Wind Turbine Payback in Fond du Lac County, WI
Wind turbine payback in Fond du Lac 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 Fond du Lac County, WI averages 6.12 m/s (13.7 mph). A 10 kW turbine there would make about 20,594 kWh a year, worth $3,923 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 Fond du Lac County
A home turbine is not worth buying for savings in Fond du Lac County unless your spot is far windier than the county average, 6.9 m/s at the hub against 6.12 m/s here. Per kW, solar panels would make about 1,121 kWh a year here against the turbine's 2,059, so get a solar quote first.
What would have to change
- Power would have to cost 24¢/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 6.12. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WI
Fond du Lac County is the 664th 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 Fond du Lac County
April is the strongest month here, at 6.85 m/s and about 2,132 kWh. August is the weakest, 4.99 m/s and 1,061 kWh, so the best month makes 2.0 times the worst. November to March brings in 48% of the year's output in Fond du Lac County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.63 m/s | 2,071 kWh | $395 |
| February | 6.78 m/s | 1,955 kWh | $372 |
| March | 6.53 m/s | 2,004 kWh | $382 |
| April | 6.85 m/s | 2,132 kWh | $406 |
| May | 6.10 m/s | 1,739 kWh | $331 |
| June | 5.45 m/s | 1,289 kWh | $246 |
| July | 5.04 m/s | 1,087 kWh | $207 |
| August | 4.99 m/s | 1,061 kWh | $202 |
| September | 5.78 m/s | 1,487 kWh | $283 |
| October | 6.44 m/s | 1,948 kWh | $371 |
| November | 6.47 m/s | 1,907 kWh | $363 |
| December | 6.43 m/s | 1,942 kWh | $370 |
What a taller tower would buy
Measured at 10 m the wind in Fond du Lac County averages 4.82 m/s; at 50 m it is 6.84 m/s. That gives a shear exponent of 0.217, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,810 to 25,892 kWh a year, 54% 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 | 5.61 m/s | 16,810 kWh | 31 years |
| 30 m | 6.12 m/s | 20,611 kWh | 26 years |
| 40 m | 6.52 m/s | 23,530 kWh | 22 years |
| 50 m | 6.84 m/s | 25,892 kWh | 20 years |
Counties around Fond du Lac County
3 of the 6 closest counties are windier at turbine height; the windiest, Calumet County, averages 6.53 m/s.
- Green Lake County, WI: 6.12 m/s, 20,594 kWh, payback 26 years (24 mi)
- Winnebago County, WI: 6.12 m/s, 20,594 kWh, payback 26 years (24 mi)
- Dodge County, WI: 6.09 m/s, 20,371 kWh, payback 26 years (25 mi)
- Calumet County, WI: 6.53 m/s, 23,628 kWh, payback 22 years (26 mi)
- Washington County, WI: 6.43 m/s, 22,891 kWh, payback 23 years (28 mi)
- Ozaukee County, WI: 6.43 m/s, 22,891 kWh, payback 23 years (37 mi)
Sun versus wind in Fond du Lac County
Fond du Lac 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 2,059. 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.