Wind Turbine Payback in Hillsborough County, NH
Wind turbine payback in Hillsborough 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 Hillsborough County, NH averages 3.54 m/s (7.9 mph). A 10 kW turbine there would make about 4,489 kWh a year, worth $1,208 at NH's 26.91¢/kWh. Against an installed cost of about $100,000, that is a payback of 83 years, and the turbine is built to last about 20.
What to do in Hillsborough County
A home turbine is not worth buying for savings in Hillsborough County unless your spot is far windier than the county average, 5.8 m/s at the hub against 3.54 m/s here. Per kW, solar panels would make about 1,113 kWh a year here against the turbine's 449, so get a solar quote first.
What would have to change
- Power would have to cost 111¢/kWh, 4.1 times what NH pays now.
- Or the average wind at the hub would have to be 5.8 m/s instead of 3.54. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of NH
Hillsborough County is the 2,473rd 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 Hillsborough County
March is the strongest month here, at 4.24 m/s and about 665 kWh. August is the weakest, 2.84 m/s and 182 kWh, so the best month makes 3.7 times the worst. November to March brings in 59% of the year's output in Hillsborough County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 4.12 m/s | 611 kWh | $164 |
| February | 4.34 m/s | 645 kWh | $174 |
| March | 4.24 m/s | 665 kWh | $179 |
| April | 3.90 m/s | 502 kWh | $135 |
| May | 3.29 m/s | 301 kWh | $81 |
| June | 2.96 m/s | 205 kWh | $55 |
| July | 2.84 m/s | 182 kWh | $49 |
| August | 2.84 m/s | 182 kWh | $49 |
| September | 3.04 m/s | 222 kWh | $60 |
| October | 3.46 m/s | 353 kWh | $95 |
| November | 3.62 m/s | 395 kWh | $106 |
| December | 3.84 m/s | 493 kWh | $133 |
What a taller tower would buy
Measured at 10 m the wind in Hillsborough County averages 2.17 m/s; at 50 m it is 4.44 m/s. That gives a shear exponent of 0.445, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 2,465 to 8,982 kWh a year, 264% 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 | 2.95 m/s | 2,465 kWh | over 100 years |
| 30 m | 3.54 m/s | 4,478 kWh | 83 years |
| 40 m | 4.02 m/s | 6,680 kWh | 56 years |
| 50 m | 4.44 m/s | 8,982 kWh | 41 years |
Counties around Hillsborough County
6 of the 6 closest counties are windier at turbine height; the windiest, Middlesex County, averages 3.87 m/s.
- Cheshire County, NH: 3.64 m/s, 4,905 kWh, payback 76 years (27 mi)
- Merrimack County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (27 mi)
- Rockingham County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (32 mi)
- Middlesex County, MA: 3.87 m/s, 5,942 kWh, payback 56 years (34 mi)
- Sullivan County, NH: 3.58 m/s, 4,653 kWh, payback 80 years (40 mi)
- Worcester County, MA: 3.56 m/s, 4,570 kWh, payback 73 years (43 mi)
Sun versus wind in Hillsborough County
Hillsborough County gets 3.81 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,113 kWh a year; one kW of the turbine above makes 449. 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.