Wind Turbine Payback in Sumner County, KS
Wind turbine payback in Sumner 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 Sumner County, KS averages 6.29 m/s (14.1 mph). A 10 kW turbine there would make about 21,855 kWh a year, worth $3,335 at KS's 15.26¢/kWh. Against an installed cost of about $100,000, that is a payback of 30 years, and the turbine is built to last about 20.
What to do in Sumner County
A home turbine is not worth buying for savings in Sumner County unless your spot is far windier than the county average, 7.8 m/s at the hub against 6.29 m/s here. Per kW, solar panels would make about 1,349 kWh a year here against the turbine's 2,186, so get a solar quote first.
What would have to change
- Power would have to cost 23¢/kWh, 1.5 times what KS pays now.
- Or the average wind at the hub would have to be 7.8 m/s instead of 6.29. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of KS
Sumner County is the 482nd windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in KS is Edwards County at 6.68 m/s, payback 27 years.
Month by month in Sumner County
April is the strongest month here, at 7.23 m/s and about 2,359 kWh. August is the weakest, 5.43 m/s and 1,319 kWh, so the best month makes 1.8 times the worst. November to March brings in 43% of the year's output in Sumner County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.15 m/s | 1,768 kWh | $270 |
| February | 6.24 m/s | 1,647 kWh | $251 |
| March | 6.77 m/s | 2,157 kWh | $329 |
| April | 7.23 m/s | 2,359 kWh | $360 |
| May | 6.45 m/s | 1,958 kWh | $299 |
| June | 6.38 m/s | 1,852 kWh | $283 |
| July | 5.60 m/s | 1,423 kWh | $217 |
| August | 5.43 m/s | 1,319 kWh | $201 |
| September | 6.02 m/s | 1,630 kWh | $249 |
| October | 6.53 m/s | 2,008 kWh | $306 |
| November | 6.59 m/s | 1,981 kWh | $302 |
| December | 6.16 m/s | 1,773 kWh | $271 |
What a taller tower would buy
Measured at 10 m the wind in Sumner County averages 4.88 m/s; at 50 m it is 7.08 m/s. That gives a shear exponent of 0.231, typical of ordinary open country. Going from 20 m to 50 m takes output from 17,707 to 27,613 kWh a year, 56% 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 | 5.73 m/s | 17,707 kWh | 37 years |
| 30 m | 6.29 m/s | 21,869 kWh | 30 years |
| 40 m | 6.72 m/s | 25,052 kWh | 26 years |
| 50 m | 7.08 m/s | 27,613 kWh | 24 years |
Counties around Sumner County
2 of the 6 closest counties are windier at turbine height; the windiest, Kingman County, averages 6.45 m/s.
- Sedgwick County, KS: 6.41 m/s, 22,743 kWh, payback 29 years (31 mi)
- Harper County, KS: 6.27 m/s, 21,706 kWh, payback 30 years (32 mi)
- Kay County, OK: 6.29 m/s, 21,855 kWh, payback 33 years (35 mi)
- Grant County, OK: 6.29 m/s, 21,855 kWh, payback 33 years (35 mi)
- Cowley County, KS: 6.29 m/s, 21,855 kWh, payback 30 years (36 mi)
- Kingman County, KS: 6.45 m/s, 23,038 kWh, payback 28 years (42 mi)
Sun versus wind in Sumner County
Sumner 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 2,186. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.6 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.