Wind Turbine Payback in Grundy County, MO
Wind turbine payback in Grundy 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 Grundy County, MO averages 5.91 m/s (13.2 mph). A 10 kW turbine there would make about 19,038 kWh a year, worth $2,719 at MO's 14.28¢/kWh. Against an installed cost of about $100,000, that is a payback of 37 years, and the turbine is built to last about 20.
What to do in Grundy County
A home turbine is not worth buying for savings in Grundy County unless your spot is far windier than the county average, 8.2 m/s at the hub against 5.91 m/s here. Per kW, solar panels would make about 1,209 kWh a year here against the turbine's 1,904, so get a solar quote first.
What would have to change
- Power would have to cost 26¢/kWh, 1.8 times what MO pays now.
- Or the average wind at the hub would have to be 8.2 m/s instead of 5.91. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MO
Grundy County is the 978th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MO is Atchison County at 6.17 m/s, payback 33 years.
Month by month in Grundy County
April is the strongest month here, at 6.82 m/s and about 2,113 kWh. August is the weakest, 4.63 m/s and 860 kWh, so the best month makes 2.5 times the worst. November to March brings in 49% of the year's output in Grundy County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.33 m/s | 1,880 kWh | $268 |
| February | 6.33 m/s | 1,698 kWh | $242 |
| March | 6.64 m/s | 2,074 kWh | $296 |
| April | 6.82 m/s | 2,113 kWh | $302 |
| May | 5.97 m/s | 1,657 kWh | $237 |
| June | 5.43 m/s | 1,274 kWh | $182 |
| July | 4.69 m/s | 893 kWh | $128 |
| August | 4.63 m/s | 860 kWh | $123 |
| September | 5.42 m/s | 1,269 kWh | $181 |
| October | 6.19 m/s | 1,791 kWh | $256 |
| November | 6.43 m/s | 1,879 kWh | $268 |
| December | 6.14 m/s | 1,763 kWh | $252 |
What a taller tower would buy
Measured at 10 m the wind in Grundy County averages 4.55 m/s; at 50 m it is 6.68 m/s. That gives a shear exponent of 0.239, typical of ordinary open country. Going from 20 m to 50 m takes output from 15,078 to 24,728 kWh a year, 64% 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 | 5.37 m/s | 15,078 kWh | 46 years |
| 30 m | 5.91 m/s | 19,055 kWh | 37 years |
| 40 m | 6.33 m/s | 22,174 kWh | 32 years |
| 50 m | 6.68 m/s | 24,728 kWh | 28 years |
Counties around Grundy County
2 of the 6 closest counties are windier at turbine height; the windiest, Mercer County, averages 6.05 m/s.
- Mercer County, MO: 6.05 m/s, 20,075 kWh, payback 35 years (21 mi)
- Livingston County, MO: 5.91 m/s, 19,038 kWh, payback 37 years (23 mi)
- Daviess County, MO: 5.91 m/s, 19,038 kWh, payback 37 years (24 mi)
- Sullivan County, MO: 5.83 m/s, 18,447 kWh, payback 38 years (25 mi)
- Harrison County, MO: 6.05 m/s, 20,075 kWh, payback 35 years (28 mi)
- Linn County, MO: 5.83 m/s, 18,447 kWh, payback 38 years (30 mi)
Sun versus wind in Grundy County
Grundy County gets 4.14 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,209 kWh a year; one kW of the turbine above makes 1,904. 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.