Wind Turbine Payback in Ada County, ID
Wind turbine payback in Ada 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 Ada County, ID averages 4.17 m/s (9.3 mph). A 10 kW turbine there would make about 7,461 kWh a year, worth $971 at ID's 13.02¢/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 Ada County
A home turbine is not worth buying for savings in Ada County unless your spot is far windier than the county average, 8.7 m/s at the hub against 4.17 m/s here. Per kW, solar panels would make about 1,332 kWh a year here against the turbine's 746, so get a solar quote first.
What would have to change
- Power would have to cost 67¢/kWh, 5.1 times what ID pays now.
- Or the average wind at the hub would have to be 8.7 m/s instead of 4.17. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ID
Ada County is the 1,965th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in ID is Owyhee County at 5.38 m/s, payback 51 years.
Month by month in Ada County
March is the strongest month here, at 4.58 m/s and about 835 kWh. September is the weakest, 3.70 m/s and 424 kWh, so the best month makes 2.0 times the worst. November to March brings in 49% of the year's output in Ada County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.23 m/s | 663 kWh | $86 |
| February | 4.47 m/s | 705 kWh | $92 |
| March | 4.58 m/s | 835 kWh | $109 |
| April | 4.53 m/s | 782 kWh | $102 |
| May | 4.13 m/s | 614 kWh | $80 |
| June | 4.06 m/s | 568 kWh | $74 |
| July | 3.81 m/s | 479 kWh | $62 |
| August | 3.68 m/s | 432 kWh | $56 |
| September | 3.70 m/s | 424 kWh | $55 |
| October | 4.05 m/s | 579 kWh | $75 |
| November | 4.38 m/s | 708 kWh | $92 |
| December | 4.45 m/s | 767 kWh | $100 |
What a taller tower would buy
Measured at 10 m the wind in Ada County averages 3.26 m/s; at 50 m it is 4.68 m/s. That gives a shear exponent of 0.225, typical of ordinary open country. Going from 20 m to 50 m takes output from 5,652 to 10,445 kWh a year, 85% 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 | 3.81 m/s | 5,652 kWh | over 100 years |
| 30 m | 4.17 m/s | 7,471 kWh | over 100 years |
| 40 m | 4.45 m/s | 9,046 kWh | 85 years |
| 50 m | 4.68 m/s | 10,445 kWh | 74 years |
Counties around Ada County
2 of the 6 closest counties are windier at turbine height; the windiest, Owyhee County, averages 5.38 m/s.
- Canyon County, ID: 4.3 m/s, 8,176 kWh, payback 94 years (26 mi)
- Elmore County, ID: 3.85 m/s, 5,847 kWh, payback over 100 years (39 mi)
- Gem County, ID: 3.76 m/s, 5,432 kWh, payback over 100 years (43 mi)
- Boise County, ID: 2.86 m/s, 2,205 kWh, payback over 100 years (45 mi)
- Payette County, ID: 3.86 m/s, 5,894 kWh, payback over 100 years (46 mi)
- Owyhee County, ID: 5.38 m/s, 15,176 kWh, payback 51 years (61 mi)
Sun versus wind in Ada County
Ada County gets 4.56 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,332 kWh a year; one kW of the turbine above makes 746. Kilowatt for kilowatt, panels make 1.8 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.