Wind Turbine Payback in Alleghany County, NC
Wind turbine payback in Alleghany 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 Alleghany County, NC averages 3.49 m/s (7.8 mph). A 10 kW turbine there would make about 4,289 kWh a year, worth $641 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 Alleghany County
A home turbine is not worth buying for savings in Alleghany County unless your spot is far windier than the county average, 7.9 m/s at the hub against 3.49 m/s here. Per kW, solar panels would make about 1,235 kWh a year here against the turbine's 429, so get a solar quote first.
What would have to change
- Power would have to cost 117¢/kWh, 7.8 times what NC pays now.
- Or the average wind at the hub would have to be 7.9 m/s instead of 3.49. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NC
Alleghany County is the 2,519th 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 Alleghany County
January is the strongest month here, at 4.25 m/s and about 671 kWh. August is the weakest, 2.51 m/s and 116 kWh, so the best month makes 5.8 times the worst. November to March brings in 61% of the year's output in Alleghany County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.25 m/s | 671 kWh | $100 |
| February | 4.35 m/s | 647 kWh | $97 |
| March | 4.19 m/s | 641 kWh | $96 |
| April | 4.06 m/s | 565 kWh | $84 |
| May | 3.33 m/s | 313 kWh | $47 |
| June | 2.93 m/s | 197 kWh | $29 |
| July | 2.67 m/s | 146 kWh | $22 |
| August | 2.51 m/s | 116 kWh | $17 |
| September | 2.79 m/s | 165 kWh | $25 |
| October | 3.34 m/s | 315 kWh | $47 |
| November | 3.66 m/s | 409 kWh | $61 |
| December | 3.88 m/s | 509 kWh | $76 |
What a taller tower would buy
Measured at 10 m the wind in Alleghany County averages 2.16 m/s; at 50 m it is 4.36 m/s. That gives a shear exponent of 0.436, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,382 to 8,517 kWh a year, 258% 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 | 2.92 m/s | 2,382 kWh | over 100 years |
| 30 m | 3.49 m/s | 4,287 kWh | over 100 years |
| 40 m | 3.96 m/s | 6,357 kWh | over 100 years |
| 50 m | 4.36 m/s | 8,517 kWh | 79 years |
Counties around Alleghany County
4 of the 6 closest counties are windier at turbine height; the windiest, Galax city, averages 3.78 m/s.
- Grayson County, VA: 3.49 m/s, 4,289 kWh, payback over 100 years (12 mi)
- Galax city, VA: 3.78 m/s, 5,523 kWh, payback over 100 years (17 mi)
- Wilkes County, NC: 3.67 m/s, 5,034 kWh, payback over 100 years (19 mi)
- Ashe County, NC: 3.49 m/s, 4,289 kWh, payback over 100 years (21 mi)
- Surry County, NC: 3.78 m/s, 5,523 kWh, payback over 100 years (25 mi)
- Carroll County, VA: 3.78 m/s, 5,523 kWh, payback over 100 years (28 mi)
Sun versus wind in Alleghany County
Alleghany County gets 4.23 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,235 kWh a year; one kW of the turbine above makes 429. Kilowatt for kilowatt, panels make 2.9 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.