Wind Turbine Payback in St. James Parish, LA
Wind turbine payback in St. James Parish
No. The turbine wears out before it pays for itself.
At 30 m, the height a home turbine tower usually reaches, the wind in St. James Parish, LA averages 4.7 m/s (10.5 mph). A 10 kW turbine there would make about 10,571 kWh a year, worth $1,403 at LA's 13.27¢/kWh. Against an installed cost of about $100,000, that is a payback of 71 years, and the turbine is built to last about 20.
What to do in St. James Parish
A home turbine is not worth buying for savings in St. James Parish unless your spot is far windier than the county average, 8.6 m/s at the hub against 4.7 m/s here. Per kW, solar panels would make about 1,361 kWh a year here against the turbine's 1,057, so get a solar quote first.
What would have to change
- Power would have to cost 47¢/kWh, 3.6 times what LA pays now.
- Or the average wind at the hub would have to be 8.6 m/s instead of 4.7. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of LA
St. James Parish is the 1,610th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in LA is Iberia Parish at 5.86 m/s, payback 40 years.
Month by month in St. James Parish
January is the strongest month here, at 5.48 m/s and about 1,350 kWh. July is the weakest, 3.46 m/s and 354 kWh, so the best month makes 3.8 times the worst. November to March brings in 57% of the year's output in St. James Parish.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.48 m/s | 1,350 kWh | $179 |
| February | 5.52 m/s | 1,239 kWh | $164 |
| March | 5.38 m/s | 1,291 kWh | $171 |
| April | 5.36 m/s | 1,234 kWh | $164 |
| May | 4.59 m/s | 842 kWh | $112 |
| June | 3.82 m/s | 470 kWh | $62 |
| July | 3.46 m/s | 354 kWh | $47 |
| August | 3.49 m/s | 363 kWh | $48 |
| September | 4.13 m/s | 597 kWh | $79 |
| October | 4.71 m/s | 903 kWh | $120 |
| November | 5.09 m/s | 1,081 kWh | $143 |
| December | 5.39 m/s | 1,296 kWh | $172 |
What a taller tower would buy
Measured at 10 m the wind in St. James Parish averages 3.63 m/s; at 50 m it is 5.3 m/s. That gives a shear exponent of 0.235, typical of ordinary open country. Going from 20 m to 50 m takes output from 8,027 to 14,608 kWh a year, 82% 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 | 4.27 m/s | 8,027 kWh | 94 years |
| 30 m | 4.7 m/s | 10,574 kWh | 71 years |
| 40 m | 5.03 m/s | 12,732 kWh | 59 years |
| 50 m | 5.3 m/s | 14,608 kWh | 52 years |
Counties around St. James Parish
1 of the 6 closest counties is windier at turbine height; the windiest, Assumption Parish, averages 4.84 m/s.
- Ascension Parish, LA: 4.7 m/s, 10,571 kWh, payback 71 years (14 mi)
- Assumption Parish, LA: 4.84 m/s, 11,472 kWh, payback 66 years (18 mi)
- St. John the Baptist Parish, LA: 4.7 m/s, 10,571 kWh, payback 71 years (20 mi)
- St. Charles Parish, LA: 4.7 m/s, 10,571 kWh, payback 71 years (27 mi)
- Livingston Parish, LA: 3.25 m/s, 3,402 kWh, payback over 100 years (29 mi)
- Iberville Parish, LA: 4.13 m/s, 7,248 kWh, payback over 100 years (38 mi)
Sun versus wind in St. James Parish
St. James Parish gets 4.66 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,361 kWh a year; one kW of the turbine above makes 1,057. Kilowatt for kilowatt, panels make 1.3 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.