Wind Turbine Payback in Calhoun County, SC
Wind turbine payback in Calhoun 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 Calhoun County, SC averages 4.42 m/s (9.9 mph). A 10 kW turbine there would make about 8,865 kWh a year, worth $1,410 at SC's 15.9¢/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 Calhoun County
A home turbine is not worth buying for savings in Calhoun County unless your spot is far windier than the county average, 7.6 m/s at the hub against 4.42 m/s here. Per kW, solar panels would make about 1,355 kWh a year here against the turbine's 887, so get a solar quote first.
What would have to change
- Power would have to cost 56¢/kWh, 3.5 times what SC pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 4.42. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of SC
Calhoun County is the 1,799th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in SC is Beaufort County at 5.71 m/s, payback 36 years.
Month by month in Calhoun County
March is the strongest month here, at 5.06 m/s and about 1,100 kWh. August is the weakest, 3.50 m/s and 368 kWh, so the best month makes 3.0 times the worst. November to March brings in 51% of the year's output in Calhoun County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.78 m/s | 940 kWh | $149 |
| February | 4.94 m/s | 932 kWh | $148 |
| March | 5.06 m/s | 1,100 kWh | $175 |
| April | 5.08 m/s | 1,074 kWh | $171 |
| May | 4.44 m/s | 761 kWh | $121 |
| June | 3.85 m/s | 481 kWh | $76 |
| July | 3.70 m/s | 438 kWh | $70 |
| August | 3.50 m/s | 368 kWh | $59 |
| September | 4.20 m/s | 624 kWh | $99 |
| October | 4.38 m/s | 735 kWh | $117 |
| November | 4.56 m/s | 795 kWh | $126 |
| December | 4.56 m/s | 822 kWh | $131 |
What a taller tower would buy
Measured at 10 m the wind in Calhoun County averages 3.18 m/s; at 50 m it is 5.15 m/s. That gives a shear exponent of 0.300, typical of ordinary open country. Going from 20 m to 50 m takes output from 6,144 to 13,560 kWh a year, 121% 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 | 3.91 m/s | 6,144 kWh | over 100 years |
| 30 m | 4.42 m/s | 8,855 kWh | 71 years |
| 40 m | 4.82 m/s | 11,319 kWh | 56 years |
| 50 m | 5.15 m/s | 13,560 kWh | 46 years |
Counties around Calhoun County
2 of the 6 closest counties are windier at turbine height; the windiest, Richland County, averages 4.7 m/s.
- Orangeburg County, SC: 4.42 m/s, 8,865 kWh, payback 71 years (17 mi)
- Richland County, SC: 4.7 m/s, 10,571 kWh, payback 60 years (25 mi)
- Sumter County, SC: 4.7 m/s, 10,571 kWh, payback 60 years (28 mi)
- Lexington County, SC: 3.93 m/s, 6,231 kWh, payback over 100 years (32 mi)
- Clarendon County, SC: 4.34 m/s, 8,403 kWh, payback 75 years (32 mi)
- Bamberg County, SC: 4.02 m/s, 6,678 kWh, payback 94 years (36 mi)
Sun versus wind in Calhoun County
Calhoun County gets 4.64 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,355 kWh a year; one kW of the turbine above makes 887. Kilowatt for kilowatt, panels make 1.5 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.