Wind Turbine Payback in Knox County, NE
Wind turbine payback in Knox 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 Knox County, NE averages 6.62 m/s (14.8 mph). A 10 kW turbine there would make about 24,289 kWh a year, worth $3,138 at NE's 12.92¢/kWh. Against an installed cost of about $100,000, that is a payback of 32 years, and the turbine is built to last about 20.
What to do in Knox County
A home turbine is not worth buying for savings in Knox County unless your spot is far windier than the county average, 8.8 m/s at the hub against 6.62 m/s here. Per kW, solar panels would make about 1,226 kWh a year here against the turbine's 2,429, so get a solar quote first.
What would have to change
- Power would have to cost 21¢/kWh, 1.6 times what NE pays now.
- Or the average wind at the hub would have to be 8.8 m/s instead of 6.62. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NE
Knox County is the 102nd windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in NE is Cherry County at 6.83 m/s, payback 30 years.
Month by month in Knox County
April is the strongest month here, at 7.25 m/s and about 2,368 kWh. July is the weakest, 5.56 m/s and 1,401 kWh, so the best month makes 1.7 times the worst. November to March brings in 45% of the year's output in Knox County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.96 m/s | 2,275 kWh | $294 |
| February | 6.85 m/s | 1,990 kWh | $257 |
| March | 7.02 m/s | 2,307 kWh | $298 |
| April | 7.25 m/s | 2,368 kWh | $306 |
| May | 6.72 m/s | 2,126 kWh | $275 |
| June | 6.15 m/s | 1,709 kWh | $221 |
| July | 5.56 m/s | 1,401 kWh | $181 |
| August | 5.59 m/s | 1,418 kWh | $183 |
| September | 6.73 m/s | 2,063 kWh | $267 |
| October | 6.94 m/s | 2,258 kWh | $292 |
| November | 6.95 m/s | 2,191 kWh | $283 |
| December | 6.82 m/s | 2,187 kWh | $283 |
What a taller tower would buy
Measured at 10 m the wind in Knox County averages 5.25 m/s; at 50 m it is 7.38 m/s. That gives a shear exponent of 0.212, typical of ordinary open country. Going from 20 m to 50 m takes output from 20,275 to 29,714 kWh a year, 47% 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 | 6.08 m/s | 20,275 kWh | 38 years |
| 30 m | 6.62 m/s | 24,308 kWh | 32 years |
| 40 m | 7.04 m/s | 27,321 kWh | 28 years |
| 50 m | 7.38 m/s | 29,714 kWh | 26 years |
Counties around Knox County
4 of the 6 closest counties are windier at turbine height; the windiest, Antelope County, averages 6.71 m/s.
- Bon Homme County, SD: 6.45 m/s, 23,038 kWh, payback 30 years (24 mi)
- Pierce County, NE: 6.66 m/s, 24,582 kWh, payback 32 years (29 mi)
- Antelope County, NE: 6.71 m/s, 24,947 kWh, payback 31 years (32 mi)
- Cedar County, NE: 6.66 m/s, 24,582 kWh, payback 32 years (32 mi)
- Yankton County, SD: 6.47 m/s, 23,186 kWh, payback 30 years (36 mi)
- Holt County, NE: 6.68 m/s, 24,728 kWh, payback 31 years (47 mi)
Sun versus wind in Knox County
Knox County gets 4.2 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,226 kWh a year; one kW of the turbine above makes 2,429. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 2.0 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.