Wind Turbine Payback in Washington County, OR
Wind turbine payback in Washington 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 Washington County, OR averages 3.29 m/s (7.4 mph). A 10 kW turbine there would make about 3,541 kWh a year, worth $547 at OR's 15.46¢/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 Washington County
A home turbine is not worth buying for savings in Washington County unless your spot is far windier than the county average, 7.8 m/s at the hub against 3.29 m/s here. Per kW, solar panels would make about 1,072 kWh a year here against the turbine's 354, so get a solar quote first.
What would have to change
- Power would have to cost 141¢/kWh, 9.1 times what OR pays now.
- Or the average wind at the hub would have to be 7.8 m/s instead of 3.29. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of OR
Washington County is the 2,761st windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in OR is Gilliam County at 5.48 m/s, payback 41 years.
Month by month in Washington County
December is the strongest month here, at 3.81 m/s and about 482 kWh. August is the weakest, 2.85 m/s and 186 kWh, so the best month makes 2.6 times the worst. November to March brings in 57% of the year's output in Washington County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.81 m/s | 479 kWh | $74 |
| February | 3.52 m/s | 340 kWh | $53 |
| March | 3.51 m/s | 370 kWh | $57 |
| April | 3.19 m/s | 264 kWh | $41 |
| May | 2.90 m/s | 198 kWh | $31 |
| June | 2.92 m/s | 195 kWh | $30 |
| July | 2.89 m/s | 194 kWh | $30 |
| August | 2.85 m/s | 186 kWh | $29 |
| September | 3.00 m/s | 215 kWh | $33 |
| October | 3.35 m/s | 319 kWh | $49 |
| November | 3.75 m/s | 442 kWh | $68 |
| December | 3.81 m/s | 482 kWh | $75 |
What a taller tower would buy
Measured at 10 m the wind in Washington County averages 2.19 m/s; at 50 m it is 3.98 m/s. That gives a shear exponent of 0.371, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,133 to 6,477 kWh a year, 204% 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 | 2.83 m/s | 2,133 kWh | over 100 years |
| 30 m | 3.29 m/s | 3,552 kWh | over 100 years |
| 40 m | 3.66 m/s | 5,007 kWh | over 100 years |
| 50 m | 3.98 m/s | 6,477 kWh | 100 years |
Counties around Washington County
4 of the 6 closest counties are windier at turbine height; the windiest, Tillamook County, averages 4.01 m/s.
- Yamhill County, OR: 3.46 m/s, 4,172 kWh, payback over 100 years (24 mi)
- Columbia County, OR: 3 m/s, 2,601 kWh, payback over 100 years (27 mi)
- Tillamook County, OR: 4.01 m/s, 6,628 kWh, payback 98 years (33 mi)
- Multnomah County, OR: 3.39 m/s, 3,905 kWh, payback over 100 years (33 mi)
- Clark County, WA: 2.96 m/s, 2,484 kWh, payback over 100 years (33 mi)
- Clatsop County, OR: 3.95 m/s, 6,329 kWh, payback over 100 years (44 mi)
Sun versus wind in Washington County
Washington County gets 3.67 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,072 kWh a year; one kW of the turbine above makes 354. Kilowatt for kilowatt, panels make 3.0 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.