Wind Turbine Payback in Harper County, KS
Wind turbine payback in Harper 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 Harper County, KS averages 6.27 m/s (14 mph). A 10 kW turbine there would make about 21,706 kWh a year, worth $3,312 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 Harper County
A home turbine is not worth buying for savings in Harper County unless your spot is far windier than the county average, 7.8 m/s at the hub against 6.27 m/s here. Per kW, solar panels would make about 1,387 kWh a year here against the turbine's 2,171, 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 6.27. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of KS
Harper County is the 510th 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 Harper County
April is the strongest month here, at 7.17 m/s and about 2,322 kWh. August is the weakest, 5.52 m/s and 1,377 kWh, so the best month makes 1.7 times the worst. November to March brings in 42% of the year's output in Harper County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.07 m/s | 1,716 kWh | $262 |
| February | 6.14 m/s | 1,590 kWh | $243 |
| March | 6.70 m/s | 2,112 kWh | $322 |
| April | 7.17 m/s | 2,322 kWh | $354 |
| May | 6.46 m/s | 1,962 kWh | $299 |
| June | 6.43 m/s | 1,883 kWh | $287 |
| July | 5.68 m/s | 1,470 kWh | $224 |
| August | 5.52 m/s | 1,377 kWh | $210 |
| September | 6.10 m/s | 1,682 kWh | $257 |
| October | 6.48 m/s | 1,973 kWh | $301 |
| November | 6.49 m/s | 1,920 kWh | $293 |
| December | 6.05 m/s | 1,705 kWh | $260 |
What a taller tower would buy
Measured at 10 m the wind in Harper County averages 4.88 m/s; at 50 m it is 7.05 m/s. That gives a shear exponent of 0.229, typical of ordinary open country. Going from 20 m to 50 m takes output from 17,606 to 27,400 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 | 5.72 m/s | 17,606 kWh | 37 years |
| 30 m | 6.27 m/s | 21,719 kWh | 30 years |
| 40 m | 6.7 m/s | 24,865 kWh | 26 years |
| 50 m | 7.05 m/s | 27,400 kWh | 24 years |
Counties around Harper County
6 of the 6 closest counties are windier at turbine height; the windiest, Kingman County, averages 6.45 m/s.
- Kingman County, KS: 6.45 m/s, 23,038 kWh, payback 28 years (26 mi)
- Grant County, OK: 6.29 m/s, 21,855 kWh, payback 33 years (32 mi)
- Sumner County, KS: 6.29 m/s, 21,855 kWh, payback 30 years (32 mi)
- Barber County, KS: 6.3 m/s, 21,929 kWh, payback 30 years (34 mi)
- Alfalfa County, OK: 6.31 m/s, 22,003 kWh, payback 33 years (35 mi)
- Sedgwick County, KS: 6.41 m/s, 22,743 kWh, payback 29 years (48 mi)
Sun versus wind in Harper County
Harper County gets 4.75 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,387 kWh a year; one kW of the turbine above makes 2,171. 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.