Wind Turbine Payback in Spokane County, WA
Wind turbine payback in Spokane 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 Spokane County, WA averages 4.42 m/s (9.9 mph). A 10 kW turbine there would make about 8,865 kWh a year, worth $1,278 at WA's 14.42¢/kWh. Against an installed cost of about $100,000, that is a payback of 78 years, and the turbine is built to last about 20.
What to do in Spokane County
A home turbine is not worth buying for savings in Spokane County unless your spot is far windier than the county average, 8.1 m/s at the hub against 4.42 m/s here. Per kW, solar panels would make about 1,121 kWh a year here against the turbine's 887, so get a solar quote first.
What would have to change
- Power would have to cost 56¢/kWh, 3.9 times what WA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 4.42. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WA
Spokane County is the 1,799th 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 Spokane County
March is the strongest month here, at 5.04 m/s and about 1,085 kWh. August is the weakest, 3.90 m/s and 515 kWh, so the best month makes 2.1 times the worst. November to March brings in 48% of the year's output in Spokane County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.59 m/s | 839 kWh | $121 |
| February | 4.49 m/s | 713 kWh | $103 |
| March | 5.04 m/s | 1,085 kWh | $156 |
| April | 4.73 m/s | 884 kWh | $127 |
| May | 4.27 m/s | 682 kWh | $98 |
| June | 4.26 m/s | 656 kWh | $95 |
| July | 4.01 m/s | 563 kWh | $81 |
| August | 3.90 m/s | 515 kWh | $74 |
| September | 4.10 m/s | 582 kWh | $84 |
| October | 4.47 m/s | 776 kWh | $112 |
| November | 4.71 m/s | 875 kWh | $126 |
| December | 4.49 m/s | 789 kWh | $114 |
What a taller tower would buy
Measured at 10 m the wind in Spokane County averages 3.34 m/s; at 50 m it is 5.04 m/s. That gives a shear exponent of 0.256, typical of ordinary open country. Going from 20 m to 50 m takes output from 6,508 to 12,805 kWh a year, 97% 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 | 3.99 m/s | 6,508 kWh | over 100 years |
| 30 m | 4.42 m/s | 8,878 kWh | 78 years |
| 40 m | 4.76 m/s | 10,955 kWh | 63 years |
| 50 m | 5.04 m/s | 12,805 kWh | 54 years |
Counties around Spokane County
2 of the 6 closest counties are windier at turbine height; the windiest, Lincoln County, averages 4.88 m/s.
- Kootenai County, ID: 3.64 m/s, 4,905 kWh, payback over 100 years (33 mi)
- Benewah County, ID: 3.61 m/s, 4,778 kWh, payback over 100 years (45 mi)
- Lincoln County, WA: 4.88 m/s, 11,734 kWh, payback 59 years (47 mi)
- Whitman County, WA: 4.84 m/s, 11,472 kWh, payback 61 years (50 mi)
- Stevens County, WA: 2.55 m/s, 1,456 kWh, payback over 100 years (57 mi)
- Bonner County, ID: 2.53 m/s, 1,413 kWh, payback over 100 years (60 mi)
Sun versus wind in Spokane County
Spokane County gets 3.84 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,121 kWh a year; one kW of the turbine above makes 887. Kilowatt for kilowatt, panels make 1.3 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.