Wind Turbine Payback in Prairie County, MT
Wind turbine payback in Prairie 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 Prairie County, MT averages 6.37 m/s (14.2 mph). A 10 kW turbine there would make about 22,447 kWh a year, worth $3,172 at MT's 14.13¢/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 Prairie County
A home turbine is not worth buying for savings in Prairie County unless your spot is far windier than the county average, 8.2 m/s at the hub against 6.37 m/s here. Per kW, solar panels would make about 1,209 kWh a year here against the turbine's 2,245, so get a solar quote first.
What would have to change
- Power would have to cost 22¢/kWh, 1.6 times what MT pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 6.37. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MT
Prairie County is the 380th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MT is Fallon County at 6.64 m/s, payback 29 years.
Month by month in Prairie County
January is the strongest month here, at 6.95 m/s and about 2,267 kWh. July is the weakest, 5.63 m/s and 1,442 kWh, so the best month makes 1.6 times the worst. November to March brings in 46% of the year's output in Prairie County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.95 m/s | 2,267 kWh | $320 |
| February | 6.29 m/s | 1,674 kWh | $237 |
| March | 6.55 m/s | 2,017 kWh | $285 |
| April | 6.56 m/s | 1,957 kWh | $277 |
| May | 6.36 m/s | 1,899 kWh | $268 |
| June | 6.02 m/s | 1,635 kWh | $231 |
| July | 5.63 m/s | 1,442 kWh | $204 |
| August | 5.67 m/s | 1,469 kWh | $208 |
| September | 6.10 m/s | 1,678 kWh | $237 |
| October | 6.75 m/s | 2,145 kWh | $303 |
| November | 6.89 m/s | 2,157 kWh | $305 |
| December | 6.76 m/s | 2,151 kWh | $304 |
What a taller tower would buy
Measured at 10 m the wind in Prairie County averages 5.07 m/s; at 50 m it is 7.09 m/s. That gives a shear exponent of 0.208, typical of ordinary open country. Going from 20 m to 50 m takes output from 18,666 to 27,684 kWh a year, 48% 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 | 5.86 m/s | 18,666 kWh | 38 years |
| 30 m | 6.38 m/s | 22,486 kWh | 32 years |
| 40 m | 6.77 m/s | 25,373 kWh | 28 years |
| 50 m | 7.09 m/s | 27,684 kWh | 26 years |
Counties around Prairie County
4 of the 6 closest counties are windier at turbine height; the windiest, Fallon County, averages 6.64 m/s.
- Custer County, MT: 6.09 m/s, 20,371 kWh, payback 35 years (38 mi)
- Dawson County, MT: 6.49 m/s, 23,333 kWh, payback 30 years (42 mi)
- McCone County, MT: 6.43 m/s, 22,891 kWh, payback 31 years (58 mi)
- Wibaux County, MT: 6.43 m/s, 22,891 kWh, payback 31 years (59 mi)
- Fallon County, MT: 6.64 m/s, 24,436 kWh, payback 29 years (62 mi)
- Rosebud County, MT: 5.92 m/s, 19,112 kWh, payback 37 years (71 mi)
Sun versus wind in Prairie County
Prairie County gets 4.14 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,209 kWh a year; one kW of the turbine above makes 2,245. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.9 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.