Wind Turbine Payback in Polk County, WI
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, WI averages 6.08 m/s (13.6 mph). A 10 kW turbine there would make about 20,297 kWh a year, worth $3,867 at WI's 19.05¢/kWh. Against an installed cost of about $100,000, that is a payback of 26 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, 6.9 m/s at the hub against 6.08 m/s here. Per kW, solar panels would make about 1,110 kWh a year here against the turbine's 2,030, so get a solar quote first.
What would have to change
- Power would have to cost 25¢/kWh, 1.3 times what WI pays now.
- Or the average wind at the hub would have to be 6.9 m/s instead of 6.08. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WI
Polk County is the 714th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in WI is Manitowoc County at 7.32 m/s, payback 18 years.
Month by month in Polk County
April is the strongest month here, at 6.66 m/s and about 2,019 kWh. July is the weakest, 5.11 m/s and 1,130 kWh, so the best month makes 1.8 times the worst. November to March brings in 45% of the year's output in Polk County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.34 m/s | 1,890 kWh | $360 |
| February | 6.52 m/s | 1,809 kWh | $345 |
| March | 6.36 m/s | 1,902 kWh | $362 |
| April | 6.66 m/s | 2,019 kWh | $385 |
| May | 6.19 m/s | 1,795 kWh | $342 |
| June | 5.70 m/s | 1,439 kWh | $274 |
| July | 5.11 m/s | 1,130 kWh | $215 |
| August | 5.24 m/s | 1,204 kWh | $229 |
| September | 6.09 m/s | 1,672 kWh | $319 |
| October | 6.39 m/s | 1,918 kWh | $365 |
| November | 6.29 m/s | 1,797 kWh | $342 |
| December | 6.08 m/s | 1,722 kWh | $328 |
What a taller tower would buy
Measured at 10 m the wind in Polk County averages 4.76 m/s; at 50 m it is 6.81 m/s. That gives a shear exponent of 0.223, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,409 to 25,675 kWh a year, 56% 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 | 5.55 m/s | 16,409 kWh | 32 years |
| 30 m | 6.08 m/s | 20,273 kWh | 26 years |
| 40 m | 6.48 m/s | 23,255 kWh | 23 years |
| 50 m | 6.81 m/s | 25,675 kWh | 20 years |
Counties around Polk County
None of the 6 closest counties is windier than Polk County.
- Chisago County, MN: 5.96 m/s, 19,408 kWh, payback 31 years (22 mi)
- Burnett County, WI: 5.77 m/s, 18,006 kWh, payback 29 years (28 mi)
- Barron County, WI: 6.03 m/s, 19,926 kWh, payback 26 years (29 mi)
- St. Croix County, WI: 5.94 m/s, 19,260 kWh, payback 27 years (30 mi)
- Washington County, MN: 5.52 m/s, 16,181 kWh, payback 38 years (36 mi)
- Anoka County, MN: 5.96 m/s, 19,408 kWh, payback 31 years (41 mi)
Sun versus wind in Polk County
Polk County gets 3.8 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,110 kWh a year; one kW of the turbine above makes 2,030. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.8 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.