Wind Turbine Payback in Northampton County, NC
Wind turbine payback in Northampton 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 Northampton County, NC averages 3.99 m/s (8.9 mph). A 10 kW turbine there would make about 6,527 kWh a year, worth $975 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 Northampton County
A home turbine is not worth buying for savings in Northampton County unless your spot is far windier than the county average, 7.9 m/s at the hub against 3.99 m/s here. Per kW, solar panels would make about 1,270 kWh a year here against the turbine's 653, so get a solar quote first.
What would have to change
- Power would have to cost 77¢/kWh, 5.1 times what NC pays now.
- Or the average wind at the hub would have to be 7.9 m/s instead of 3.99. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NC
Northampton County is the 2,064th 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 Northampton County
March is the strongest month here, at 4.61 m/s and about 851 kWh. August is the weakest, 3.15 m/s and 262 kWh, so the best month makes 3.2 times the worst. November to March brings in 52% of the year's output in Northampton County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.37 m/s | 728 kWh | $109 |
| February | 4.55 m/s | 741 kWh | $111 |
| March | 4.61 m/s | 851 kWh | $127 |
| April | 4.64 m/s | 836 kWh | $125 |
| May | 4.03 m/s | 571 kWh | $85 |
| June | 3.55 m/s | 371 kWh | $55 |
| July | 3.30 m/s | 305 kWh | $46 |
| August | 3.15 m/s | 262 kWh | $39 |
| September | 3.60 m/s | 388 kWh | $58 |
| October | 3.87 m/s | 505 kWh | $75 |
| November | 4.09 m/s | 577 kWh | $86 |
| December | 4.14 m/s | 619 kWh | $92 |
What a taller tower would buy
Measured at 10 m the wind in Northampton County averages 2.69 m/s; at 50 m it is 4.79 m/s. That gives a shear exponent of 0.359, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,122 to 11,147 kWh a year, 170% 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 | 3.45 m/s | 4,122 kWh | over 100 years |
| 30 m | 3.99 m/s | 6,514 kWh | over 100 years |
| 40 m | 4.42 m/s | 8,872 kWh | 75 years |
| 50 m | 4.79 m/s | 11,147 kWh | 60 years |
Counties around Northampton County
3 of the 6 closest counties are windier at turbine height; the windiest, Hertford County, averages 5.06 m/s.
- Halifax County, NC: 3.99 m/s, 6,527 kWh, payback over 100 years (18 mi)
- Greensville County, VA: 3.99 m/s, 6,527 kWh, payback 90 years (20 mi)
- Emporia city, VA: 3.99 m/s, 6,527 kWh, payback 90 years (20 mi)
- Hertford County, NC: 5.06 m/s, 12,941 kWh, payback 52 years (24 mi)
- Southampton County, VA: 5.06 m/s, 12,941 kWh, payback 46 years (26 mi)
- Franklin city, VA: 5.06 m/s, 12,941 kWh, payback 46 years (31 mi)
Sun versus wind in Northampton County
Northampton County gets 4.35 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,270 kWh a year; one kW of the turbine above makes 653. Kilowatt for kilowatt, panels make 1.9 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.