Wind Turbine Payback in San Diego County, CA
Wind turbine payback in San Diego 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 Diego County, CA averages 3.87 m/s (8.7 mph). A 10 kW turbine there would make about 5,942 kWh a year, worth $1,936 at CA's 32.58¢/kWh. Against an installed cost of about $100,000, that is a payback of 52 years, and the turbine is built to last about 20.
What to do in San Diego County
A home turbine is not worth buying for savings in San Diego County unless your spot is far windier than the county average, 5.4 m/s at the hub against 3.87 m/s here. Per kW, solar panels would make about 1,699 kWh a year here against the turbine's 594, so get a solar quote first.
What would have to change
- Power would have to cost 84¢/kWh, 2.6 times what CA pays now.
- Or the average wind at the hub would have to be 5.4 m/s instead of 3.87. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of CA
San Diego County is the 2,157th 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 Diego County
December is the strongest month here, at 4.42 m/s and about 751 kWh. August is the weakest, 3.16 m/s and 264 kWh, so the best month makes 2.8 times the worst. November to March brings in 52% of the year's output in San Diego County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.33 m/s | 710 kWh | $231 |
| February | 4.30 m/s | 629 kWh | $205 |
| March | 4.09 m/s | 598 kWh | $195 |
| April | 4.33 m/s | 687 kWh | $224 |
| May | 4.08 m/s | 594 kWh | $194 |
| June | 3.71 m/s | 428 kWh | $139 |
| July | 3.27 m/s | 296 kWh | $96 |
| August | 3.16 m/s | 264 kWh | $86 |
| September | 3.21 m/s | 268 kWh | $87 |
| October | 3.54 m/s | 383 kWh | $125 |
| November | 3.98 m/s | 532 kWh | $173 |
| December | 4.42 m/s | 751 kWh | $245 |
What a taller tower would buy
Measured at 10 m the wind in San Diego County averages 3.29 m/s; at 50 m it is 4.17 m/s. That gives a shear exponent of 0.147, typical of very open, smooth ground where height adds little. Going from 20 m to 50 m takes output from 4,924 to 7,461 kWh a year, 52% 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 | 3.64 m/s | 4,924 kWh | 62 years |
| 30 m | 3.87 m/s | 5,934 kWh | 52 years |
| 40 m | 4.04 m/s | 6,757 kWh | 45 years |
| 50 m | 4.17 m/s | 7,461 kWh | 41 years |
Counties around San Diego County
3 of the 6 closest counties are windier at turbine height; the windiest, Imperial County, averages 4.5 m/s.
- Riverside County, CA: 3.95 m/s, 6,329 kWh, payback 49 years (66 mi)
- Orange County, CA: 3.16 m/s, 3,099 kWh, payback 99 years (73 mi)
- Imperial County, CA: 4.5 m/s, 9,339 kWh, payback 33 years (82 mi)
- Los Angeles County, CA: 3.34 m/s, 3,720 kWh, payback 83 years (118 mi)
- San Bernardino County, CA: 4.3 m/s, 8,176 kWh, payback 38 years (131 mi)
- Ventura County, CA: 3.36 m/s, 3,794 kWh, payback 81 years (164 mi)
Sun versus wind in San Diego County
San Diego County gets 5.82 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,699 kWh a year; one kW of the turbine above makes 594. Kilowatt for kilowatt, panels make 2.9 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.