Wind Turbine Payback in Riley County, KS
Wind turbine payback in Riley 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 Riley 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 Riley County
A home turbine is not worth buying for savings in Riley 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 1,273 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
Riley 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 Riley County
April is the strongest month here, at 7.18 m/s and about 2,325 kWh. August is the weakest, 5.22 m/s and 1,195 kWh, so the best month makes 1.9 times the worst. November to March brings in 44% of the year's output in Riley County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.31 m/s | 1,870 kWh | $285 |
| February | 6.36 m/s | 1,714 kWh | $262 |
| March | 6.86 m/s | 2,208 kWh | $337 |
| April | 7.18 m/s | 2,325 kWh | $355 |
| May | 6.40 m/s | 1,926 kWh | $294 |
| June | 6.21 m/s | 1,749 kWh | $267 |
| July | 5.36 m/s | 1,275 kWh | $195 |
| August | 5.22 m/s | 1,195 kWh | $182 |
| September | 6.14 m/s | 1,706 kWh | $260 |
| October | 6.55 m/s | 2,020 kWh | $308 |
| November | 6.61 m/s | 1,993 kWh | $304 |
| December | 6.23 m/s | 1,819 kWh | $278 |
What a taller tower would buy
Measured at 10 m the wind in Riley County averages 4.91 m/s; at 50 m it is 7.05 m/s. That gives a shear exponent of 0.225, typical of ordinary open country. Going from 20 m to 50 m takes output from 17,760 to 27,400 kWh a year, 54% 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 | 5.74 m/s | 17,760 kWh | 37 years |
| 30 m | 6.28 m/s | 21,814 kWh | 30 years |
| 40 m | 6.7 m/s | 24,909 kWh | 26 years |
| 50 m | 7.05 m/s | 27,400 kWh | 24 years |
Counties around Riley County
3 of the 6 closest counties are windier at turbine height; the windiest, Geary County, averages 6.35 m/s.
- Geary County, KS: 6.35 m/s, 22,299 kWh, payback 29 years (20 mi)
- Pottawatomie County, KS: 6.24 m/s, 21,484 kWh, payback 31 years (22 mi)
- Clay County, KS: 6.29 m/s, 21,855 kWh, payback 30 years (24 mi)
- Marshall County, KS: 6.34 m/s, 22,225 kWh, payback 30 years (36 mi)
- Wabaunsee County, KS: 6.28 m/s, 21,781 kWh, payback 30 years (37 mi)
- Dickinson County, KS: 6.35 m/s, 22,299 kWh, payback 29 years (37 mi)
Sun versus wind in Riley County
Riley County gets 4.36 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,273 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 1.7 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.