Wind Turbine Payback in Lemhi County, ID
Wind turbine payback in Lemhi 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 Lemhi County, ID averages 3.22 m/s (7.2 mph). A 10 kW turbine there would make about 3,299 kWh a year, worth $430 at ID's 13.02¢/kWh. Against an installed cost of about $100,000, that is a payback of over 100 years, and the turbine is built to last about 20.
What to do in Lemhi County
A home turbine is not worth buying for savings in Lemhi County unless your spot is far windier than the county average, 8.7 m/s at the hub against 3.22 m/s here. Per kW, solar panels would make about 1,279 kWh a year here against the turbine's 330, so get a solar quote first.
What would have to change
- Power would have to cost 152¢/kWh, 11.6 times what ID pays now.
- Or the average wind at the hub would have to be 8.7 m/s instead of 3.22. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ID
Lemhi County is the 2,857th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in ID is Owyhee County at 5.38 m/s, payback 51 years.
Month by month in Lemhi County
March is the strongest month here, at 3.69 m/s and about 436 kWh. August is the weakest, 2.77 m/s and 167 kWh, so the best month makes 2.6 times the worst. November to March brings in 51% of the year's output in Lemhi County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.31 m/s | 307 kWh | $40 |
| February | 3.35 m/s | 287 kWh | $37 |
| March | 3.69 m/s | 436 kWh | $57 |
| April | 3.51 m/s | 358 kWh | $47 |
| May | 3.13 m/s | 256 kWh | $33 |
| June | 3.04 m/s | 222 kWh | $29 |
| July | 2.85 m/s | 185 kWh | $24 |
| August | 2.77 m/s | 167 kWh | $22 |
| September | 2.87 m/s | 185 kWh | $24 |
| October | 3.28 m/s | 299 kWh | $39 |
| November | 3.49 m/s | 352 kWh | $46 |
| December | 3.41 m/s | 338 kWh | $44 |
What a taller tower would buy
Measured at 10 m the wind in Lemhi County averages 2.51 m/s; at 50 m it is 3.62 m/s. That gives a shear exponent of 0.228, typical of ordinary open country. Going from 20 m to 50 m takes output from 2,420 to 4,820 kWh a year, 99% 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 | 2.94 m/s | 2,420 kWh | over 100 years |
| 30 m | 3.22 m/s | 3,306 kWh | over 100 years |
| 40 m | 3.44 m/s | 4,096 kWh | over 100 years |
| 50 m | 3.62 m/s | 4,820 kWh | over 100 years |
Counties around Lemhi County
4 of the 6 closest counties are windier at turbine height; the windiest, Beaverhead County, averages 3.95 m/s.
- Custer County, ID: 3.3 m/s, 3,577 kWh, payback over 100 years (49 mi)
- Beaverhead County, MT: 3.95 m/s, 6,329 kWh, payback over 100 years (51 mi)
- Ravalli County, MT: 2.71 m/s, 1,821 kWh, payback over 100 years (80 mi)
- Valley County, ID: 2.82 m/s, 2,099 kWh, payback over 100 years (85 mi)
- Clark County, ID: 3.94 m/s, 6,280 kWh, payback over 100 years (87 mi)
- Deer Lodge County, MT: 3.65 m/s, 4,948 kWh, payback over 100 years (88 mi)
Sun versus wind in Lemhi County
Lemhi County gets 4.38 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,279 kWh a year; one kW of the turbine above makes 330. Kilowatt for kilowatt, panels make 3.9 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.