Wind Turbine Payback in Asotin County, WA
Wind turbine payback in Asotin 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 Asotin County, WA averages 3.69 m/s (8.3 mph). A 10 kW turbine there would make about 5,121 kWh a year, worth $738 at WA's 14.42¢/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 Asotin County
A home turbine is not worth buying for savings in Asotin County unless your spot is far windier than the county average, 8.1 m/s at the hub against 3.69 m/s here. Per kW, solar panels would make about 1,168 kWh a year here against the turbine's 512, so get a solar quote first.
What would have to change
- Power would have to cost 98¢/kWh, 6.8 times what WA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 3.69. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WA
Asotin County is the 2,300th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in WA is Columbia County at 5.18 m/s, payback 50 years.
Month by month in Asotin County
January is the strongest month here, at 4.36 m/s and about 724 kWh. August is the weakest, 3.07 m/s and 240 kWh, so the best month makes 3.0 times the worst. November to March brings in 59% of the year's output in Asotin County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.36 m/s | 724 kWh | $104 |
| February | 4.07 m/s | 531 kWh | $77 |
| March | 4.09 m/s | 596 kWh | $86 |
| April | 3.71 m/s | 428 kWh | $62 |
| May | 3.22 m/s | 282 kWh | $41 |
| June | 3.27 m/s | 284 kWh | $41 |
| July | 3.11 m/s | 249 kWh | $36 |
| August | 3.07 m/s | 240 kWh | $35 |
| September | 3.19 m/s | 263 kWh | $38 |
| October | 3.73 m/s | 448 kWh | $65 |
| November | 4.23 m/s | 639 kWh | $92 |
| December | 4.25 m/s | 672 kWh | $97 |
What a taller tower would buy
Measured at 10 m the wind in Asotin County averages 2.51 m/s; at 50 m it is 4.42 m/s. That gives a shear exponent of 0.352, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 3,236 to 8,865 kWh a year, 174% 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 | 3.2 m/s | 3,236 kWh | over 100 years |
| 30 m | 3.69 m/s | 5,132 kWh | over 100 years |
| 40 m | 4.09 m/s | 7,018 kWh | 99 years |
| 50 m | 4.42 m/s | 8,865 kWh | 78 years |
Counties around Asotin County
3 of the 6 closest counties are windier at turbine height; the windiest, Columbia County, averages 5.18 m/s.
- Garfield County, WA: 4.91 m/s, 11,933 kWh, payback 58 years (23 mi)
- Nez Perce County, ID: 3.94 m/s, 6,280 kWh, payback over 100 years (25 mi)
- Columbia County, WA: 5.18 m/s, 13,768 kWh, payback 50 years (34 mi)
- Lewis County, ID: 3.33 m/s, 3,684 kWh, payback over 100 years (39 mi)
- Wallowa County, OR: 3.38 m/s, 3,868 kWh, payback over 100 years (41 mi)
- Latah County, ID: 3.61 m/s, 4,778 kWh, payback over 100 years (50 mi)
Sun versus wind in Asotin County
Asotin 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 512. Kilowatt for kilowatt, panels make 2.3 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.