Wind Turbine Payback in St. Francis County, AR
Wind turbine payback in St. Francis 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 St. Francis County, AR averages 5.3 m/s (11.9 mph). A 10 kW turbine there would make about 14,608 kWh a year, worth $2,007 at AR's 13.74¢/kWh. Against an installed cost of about $100,000, that is a payback of 50 years, and the turbine is built to last about 20.
What to do in St. Francis County
A home turbine is not worth buying for savings in St. Francis County unless your spot is far windier than the county average, 8.4 m/s at the hub against 5.3 m/s here. Per kW, solar panels would make about 1,299 kWh a year here against the turbine's 1,461, so get a solar quote first.
What would have to change
- Power would have to cost 34¢/kWh, 2.5 times what AR pays now.
- Or the average wind at the hub would have to be 8.4 m/s instead of 5.3. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of AR
St. Francis County is the 1,324th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in AR is Mississippi County at 5.35 m/s, payback 49 years.
Month by month in St. Francis County
March is the strongest month here, at 6.22 m/s and about 1,812 kWh. July is the weakest, 3.82 m/s and 484 kWh, so the best month makes 3.7 times the worst. November to March brings in 55% of the year's output in St. Francis County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.03 m/s | 1,690 kWh | $232 |
| February | 6.11 m/s | 1,576 kWh | $217 |
| March | 6.22 m/s | 1,812 kWh | $249 |
| April | 6.27 m/s | 1,785 kWh | $245 |
| May | 5.31 m/s | 1,249 kWh | $172 |
| June | 4.36 m/s | 702 kWh | $96 |
| July | 3.82 m/s | 484 kWh | $67 |
| August | 3.94 m/s | 534 kWh | $73 |
| September | 4.60 m/s | 818 kWh | $112 |
| October | 5.27 m/s | 1,222 kWh | $168 |
| November | 5.83 m/s | 1,518 kWh | $209 |
| December | 5.87 m/s | 1,590 kWh | $218 |
What a taller tower would buy
Measured at 10 m the wind in St. Francis County averages 4.02 m/s; at 50 m it is 6.02 m/s. That gives a shear exponent of 0.251, typical of ordinary open country. Going from 20 m to 50 m takes output from 11,103 to 19,852 kWh a year, 79% 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 | 4.78 m/s | 11,103 kWh | 66 years |
| 30 m | 5.3 m/s | 14,577 kWh | 50 years |
| 40 m | 5.69 m/s | 17,434 kWh | 42 years |
| 50 m | 6.02 m/s | 19,852 kWh | 37 years |
Counties around St. Francis County
None of the 6 closest counties is windier than St. Francis County.
- Lee County, AR: 5.3 m/s, 14,608 kWh, payback 50 years (17 mi)
- Cross County, AR: 5.27 m/s, 14,397 kWh, payback 51 years (18 mi)
- Crittenden County, AR: 5.13 m/s, 13,421 kWh, payback 54 years (28 mi)
- Woodruff County, AR: 5.12 m/s, 13,353 kWh, payback 55 years (30 mi)
- Tunica County, MS: 5.08 m/s, 13,078 kWh, payback 51 years (33 mi)
- Monroe County, AR: 4.94 m/s, 12,132 kWh, payback 60 years (35 mi)
Sun versus wind in St. Francis County
St. Francis County gets 4.45 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,299 kWh a year; one kW of the turbine above makes 1,461. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.1 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.