Wind Turbine Payback in Green Lake County, WI
Wind turbine payback in Green Lake 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 Green Lake 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 Green Lake County
A home turbine is not worth buying for savings in Green Lake 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
Green Lake 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 Green Lake 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 Green Lake 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 Green Lake 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 Green Lake County
None of the 6 closest counties is windier than Green Lake County.
- Marquette County, WI: 6.06 m/s, 20,149 kWh, payback 26 years (22 mi)
- Fond du Lac 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 (26 mi)
- Waushara County, WI: 6.06 m/s, 20,149 kWh, payback 26 years (27 mi)
- Dodge County, WI: 6.09 m/s, 20,371 kWh, payback 26 years (28 mi)
- Columbia County, WI: 6.06 m/s, 20,149 kWh, payback 26 years (28 mi)
Sun versus wind in Green Lake County
Green Lake 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.