Wind Turbine Payback in St. Louis County, MN
Wind turbine payback in St. Louis 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 St. Louis County, MN averages 5.59 m/s (12.5 mph). A 10 kW turbine there would make about 16,689 kWh a year, worth $2,744 at MN's 16.44¢/kWh. Against an installed cost of about $100,000, that is a payback of 36 years, and the turbine is built to last about 20.
What to do in St. Louis County
A home turbine is not worth buying for savings in St. Louis County unless your spot is far windier than the county average, 7.5 m/s at the hub against 5.59 m/s here. Per kW, solar panels would make about 1,045 kWh a year here against the turbine's 1,669, so get a solar quote first.
What would have to change
- Power would have to cost 30¢/kWh, 1.8 times what MN pays now.
- Or the average wind at the hub would have to be 7.5 m/s instead of 5.59. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of MN
St. Louis County is the 1,174th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in MN is Lincoln County at 6.68 m/s, payback 25 years.
Month by month in St. Louis County
April is the strongest month here, at 6.03 m/s and about 1,637 kWh. July is the weakest, 5.03 m/s and 1,083 kWh, so the best month makes 1.5 times the worst. November to March brings in 43% of the year's output in St. Louis County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.70 m/s | 1,485 kWh | $244 |
| February | 5.87 m/s | 1,437 kWh | $236 |
| March | 5.80 m/s | 1,546 kWh | $254 |
| April | 6.03 m/s | 1,637 kWh | $269 |
| May | 5.59 m/s | 1,419 kWh | $233 |
| June | 5.30 m/s | 1,200 kWh | $197 |
| July | 5.03 m/s | 1,083 kWh | $178 |
| August | 5.11 m/s | 1,130 kWh | $186 |
| September | 5.68 m/s | 1,427 kWh | $235 |
| October | 5.80 m/s | 1,546 kWh | $254 |
| November | 5.70 m/s | 1,437 kWh | $236 |
| December | 5.47 m/s | 1,343 kWh | $221 |
What a taller tower would buy
Measured at 10 m the wind in St. Louis County averages 4.34 m/s; at 50 m it is 6.28 m/s. That gives a shear exponent of 0.230, typical of ordinary open country. Going from 20 m to 50 m takes output from 13,124 to 21,781 kWh a year, 66% 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 | 5.09 m/s | 13,124 kWh | 46 years |
| 30 m | 5.58 m/s | 16,644 kWh | 37 years |
| 40 m | 5.97 m/s | 19,451 kWh | 31 years |
| 50 m | 6.28 m/s | 21,781 kWh | 28 years |
Counties around St. Louis County
3 of the 6 closest counties are windier at turbine height; the windiest, Aitkin County, averages 6.32 m/s.
- Itasca County, MN: 5.88 m/s, 18,816 kWh, payback 32 years (52 mi)
- Lake County, MN: 4.46 m/s, 9,100 kWh, payback 67 years (52 mi)
- Carlton County, MN: 5.93 m/s, 19,186 kWh, payback 32 years (68 mi)
- Koochiching County, MN: 4.1 m/s, 7,090 kWh, payback 86 years (75 mi)
- Aitkin County, MN: 6.32 m/s, 22,077 kWh, payback 28 years (80 mi)
- Douglas County, WI: 5.45 m/s, 15,677 kWh, payback 34 years (82 mi)
Sun versus wind in St. Louis County
St. Louis County gets 3.58 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,045 kWh a year; one kW of the turbine above makes 1,669. 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.