Wind Turbine Payback in Columbia County, WA
Wind turbine payback in Columbia 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 Columbia County, WA averages 5.18 m/s (11.6 mph). A 10 kW turbine there would make about 13,768 kWh a year, worth $1,985 at WA's 14.42¢/kWh. Against an installed cost of about $100,000, that is a payback of 50 years, and the turbine is built to last about 20.
What to do in Columbia County
A home turbine is not worth buying for savings in Columbia County unless your spot is far windier than the county average, 8.1 m/s at the hub against 5.18 m/s here. Per kW, solar panels would make about 1,168 kWh a year here against the turbine's 1,377, so get a solar quote first.
What would have to change
- Power would have to cost 36¢/kWh, 2.5 times what WA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 5.18. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WA
Columbia County is the 1,389th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. It is the windiest county in WA.
Month by month in Columbia County
March is the strongest month here, at 5.77 m/s and about 1,531 kWh. August is the weakest, 4.57 m/s and 829 kWh, so the best month makes 1.8 times the worst. November to March brings in 51% of the year's output in Columbia County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.62 m/s | 1,438 kWh | $207 |
| February | 5.41 m/s | 1,181 kWh | $170 |
| March | 5.77 m/s | 1,531 kWh | $221 |
| April | 5.35 m/s | 1,229 kWh | $177 |
| May | 4.74 m/s | 918 kWh | $132 |
| June | 4.89 m/s | 969 kWh | $140 |
| July | 4.61 m/s | 852 kWh | $123 |
| August | 4.57 m/s | 829 kWh | $120 |
| September | 4.68 m/s | 861 kWh | $124 |
| October | 5.24 m/s | 1,206 kWh | $174 |
| November | 5.72 m/s | 1,450 kWh | $209 |
| December | 5.59 m/s | 1,416 kWh | $204 |
What a taller tower would buy
Measured at 10 m the wind in Columbia County averages 3.99 m/s; at 50 m it is 5.85 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 10,595 to 18,595 kWh a year, 76% 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 | 4.7 m/s | 10,595 kWh | 66 years |
| 30 m | 5.18 m/s | 13,770 kWh | 50 years |
| 40 m | 5.55 m/s | 16,380 kWh | 42 years |
| 50 m | 5.85 m/s | 18,595 kWh | 37 years |
Counties around Columbia County
None of the 6 closest counties is windier than Columbia County.
- Garfield County, WA: 4.91 m/s, 11,933 kWh, payback 58 years (20 mi)
- Walla Walla County, WA: 4.61 m/s, 10,008 kWh, payback 69 years (27 mi)
- Asotin County, WA: 3.69 m/s, 5,121 kWh, payback over 100 years (34 mi)
- Whitman County, WA: 4.84 m/s, 11,472 kWh, payback 61 years (46 mi)
- Franklin County, WA: 4.61 m/s, 10,008 kWh, payback 69 years (50 mi)
- Nez Perce County, ID: 3.94 m/s, 6,280 kWh, payback over 100 years (55 mi)
Sun versus wind in Columbia County
Columbia 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 1,377. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.2 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.