Wind Turbine Payback in Clarke County, VA
Wind turbine payback in Clarke 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 Clarke County, VA averages 3.48 m/s (7.8 mph). A 10 kW turbine there would make about 4,250 kWh a year, worth $720 at VA's 16.95¢/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 Clarke County
A home turbine is not worth buying for savings in Clarke County unless your spot is far windier than the county average, 7.3 m/s at the hub against 3.48 m/s here. Per kW, solar panels would make about 1,162 kWh a year here against the turbine's 425, so get a solar quote first.
What would have to change
- Power would have to cost 118¢/kWh, 6.9 times what VA pays now.
- Or the average wind at the hub would have to be 7.3 m/s instead of 3.48. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of VA
Clarke County is the 2,536th 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 Clarke County
March is the strongest month here, at 4.15 m/s and about 626 kWh. August is the weakest, 2.63 m/s and 139 kWh, so the best month makes 4.5 times the worst. November to March brings in 60% of the year's output in Clarke County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.11 m/s | 608 kWh | $103 |
| February | 4.23 m/s | 596 kWh | $101 |
| March | 4.15 m/s | 626 kWh | $106 |
| April | 3.94 m/s | 514 kWh | $87 |
| May | 3.26 m/s | 291 kWh | $49 |
| June | 2.98 m/s | 208 kWh | $35 |
| July | 2.69 m/s | 150 kWh | $25 |
| August | 2.63 m/s | 139 kWh | $24 |
| September | 2.95 m/s | 202 kWh | $34 |
| October | 3.40 m/s | 333 kWh | $56 |
| November | 3.66 m/s | 411 kWh | $70 |
| December | 3.77 m/s | 464 kWh | $79 |
What a taller tower would buy
Measured at 10 m the wind in Clarke County averages 2.19 m/s; at 50 m it is 4.31 m/s. That gives a shear exponent of 0.421, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,400 to 8,233 kWh a year, 243% 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 | 2.93 m/s | 2,400 kWh | over 100 years |
| 30 m | 3.48 m/s | 4,234 kWh | over 100 years |
| 40 m | 3.92 m/s | 6,199 kWh | 95 years |
| 50 m | 4.31 m/s | 8,233 kWh | 72 years |
Counties around Clarke County
3 of the 6 closest counties are windier at turbine height; the windiest, Loudoun County, averages 4.57 m/s.
- Winchester city, VA: 3.48 m/s, 4,250 kWh, payback over 100 years (11 mi)
- Jefferson County, WV: 3.62 m/s, 4,820 kWh, payback over 100 years (15 mi)
- Frederick County, VA: 3.48 m/s, 4,250 kWh, payback over 100 years (16 mi)
- Warren County, VA: 3.48 m/s, 4,250 kWh, payback over 100 years (18 mi)
- Loudoun County, VA: 4.57 m/s, 9,763 kWh, payback 60 years (19 mi)
- Berkeley County, WV: 3.62 m/s, 4,820 kWh, payback over 100 years (23 mi)
Sun versus wind in Clarke County
Clarke County gets 3.98 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,162 kWh a year; one kW of the turbine above makes 425. Kilowatt for kilowatt, panels make 2.7 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.