Wind Turbine Payback in Northampton County, VA
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, VA averages 7.01 m/s (15.7 mph). A 10 kW turbine there would make about 27,114 kWh a year, worth $4,596 at VA's 16.95¢/kWh. Against an installed cost of about $100,000, that is a payback of 22 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, 7.3 m/s at the hub against 7.01 m/s here. Per kW, solar panels would make about 1,259 kWh a year here against the turbine's 2,711, so get a solar quote first.
What would have to change
- Power would have to cost 18¢/kWh, 1.1 times what VA pays now.
- Or the average wind at the hub would have to be 7.3 m/s instead of 7.01. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of VA
Northampton County is the 17th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. It is the windiest county in VA.
Month by month in Northampton County
January is the strongest month here, at 8.06 m/s and about 2,906 kWh. August is the weakest, 5.30 m/s and 1,240 kWh, so the best month makes 2.3 times the worst. November to March brings in 50% of the year's output in Northampton County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 8.06 m/s | 2,906 kWh | $493 |
| February | 7.92 m/s | 2,556 kWh | $433 |
| March | 8.01 m/s | 2,881 kWh | $488 |
| April | 8.00 m/s | 2,783 kWh | $472 |
| May | 6.92 m/s | 2,249 kWh | $381 |
| June | 6.09 m/s | 1,675 kWh | $284 |
| July | 5.58 m/s | 1,410 kWh | $239 |
| August | 5.30 m/s | 1,240 kWh | $210 |
| September | 6.23 m/s | 1,761 kWh | $298 |
| October | 6.91 m/s | 2,244 kWh | $380 |
| November | 7.46 m/s | 2,489 kWh | $422 |
| December | 7.78 m/s | 2,753 kWh | $467 |
What a taller tower would buy
Measured at 10 m the wind in Northampton County averages 6.04 m/s; at 50 m it is 7.52 m/s. That gives a shear exponent of 0.136, typical of very open, smooth ground where height adds little. Going from 20 m to 50 m takes output from 24,428 to 30,672 kWh a year, 26% 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 | 6.64 m/s | 24,428 kWh | 24 years |
| 30 m | 7.02 m/s | 27,152 kWh | 22 years |
| 40 m | 7.3 m/s | 29,126 kWh | 20 years |
| 50 m | 7.52 m/s | 30,672 kWh | 19 years |
Counties around Northampton County
None of the 6 closest counties is windier than Northampton County.
- Mathews County, VA: 5.5 m/s, 16,037 kWh, payback 37 years (21 mi)
- Poquoson city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (24 mi)
- York County, VA: 5.92 m/s, 19,112 kWh, payback 31 years (27 mi)
- Hampton city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (27 mi)
- Norfolk city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (32 mi)
- Accomack County, VA: 6.35 m/s, 22,299 kWh, payback 27 years (33 mi)
Sun versus wind in Northampton County
Northampton County gets 4.31 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,259 kWh a year; one kW of the turbine above makes 2,711. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 2.2 times. 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.