Wind Turbine Payback in Wake County, NC
Wind turbine payback in Wake 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 Wake County, NC averages 3.47 m/s (7.8 mph). A 10 kW turbine there would make about 4,211 kWh a year, worth $629 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 Wake County
A home turbine is not worth buying for savings in Wake County unless your spot is far windier than the county average, 7.9 m/s at the hub against 3.47 m/s here. Per kW, solar panels would make about 1,305 kWh a year here against the turbine's 421, so get a solar quote first.
What would have to change
- Power would have to cost 119¢/kWh, 7.9 times what NC pays now.
- Or the average wind at the hub would have to be 7.9 m/s instead of 3.47. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NC
Wake County is the 2,548th 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 Wake County
March is the strongest month here, at 4.05 m/s and about 581 kWh. August is the weakest, 2.67 m/s and 147 kWh, so the best month makes 4.0 times the worst. November to March brings in 55% of the year's output in Wake County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 3.90 m/s | 517 kWh | $77 |
| February | 4.04 m/s | 518 kWh | $77 |
| March | 4.05 m/s | 581 kWh | $87 |
| April | 4.01 m/s | 545 kWh | $81 |
| May | 3.43 m/s | 344 kWh | $51 |
| June | 3.00 m/s | 214 kWh | $32 |
| July | 2.75 m/s | 164 kWh | $25 |
| August | 2.67 m/s | 147 kWh | $22 |
| September | 3.11 m/s | 241 kWh | $36 |
| October | 3.40 m/s | 333 kWh | $50 |
| November | 3.60 m/s | 388 kWh | $58 |
| December | 3.68 m/s | 432 kWh | $65 |
What a taller tower would buy
Measured at 10 m the wind in Wake County averages 2.15 m/s; at 50 m it is 4.33 m/s. That gives a shear exponent of 0.435, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,333 to 8,346 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 | 2.91 m/s | 2,333 kWh | over 100 years |
| 30 m | 3.47 m/s | 4,200 kWh | over 100 years |
| 40 m | 3.93 m/s | 6,228 kWh | over 100 years |
| 50 m | 4.33 m/s | 8,346 kWh | 80 years |
Counties around Wake County
5 of the 6 closest counties are windier at turbine height; the windiest, Johnston County, averages 5.2 m/s.
- Durham County, NC: 3.47 m/s, 4,211 kWh, payback over 100 years (21 mi)
- Johnston County, NC: 5.2 m/s, 13,907 kWh, payback 48 years (25 mi)
- Franklin County, NC: 4.35 m/s, 8,460 kWh, payback 79 years (29 mi)
- Harnett County, NC: 4.39 m/s, 8,690 kWh, payback 77 years (32 mi)
- Orange County, NC: 3.82 m/s, 5,707 kWh, payback over 100 years (32 mi)
- Chatham County, NC: 3.54 m/s, 4,489 kWh, payback over 100 years (34 mi)
Sun versus wind in Wake County
Wake County gets 4.47 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,305 kWh a year; one kW of the turbine above makes 421. Kilowatt for kilowatt, panels make 3.1 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.