Wind Turbine Payback in Portsmouth city, VA
Wind turbine payback in Portsmouth city
No. The turbine wears out before it pays for itself.
At 30 m, the height a home turbine tower usually reaches, the wind in Portsmouth city, VA averages 5.92 m/s (13.2 mph). A 10 kW turbine there would make about 19,112 kWh a year, worth $3,239 at VA's 16.95¢/kWh. Against an installed cost of about $100,000, that is a payback of 31 years, and the turbine is built to last about 20.
What to do in Portsmouth city
A home turbine is not worth buying for savings in Portsmouth city unless your spot is far windier than the county average, 7.3 m/s at the hub against 5.92 m/s here. Per kW, solar panels would make about 1,270 kWh a year here against the turbine's 1,911, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/kWh, 1.5 times what VA pays now.
- Or the average wind at the hub would have to be 7.3 m/s instead of 5.92. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of VA
Portsmouth city is the 959th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in VA is Northampton County at 7.01 m/s, payback 22 years.
Month by month in Portsmouth city
March is the strongest month here, at 6.77 m/s and about 2,155 kWh. August is the weakest, 4.60 m/s and 846 kWh, so the best month makes 2.5 times the worst. November to March brings in 51% of the year's output in Portsmouth city.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.64 m/s | 2,076 kWh | $352 |
| February | 6.68 m/s | 1,896 kWh | $321 |
| March | 6.77 m/s | 2,155 kWh | $365 |
| April | 6.76 m/s | 2,080 kWh | $353 |
| May | 5.86 m/s | 1,587 kWh | $269 |
| June | 5.11 m/s | 1,092 kWh | $185 |
| July | 4.85 m/s | 979 kWh | $166 |
| August | 4.60 m/s | 846 kWh | $143 |
| September | 5.45 m/s | 1,286 kWh | $218 |
| October | 5.84 m/s | 1,570 kWh | $266 |
| November | 6.22 m/s | 1,751 kWh | $297 |
| December | 6.37 m/s | 1,906 kWh | $323 |
What a taller tower would buy
Measured at 10 m the wind in Portsmouth city averages 4.79 m/s; at 50 m it is 6.54 m/s. That gives a shear exponent of 0.193, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,892 to 23,702 kWh a year, 49% 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 | 5.48 m/s | 15,892 kWh | 37 years |
| 30 m | 5.93 m/s | 19,156 kWh | 31 years |
| 40 m | 6.26 m/s | 21,664 kWh | 27 years |
| 50 m | 6.54 m/s | 23,702 kWh | 25 years |
Counties around Portsmouth city
None of the 6 closest counties is windier than Portsmouth city.
- Norfolk city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (8 mi)
- Chesapeake city, VA: 5.82 m/s, 18,374 kWh, payback 32 years (13 mi)
- Hampton city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (13 mi)
- Newport News city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (18 mi)
- Poquoson city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (19 mi)
- Virginia Beach city, VA: 5.92 m/s, 19,112 kWh, payback 31 years (19 mi)
Sun versus wind in Portsmouth city
Portsmouth city 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 1,911. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 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.