Wind Turbine Payback in Walla Walla County, WA
Wind turbine payback in Walla Walla 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 Walla Walla County, WA averages 4.61 m/s (10.3 mph). A 10 kW turbine there would make about 10,008 kWh a year, worth $1,443 at WA's 14.42¢/kWh. Against an installed cost of about $100,000, that is a payback of 69 years, and the turbine is built to last about 20.
What to do in Walla Walla County
A home turbine is not worth buying for savings in Walla Walla County unless your spot is far windier than the county average, 8.1 m/s at the hub against 4.61 m/s here. Per kW, solar panels would make about 1,232 kWh a year here against the turbine's 1,001, so get a solar quote first.
What would have to change
- Power would have to cost 50¢/kWh, 3.5 times what WA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 4.61. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WA
Walla Walla County is the 1,685th 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 Walla Walla County
March is the strongest month here, at 5.28 m/s and about 1,229 kWh. August is the weakest, 4.08 m/s and 591 kWh, so the best month makes 2.1 times the worst. November to March brings in 48% of the year's output in Walla Walla County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.65 m/s | 872 kWh | $126 |
| February | 4.72 m/s | 822 kWh | $119 |
| March | 5.28 m/s | 1,229 kWh | $177 |
| April | 4.95 m/s | 1,004 kWh | $145 |
| May | 4.42 m/s | 753 kWh | $109 |
| June | 4.57 m/s | 803 kWh | $116 |
| July | 4.18 m/s | 639 kWh | $92 |
| August | 4.08 m/s | 591 kWh | $85 |
| September | 4.19 m/s | 622 kWh | $90 |
| October | 4.62 m/s | 858 kWh | $124 |
| November | 4.94 m/s | 999 kWh | $144 |
| December | 4.68 m/s | 886 kWh | $128 |
What a taller tower would buy
Measured at 10 m the wind in Walla Walla County averages 3.55 m/s; at 50 m it is 5.2 m/s. That gives a shear exponent of 0.237, typical of ordinary open country. Going from 20 m to 50 m takes output from 7,542 to 13,907 kWh a year, 84% 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 | 4.18 m/s | 7,542 kWh | 92 years |
| 30 m | 4.61 m/s | 9,990 kWh | 69 years |
| 40 m | 4.93 m/s | 12,080 kWh | 57 years |
| 50 m | 5.2 m/s | 13,907 kWh | 50 years |
Counties around Walla Walla County
5 of the 6 closest counties are 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 (27 mi)
- Franklin County, WA: 4.61 m/s, 10,008 kWh, payback 69 years (28 mi)
- Garfield County, WA: 4.91 m/s, 11,933 kWh, payback 58 years (47 mi)
- Umatilla County, OR: 5.02 m/s, 12,670 kWh, payback 51 years (47 mi)
- Benton County, WA: 4.84 m/s, 11,472 kWh, payback 61 years (50 mi)
- Adams County, WA: 4.83 m/s, 11,407 kWh, payback 61 years (52 mi)
Sun versus wind in Walla Walla County
Walla Walla County gets 4.22 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,232 kWh a year; one kW of the turbine above makes 1,001. Kilowatt for kilowatt, panels make 1.2 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.