Wind Turbine Payback in Carbon County, MT
Wind turbine payback in Carbon 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 Carbon County, MT averages 4.41 m/s (9.9 mph). A 10 kW turbine there would make about 8,807 kWh a year, worth $1,244 at MT's 14.13¢/kWh. Against an installed cost of about $100,000, that is a payback of 80 years, and the turbine is built to last about 20.
What to do in Carbon County
A home turbine is not worth buying for savings in Carbon County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.41 m/s here. Per kW, solar panels would make about 1,203 kWh a year here against the turbine's 881, so get a solar quote first.
What would have to change
- Power would have to cost 57¢/kWh, 4.0 times what MT pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.41. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MT
Carbon County is the 1,810th 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 Carbon County
January is the strongest month here, at 5.12 m/s and about 1,132 kWh. August is the weakest, 3.64 m/s and 417 kWh, so the best month makes 2.7 times the worst. November to March brings in 54% of the year's output in Carbon County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.12 m/s | 1,132 kWh | $160 |
| February | 4.90 m/s | 912 kWh | $129 |
| March | 4.77 m/s | 935 kWh | $132 |
| April | 4.69 m/s | 863 kWh | $122 |
| May | 4.25 m/s | 670 kWh | $95 |
| June | 3.78 m/s | 452 kWh | $64 |
| July | 3.64 m/s | 417 kWh | $59 |
| August | 3.64 m/s | 417 kWh | $59 |
| September | 4.02 m/s | 548 kWh | $77 |
| October | 4.49 m/s | 789 kWh | $111 |
| November | 4.70 m/s | 867 kWh | $123 |
| December | 4.97 m/s | 1,050 kWh | $148 |
What a taller tower would buy
Measured at 10 m the wind in Carbon County averages 3.47 m/s; at 50 m it is 4.93 m/s. That gives a shear exponent of 0.218, typical of ordinary open country. Going from 20 m to 50 m takes output from 6,766 to 12,065 kWh a year, 78% 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 | 4.04 m/s | 6,766 kWh | over 100 years |
| 30 m | 4.41 m/s | 8,809 kWh | 80 years |
| 40 m | 4.7 m/s | 10,546 kWh | 67 years |
| 50 m | 4.93 m/s | 12,065 kWh | 59 years |
Counties around Carbon County
5 of the 6 closest counties are windier at turbine height; the windiest, Sweet Grass County, averages 5.94 m/s.
- Stillwater County, MT: 5.8 m/s, 18,226 kWh, payback 39 years (35 mi)
- Park County, WY: 4.5 m/s, 9,339 kWh, payback 76 years (58 mi)
- Sweet Grass County, MT: 5.94 m/s, 19,260 kWh, payback 37 years (60 mi)
- Yellowstone County, MT: 5.74 m/s, 17,785 kWh, payback 40 years (61 mi)
- Big Horn County, WY: 4.34 m/s, 8,403 kWh, payback 85 years (70 mi)
- Big Horn County, MT: 5.44 m/s, 15,605 kWh, payback 45 years (74 mi)
Sun versus wind in Carbon County
Carbon County gets 4.12 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,203 kWh a year; one kW of the turbine above makes 881. Kilowatt for kilowatt, panels make 1.4 times as much here as the turbine. 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.