Wind Turbine Payback in Gem County, ID
Wind turbine payback in Gem 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 Gem County, ID averages 3.76 m/s (8.4 mph). A 10 kW turbine there would make about 5,432 kWh a year, worth $707 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 Gem County
A home turbine is not worth buying for savings in Gem County unless your spot is far windier than the county average, 8.7 m/s at the hub against 3.76 m/s here. Per kW, solar panels would make about 1,279 kWh a year here against the turbine's 543, so get a solar quote first.
What would have to change
- Power would have to cost 92¢/kWh, 7.1 times what ID pays now.
- Or the average wind at the hub would have to be 8.7 m/s instead of 3.76. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ID
Gem County is the 2,236th 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 Gem County
March is the strongest month here, at 4.13 m/s and about 614 kWh. September is the weakest, 3.57 m/s and 379 kWh, so the best month makes 1.6 times the worst. November to March brings in 45% of the year's output in Gem County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.55 m/s | 385 kWh | $50 |
| February | 3.90 m/s | 468 kWh | $61 |
| March | 4.13 m/s | 614 kWh | $80 |
| April | 4.03 m/s | 552 kWh | $72 |
| May | 3.72 m/s | 447 kWh | $58 |
| June | 3.61 m/s | 391 kWh | $51 |
| July | 3.63 m/s | 414 kWh | $54 |
| August | 3.60 m/s | 401 kWh | $52 |
| September | 3.57 m/s | 379 kWh | $49 |
| October | 3.67 m/s | 427 kWh | $56 |
| November | 3.79 m/s | 459 kWh | $60 |
| December | 3.88 m/s | 507 kWh | $66 |
What a taller tower would buy
Measured at 10 m the wind in Gem County averages 2.99 m/s; at 50 m it is 4.18 m/s. That gives a shear exponent of 0.208, typical of ordinary open country. Going from 20 m to 50 m takes output from 4,151 to 7,515 kWh a year, 81% 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 | 3.45 m/s | 4,151 kWh | over 100 years |
| 30 m | 3.76 m/s | 5,426 kWh | over 100 years |
| 40 m | 3.99 m/s | 6,529 kWh | over 100 years |
| 50 m | 4.18 m/s | 7,515 kWh | over 100 years |
Counties around Gem County
3 of the 6 closest counties are windier at turbine height; the windiest, Canyon County, averages 4.3 m/s.
- Payette County, ID: 3.86 m/s, 5,894 kWh, payback over 100 years (18 mi)
- Washington County, ID: 3.6 m/s, 4,736 kWh, payback over 100 years (33 mi)
- Canyon County, ID: 4.3 m/s, 8,176 kWh, payback 94 years (34 mi)
- Boise County, ID: 2.86 m/s, 2,205 kWh, payback over 100 years (34 mi)
- Ada County, ID: 4.17 m/s, 7,461 kWh, payback over 100 years (43 mi)
- Adams County, ID: 2.96 m/s, 2,484 kWh, payback over 100 years (56 mi)
Sun versus wind in Gem County
Gem County gets 4.38 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,279 kWh a year; one kW of the turbine above makes 543. Kilowatt for kilowatt, panels make 2.4 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.