Wind Turbine Payback in Marion County, IN
Wind turbine payback in Marion 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 Marion County, IN averages 5.8 m/s (13 mph). A 10 kW turbine there would make about 18,226 kWh a year, worth $3,106 at IN's 17.04¢/kWh. Against an installed cost of about $100,000, that is a payback of 32 years, and the turbine is built to last about 20.
What to do in Marion County
A home turbine is not worth buying for savings in Marion County unless your spot is far windier than the county average, 7.3 m/s at the hub against 5.8 m/s here. Per kW, solar panels would make about 1,168 kWh a year here against the turbine's 1,823, so get a solar quote first.
What would have to change
- Power would have to cost 27¢/kWh, 1.6 times what IN pays now.
- Or the average wind at the hub would have to be 7.3 m/s instead of 5.8. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of IN
Marion County is the 1,064th 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 Marion County
April is the strongest month here, at 6.76 m/s and about 2,080 kWh. August is the weakest, 4.33 m/s and 710 kWh, so the best month makes 2.9 times the worst. November to March brings in 53% of the year's output in Marion County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.62 m/s | 2,062 kWh | $351 |
| February | 6.54 m/s | 1,817 kWh | $310 |
| March | 6.51 m/s | 1,995 kWh | $340 |
| April | 6.76 m/s | 2,080 kWh | $354 |
| May | 5.77 m/s | 1,528 kWh | $260 |
| June | 5.03 m/s | 1,048 kWh | $179 |
| July | 4.33 m/s | 710 kWh | $121 |
| August | 4.33 m/s | 710 kWh | $121 |
| September | 4.93 m/s | 990 kWh | $169 |
| October | 6.02 m/s | 1,683 kWh | $287 |
| November | 6.43 m/s | 1,883 kWh | $321 |
| December | 6.40 m/s | 1,923 kWh | $328 |
What a taller tower would buy
Measured at 10 m the wind in Marion County averages 4.47 m/s; at 50 m it is 6.55 m/s. That gives a shear exponent of 0.237, typical of ordinary open country. Going from 20 m to 50 m takes output from 14,407 to 23,775 kWh a year, 65% 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 | 5.27 m/s | 14,407 kWh | 41 years |
| 30 m | 5.8 m/s | 18,249 kWh | 32 years |
| 40 m | 6.21 m/s | 21,281 kWh | 28 years |
| 50 m | 6.55 m/s | 23,775 kWh | 25 years |
Counties around Marion County
1 of the 6 closest counties is windier at turbine height; the windiest, Hancock County, averages 5.87 m/s.
- Hancock County, IN: 5.87 m/s, 18,742 kWh, payback 31 years (19 mi)
- Hamilton County, IN: 5.8 m/s, 18,226 kWh, payback 32 years (20 mi)
- Hendricks County, IN: 5.8 m/s, 18,226 kWh, payback 32 years (20 mi)
- Johnson County, IN: 5.09 m/s, 13,146 kWh, payback 45 years (20 mi)
- Shelby County, IN: 5.58 m/s, 16,616 kWh, payback 35 years (26 mi)
- Boone County, IN: 5.8 m/s, 18,226 kWh, payback 32 years (26 mi)
Sun versus wind in Marion County
Marion County gets 4 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,168 kWh a year; one kW of the turbine above makes 1,823. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.6 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.