Wind Turbine Payback in Valley County, ID
Wind turbine payback in Valley 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 Valley County, ID averages 2.82 m/s (6.3 mph). A 10 kW turbine there would make about 2,099 kWh a year, worth $273 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 Valley County
A home turbine is not worth buying for savings in Valley County unless your spot is far windier than the county average, 8.7 m/s at the hub against 2.82 m/s here. Per kW, solar panels would make about 1,250 kWh a year here against the turbine's 210, so get a solar quote first.
What would have to change
- Power would have to cost 238¢/kWh, 18.3 times what ID pays now.
- Or the average wind at the hub would have to be 8.7 m/s instead of 2.82. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ID
Valley County is the 3,121st 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 Valley County
November is the strongest month here, at 3.18 m/s and about 260 kWh. July is the weakest, 2.48 m/s and 111 kWh, so the best month makes 2.3 times the worst. November to March brings in 55% of the year's output in Valley County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.05 m/s | 234 kWh | $30 |
| February | 2.99 m/s | 196 kWh | $26 |
| March | 3.10 m/s | 248 kWh | $32 |
| April | 2.86 m/s | 181 kWh | $24 |
| May | 2.59 m/s | 131 kWh | $17 |
| June | 2.50 m/s | 112 kWh | $15 |
| July | 2.48 m/s | 111 kWh | $14 |
| August | 2.55 m/s | 124 kWh | $16 |
| September | 2.61 m/s | 131 kWh | $17 |
| October | 2.88 m/s | 193 kWh | $25 |
| November | 3.18 m/s | 260 kWh | $34 |
| December | 3.15 m/s | 259 kWh | $34 |
What a taller tower would buy
Measured at 10 m the wind in Valley County averages 1.97 m/s; at 50 m it is 3.34 m/s. That gives a shear exponent of 0.328, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,296 to 3,720 kWh a year, 187% 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 | 2.47 m/s | 1,296 kWh | over 100 years |
| 30 m | 2.82 m/s | 2,111 kWh | over 100 years |
| 40 m | 3.1 m/s | 2,920 kWh | over 100 years |
| 50 m | 3.34 m/s | 3,720 kWh | over 100 years |
Counties around Valley County
5 of the 6 closest counties are windier at turbine height; the windiest, Gem County, averages 3.76 m/s.
- Adams County, ID: 2.96 m/s, 2,484 kWh, payback over 100 years (41 mi)
- Boise County, ID: 2.86 m/s, 2,205 kWh, payback over 100 years (60 mi)
- Washington County, ID: 3.6 m/s, 4,736 kWh, payback over 100 years (64 mi)
- Gem County, ID: 3.76 m/s, 5,432 kWh, payback over 100 years (67 mi)
- Idaho County, ID: 2.77 m/s, 1,970 kWh, payback over 100 years (69 mi)
- Custer County, ID: 3.3 m/s, 3,577 kWh, payback over 100 years (78 mi)
Sun versus wind in Valley County
Valley County gets 4.28 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,250 kWh a year; one kW of the turbine above makes 210. Kilowatt for kilowatt, panels make 6.0 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.