Wind Turbine Payback in Granville County, NC
Wind turbine payback in Granville 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 Granville County, NC averages 3.75 m/s (8.4 mph). A 10 kW turbine there would make about 5,387 kWh a year, worth $805 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 Granville County
A home turbine is not worth buying for savings in Granville County unless your spot is far windier than the county average, 7.9 m/s at the hub against 3.75 m/s here. Per kW, solar panels would make about 1,276 kWh a year here against the turbine's 539, so get a solar quote first.
What would have to change
- Power would have to cost 93¢/kWh, 6.2 times what NC pays now.
- Or the average wind at the hub would have to be 7.9 m/s instead of 3.75. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NC
Granville County is the 2,250th 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 Granville County
March is the strongest month here, at 4.41 m/s and about 749 kWh. August is the weakest, 2.88 m/s and 191 kWh, so the best month makes 3.9 times the worst. November to March brings in 55% of the year's output in Granville County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.28 m/s | 684 kWh | $102 |
| February | 4.43 m/s | 684 kWh | $102 |
| March | 4.41 m/s | 749 kWh | $112 |
| April | 4.37 m/s | 705 kWh | $105 |
| May | 3.69 m/s | 435 kWh | $65 |
| June | 3.25 m/s | 279 kWh | $42 |
| July | 2.96 m/s | 211 kWh | $32 |
| August | 2.88 m/s | 191 kWh | $29 |
| September | 3.29 m/s | 291 kWh | $43 |
| October | 3.66 m/s | 423 kWh | $63 |
| November | 3.88 m/s | 491 kWh | $73 |
| December | 3.98 m/s | 552 kWh | $82 |
What a taller tower would buy
Measured at 10 m the wind in Granville County averages 2.57 m/s; at 50 m it is 4.47 m/s. That gives a shear exponent of 0.344, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 3,441 to 9,160 kWh a year, 166% 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 | 3.26 m/s | 3,441 kWh | over 100 years |
| 30 m | 3.75 m/s | 5,385 kWh | over 100 years |
| 40 m | 4.14 m/s | 7,299 kWh | 92 years |
| 50 m | 4.47 m/s | 9,160 kWh | 73 years |
Counties around Granville County
2 of the 6 closest counties are windier at turbine height; the windiest, Franklin County, averages 4.35 m/s.
- Vance County, NC: 3.49 m/s, 4,289 kWh, payback over 100 years (15 mi)
- Person County, NC: 3.75 m/s, 5,387 kWh, payback over 100 years (18 mi)
- Durham County, NC: 3.47 m/s, 4,211 kWh, payback over 100 years (22 mi)
- Franklin County, NC: 4.35 m/s, 8,460 kWh, payback 79 years (25 mi)
- Orange County, NC: 3.82 m/s, 5,707 kWh, payback over 100 years (31 mi)
- Mecklenburg County, VA: 3.49 m/s, 4,289 kWh, payback over 100 years (31 mi)
Sun versus wind in Granville County
Granville County gets 4.37 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,276 kWh a year; one kW of the turbine above makes 539. 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.