Wind Turbine Payback in Multnomah County, OR
Wind turbine payback in Multnomah 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 Multnomah County, OR averages 3.39 m/s (7.6 mph). A 10 kW turbine there would make about 3,905 kWh a year, worth $604 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 Multnomah County
A home turbine is not worth buying for savings in Multnomah County unless your spot is far windier than the county average, 7.8 m/s at the hub against 3.39 m/s here. Per kW, solar panels would make about 1,072 kWh a year here against the turbine's 391, so get a solar quote first.
What would have to change
- Power would have to cost 128¢/kWh, 8.3 times what OR pays now.
- Or the average wind at the hub would have to be 7.8 m/s instead of 3.39. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of OR
Multnomah County is the 2,638th 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 Multnomah County
January is the strongest month here, at 4.35 m/s and about 718 kWh. August is the weakest, 2.60 m/s and 134 kWh, so the best month makes 5.4 times the worst. November to March brings in 67% of the year's output in Multnomah County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.35 m/s | 718 kWh | $111 |
| February | 3.89 m/s | 462 kWh | $71 |
| March | 3.74 m/s | 452 kWh | $70 |
| April | 3.27 m/s | 284 kWh | $44 |
| May | 2.84 m/s | 182 kWh | $28 |
| June | 2.80 m/s | 167 kWh | $26 |
| July | 2.60 m/s | 134 kWh | $21 |
| August | 2.60 m/s | 134 kWh | $21 |
| September | 2.84 m/s | 176 kWh | $27 |
| October | 3.43 m/s | 343 kWh | $53 |
| November | 4.13 m/s | 596 kWh | $92 |
| December | 4.30 m/s | 694 kWh | $107 |
What a taller tower would buy
Measured at 10 m the wind in Multnomah County averages 2.33 m/s; at 50 m it is 4.04 m/s. That gives a shear exponent of 0.342, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,464 to 6,780 kWh a year, 175% 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 | 2.95 m/s | 2,464 kWh | over 100 years |
| 30 m | 3.39 m/s | 3,914 kWh | over 100 years |
| 40 m | 3.74 m/s | 5,356 kWh | over 100 years |
| 50 m | 4.04 m/s | 6,780 kWh | 95 years |
Counties around Multnomah County
None of the 6 closest counties is windier than Multnomah County.
- Clark County, WA: 2.96 m/s, 2,484 kWh, payback over 100 years (16 mi)
- Clackamas County, OR: 3.23 m/s, 3,333 kWh, payback over 100 years (29 mi)
- Washington County, OR: 3.29 m/s, 3,541 kWh, payback over 100 years (33 mi)
- Hood River County, OR: 3.14 m/s, 3,034 kWh, payback over 100 years (37 mi)
- Skamania County, WA: 3.12 m/s, 2,970 kWh, payback over 100 years (40 mi)
- Columbia County, OR: 3 m/s, 2,601 kWh, payback over 100 years (42 mi)
Sun versus wind in Multnomah County
Multnomah 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 391. Kilowatt for kilowatt, panels make 2.7 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.