Wind Turbine Payback in Phillips County, MT
Wind turbine payback in Phillips 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 Phillips County, MT averages 6.17 m/s (13.8 mph). A 10 kW turbine there would make about 20,965 kWh a year, worth $2,962 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 Phillips County
A home turbine is not worth buying for savings in Phillips County unless your spot is far windier than the county average, 8.2 m/s at the hub against 6.17 m/s here. Per kW, solar panels would make about 1,159 kWh a year here against the turbine's 2,097, 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 6.17. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MT
Phillips County is the 608th 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 Phillips County
January is the strongest month here, at 6.83 m/s and about 2,191 kWh. August is the weakest, 5.37 m/s and 1,284 kWh, so the best month makes 1.7 times the worst. November to March brings in 47% of the year's output in Phillips County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.83 m/s | 2,191 kWh | $310 |
| February | 6.07 m/s | 1,550 kWh | $219 |
| March | 6.41 m/s | 1,930 kWh | $273 |
| April | 6.34 m/s | 1,824 kWh | $258 |
| May | 6.14 m/s | 1,761 kWh | $249 |
| June | 5.84 m/s | 1,520 kWh | $215 |
| July | 5.40 m/s | 1,300 kWh | $184 |
| August | 5.37 m/s | 1,284 kWh | $181 |
| September | 5.70 m/s | 1,439 kWh | $203 |
| October | 6.51 m/s | 1,991 kWh | $281 |
| November | 6.78 m/s | 2,093 kWh | $296 |
| December | 6.56 m/s | 2,025 kWh | $286 |
What a taller tower would buy
Measured at 10 m the wind in Phillips County averages 4.83 m/s; at 50 m it is 6.91 m/s. That gives a shear exponent of 0.223, typical of ordinary open country. Going from 20 m to 50 m takes output from 17,002 to 26,397 kWh a year, 55% 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 | 5.63 m/s | 17,002 kWh | 42 years |
| 30 m | 6.17 m/s | 20,935 kWh | 34 years |
| 40 m | 6.57 m/s | 23,956 kWh | 30 years |
| 50 m | 6.91 m/s | 26,397 kWh | 27 years |
Counties around Phillips County
4 of the 6 closest counties are windier at turbine height; the windiest, Garfield County, averages 6.41 m/s.
- Blaine County, MT: 6.31 m/s, 22,003 kWh, payback 32 years (49 mi)
- Valley County, MT: 6.11 m/s, 20,520 kWh, payback 35 years (58 mi)
- Petroleum County, MT: 5.89 m/s, 18,890 kWh, payback 38 years (78 mi)
- Garfield County, MT: 6.41 m/s, 22,743 kWh, payback 31 years (81 mi)
- Fergus County, MT: 6.18 m/s, 21,039 kWh, payback 34 years (93 mi)
- Hill County, MT: 6.21 m/s, 21,262 kWh, payback 33 years (103 mi)
Sun versus wind in Phillips County
Phillips County gets 3.97 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,159 kWh a year; one kW of the turbine above makes 2,097. 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.