Wind Turbine Payback in St. Martin Parish, LA
Wind turbine payback in St. Martin 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. Martin Parish, LA averages 5.19 m/s (11.6 mph). A 10 kW turbine there would make about 13,837 kWh a year, worth $1,836 at LA's 13.27¢/kWh. Against an installed cost of about $100,000, that is a payback of 55 years, and the turbine is built to last about 20.
What to do in St. Martin Parish
A home turbine is not worth buying for savings in St. Martin Parish unless your spot is far windier than the county average, 8.6 m/s at the hub against 5.19 m/s here. Per kW, solar panels would make about 1,364 kWh a year here against the turbine's 1,384, so get a solar quote first.
What would have to change
- Power would have to cost 36¢/kWh, 2.7 times what LA pays now.
- Or the average wind at the hub would have to be 8.6 m/s instead of 5.19. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of LA
St. Martin Parish is the 1,386th 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. Martin Parish
January is the strongest month here, at 6.08 m/s and about 1,726 kWh. July is the weakest, 3.75 m/s and 459 kWh, so the best month makes 3.8 times the worst. November to March brings in 57% of the year's output in St. Martin Parish.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.08 m/s | 1,726 kWh | $229 |
| February | 6.16 m/s | 1,604 kWh | $213 |
| March | 5.97 m/s | 1,653 kWh | $219 |
| April | 5.99 m/s | 1,616 kWh | $214 |
| May | 5.16 m/s | 1,160 kWh | $154 |
| June | 4.25 m/s | 651 kWh | $86 |
| July | 3.75 m/s | 459 kWh | $61 |
| August | 3.78 m/s | 470 kWh | $62 |
| September | 4.43 m/s | 735 kWh | $98 |
| October | 5.08 m/s | 1,113 kWh | $148 |
| November | 5.67 m/s | 1,421 kWh | $189 |
| December | 6.02 m/s | 1,686 kWh | $224 |
What a taller tower would buy
Measured at 10 m the wind in St. Martin Parish averages 4.06 m/s; at 50 m it is 5.82 m/s. That gives a shear exponent of 0.224, typical of ordinary open country. Going from 20 m to 50 m takes output from 10,826 to 18,374 kWh a year, 70% 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 | 4.74 m/s | 10,826 kWh | 70 years |
| 30 m | 5.19 m/s | 13,842 kWh | 54 years |
| 40 m | 5.54 m/s | 16,299 kWh | 46 years |
| 50 m | 5.82 m/s | 18,374 kWh | 41 years |
Counties around St. Martin Parish
2 of the 6 closest counties are windier at turbine height; the windiest, Iberia Parish, averages 5.86 m/s.
- Iberville Parish, LA: 4.13 m/s, 7,248 kWh, payback over 100 years (18 mi)
- Lafayette Parish, LA: 5.19 m/s, 13,837 kWh, payback 55 years (28 mi)
- West Baton Rouge Parish, LA: 4.13 m/s, 7,248 kWh, payback over 100 years (30 mi)
- St. Mary Parish, LA: 5.5 m/s, 16,037 kWh, payback 47 years (35 mi)
- Assumption Parish, LA: 4.84 m/s, 11,472 kWh, payback 66 years (36 mi)
- Iberia Parish, LA: 5.86 m/s, 18,669 kWh, payback 40 years (38 mi)
Sun versus wind in St. Martin Parish
St. Martin Parish gets 4.67 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,364 kWh a year; one kW of the turbine above makes 1,384. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.0 times. 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.