Wind Turbine Payback in St. Croix County, WI
Wind turbine payback in St. Croix 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 St. Croix County, WI averages 5.94 m/s (13.3 mph). A 10 kW turbine there would make about 19,260 kWh a year, worth $3,669 at WI's 19.05¢/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 St. Croix County
A home turbine is not worth buying for savings in St. Croix County unless your spot is far windier than the county average, 6.9 m/s at the hub against 5.94 m/s here. Per kW, solar panels would make about 1,110 kWh a year here against the turbine's 1,926, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/kWh, 1.4 times what WI pays now.
- Or the average wind at the hub would have to be 6.9 m/s instead of 5.94. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WI
St. Croix County is the 934th 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 St. Croix County
April is the strongest month here, at 6.60 m/s and about 1,983 kWh. July is the weakest, 4.92 m/s and 1,017 kWh, so the best month makes 1.9 times the worst. November to March brings in 46% of the year's output in St. Croix County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.33 m/s | 1,882 kWh | $359 |
| February | 6.46 m/s | 1,775 kWh | $338 |
| March | 6.31 m/s | 1,871 kWh | $356 |
| April | 6.60 m/s | 1,983 kWh | $378 |
| May | 6.06 m/s | 1,714 kWh | $327 |
| June | 5.51 m/s | 1,326 kWh | $253 |
| July | 4.92 m/s | 1,017 kWh | $194 |
| August | 4.97 m/s | 1,048 kWh | $200 |
| September | 5.81 m/s | 1,502 kWh | $286 |
| October | 6.20 m/s | 1,798 kWh | $343 |
| November | 6.17 m/s | 1,724 kWh | $328 |
| December | 6.02 m/s | 1,686 kWh | $321 |
What a taller tower would buy
Measured at 10 m the wind in St. Croix County averages 4.61 m/s; at 50 m it is 6.68 m/s. That gives a shear exponent of 0.230, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,395 to 24,728 kWh a year, 61% 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 | 5.41 m/s | 15,395 kWh | 34 years |
| 30 m | 5.94 m/s | 19,256 kWh | 27 years |
| 40 m | 6.35 m/s | 22,268 kWh | 24 years |
| 50 m | 6.68 m/s | 24,728 kWh | 21 years |
Counties around St. Croix County
4 of the 6 closest counties are windier at turbine height; the windiest, Dakota County, averages 6.17 m/s.
- Pierce County, WI: 6.14 m/s, 20,742 kWh, payback 25 years (21 mi)
- Washington County, MN: 5.52 m/s, 16,181 kWh, payback 38 years (22 mi)
- Dunn County, WI: 6.01 m/s, 19,778 kWh, payback 27 years (27 mi)
- Polk County, WI: 6.08 m/s, 20,297 kWh, payback 26 years (30 mi)
- Ramsey County, MN: 5.52 m/s, 16,181 kWh, payback 38 years (32 mi)
- Dakota County, MN: 6.17 m/s, 20,965 kWh, payback 29 years (39 mi)
Sun versus wind in St. Croix County
St. Croix 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 1,926. 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.