Wind Turbine Payback in Carroll County, NH
Wind turbine payback in Carroll 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 Carroll County, NH averages 3.51 m/s (7.9 mph). A 10 kW turbine there would make about 4,368 kWh a year, worth $1,176 at NH's 26.91¢/kWh. Against an installed cost of about $100,000, that is a payback of 85 years, and the turbine is built to last about 20.
What to do in Carroll County
A home turbine is not worth buying for savings in Carroll County unless your spot is far windier than the county average, 5.8 m/s at the hub against 3.51 m/s here. Per kW, solar panels would make about 1,083 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, 4.3 times what NH pays now.
- Or the average wind at the hub would have to be 5.8 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 NH
Carroll 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 NH is Cheshire County at 3.64 m/s, payback 76 years.
Month by month in Carroll County
March is the strongest month here, at 4.24 m/s and about 667 kWh. August is the weakest, 2.77 m/s and 166 kWh, so the best month makes 4.0 times the worst. November to March brings in 60% of the year's output in Carroll County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.15 m/s | 626 kWh | $168 |
| February | 4.37 m/s | 658 kWh | $177 |
| March | 4.24 m/s | 667 kWh | $179 |
| April | 3.89 m/s | 497 kWh | $134 |
| May | 3.28 m/s | 299 kWh | $80 |
| June | 2.96 m/s | 204 kWh | $55 |
| July | 2.78 m/s | 170 kWh | $46 |
| August | 2.77 m/s | 166 kWh | $45 |
| September | 2.97 m/s | 206 kWh | $55 |
| October | 3.40 m/s | 334 kWh | $90 |
| November | 3.58 m/s | 381 kWh | $103 |
| December | 3.85 m/s | 498 kWh | $134 |
What a taller tower would buy
Measured at 10 m the wind in Carroll County averages 2.24 m/s; at 50 m it is 4.33 m/s. That gives a shear exponent of 0.410, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,524 to 8,346 kWh a year, 231% 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 | 2.97 m/s | 2,524 kWh | over 100 years |
| 30 m | 3.51 m/s | 4,376 kWh | 85 years |
| 40 m | 3.95 m/s | 6,336 kWh | 59 years |
| 50 m | 4.33 m/s | 8,346 kWh | 45 years |
Counties around Carroll County
4 of the 6 closest counties are windier at turbine height; the windiest, York County, averages 3.93 m/s.
- Belknap County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (27 mi)
- Grafton County, NH: 3.51 m/s, 4,368 kWh, payback 85 years (32 mi)
- York County, ME: 3.93 m/s, 6,231 kWh, payback 53 years (41 mi)
- Strafford County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (41 mi)
- Cumberland County, ME: 3.5 m/s, 4,329 kWh, payback 76 years (44 mi)
- Merrimack County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (46 mi)
Sun versus wind in Carroll County
Carroll County gets 3.71 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,083 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.