Wind Turbine Payback in Martin County, NC
Wind turbine payback in Martin 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 Martin 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 Martin County
A home turbine is not worth buying for savings in Martin 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
Martin 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 Martin County
March is the strongest month here, at 5.67 m/s and about 1,468 kWh. August is the weakest, 3.94 m/s and 535 kWh, so the best month makes 2.7 times the worst. November to March brings in 50% of the year's output in Martin County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.38 m/s | 1,287 kWh | $192 |
| February | 5.57 m/s | 1,267 kWh | $189 |
| March | 5.67 m/s | 1,468 kWh | $219 |
| April | 5.71 m/s | 1,447 kWh | $216 |
| May | 5.01 m/s | 1,071 kWh | $160 |
| June | 4.39 m/s | 716 kWh | $107 |
| July | 4.19 m/s | 641 kWh | $96 |
| August | 3.94 m/s | 535 kWh | $80 |
| September | 4.60 m/s | 819 kWh | $122 |
| October | 4.83 m/s | 968 kWh | $145 |
| November | 5.06 m/s | 1,066 kWh | $159 |
| December | 5.18 m/s | 1,167 kWh | $174 |
What a taller tower would buy
Measured at 10 m the wind in Martin County averages 3.66 m/s; at 50 m it is 5.71 m/s. That gives a shear exponent of 0.276, typical of ordinary open country. Going from 20 m to 50 m takes output from 8,948 to 17,565 kWh a year, 96% 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 | 4.43 m/s | 8,948 kWh | 75 years |
| 30 m | 4.96 m/s | 12,260 kWh | 55 years |
| 40 m | 5.37 m/s | 15,097 kWh | 44 years |
| 50 m | 5.71 m/s | 17,565 kWh | 38 years |
Counties around Martin County
None of the 6 closest counties is windier than Martin County.
- Bertie County, NC: 4.96 m/s, 12,266 kWh, payback 55 years (17 mi)
- Pitt County, NC: 4.94 m/s, 12,132 kWh, payback 55 years (23 mi)
- Edgecombe County, NC: 4.9 m/s, 11,866 kWh, payback 56 years (27 mi)
- Beaufort County, NC: 4.7 m/s, 10,571 kWh, payback 63 years (30 mi)
- Washington County, NC: 4.96 m/s, 12,266 kWh, payback 55 years (31 mi)
- Chowan County, NC: 4.96 m/s, 12,266 kWh, payback 55 years (35 mi)
Sun versus wind in Martin County
Martin 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.