Wind Turbine Payback in Union County, SC
Wind turbine payback in Union 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 Union County, SC averages 3.16 m/s (7.1 mph). A 10 kW turbine there would make about 3,099 kWh a year, worth $493 at SC's 15.9¢/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 Union County
A home turbine is not worth buying for savings in Union County unless your spot is far windier than the county average, 7.6 m/s at the hub against 3.16 m/s here. Per kW, solar panels would make about 1,326 kWh a year here against the turbine's 310, so get a solar quote first.
What would have to change
- Power would have to cost 161¢/kWh, 10.1 times what SC pays now.
- Or the average wind at the hub would have to be 7.6 m/s instead of 3.16. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of SC
Union County is the 2,928th 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 Union County
April is the strongest month here, at 3.70 m/s and about 424 kWh. August is the weakest, 2.44 m/s and 104 kWh, so the best month makes 4.1 times the worst. November to March brings in 53% of the year's output in Union County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.44 m/s | 349 kWh | $55 |
| February | 3.56 m/s | 349 kWh | $55 |
| March | 3.64 m/s | 418 kWh | $66 |
| April | 3.70 m/s | 424 kWh | $67 |
| May | 3.18 m/s | 269 kWh | $43 |
| June | 2.73 m/s | 154 kWh | $24 |
| July | 2.54 m/s | 122 kWh | $19 |
| August | 2.44 m/s | 104 kWh | $17 |
| September | 2.96 m/s | 205 kWh | $33 |
| October | 3.16 m/s | 264 kWh | $42 |
| November | 3.32 m/s | 299 kWh | $48 |
| December | 3.27 m/s | 294 kWh | $47 |
What a taller tower would buy
Measured at 10 m the wind in Union County averages 1.95 m/s; at 50 m it is 3.95 m/s. That gives a shear exponent of 0.439, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 1,660 to 6,329 kWh a year, 281% 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 | 2.64 m/s | 1,660 kWh | over 100 years |
| 30 m | 3.16 m/s | 3,088 kWh | over 100 years |
| 40 m | 3.58 m/s | 4,659 kWh | over 100 years |
| 50 m | 3.95 m/s | 6,329 kWh | 99 years |
Counties around Union County
3 of the 6 closest counties are windier at turbine height; the windiest, Cherokee County, averages 3.7 m/s.
- Cherokee County, SC: 3.7 m/s, 5,164 kWh, payback over 100 years (25 mi)
- Chester County, SC: 3.02 m/s, 2,661 kWh, payback over 100 years (26 mi)
- Laurens County, SC: 3.16 m/s, 3,099 kWh, payback over 100 years (26 mi)
- Spartanburg County, SC: 3.7 m/s, 5,164 kWh, payback over 100 years (27 mi)
- Newberry County, SC: 3.16 m/s, 3,099 kWh, payback over 100 years (28 mi)
- York County, SC: 3.65 m/s, 4,948 kWh, payback over 100 years (31 mi)
Sun versus wind in Union County
Union County gets 4.54 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,326 kWh a year; one kW of the turbine above makes 310. Kilowatt for kilowatt, panels make 4.3 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.