Wind Turbine Payback in Kennebec County, ME
Wind turbine payback in Kennebec 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 Kennebec County, ME averages 3.51 m/s (7.9 mph). A 10 kW turbine there would make about 4,368 kWh a year, worth $1,321 at ME's 30.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 76 years, and the turbine is built to last about 20.
What to do in Kennebec County
A home turbine is not worth buying for savings in Kennebec County unless your spot is far windier than the county average, 5.6 m/s at the hub against 3.51 m/s here. Per kW, solar panels would make about 1,080 kWh a year here against the turbine's 437, so get a solar quote first.
What would have to change
- Power would have to cost 114¢/kWh, 3.8 times what ME pays now.
- Or the average wind at the hub would have to be 5.6 m/s instead of 3.51. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ME
Kennebec County is the 2,496th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in ME is Knox County at 6.26 m/s, payback 15 years.
Month by month in Kennebec County
March is the strongest month here, at 4.32 m/s and about 703 kWh. July is the weakest, 2.77 m/s and 168 kWh, so the best month makes 4.2 times the worst. November to March brings in 59% of the year's output in Kennebec County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.03 m/s | 573 kWh | $173 |
| February | 4.33 m/s | 642 kWh | $194 |
| March | 4.32 m/s | 703 kWh | $213 |
| April | 3.90 m/s | 501 kWh | $151 |
| May | 3.26 m/s | 292 kWh | $88 |
| June | 2.95 m/s | 202 kWh | $61 |
| July | 2.77 m/s | 168 kWh | $51 |
| August | 2.81 m/s | 175 kWh | $53 |
| September | 3.06 m/s | 228 kWh | $69 |
| October | 3.49 m/s | 364 kWh | $110 |
| November | 3.58 m/s | 382 kWh | $115 |
| December | 3.74 m/s | 454 kWh | $137 |
What a taller tower would buy
Measured at 10 m the wind in Kennebec County averages 2.25 m/s; at 50 m it is 4.32 m/s. That gives a shear exponent of 0.405, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,544 to 8,289 kWh a year, 226% 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 | 2.98 m/s | 2,544 kWh | over 100 years |
| 30 m | 3.51 m/s | 4,379 kWh | 76 years |
| 40 m | 3.95 m/s | 6,313 kWh | 52 years |
| 50 m | 4.32 m/s | 8,289 kWh | 40 years |
Counties around Kennebec County
5 of the 6 closest counties are windier at turbine height; the windiest, Knox County, averages 6.26 m/s.
- Androscoggin County, ME: 3.65 m/s, 4,948 kWh, payback 67 years (28 mi)
- Lincoln County, ME: 4.86 m/s, 11,603 kWh, payback 29 years (32 mi)
- Waldo County, ME: 3.48 m/s, 4,250 kWh, payback 78 years (32 mi)
- Sagadahoc County, ME: 3.65 m/s, 4,948 kWh, payback 67 years (35 mi)
- Knox County, ME: 6.26 m/s, 21,632 kWh, payback 15 years (44 mi)
- Oxford County, ME: 3.52 m/s, 4,408 kWh, payback 75 years (48 mi)
Sun versus wind in Kennebec County
Kennebec County gets 3.7 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,080 kWh a year; one kW of the turbine above makes 437. Kilowatt for kilowatt, panels make 2.5 times as much here as the turbine. 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.