 kWh, payback 30 years (30 mi)
Sun versus wind in Lake County
Lake County gets 4.08 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,191 kWh a year; one kW of the turbine above makes 2,422. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 2.0 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.