Wind Turbine Payback in Charleston County, SC
Wind turbine payback in Charleston 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 Charleston County, SC averages 4.13 m/s (9.2 mph). A 10 kW turbine there would make about 7,248 kWh a year, worth $1,152 at SC's 15.9¢/kWh. Against an installed cost of about $100,000, that is a payback of 87 years, and the turbine is built to last about 20.
What to do in Charleston County
A home turbine is not worth buying for savings in Charleston County unless your spot is far windier than the county average, 7.6 m/s at the hub against 4.13 m/s here. Per kW, solar panels would make about 1,372 kWh a year here against the turbine's 725, so get a solar quote first.
What would have to change
- Power would have to cost 69¢/kWh, 4.3 times what SC pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 4.13. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of SC
Charleston County is the 1,981st 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 Charleston County
March is the strongest month here, at 4.62 m/s and about 855 kWh. August is the weakest, 3.43 m/s and 344 kWh, so the best month makes 2.5 times the worst. November to March brings in 49% of the year's output in Charleston County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.45 m/s | 767 kWh | $122 |
| February | 4.54 m/s | 736 kWh | $117 |
| March | 4.62 m/s | 855 kWh | $136 |
| April | 4.63 m/s | 831 kWh | $132 |
| May | 4.20 m/s | 647 kWh | $103 |
| June | 3.73 m/s | 435 kWh | $69 |
| July | 3.64 m/s | 418 kWh | $66 |
| August | 3.43 m/s | 344 kWh | $55 |
| September | 3.92 m/s | 507 kWh | $81 |
| October | 4.00 m/s | 560 kWh | $89 |
| November | 4.19 m/s | 623 kWh | $99 |
| December | 4.26 m/s | 675 kWh | $107 |
What a taller tower would buy
Measured at 10 m the wind in Charleston County averages 2.95 m/s; at 50 m it is 4.83 m/s. That gives a shear exponent of 0.306, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,943 to 11,407 kWh a year, 131% 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 | 3.65 m/s | 4,943 kWh | over 100 years |
| 30 m | 4.13 m/s | 7,254 kWh | 87 years |
| 40 m | 4.51 m/s | 9,406 kWh | 67 years |
| 50 m | 4.83 m/s | 11,407 kWh | 55 years |
Counties around Charleston County
3 of the 6 closest counties are windier at turbine height; the windiest, Beaufort County, averages 5.71 m/s.
- Berkeley County, SC: 4.13 m/s, 7,248 kWh, payback 87 years (28 mi)
- Dorchester County, SC: 4.05 m/s, 6,831 kWh, payback 92 years (33 mi)
- Colleton County, SC: 4.05 m/s, 6,831 kWh, payback 92 years (42 mi)
- Beaufort County, SC: 5.71 m/s, 17,565 kWh, payback 36 years (53 mi)
- Georgetown County, SC: 4.38 m/s, 8,632 kWh, payback 73 years (57 mi)
- Williamsburg County, SC: 4.34 m/s, 8,403 kWh, payback 75 years (59 mi)
Sun versus wind in Charleston County
Charleston County gets 4.7 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,372 kWh a year; one kW of the turbine above makes 725. Kilowatt for kilowatt, panels make 1.9 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.