Wind Turbine Payback in Charles County, MD
Wind turbine payback in Charles 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 Charles County, MD averages 4.04 m/s (9 mph). A 10 kW turbine there would make about 6,780 kWh a year, worth $1,445 at MD's 21.31¢/kWh. Against an installed cost of about $100,000, that is a payback of 69 years, and the turbine is built to last about 20.
What to do in Charles County
A home turbine is not worth buying for savings in Charles County unless your spot is far windier than the county average, 6.5 m/s at the hub against 4.04 m/s here. Per kW, solar panels would make about 1,203 kWh a year here against the turbine's 678, so get a solar quote first.
What would have to change
- Power would have to cost 74¢/kWh, 3.5 times what MD pays now.
- Or the average wind at the hub would have to be 6.5 m/s instead of 4.04. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MD
Charles County is the 2,033rd windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MD is Worcester County at 7.01 m/s, payback 17 years.
Month by month in Charles County
March is the strongest month here, at 4.77 m/s and about 937 kWh. August is the weakest, 3.06 m/s and 237 kWh, so the best month makes 4.0 times the worst. November to March brings in 58% of the year's output in Charles County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.70 m/s | 896 kWh | $191 |
| February | 4.81 m/s | 863 kWh | $184 |
| March | 4.77 m/s | 937 kWh | $200 |
| April | 4.54 m/s | 789 kWh | $168 |
| May | 3.80 m/s | 477 kWh | $102 |
| June | 3.43 m/s | 332 kWh | $71 |
| July | 3.07 m/s | 239 kWh | $51 |
| August | 3.06 m/s | 237 kWh | $51 |
| September | 3.55 m/s | 371 kWh | $79 |
| October | 4.04 m/s | 574 kWh | $122 |
| November | 4.31 m/s | 675 kWh | $144 |
| December | 4.38 m/s | 735 kWh | $157 |
What a taller tower would buy
Measured at 10 m the wind in Charles County averages 2.82 m/s; at 50 m it is 4.77 m/s. That gives a shear exponent of 0.327, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,469 to 11,018 kWh a year, 147% 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 | 3.54 m/s | 4,469 kWh | over 100 years |
| 30 m | 4.04 m/s | 6,761 kWh | 69 years |
| 40 m | 4.43 m/s | 8,949 kWh | 52 years |
| 50 m | 4.77 m/s | 11,018 kWh | 43 years |
Counties around Charles County
3 of the 6 closest counties are windier at turbine height; the windiest, Alexandria city, averages 5.23 m/s.
- King George County, VA: 4.04 m/s, 6,780 kWh, payback 87 years (16 mi)
- Stafford County, VA: 3.65 m/s, 4,948 kWh, payback over 100 years (24 mi)
- Alexandria city, VA: 5.23 m/s, 14,116 kWh, payback 42 years (24 mi)
- Prince George's County, MD: 5.23 m/s, 14,116 kWh, payback 33 years (26 mi)
- Calvert County, MD: 5.21 m/s, 13,976 kWh, payback 34 years (26 mi)
- Westmoreland County, VA: 3.63 m/s, 4,862 kWh, payback over 100 years (28 mi)
Sun versus wind in Charles County
Charles County gets 4.12 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,203 kWh a year; one kW of the turbine above makes 678. Kilowatt for kilowatt, panels make 1.8 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.