Wind Turbine Payback in Gallatin County, MT
Wind turbine payback in Gallatin 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 Gallatin County, MT averages 4.18 m/s (9.4 mph). A 10 kW turbine there would make about 7,515 kWh a year, worth $1,062 at MT's 14.13¢/kWh. Against an installed cost of about $100,000, that is a payback of 94 years, and the turbine is built to last about 20.
What to do in Gallatin County
A home turbine is not worth buying for savings in Gallatin County unless your spot is far windier than the county average, 8.2 m/s at the hub against 4.18 m/s here. Per kW, solar panels would make about 1,197 kWh a year here against the turbine's 752, so get a solar quote first.
What would have to change
- Power would have to cost 67¢/kWh, 4.7 times what MT pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 4.18. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MT
Gallatin County is the 1,957th 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 Gallatin County
January is the strongest month here, at 5.29 m/s and about 1,234 kWh. July is the weakest, 3.19 m/s and 273 kWh, so the best month makes 4.5 times the worst. November to March brings in 63% of the year's output in Gallatin County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.29 m/s | 1,234 kWh | $174 |
| February | 4.78 m/s | 851 kWh | $120 |
| March | 4.66 m/s | 874 kWh | $123 |
| April | 4.08 m/s | 574 kWh | $81 |
| May | 3.52 m/s | 375 kWh | $53 |
| June | 3.48 m/s | 350 kWh | $49 |
| July | 3.19 m/s | 273 kWh | $39 |
| August | 3.26 m/s | 292 kWh | $41 |
| September | 3.65 m/s | 407 kWh | $58 |
| October | 4.25 m/s | 671 kWh | $95 |
| November | 4.90 m/s | 975 kWh | $138 |
| December | 5.14 m/s | 1,144 kWh | $162 |
What a taller tower would buy
Measured at 10 m the wind in Gallatin County averages 2.91 m/s; at 50 m it is 4.95 m/s. That gives a shear exponent of 0.330, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,983 to 12,199 kWh a year, 145% 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 | 3.66 m/s | 4,983 kWh | over 100 years |
| 30 m | 4.18 m/s | 7,526 kWh | 94 years |
| 40 m | 4.6 m/s | 9,938 kWh | 71 years |
| 50 m | 4.95 m/s | 12,199 kWh | 58 years |
Counties around Gallatin County
4 of the 6 closest counties are windier at turbine height; the windiest, Sweet Grass County, averages 5.94 m/s.
- Park County, MT: 4.68 m/s, 10,445 kWh, payback 68 years (31 mi)
- Madison County, MT: 4.63 m/s, 10,132 kWh, payback 70 years (39 mi)
- Broadwater County, MT: 3.97 m/s, 6,428 kWh, payback over 100 years (58 mi)
- Jefferson County, MT: 4.03 m/s, 6,729 kWh, payback over 100 years (60 mi)
- Sweet Grass County, MT: 5.94 m/s, 19,260 kWh, payback 37 years (62 mi)
- Meagher County, MT: 4.63 m/s, 10,132 kWh, payback 70 years (75 mi)
Sun versus wind in Gallatin County
Gallatin County gets 4.1 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,197 kWh a year; one kW of the turbine above makes 752. Kilowatt for kilowatt, panels make 1.6 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.