Wind Turbine Payback in Merrimack County, NH
Wind turbine payback in Merrimack 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 Merrimack County, NH averages 3.58 m/s (8 mph). A 10 kW turbine there would make about 4,653 kWh a year, worth $1,252 at NH's 26.91¢/kWh. Against an installed cost of about $100,000, that is a payback of 80 years, and the turbine is built to last about 20.
What to do in Merrimack County
A home turbine is not worth buying for savings in Merrimack County unless your spot is far windier than the county average, 5.8 m/s at the hub against 3.58 m/s here. Per kW, solar panels would make about 1,083 kWh a year here against the turbine's 465, so get a solar quote first.
What would have to change
- Power would have to cost 107¢/kWh, 4.0 times what NH pays now.
- Or the average wind at the hub would have to be 5.8 m/s instead of 3.58. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NH
Merrimack County is the 2,429th 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 Merrimack County
March is the strongest month here, at 4.31 m/s and about 701 kWh. August is the weakest, 2.83 m/s and 182 kWh, so the best month makes 3.9 times the worst. November to March brings in 59% of the year's output in Merrimack County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.17 m/s | 632 kWh | $170 |
| February | 4.42 m/s | 680 kWh | $183 |
| March | 4.31 m/s | 701 kWh | $189 |
| April | 4.00 m/s | 539 kWh | $145 |
| May | 3.38 m/s | 328 kWh | $88 |
| June | 3.04 m/s | 223 kWh | $60 |
| July | 2.87 m/s | 189 kWh | $51 |
| August | 2.83 m/s | 182 kWh | $49 |
| September | 3.05 m/s | 227 kWh | $61 |
| October | 3.48 m/s | 360 kWh | $97 |
| November | 3.64 m/s | 403 kWh | $108 |
| December | 3.87 m/s | 506 kWh | $136 |
What a taller tower would buy
Measured at 10 m the wind in Merrimack County averages 2.29 m/s; at 50 m it is 4.41 m/s. That gives a shear exponent of 0.407, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,712 to 8,807 kWh a year, 225% 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 | 3.04 m/s | 2,712 kWh | over 100 years |
| 30 m | 3.58 m/s | 4,662 kWh | 80 years |
| 40 m | 4.03 m/s | 6,714 kWh | 55 years |
| 50 m | 4.41 m/s | 8,807 kWh | 42 years |
Counties around Merrimack County
1 of the 6 closest counties is windier at turbine height; the windiest, Cheshire County, averages 3.64 m/s.
- Belknap County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (20 mi)
- Hillsborough County, NH: 3.54 m/s, 4,489 kWh, payback 83 years (27 mi)
- Sullivan County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (28 mi)
- Strafford County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (32 mi)
- Rockingham County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (36 mi)
- Cheshire County, NH: 3.64 m/s, 4,905 kWh, payback 76 years (39 mi)
Sun versus wind in Merrimack County
Merrimack 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 465. Kilowatt for kilowatt, panels make 2.3 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.