Wind Turbine Payback in Marshall County, IN
Wind turbine payback in Marshall 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 Marshall County, IN averages 5.96 m/s (13.3 mph). A 10 kW turbine there would make about 19,408 kWh a year, worth $3,307 at IN's 17.04¢/kWh. Against an installed cost of about $100,000, that is a payback of 30 years, and the turbine is built to last about 20.
What to do in Marshall County
A home turbine is not worth buying for savings in Marshall County unless your spot is far windier than the county average, 7.3 m/s at the hub against 5.96 m/s here. Per kW, solar panels would make about 1,113 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, 1.5 times what IN pays now.
- Or the average wind at the hub would have to be 7.3 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 IN
Marshall County is the 901st windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in IN is Lake County at 6.17 m/s, payback 28 years.
Month by month in Marshall County
January is the strongest month here, at 6.83 m/s and about 2,193 kWh. July is the weakest, 4.53 m/s and 810 kWh, so the best month makes 2.7 times the worst. November to March brings in 52% of the year's output in Marshall County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.83 m/s | 2,193 kWh | $374 |
| February | 6.69 m/s | 1,901 kWh | $324 |
| March | 6.53 m/s | 2,005 kWh | $342 |
| April | 6.80 m/s | 2,106 kWh | $359 |
| May | 5.86 m/s | 1,585 kWh | $270 |
| June | 5.09 m/s | 1,083 kWh | $185 |
| July | 4.53 m/s | 810 kWh | $138 |
| August | 4.55 m/s | 819 kWh | $140 |
| September | 5.19 m/s | 1,138 kWh | $194 |
| October | 6.24 m/s | 1,826 kWh | $311 |
| November | 6.64 m/s | 2,010 kWh | $343 |
| December | 6.59 m/s | 2,044 kWh | $348 |
What a taller tower would buy
Measured at 10 m the wind in Marshall 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 | 38 years |
| 30 m | 5.96 m/s | 19,390 kWh | 30 years |
| 40 m | 6.36 m/s | 22,370 kWh | 26 years |
| 50 m | 6.69 m/s | 24,801 kWh | 24 years |
Counties around Marshall County
3 of the 6 closest counties are windier at turbine height; the windiest, Starke County, averages 6.1 m/s.
- Fulton County, IN: 5.94 m/s, 19,260 kWh, payback 31 years (19 mi)
- Starke County, IN: 6.1 m/s, 20,446 kWh, payback 29 years (20 mi)
- St. Joseph County, IN: 5.96 m/s, 19,408 kWh, payback 30 years (20 mi)
- Kosciusko County, IN: 5.95 m/s, 19,334 kWh, payback 30 years (22 mi)
- Elkhart County, IN: 5.99 m/s, 19,630 kWh, payback 30 years (28 mi)
- LaPorte County, IN: 6.1 m/s, 20,446 kWh, payback 29 years (29 mi)
Sun versus wind in Marshall County
Marshall County gets 3.81 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,113 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.