Wind Turbine Payback in St. Joseph County, MI
Wind turbine payback in St. Joseph 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. Joseph County, MI averages 6.05 m/s (13.5 mph). A 10 kW turbine there would make about 20,075 kWh a year, worth $4,362 at MI's 21.73¢/kWh. Against an installed cost of about $100,000, that is a payback of 23 years, and the turbine is built to last about 20.
What to do in St. Joseph County
A home turbine is not worth buying for savings in St. Joseph County unless your spot is far windier than the county average, 6.4 m/s at the hub against 6.05 m/s here. Per kW, solar panels would make about 1,115 kWh a year here against the turbine's 2,008, so get a solar quote first.
What would have to change
- Power would have to cost 25¢/kWh, 1.1 times what MI pays now.
- Or the average wind at the hub would have to be 6.4 m/s instead of 6.05. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MI
St. Joseph County is the 769th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MI is Keweenaw County at 7.4 m/s, payback 15 years.
Month by month in St. Joseph County
January is the strongest month here, at 6.88 m/s and about 2,221 kWh. July is the weakest, 4.69 m/s and 893 kWh, so the best month makes 2.5 times the worst. November to March brings in 51% of the year's output in St. Joseph County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.88 m/s | 2,221 kWh | $483 |
| February | 6.82 m/s | 1,977 kWh | $430 |
| March | 6.57 m/s | 2,034 kWh | $442 |
| April | 6.81 m/s | 2,113 kWh | $459 |
| May | 5.92 m/s | 1,625 kWh | $353 |
| June | 5.18 m/s | 1,133 kWh | $246 |
| July | 4.69 m/s | 893 kWh | $194 |
| August | 4.70 m/s | 898 kWh | $195 |
| September | 5.36 m/s | 1,236 kWh | $269 |
| October | 6.39 m/s | 1,916 kWh | $416 |
| November | 6.70 m/s | 2,043 kWh | $444 |
| December | 6.66 m/s | 2,089 kWh | $454 |
What a taller tower would buy
Measured at 10 m the wind in St. Joseph County averages 4.73 m/s; at 50 m it is 6.78 m/s. That gives a shear exponent of 0.224, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,195 to 25,457 kWh a year, 57% 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 | 5.52 m/s | 16,195 kWh | 28 years |
| 30 m | 6.05 m/s | 20,052 kWh | 23 years |
| 40 m | 6.45 m/s | 23,034 kWh | 20 years |
| 50 m | 6.78 m/s | 25,457 kWh | 18 years |
Counties around St. Joseph County
2 of the 6 closest counties are windier at turbine height; the windiest, Cass County, averages 6.35 m/s.
- LaGrange County, IN: 5.99 m/s, 19,630 kWh, payback 30 years (19 mi)
- Kalamazoo County, MI: 6.05 m/s, 20,075 kWh, payback 23 years (23 mi)
- Branch County, MI: 6.1 m/s, 20,446 kWh, payback 23 years (23 mi)
- Cass County, MI: 6.35 m/s, 22,299 kWh, payback 21 years (25 mi)
- Elkhart County, IN: 5.99 m/s, 19,630 kWh, payback 30 years (28 mi)
- Steuben County, IN: 5.98 m/s, 19,556 kWh, payback 30 years (33 mi)
Sun versus wind in St. Joseph County
St. Joseph 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 2,008. 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.