Wind Turbine Payback in Lafayette County, WI
Wind turbine payback in Lafayette 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 Lafayette County, WI averages 5.96 m/s (13.3 mph). A 10 kW turbine there would make about 19,408 kWh a year, worth $3,697 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 Lafayette County
A home turbine is not worth buying for savings in Lafayette County unless your spot is far windier than the county average, 6.9 m/s at the hub against 5.96 m/s here. Per kW, solar panels would make about 1,148 kWh a year here against the turbine's 1,941, 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 5.96. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WI
Lafayette County is the 901st 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 Lafayette County
April is the strongest month here, at 6.82 m/s and about 2,117 kWh. August is the weakest, 4.64 m/s and 866 kWh, so the best month makes 2.4 times the worst. November to March brings in 49% of the year's output in Lafayette County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.47 m/s | 1,972 kWh | $376 |
| February | 6.57 m/s | 1,836 kWh | $350 |
| March | 6.51 m/s | 1,994 kWh | $380 |
| April | 6.82 m/s | 2,117 kWh | $403 |
| May | 6.06 m/s | 1,708 kWh | $325 |
| June | 5.33 m/s | 1,215 kWh | $231 |
| July | 4.72 m/s | 908 kWh | $173 |
| August | 4.64 m/s | 866 kWh | $165 |
| September | 5.54 m/s | 1,341 kWh | $255 |
| October | 6.28 m/s | 1,849 kWh | $352 |
| November | 6.44 m/s | 1,887 kWh | $359 |
| December | 6.21 m/s | 1,804 kWh | $344 |
What a taller tower would buy
Measured at 10 m the wind in Lafayette County averages 4.64 m/s; at 50 m it is 6.69 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 15,560 to 24,801 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 | 5.43 m/s | 15,560 kWh | 34 years |
| 30 m | 5.96 m/s | 19,390 kWh | 27 years |
| 40 m | 6.36 m/s | 22,370 kWh | 24 years |
| 50 m | 6.69 m/s | 24,801 kWh | 21 years |
Counties around Lafayette County
5 of the 6 closest counties are windier at turbine height; the windiest, Iowa County, averages 6.01 m/s.
- Jo Daviess County, IL: 5.96 m/s, 19,408 kWh, payback 27 years (21 mi)
- Iowa County, WI: 6.01 m/s, 19,778 kWh, payback 27 years (24 mi)
- Green County, WI: 5.98 m/s, 19,556 kWh, payback 27 years (27 mi)
- Stephenson County, IL: 5.98 m/s, 19,556 kWh, payback 27 years (32 mi)
- Grant County, WI: 6 m/s, 19,704 kWh, payback 27 years (32 mi)
- Dubuque County, IA: 5.97 m/s, 19,482 kWh, payback 35 years (40 mi)
Sun versus wind in Lafayette County
Lafayette County gets 3.93 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,148 kWh a year; one kW of the turbine above makes 1,941. 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.