Wind Turbine Payback in Cascade County, MT
Wind turbine payback in Cascade 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 Cascade County, MT averages 5.69 m/s (12.7 mph). A 10 kW turbine there would make about 17,419 kWh a year, worth $2,461 at MT's 14.13¢/kWh. Against an installed cost of about $100,000, that is a payback of 41 years, and the turbine is built to last about 20.
What to do in Cascade County
A home turbine is not worth buying for savings in Cascade County unless your spot is far windier than the county average, 8.2 m/s at the hub against 5.69 m/s here. Per kW, solar panels would make about 1,165 kWh a year here against the turbine's 1,742, so get a solar quote first.
What would have to change
- Power would have to cost 29¢/kWh, 2.0 times what MT pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 5.69. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MT
Cascade County is the 1,136th 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 Cascade County
January is the strongest month here, at 7.05 m/s and about 2,327 kWh. August is the weakest, 4.43 m/s and 758 kWh, so the best month makes 3.1 times the worst. November to March brings in 57% of the year's output in Cascade County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 7.05 m/s | 2,327 kWh | $329 |
| February | 6.13 m/s | 1,587 kWh | $224 |
| March | 6.10 m/s | 1,735 kWh | $245 |
| April | 5.51 m/s | 1,327 kWh | $188 |
| May | 5.05 m/s | 1,092 kWh | $154 |
| June | 4.86 m/s | 955 kWh | $135 |
| July | 4.46 m/s | 775 kWh | $110 |
| August | 4.43 m/s | 758 kWh | $107 |
| September | 4.99 m/s | 1,022 kWh | $144 |
| October | 6.00 m/s | 1,674 kWh | $237 |
| November | 6.90 m/s | 2,164 kWh | $306 |
| December | 6.81 m/s | 2,182 kWh | $308 |
What a taller tower would buy
Measured at 10 m the wind in Cascade County averages 4.35 m/s; at 50 m it is 6.45 m/s. That gives a shear exponent of 0.245, typical of ordinary open country. Going from 20 m to 50 m takes output from 13,581 to 23,038 kWh a year, 70% 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 | 5.15 m/s | 13,581 kWh | 52 years |
| 30 m | 5.69 m/s | 17,428 kWh | 41 years |
| 40 m | 6.11 m/s | 20,496 kWh | 35 years |
| 50 m | 6.45 m/s | 23,038 kWh | 31 years |
Counties around Cascade County
2 of the 6 closest counties are windier at turbine height; the windiest, Chouteau County, averages 6.09 m/s.
- Lewis and Clark County, MT: 3.93 m/s, 6,231 kWh, payback over 100 years (50 mi)
- Judith Basin County, MT: 5.97 m/s, 19,482 kWh, payback 36 years (53 mi)
- Meagher County, MT: 4.63 m/s, 10,132 kWh, payback 70 years (54 mi)
- Teton County, MT: 5.4 m/s, 15,319 kWh, payback 46 years (56 mi)
- Chouteau County, MT: 6.09 m/s, 20,371 kWh, payback 35 years (58 mi)
- Broadwater County, MT: 3.97 m/s, 6,428 kWh, payback over 100 years (69 mi)
Sun versus wind in Cascade County
Cascade County gets 3.99 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,165 kWh a year; one kW of the turbine above makes 1,742. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 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.