Wind Turbine Payback in Rockingham County, NC
Wind turbine payback in Rockingham 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 Rockingham County, NC averages 3.73 m/s (8.3 mph). A 10 kW turbine there would make about 5,297 kWh a year, worth $791 at NC's 14.94¢/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 Rockingham County
A home turbine is not worth buying for savings in Rockingham County unless your spot is far windier than the county average, 7.9 m/s at the hub against 3.73 m/s here. Per kW, solar panels would make about 1,267 kWh a year here against the turbine's 530, so get a solar quote first.
What would have to change
- Power would have to cost 94¢/kWh, 6.3 times what NC pays now.
- Or the average wind at the hub would have to be 7.9 m/s instead of 3.73. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NC
Rockingham County is the 2,261st windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in NC is Dare County at 6.91 m/s, payback 25 years.
Month by month in Rockingham County
March is the strongest month here, at 4.43 m/s and about 760 kWh. August is the weakest, 2.81 m/s and 175 kWh, so the best month makes 4.3 times the worst. November to March brings in 56% of the year's output in Rockingham County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.29 m/s | 687 kWh | $103 |
| February | 4.43 m/s | 683 kWh | $102 |
| March | 4.43 m/s | 760 kWh | $114 |
| April | 4.42 m/s | 727 kWh | $109 |
| May | 3.66 m/s | 423 kWh | $63 |
| June | 3.17 m/s | 258 kWh | $39 |
| July | 2.90 m/s | 196 kWh | $29 |
| August | 2.81 m/s | 175 kWh | $26 |
| September | 3.24 m/s | 278 kWh | $42 |
| October | 3.67 m/s | 426 kWh | $64 |
| November | 3.90 m/s | 499 kWh | $75 |
| December | 3.99 m/s | 554 kWh | $83 |
What a taller tower would buy
Measured at 10 m the wind in Rockingham County averages 2.47 m/s; at 50 m it is 4.52 m/s. That gives a shear exponent of 0.375, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 3,250 to 9,459 kWh a year, 191% 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 | 3.21 m/s | 3,250 kWh | over 100 years |
| 30 m | 3.73 m/s | 5,306 kWh | over 100 years |
| 40 m | 4.16 m/s | 7,392 kWh | 91 years |
| 50 m | 4.52 m/s | 9,459 kWh | 71 years |
Counties around Rockingham County
3 of the 6 closest counties are windier at turbine height; the windiest, Guilford County, averages 4.47 m/s.
- Henry County, VA: 3.73 m/s, 5,297 kWh, payback over 100 years (20 mi)
- Guilford County, NC: 4.47 m/s, 9,160 kWh, payback 73 years (21 mi)
- Martinsville city, VA: 3.73 m/s, 5,297 kWh, payback over 100 years (21 mi)
- Caswell County, NC: 3.86 m/s, 5,894 kWh, payback over 100 years (25 mi)
- Danville city, VA: 3.86 m/s, 5,894 kWh, payback over 100 years (25 mi)
- Stokes County, NC: 3.73 m/s, 5,297 kWh, payback over 100 years (27 mi)
Sun versus wind in Rockingham County
Rockingham County gets 4.34 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,267 kWh a year; one kW of the turbine above makes 530. Kilowatt for kilowatt, panels make 2.4 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.