Wind Turbine Payback in Polk County, MN
Wind turbine payback in Polk 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 Polk County, MN averages 6.34 m/s (14.2 mph). A 10 kW turbine there would make about 22,225 kWh a year, worth $3,654 at MN's 16.44¢/kWh. Against an installed cost of about $100,000, that is a payback of 27 years, and the turbine is built to last about 20.
What to do in Polk County
A home turbine is not worth buying for savings in Polk County unless your spot is far windier than the county average, 7.5 m/s at the hub against 6.34 m/s here. Per kW, solar panels would make about 1,121 kWh a year here against the turbine's 2,223, so get a solar quote first.
What would have to change
- Power would have to cost 22¢/kWh, 1.4 times what MN pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 6.34. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MN
Polk County is the 420th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MN is Lincoln County at 6.68 m/s, payback 25 years.
Month by month in Polk County
October is the strongest month here, at 6.73 m/s and about 2,132 kWh. July is the weakest, 5.60 m/s and 1,423 kWh, so the best month makes 1.5 times the worst. November to March brings in 42% of the year's output in Polk County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.39 m/s | 1,919 kWh | $315 |
| February | 6.37 m/s | 1,723 kWh | $283 |
| March | 6.58 m/s | 2,037 kWh | $335 |
| April | 6.81 m/s | 2,112 kWh | $347 |
| May | 6.61 m/s | 2,060 kWh | $339 |
| June | 6.08 m/s | 1,671 kWh | $275 |
| July | 5.60 m/s | 1,423 kWh | $234 |
| August | 5.68 m/s | 1,473 kWh | $242 |
| September | 6.45 m/s | 1,895 kWh | $312 |
| October | 6.73 m/s | 2,132 kWh | $351 |
| November | 6.54 m/s | 1,950 kWh | $321 |
| December | 6.19 m/s | 1,795 kWh | $295 |
What a taller tower would buy
Measured at 10 m the wind in Polk County averages 5.04 m/s; at 50 m it is 7.05 m/s. That gives a shear exponent of 0.209, typical of ordinary open country. Going from 20 m to 50 m takes output from 18,383 to 27,400 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 | 5.82 m/s | 18,383 kWh | 33 years |
| 30 m | 6.34 m/s | 22,196 kWh | 27 years |
| 40 m | 6.73 m/s | 25,084 kWh | 24 years |
| 50 m | 7.05 m/s | 27,400 kWh | 22 years |
Counties around Polk County
2 of the 6 closest counties are windier at turbine height; the windiest, Mahnomen County, averages 6.56 m/s.
- Red Lake County, MN: 6.34 m/s, 22,225 kWh, payback 27 years (16 mi)
- Pennington County, MN: 6.34 m/s, 22,225 kWh, payback 27 years (26 mi)
- Norman County, MN: 6.37 m/s, 22,447 kWh, payback 27 years (31 mi)
- Marshall County, MN: 6.31 m/s, 22,003 kWh, payback 28 years (41 mi)
- Mahnomen County, MN: 6.56 m/s, 23,849 kWh, payback 26 years (41 mi)
- Traill County, ND: 6.29 m/s, 21,855 kWh, payback 37 years (42 mi)
Sun versus wind in Polk County
Polk County gets 3.84 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,121 kWh a year; one kW of the turbine above makes 2,223. 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.