Wind Turbine Payback in San Luis Obispo County, CA
Wind turbine payback in San Luis Obispo 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 San Luis Obispo County, CA averages 4.12 m/s (9.2 mph). A 10 kW turbine there would make about 7,195 kWh a year, worth $2,344 at CA's 32.58¢/kWh. Against an installed cost of about $100,000, that is a payback of 43 years, and the turbine is built to last about 20.
What to do in San Luis Obispo County
A home turbine is not worth buying for savings in San Luis Obispo County unless your spot is far windier than the county average, 5.4 m/s at the hub against 4.12 m/s here. Per kW, solar panels would make about 1,618 kWh a year here against the turbine's 720, so get a solar quote first.
What would have to change
- Power would have to cost 69¢/kWh, 2.1 times what CA pays now.
- Or the average wind at the hub would have to be 5.4 m/s instead of 4.12. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of CA
San Luis Obispo County is the 1,987th 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 San Luis Obispo County
April is the strongest month here, at 4.59 m/s and about 810 kWh. September is the weakest, 3.48 m/s and 348 kWh, so the best month makes 2.3 times the worst. November to March brings in 50% of the year's output in San Luis Obispo County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.46 m/s | 772 kWh | $252 |
| February | 4.54 m/s | 735 kWh | $239 |
| March | 4.43 m/s | 758 kWh | $247 |
| April | 4.59 m/s | 810 kWh | $264 |
| May | 4.39 m/s | 736 kWh | $240 |
| June | 4.11 m/s | 588 kWh | $192 |
| July | 3.62 m/s | 410 kWh | $134 |
| August | 3.44 m/s | 348 kWh | $113 |
| September | 3.48 m/s | 348 kWh | $113 |
| October | 3.81 m/s | 482 kWh | $157 |
| November | 4.16 m/s | 608 kWh | $198 |
| December | 4.51 m/s | 800 kWh | $261 |
What a taller tower would buy
Measured at 10 m the wind in San Luis Obispo County averages 3.35 m/s; at 50 m it is 4.54 m/s. That gives a shear exponent of 0.189, typical of ordinary open country. Going from 20 m to 50 m takes output from 5,698 to 9,580 kWh a year, 68% 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 | 3.82 m/s | 5,698 kWh | 54 years |
| 30 m | 4.12 m/s | 7,207 kWh | 43 years |
| 40 m | 4.35 m/s | 8,474 kWh | 36 years |
| 50 m | 4.54 m/s | 9,580 kWh | 32 years |
Counties around San Luis Obispo County
1 of the 6 closest counties is windier at turbine height; the windiest, Santa Barbara County, averages 4.51 m/s.
- Kings County, CA: 4.07 m/s, 6,934 kWh, payback 44 years (59 mi)
- Santa Barbara County, CA: 4.51 m/s, 9,399 kWh, payback 33 years (63 mi)
- Monterey County, CA: 4.07 m/s, 6,934 kWh, payback 44 years (76 mi)
- San Benito County, CA: 3.61 m/s, 4,778 kWh, payback 64 years (92 mi)
- Kern County, CA: 3.43 m/s, 4,056 kWh, payback 76 years (97 mi)
- Ventura County, CA: 3.36 m/s, 3,794 kWh, payback 81 years (103 mi)
Sun versus wind in San Luis Obispo County
San Luis Obispo County gets 5.54 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,618 kWh a year; one kW of the turbine above makes 720. Kilowatt for kilowatt, panels make 2.2 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.