Wind Turbine Payback in Franklin County, ID
Wind turbine payback in Franklin 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 Franklin County, ID averages 3.67 m/s (8.2 mph). A 10 kW turbine there would make about 5,034 kWh a year, worth $655 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 Franklin County
A home turbine is not worth buying for savings in Franklin County unless your spot is far windier than the county average, 8.7 m/s at the hub against 3.67 m/s here. Per kW, solar panels would make about 1,326 kWh a year here against the turbine's 503, so get a solar quote first.
What would have to change
- Power would have to cost 99¢/kWh, 7.6 times what ID pays now.
- Or the average wind at the hub would have to be 8.7 m/s instead of 3.67. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ID
Franklin County is the 2,308th 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 Franklin County
March is the strongest month here, at 4.05 m/s and about 578 kWh. July is the weakest, 3.35 m/s and 320 kWh, so the best month makes 1.8 times the worst. November to March brings in 44% of the year's output in Franklin County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.60 m/s | 401 kWh | $52 |
| February | 3.86 m/s | 451 kWh | $59 |
| March | 4.05 m/s | 578 kWh | $75 |
| April | 4.04 m/s | 556 kWh | $72 |
| May | 3.71 m/s | 443 kWh | $58 |
| June | 3.78 m/s | 456 kWh | $59 |
| July | 3.35 m/s | 320 kWh | $42 |
| August | 3.38 m/s | 328 kWh | $43 |
| September | 3.51 m/s | 360 kWh | $47 |
| October | 3.51 m/s | 372 kWh | $48 |
| November | 3.64 m/s | 403 kWh | $52 |
| December | 3.65 m/s | 420 kWh | $55 |
What a taller tower would buy
Measured at 10 m the wind in Franklin County averages 2.93 m/s; at 50 m it is 4.07 m/s. That gives a shear exponent of 0.204, typical of ordinary open country. Going from 20 m to 50 m takes output from 3,853 to 6,934 kWh a year, 80% 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 | 3.38 m/s | 3,853 kWh | over 100 years |
| 30 m | 3.67 m/s | 5,022 kWh | over 100 years |
| 40 m | 3.89 m/s | 6,032 kWh | over 100 years |
| 50 m | 4.07 m/s | 6,934 kWh | over 100 years |
Counties around Franklin County
3 of the 6 closest counties are windier at turbine height; the windiest, Rich County, averages 4.61 m/s.
- Bear Lake County, ID: 3.5 m/s, 4,329 kWh, payback over 100 years (27 mi)
- Cache County, UT: 3.08 m/s, 2,844 kWh, payback over 100 years (31 mi)
- Oneida County, ID: 3.88 m/s, 5,989 kWh, payback over 100 years (36 mi)
- Bannock County, ID: 4.31 m/s, 8,233 kWh, payback 93 years (41 mi)
- Caribou County, ID: 3.51 m/s, 4,368 kWh, payback over 100 years (45 mi)
- Rich County, UT: 4.61 m/s, 10,008 kWh, payback 76 years (48 mi)
Sun versus wind in Franklin County
Franklin County gets 4.54 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,326 kWh a year; one kW of the turbine above makes 503. Kilowatt for kilowatt, panels make 2.6 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.