Wind Turbine Payback in Putnam County, FL
Wind turbine payback in Putnam 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 Putnam County, FL averages 3.78 m/s (8.5 mph). A 10 kW turbine there would make about 5,523 kWh a year, worth $846 at FL's 15.32¢/kWh. Against an installed cost of about $100,000, that is a payback of over 100 years, and the turbine is built to last about 20.
What to do in Putnam County
A home turbine is not worth buying for savings in Putnam County unless your spot is far windier than the county average, 7.8 m/s at the hub against 3.78 m/s here. Per kW, solar panels would make about 1,393 kWh a year here against the turbine's 552, so get a solar quote first.
What would have to change
- Power would have to cost 91¢/kWh, 5.9 times what FL pays now.
- Or the average wind at the hub would have to be 7.8 m/s instead of 3.78. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of FL
Putnam County is the 2,219th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in FL is Brevard County at 5.62 m/s, payback 39 years.
Month by month in Putnam County
March is the strongest month here, at 4.22 m/s and about 659 kWh. July is the weakest, 2.96 m/s and 212 kWh, so the best month makes 3.1 times the worst. November to March brings in 52% of the year's output in Putnam County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.16 m/s | 628 kWh | $96 |
| February | 4.11 m/s | 550 kWh | $84 |
| March | 4.22 m/s | 659 kWh | $101 |
| April | 4.12 m/s | 593 kWh | $91 |
| May | 3.79 m/s | 474 kWh | $73 |
| June | 3.23 m/s | 273 kWh | $42 |
| July | 2.96 m/s | 212 kWh | $32 |
| August | 3.10 m/s | 246 kWh | $38 |
| September | 3.65 m/s | 406 kWh | $62 |
| October | 3.91 m/s | 521 kWh | $80 |
| November | 4.05 m/s | 560 kWh | $86 |
| December | 4.05 m/s | 579 kWh | $89 |
What a taller tower would buy
Measured at 10 m the wind in Putnam County averages 2.64 m/s; at 50 m it is 4.46 m/s. That gives a shear exponent of 0.326, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 3,606 to 9,100 kWh a year, 152% 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 | 3.31 m/s | 3,606 kWh | over 100 years |
| 30 m | 3.78 m/s | 5,504 kWh | over 100 years |
| 40 m | 4.15 m/s | 7,339 kWh | 89 years |
| 50 m | 4.46 m/s | 9,100 kWh | 72 years |
Counties around Putnam County
5 of the 6 closest counties are windier at turbine height; the windiest, St. Johns County, averages 4.52 m/s.
- Flagler County, FL: 4.01 m/s, 6,628 kWh, payback 99 years (28 mi)
- Clay County, FL: 3.85 m/s, 5,847 kWh, payback over 100 years (28 mi)
- St. Johns County, FL: 4.52 m/s, 9,459 kWh, payback 69 years (29 mi)
- Marion County, FL: 4.42 m/s, 8,865 kWh, payback 74 years (33 mi)
- Bradford County, FL: 3.85 m/s, 5,847 kWh, payback over 100 years (36 mi)
- Alachua County, FL: 3.59 m/s, 4,694 kWh, payback over 100 years (38 mi)
Sun versus wind in Putnam County
Putnam County gets 4.77 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,393 kWh a year; one kW of the turbine above makes 552. Kilowatt for kilowatt, panels make 2.5 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.