Wind Turbine Payback in Marshall County, OK
Wind turbine payback in Marshall 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 Marshall County, OK averages 5.95 m/s (13.3 mph). A 10 kW turbine there would make about 19,334 kWh a year, worth $2,670 at OK's 13.81¢/kWh. Against an installed cost of about $100,000, that is a payback of 38 years, and the turbine is built to last about 20.
What to do in Marshall County
A home turbine is not worth buying for savings in Marshall County unless your spot is far windier than the county average, 8.4 m/s at the hub against 5.95 m/s here. Per kW, solar panels would make about 1,349 kWh a year here against the turbine's 1,933, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/kWh, 1.9 times what OK pays now.
- Or the average wind at the hub would have to be 8.4 m/s instead of 5.95. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of OK
Marshall County is the 914th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in OK is Cimarron County at 6.82 m/s, payback 28 years.
Month by month in Marshall County
April is the strongest month here, at 6.93 m/s and about 2,180 kWh. August is the weakest, 4.78 m/s and 941 kWh, so the best month makes 2.3 times the worst. November to March brings in 49% of the year's output in Marshall County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.30 m/s | 1,861 kWh | $257 |
| February | 6.48 m/s | 1,787 kWh | $247 |
| March | 6.76 m/s | 2,149 kWh | $297 |
| April | 6.93 m/s | 2,180 kWh | $301 |
| May | 6.16 m/s | 1,777 kWh | $245 |
| June | 5.58 m/s | 1,365 kWh | $189 |
| July | 4.87 m/s | 990 kWh | $137 |
| August | 4.78 m/s | 941 kWh | $130 |
| September | 5.03 m/s | 1,045 kWh | $144 |
| October | 5.94 m/s | 1,637 kWh | $226 |
| November | 6.40 m/s | 1,866 kWh | $258 |
| December | 6.21 m/s | 1,805 kWh | $249 |
What a taller tower would buy
Measured at 10 m the wind in Marshall County averages 4.61 m/s; at 50 m it is 6.7 m/s. That gives a shear exponent of 0.232, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,440 to 24,874 kWh a year, 61% 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 | 5.42 m/s | 15,440 kWh | 47 years |
| 30 m | 5.95 m/s | 19,343 kWh | 37 years |
| 40 m | 6.36 m/s | 22,388 kWh | 32 years |
| 50 m | 6.7 m/s | 24,874 kWh | 29 years |
Counties around Marshall County
4 of the 6 closest counties are windier at turbine height; the windiest, Johnston County, averages 6.07 m/s.
- Johnston County, OK: 6.07 m/s, 20,223 kWh, payback 36 years (21 mi)
- Love County, OK: 5.96 m/s, 19,408 kWh, payback 37 years (28 mi)
- Grayson County, TX: 5.89 m/s, 18,890 kWh, payback 33 years (28 mi)
- Bryan County, OK: 5.29 m/s, 14,538 kWh, payback 50 years (29 mi)
- Carter County, OK: 6.07 m/s, 20,223 kWh, payback 36 years (33 mi)
- Murray County, OK: 6.07 m/s, 20,223 kWh, payback 36 years (36 mi)
Sun versus wind in Marshall County
Marshall County gets 4.62 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,349 kWh a year; one kW of the turbine above makes 1,933. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.4 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.