Wind Turbine Payback in Marathon County, WI
Wind turbine payback in Marathon 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 Marathon County, WI averages 6.02 m/s (13.5 mph). A 10 kW turbine there would make about 19,852 kWh a year, worth $3,782 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 Marathon County
A home turbine is not worth buying for savings in Marathon County unless your spot is far windier than the county average, 6.9 m/s at the hub against 6.02 m/s here. Per kW, solar panels would make about 1,115 kWh a year here against the turbine's 1,985, 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 6.02. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WI
Marathon County is the 816th 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 Marathon County
April is the strongest month here, at 6.71 m/s and about 2,048 kWh. August is the weakest, 5.02 m/s and 1,077 kWh, so the best month makes 1.9 times the worst. November to March brings in 47% of the year's output in Marathon County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.43 m/s | 1,944 kWh | $370 |
| February | 6.67 m/s | 1,891 kWh | $360 |
| March | 6.41 m/s | 1,933 kWh | $368 |
| April | 6.71 m/s | 2,048 kWh | $390 |
| May | 6.05 m/s | 1,703 kWh | $324 |
| June | 5.50 m/s | 1,320 kWh | $251 |
| July | 5.05 m/s | 1,093 kWh | $208 |
| August | 5.02 m/s | 1,077 kWh | $205 |
| September | 5.76 m/s | 1,475 kWh | $281 |
| October | 6.28 m/s | 1,849 kWh | $352 |
| November | 6.22 m/s | 1,751 kWh | $334 |
| December | 6.16 m/s | 1,776 kWh | $338 |
What a taller tower would buy
Measured at 10 m the wind in Marathon County averages 4.69 m/s; at 50 m it is 6.76 m/s. That gives a shear exponent of 0.227, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,969 to 25,311 kWh a year, 59% 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 | 5.49 m/s | 15,969 kWh | 33 years |
| 30 m | 6.02 m/s | 19,851 kWh | 26 years |
| 40 m | 6.43 m/s | 22,862 kWh | 23 years |
| 50 m | 6.76 m/s | 25,311 kWh | 21 years |
Counties around Marathon County
3 of the 6 closest counties are windier at turbine height; the windiest, Lincoln County, averages 6.15 m/s.
- Lincoln County, WI: 6.15 m/s, 20,816 kWh, payback 25 years (30 mi)
- Portage County, WI: 6.07 m/s, 20,223 kWh, payback 26 years (32 mi)
- Wood County, WI: 6.06 m/s, 20,149 kWh, payback 26 years (33 mi)
- Langlade County, WI: 5.8 m/s, 18,226 kWh, payback 29 years (42 mi)
- Taylor County, WI: 5.99 m/s, 19,630 kWh, payback 27 years (42 mi)
- Clark County, WI: 6.02 m/s, 19,852 kWh, payback 26 years (43 mi)
Sun versus wind in Marathon County
Marathon County gets 3.82 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,115 kWh a year; one kW of the turbine above makes 1,985. 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.