Wind Turbine Payback in Garfield County, WA
Wind turbine payback in Garfield 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 Garfield County, WA averages 4.91 m/s (11 mph). A 10 kW turbine there would make about 11,933 kWh a year, worth $1,721 at WA's 14.42¢/kWh. Against an installed cost of about $100,000, that is a payback of 58 years, and the turbine is built to last about 20.
What to do in Garfield County
A home turbine is not worth buying for savings in Garfield County unless your spot is far windier than the county average, 8.1 m/s at the hub against 4.91 m/s here. Per kW, solar panels would make about 1,168 kWh a year here against the turbine's 1,193, so get a solar quote first.
What would have to change
- Power would have to cost 42¢/kWh, 2.9 times what WA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 4.91. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WA
Garfield County is the 1,500th 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 Garfield County
January is the strongest month here, at 5.45 m/s and about 1,334 kWh. August is the weakest, 4.29 m/s and 688 kWh, so the best month makes 1.9 times the worst. November to March brings in 52% of the year's output in Garfield County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.45 m/s | 1,334 kWh | $192 |
| February | 5.22 m/s | 1,075 kWh | $155 |
| March | 5.43 m/s | 1,318 kWh | $190 |
| April | 5.08 m/s | 1,077 kWh | $155 |
| May | 4.43 m/s | 757 kWh | $109 |
| June | 4.56 m/s | 798 kWh | $115 |
| July | 4.32 m/s | 705 kWh | $102 |
| August | 4.29 m/s | 688 kWh | $99 |
| September | 4.40 m/s | 720 kWh | $104 |
| October | 4.94 m/s | 1,031 kWh | $149 |
| November | 5.44 m/s | 1,281 kWh | $185 |
| December | 5.35 m/s | 1,270 kWh | $183 |
What a taller tower would buy
Measured at 10 m the wind in Garfield County averages 3.78 m/s; at 50 m it is 5.54 m/s. That gives a shear exponent of 0.238, typical of ordinary open country. Going from 20 m to 50 m takes output from 9,068 to 16,326 kWh a year, 80% 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 | 4.45 m/s | 9,068 kWh | 77 years |
| 30 m | 4.91 m/s | 11,905 kWh | 58 years |
| 40 m | 5.25 m/s | 14,281 kWh | 49 years |
| 50 m | 5.54 m/s | 16,326 kWh | 43 years |
Counties around Garfield County
1 of the 6 closest counties is windier at turbine height; the windiest, Columbia County, averages 5.18 m/s.
- Columbia County, WA: 5.18 m/s, 13,768 kWh, payback 50 years (20 mi)
- Asotin County, WA: 3.69 m/s, 5,121 kWh, payback over 100 years (23 mi)
- Whitman County, WA: 4.84 m/s, 11,472 kWh, payback 61 years (33 mi)
- Nez Perce County, ID: 3.94 m/s, 6,280 kWh, payback over 100 years (38 mi)
- Walla Walla County, WA: 4.61 m/s, 10,008 kWh, payback 69 years (47 mi)
- Latah County, ID: 3.61 m/s, 4,778 kWh, payback over 100 years (47 mi)
Sun versus wind in Garfield County
Garfield 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 1,193. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.0 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.