Wind Turbine Payback in Grafton County, NH
Wind turbine payback in Grafton 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 Grafton 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 Grafton County
A home turbine is not worth buying for savings in Grafton 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
Grafton 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 Grafton County
March is the strongest month here, at 4.24 m/s and about 665 kWh. August is the weakest, 2.74 m/s and 160 kWh, so the best month makes 4.2 times the worst. November to March brings in 60% of the year's output in Grafton County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.09 m/s | 599 kWh | $161 |
| February | 4.35 m/s | 650 kWh | $175 |
| March | 4.24 m/s | 665 kWh | $179 |
| April | 3.95 m/s | 522 kWh | $140 |
| May | 3.31 m/s | 308 kWh | $83 |
| June | 2.96 m/s | 203 kWh | $55 |
| July | 2.76 m/s | 165 kWh | $44 |
| August | 2.74 m/s | 160 kWh | $43 |
| September | 2.96 m/s | 203 kWh | $55 |
| October | 3.36 m/s | 323 kWh | $87 |
| November | 3.56 m/s | 377 kWh | $101 |
| December | 3.83 m/s | 489 kWh | $132 |
What a taller tower would buy
Measured at 10 m the wind in Grafton County averages 2.24 m/s; at 50 m it is 4.32 m/s. That gives a shear exponent of 0.408, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,520 to 8,289 kWh a year, 229% 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 | 2,520 kWh | over 100 years |
| 30 m | 3.51 m/s | 4,358 kWh | 85 years |
| 40 m | 3.94 m/s | 6,300 kWh | 59 years |
| 50 m | 4.32 m/s | 8,289 kWh | 45 years |
Counties around Grafton County
5 of the 6 closest counties are windier at turbine height; the windiest, Caledonia County, averages 3.6 m/s.
- Orange County, VT: 3.55 m/s, 4,530 kWh, payback 92 years (27 mi)
- Carroll County, NH: 3.51 m/s, 4,368 kWh, payback 85 years (32 mi)
- Belknap County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (35 mi)
- Caledonia County, VT: 3.6 m/s, 4,736 kWh, payback 88 years (40 mi)
- Sullivan County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (43 mi)
- Merrimack County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (44 mi)
Sun versus wind in Grafton County
Grafton 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.