Wind Turbine Payback in Lewis County, ID
Wind turbine payback in Lewis 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 Lewis County, ID averages 3.33 m/s (7.4 mph). A 10 kW turbine there would make about 3,684 kWh a year, worth $480 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 Lewis County
A home turbine is not worth buying for savings in Lewis County unless your spot is far windier than the county average, 8.7 m/s at the hub against 3.33 m/s here. Per kW, solar panels would make about 1,168 kWh a year here against the turbine's 368, so get a solar quote first.
What would have to change
- Power would have to cost 136¢/kWh, 10.4 times what ID pays now.
- Or the average wind at the hub would have to be 8.7 m/s instead of 3.33. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ID
Lewis County is the 2,705th 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 Lewis County
January is the strongest month here, at 4.13 m/s and about 614 kWh. August is the weakest, 2.59 m/s and 132 kWh, so the best month makes 4.7 times the worst. November to March brings in 64% of the year's output in Lewis County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.13 m/s | 614 kWh | $80 |
| February | 3.77 m/s | 420 kWh | $55 |
| March | 3.74 m/s | 455 kWh | $59 |
| April | 3.36 m/s | 312 kWh | $41 |
| May | 2.95 m/s | 209 kWh | $27 |
| June | 2.83 m/s | 175 kWh | $23 |
| July | 2.60 m/s | 134 kWh | $17 |
| August | 2.59 m/s | 132 kWh | $17 |
| September | 2.79 m/s | 165 kWh | $21 |
| October | 3.31 m/s | 306 kWh | $40 |
| November | 3.90 m/s | 500 kWh | $65 |
| December | 3.99 m/s | 553 kWh | $72 |
What a taller tower would buy
Measured at 10 m the wind in Lewis County averages 2.47 m/s; at 50 m it is 3.82 m/s. That gives a shear exponent of 0.271, typical of ordinary open country. Going from 20 m to 50 m takes output from 2,542 to 5,707 kWh a year, 125% 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 | 2.98 m/s | 2,542 kWh | over 100 years |
| 30 m | 3.33 m/s | 3,670 kWh | over 100 years |
| 40 m | 3.6 m/s | 4,719 kWh | over 100 years |
| 50 m | 3.82 m/s | 5,707 kWh | over 100 years |
Counties around Lewis County
4 of the 6 closest counties are windier at turbine height; the windiest, Garfield County, averages 4.91 m/s.
- Nez Perce County, ID: 3.94 m/s, 6,280 kWh, payback over 100 years (17 mi)
- Asotin County, WA: 3.69 m/s, 5,121 kWh, payback over 100 years (39 mi)
- Latah County, ID: 3.61 m/s, 4,778 kWh, payback over 100 years (43 mi)
- Clearwater County, ID: 2.58 m/s, 1,521 kWh, payback over 100 years (47 mi)
- Idaho County, ID: 2.77 m/s, 1,970 kWh, payback over 100 years (53 mi)
- Garfield County, WA: 4.91 m/s, 11,933 kWh, payback 58 years (55 mi)
Sun versus wind in Lewis County
Lewis 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 368. Kilowatt for kilowatt, panels make 3.2 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.