Wind Turbine Payback in Tuolumne County, CA
Wind turbine payback in Tuolumne 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 Tuolumne County, CA averages 3.32 m/s (7.4 mph). A 10 kW turbine there would make about 3,648 kWh a year, worth $1,189 at CA's 32.58¢/kWh. Against an installed cost of about $100,000, that is a payback of 84 years, and the turbine is built to last about 20.
What to do in Tuolumne County
A home turbine is not worth buying for savings in Tuolumne County unless your spot is far windier than the county average, 5.4 m/s at the hub against 3.32 m/s here. Per kW, solar panels would make about 1,539 kWh a year here against the turbine's 365, so get a solar quote first.
What would have to change
- Power would have to cost 137¢/kWh, 4.2 times what CA pays now.
- Or the average wind at the hub would have to be 5.4 m/s instead of 3.32. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of CA
Tuolumne County is the 2,715th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in CA is San Francisco County at 6.53 m/s, payback 13 years.
Month by month in Tuolumne County
January is the strongest month here, at 3.69 m/s and about 433 kWh. July is the weakest, 3.03 m/s and 228 kWh, so the best month makes 1.9 times the worst. November to March brings in 50% of the year's output in Tuolumne County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.69 m/s | 433 kWh | $141 |
| February | 3.62 m/s | 369 kWh | $120 |
| March | 3.43 m/s | 343 kWh | $112 |
| April | 3.24 m/s | 276 kWh | $90 |
| May | 3.14 m/s | 258 kWh | $84 |
| June | 3.17 m/s | 257 kWh | $84 |
| July | 3.03 m/s | 228 kWh | $74 |
| August | 3.06 m/s | 237 kWh | $77 |
| September | 3.31 m/s | 296 kWh | $96 |
| October | 3.31 m/s | 308 kWh | $100 |
| November | 3.34 m/s | 306 kWh | $100 |
| December | 3.61 m/s | 405 kWh | $132 |
What a taller tower would buy
Measured at 10 m the wind in Tuolumne County averages 2.42 m/s; at 50 m it is 3.85 m/s. That gives a shear exponent of 0.288, typical of ordinary open country. Going from 20 m to 50 m takes output from 2,476 to 5,847 kWh a year, 136% 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 | 2.96 m/s | 2,476 kWh | over 100 years |
| 30 m | 3.32 m/s | 3,660 kWh | 84 years |
| 40 m | 3.61 m/s | 4,779 kWh | 64 years |
| 50 m | 3.85 m/s | 5,847 kWh | 53 years |
Counties around Tuolumne County
4 of the 6 closest counties are windier at turbine height; the windiest, Mono County, averages 4.05 m/s.
- Mariposa County, CA: 3.18 m/s, 3,165 kWh, payback 97 years (31 mi)
- Calaveras County, CA: 3.22 m/s, 3,299 kWh, payback 93 years (34 mi)
- Alpine County, CA: 3.53 m/s, 4,449 kWh, payback 69 years (42 mi)
- Amador County, CA: 3.59 m/s, 4,694 kWh, payback 65 years (47 mi)
- Madera County, CA: 3.56 m/s, 4,570 kWh, payback 67 years (57 mi)
- Mono County, CA: 4.05 m/s, 6,831 kWh, payback 45 years (60 mi)
Sun versus wind in Tuolumne County
Tuolumne County gets 5.27 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,539 kWh a year; one kW of the turbine above makes 365. Kilowatt for kilowatt, panels make 4.2 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.