Wind Turbine Payback in Washington County, ME
Wind turbine payback in Washington 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 Washington County, ME averages 4.11 m/s (9.2 mph). A 10 kW turbine there would make about 7,143 kWh a year, worth $2,159 at ME's 30.23¢/kWh. Against an installed cost of about $100,000, that is a payback of 46 years, and the turbine is built to last about 20.
What to do in Washington County
A home turbine is not worth buying for savings in Washington County unless your spot is far windier than the county average, 5.6 m/s at the hub against 4.11 m/s here. Per kW, solar panels would make about 1,072 kWh a year here against the turbine's 714, so get a solar quote first.
What would have to change
- Power would have to cost 70¢/kWh, 2.3 times what ME pays now.
- Or the average wind at the hub would have to be 5.6 m/s instead of 4.11. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of ME
Washington County is the 1,990th 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 Washington County
March is the strongest month here, at 4.80 m/s and about 953 kWh. July is the weakest, 3.24 m/s and 287 kWh, so the best month makes 3.3 times the worst. November to March brings in 56% of the year's output in Washington County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.58 m/s | 835 kWh | $252 |
| February | 4.73 m/s | 823 kWh | $249 |
| March | 4.80 m/s | 953 kWh | $288 |
| April | 4.40 m/s | 717 kWh | $217 |
| May | 3.82 m/s | 483 kWh | $146 |
| June | 3.56 m/s | 377 kWh | $114 |
| July | 3.24 m/s | 287 kWh | $87 |
| August | 3.30 m/s | 304 kWh | $92 |
| September | 3.75 m/s | 442 kWh | $134 |
| October | 4.26 m/s | 676 kWh | $204 |
| November | 4.41 m/s | 726 kWh | $219 |
| December | 4.51 m/s | 796 kWh | $241 |
What a taller tower would buy
Measured at 10 m the wind in Washington County averages 2.84 m/s; at 50 m it is 4.88 m/s. That gives a shear exponent of 0.336, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 4,681 to 11,734 kWh a year, 151% 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 | 3.59 m/s | 4,681 kWh | 71 years |
| 30 m | 4.11 m/s | 7,144 kWh | 46 years |
| 40 m | 4.53 m/s | 9,504 kWh | 35 years |
| 50 m | 4.88 m/s | 11,734 kWh | 28 years |
Counties around Washington County
2 of the 6 closest counties are windier at turbine height; the windiest, Knox County, averages 6.26 m/s.
- Hancock County, ME: 4.76 m/s, 10,954 kWh, payback 30 years (47 mi)
- Penobscot County, ME: 3.57 m/s, 4,612 kWh, payback 72 years (60 mi)
- Waldo County, ME: 3.48 m/s, 4,250 kWh, payback 78 years (81 mi)
- Knox County, ME: 6.26 m/s, 21,632 kWh, payback 15 years (95 mi)
- Piscataquis County, ME: 3.89 m/s, 6,037 kWh, payback 55 years (98 mi)
- Kennebec County, ME: 3.51 m/s, 4,368 kWh, payback 76 years (113 mi)
Sun versus wind in Washington County
Washington County gets 3.67 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,072 kWh a year; one kW of the turbine above makes 714. Kilowatt for kilowatt, panels make 1.5 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.