Wind Turbine Payback in Wahkiakum County, WA
Wind turbine payback in Wahkiakum 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 Wahkiakum County, WA averages 2.89 m/s (6.5 mph). A 10 kW turbine there would make about 2,287 kWh a year, worth $330 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 Wahkiakum County
A home turbine is not worth buying for savings in Wahkiakum County unless your spot is far windier than the county average, 8.1 m/s at the hub against 2.89 m/s here. Per kW, solar panels would make about 1,013 kWh a year here against the turbine's 229, so get a solar quote first.
What would have to change
- Power would have to cost 219¢/kWh, 15.2 times what WA pays now.
- Or the average wind at the hub would have to be 8.1 m/s instead of 2.89. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of WA
Wahkiakum County is the 3,113th 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 Wahkiakum County
December is the strongest month here, at 3.43 m/s and about 343 kWh. July is the weakest, 2.37 m/s and 93 kWh, so the best month makes 3.7 times the worst. November to March brings in 61% of the year's output in Wahkiakum County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.41 m/s | 338 kWh | $49 |
| February | 3.14 m/s | 232 kWh | $33 |
| March | 3.12 m/s | 253 kWh | $36 |
| April | 2.83 m/s | 175 kWh | $25 |
| May | 2.50 m/s | 114 kWh | $16 |
| June | 2.47 m/s | 107 kWh | $15 |
| July | 2.37 m/s | 93 kWh | $13 |
| August | 2.40 m/s | 98 kWh | $14 |
| September | 2.63 m/s | 135 kWh | $19 |
| October | 3.00 m/s | 221 kWh | $32 |
| November | 3.38 m/s | 317 kWh | $46 |
| December | 3.43 m/s | 343 kWh | $49 |
What a taller tower would buy
Measured at 10 m the wind in Wahkiakum County averages 1.79 m/s; at 50 m it is 3.61 m/s. That gives a shear exponent of 0.436, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,193 to 4,778 kWh a year, 301% 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 | 2.42 m/s | 1,193 kWh | over 100 years |
| 30 m | 2.89 m/s | 2,285 kWh | over 100 years |
| 40 m | 3.28 m/s | 3,490 kWh | over 100 years |
| 50 m | 3.61 m/s | 4,778 kWh | over 100 years |
Counties around Wahkiakum County
5 of the 6 closest counties are windier at turbine height; the windiest, Clatsop County, averages 3.95 m/s.
- Clatsop County, OR: 3.95 m/s, 6,329 kWh, payback over 100 years (23 mi)
- Pacific County, WA: 3.57 m/s, 4,612 kWh, payback over 100 years (25 mi)
- Columbia County, OR: 3 m/s, 2,601 kWh, payback over 100 years (29 mi)
- Cowlitz County, WA: 2.96 m/s, 2,484 kWh, payback over 100 years (36 mi)
- Thurston County, WA: 2.81 m/s, 2,073 kWh, payback over 100 years (53 mi)
- Washington County, OR: 3.29 m/s, 3,541 kWh, payback over 100 years (54 mi)
Sun versus wind in Wahkiakum County
Wahkiakum County gets 3.47 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,013 kWh a year; one kW of the turbine above makes 229. Kilowatt for kilowatt, panels make 4.4 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.