Wind Turbine Payback in Fergus County, MT
Wind turbine payback in Fergus 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 Fergus County, MT averages 6.18 m/s (13.8 mph). A 10 kW turbine there would make about 21,039 kWh a year, worth $2,973 at MT's 14.13¢/kWh. Against an installed cost of about $100,000, that is a payback of 34 years, and the turbine is built to last about 20.
What to do in Fergus County
A home turbine is not worth buying for savings in Fergus County unless your spot is far windier than the county average, 8.2 m/s at the hub against 6.18 m/s here. Per kW, solar panels would make about 1,168 kWh a year here against the turbine's 2,104, so get a solar quote first.
What would have to change
- Power would have to cost 24¢/kWh, 1.7 times what MT pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 6.18. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MT
Fergus County is the 599th 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 Fergus County
January is the strongest month here, at 7.52 m/s and about 2,605 kWh. July is the weakest, 4.91 m/s and 1,013 kWh, so the best month makes 2.6 times the worst. November to March brings in 53% of the year's output in Fergus County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 7.52 m/s | 2,605 kWh | $368 |
| February | 6.68 m/s | 1,895 kWh | $268 |
| March | 6.52 m/s | 1,998 kWh | $282 |
| April | 6.13 m/s | 1,702 kWh | $240 |
| May | 5.75 m/s | 1,519 kWh | $215 |
| June | 5.38 m/s | 1,247 kWh | $176 |
| July | 4.91 m/s | 1,013 kWh | $143 |
| August | 4.98 m/s | 1,053 kWh | $149 |
| September | 5.54 m/s | 1,342 kWh | $190 |
| October | 6.56 m/s | 2,026 kWh | $286 |
| November | 7.09 m/s | 2,277 kWh | $322 |
| December | 7.16 m/s | 2,391 kWh | $338 |
What a taller tower would buy
Measured at 10 m the wind in Fergus County averages 4.78 m/s; at 50 m it is 6.96 m/s. That gives a shear exponent of 0.233, typical of ordinary open country. Going from 20 m to 50 m takes output from 16,922 to 26,756 kWh a year, 58% 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 | 5.62 m/s | 16,922 kWh | 42 years |
| 30 m | 6.18 m/s | 21,032 kWh | 34 years |
| 40 m | 6.61 m/s | 24,197 kWh | 29 years |
| 50 m | 6.96 m/s | 26,756 kWh | 27 years |
Counties around Fergus County
None of the 6 closest counties is windier than Fergus County.
- Petroleum County, MT: 5.89 m/s, 18,890 kWh, payback 38 years (48 mi)
- Judith Basin County, MT: 5.97 m/s, 19,482 kWh, payback 36 years (52 mi)
- Wheatland County, MT: 5.89 m/s, 18,890 kWh, payback 38 years (58 mi)
- Golden Valley County, MT: 6 m/s, 19,704 kWh, payback 36 years (58 mi)
- Musselshell County, MT: 5.95 m/s, 19,334 kWh, payback 37 years (62 mi)
- Chouteau County, MT: 6.09 m/s, 20,371 kWh, payback 35 years (73 mi)
Sun versus wind in Fergus County
Fergus 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 2,104. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.8 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.