Wind Turbine Payback in Stanislaus County, CA
Wind turbine payback in Stanislaus 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 Stanislaus County, CA averages 4.35 m/s (9.7 mph). A 10 kW turbine there would make about 8,460 kWh a year, worth $2,756 at CA's 32.58¢/kWh. Against an installed cost of about $100,000, that is a payback of 36 years, and the turbine is built to last about 20.
What to do in Stanislaus County
A home turbine is not worth buying for savings in Stanislaus County unless your spot is far windier than the county average, 5.4 m/s at the hub against 4.35 m/s here. Per kW, solar panels would make about 1,553 kWh a year here against the turbine's 846, so get a solar quote first.
What would have to change
- Power would have to cost 59¢/kWh, 1.8 times what CA pays now.
- Or the average wind at the hub would have to be 5.4 m/s instead of 4.35. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of CA
Stanislaus County is the 1,852nd 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 Stanislaus County
June is the strongest month here, at 5.12 m/s and about 1,099 kWh. January is the weakest, 3.59 m/s and 399 kWh, so the best month makes 2.8 times the worst. November to March brings in 31% of the year's output in Stanislaus County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.59 m/s | 399 kWh | $130 |
| February | 4.22 m/s | 594 kWh | $194 |
| March | 4.37 m/s | 726 kWh | $237 |
| April | 4.84 m/s | 945 kWh | $308 |
| May | 5.00 m/s | 1,063 kWh | $346 |
| June | 5.12 m/s | 1,099 kWh | $358 |
| July | 4.63 m/s | 859 kWh | $280 |
| August | 4.40 m/s | 744 kWh | $242 |
| September | 4.27 m/s | 657 kWh | $214 |
| October | 4.06 m/s | 584 kWh | $190 |
| November | 3.73 m/s | 434 kWh | $141 |
| December | 3.97 m/s | 545 kWh | $178 |
What a taller tower would buy
Measured at 10 m the wind in Stanislaus County averages 3.48 m/s; at 50 m it is 4.82 m/s. That gives a shear exponent of 0.202, typical of ordinary open country. Going from 20 m to 50 m takes output from 6,605 to 11,341 kWh a year, 72% 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 | 4.01 m/s | 6,605 kWh | 47 years |
| 30 m | 4.35 m/s | 8,445 kWh | 36 years |
| 40 m | 4.61 m/s | 9,993 kWh | 31 years |
| 50 m | 4.82 m/s | 11,341 kWh | 27 years |
Counties around Stanislaus County
2 of the 6 closest counties are windier at turbine height; the windiest, Contra Costa County, averages 4.85 m/s.
- San Joaquin County, CA: 4.09 m/s, 7,038 kWh, payback 44 years (30 mi)
- Merced County, CA: 4.5 m/s, 9,339 kWh, payback 33 years (30 mi)
- Santa Clara County, CA: 3.46 m/s, 4,172 kWh, payback 74 years (44 mi)
- Calaveras County, CA: 3.22 m/s, 3,299 kWh, payback 93 years (50 mi)
- Alameda County, CA: 4.17 m/s, 7,461 kWh, payback 41 years (50 mi)
- Contra Costa County, CA: 4.85 m/s, 11,537 kWh, payback 27 years (57 mi)
Sun versus wind in Stanislaus County
Stanislaus County gets 5.32 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,553 kWh a year; one kW of the turbine above makes 846. 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.