Wind Turbine Payback in Cumberland County, NC
Wind turbine payback in Cumberland 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 Cumberland County, NC averages 4.96 m/s (11.1 mph). A 10 kW turbine there would make about 12,266 kWh a year, worth $1,833 at NC's 14.94¢/kWh. Against an installed cost of about $100,000, that is a payback of 55 years, and the turbine is built to last about 20.
What to do in Cumberland County
A home turbine is not worth buying for savings in Cumberland County unless your spot is far windier than the county average, 7.9 m/s at the hub against 4.96 m/s here. Per kW, solar panels would make about 1,305 kWh a year here against the turbine's 1,227, so get a solar quote first.
What would have to change
- Power would have to cost 41¢/kWh, 2.7 times what NC pays now.
- Or the average wind at the hub would have to be 7.9 m/s instead of 4.96. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NC
Cumberland County is the 1,472nd 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 Cumberland County
April is the strongest month here, at 5.80 m/s and about 1,501 kWh. August is the weakest, 3.90 m/s and 515 kWh, so the best month makes 2.9 times the worst. November to March brings in 50% of the year's output in Cumberland County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.33 m/s | 1,261 kWh | $188 |
| February | 5.56 m/s | 1,264 kWh | $189 |
| March | 5.68 m/s | 1,475 kWh | $220 |
| April | 5.80 m/s | 1,501 kWh | $224 |
| May | 4.99 m/s | 1,056 kWh | $158 |
| June | 4.32 m/s | 683 kWh | $102 |
| July | 4.15 m/s | 624 kWh | $93 |
| August | 3.90 m/s | 515 kWh | $77 |
| September | 4.69 m/s | 863 kWh | $129 |
| October | 4.89 m/s | 1,002 kWh | $150 |
| November | 5.10 m/s | 1,086 kWh | $162 |
| December | 5.12 m/s | 1,132 kWh | $169 |
What a taller tower would buy
Measured at 10 m the wind in Cumberland County averages 3.69 m/s; at 50 m it is 5.69 m/s. That gives a shear exponent of 0.269, typical of ordinary open country. Going from 20 m to 50 m takes output from 9,024 to 17,419 kWh a year, 93% 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 | 4.45 m/s | 9,024 kWh | 74 years |
| 30 m | 4.96 m/s | 12,262 kWh | 55 years |
| 40 m | 5.36 m/s | 15,023 kWh | 45 years |
| 50 m | 5.69 m/s | 17,419 kWh | 38 years |
Counties around Cumberland County
1 of the 6 closest counties is windier at turbine height; the windiest, Robeson County, averages 5 m/s.
- Harnett County, NC: 4.39 m/s, 8,690 kWh, payback 77 years (22 mi)
- Hoke County, NC: 4.43 m/s, 8,924 kWh, payback 75 years (23 mi)
- Sampson County, NC: 4.9 m/s, 11,866 kWh, payback 56 years (26 mi)
- Robeson County, NC: 5 m/s, 12,535 kWh, payback 53 years (32 mi)
- Lee County, NC: 3.54 m/s, 4,489 kWh, payback over 100 years (35 mi)
- Bladen County, NC: 4.42 m/s, 8,865 kWh, payback 76 years (36 mi)
Sun versus wind in Cumberland County
Cumberland 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 1,227. Kilowatt for kilowatt, panels make 1.1 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.