Wind Turbine Payback in Bristol County, RI
Wind turbine payback in Bristol 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 Bristol County, RI averages 5.04 m/s (11.3 mph). A 10 kW turbine there would make about 12,805 kWh a year, worth $3,720 at RI's 29.05¢/kWh. Against an installed cost of about $100,000, that is a payback of 27 years, and the turbine is built to last about 20.
What to do in Bristol County
A home turbine is not worth buying for savings in Bristol County unless your spot is far windier than the county average, 5.7 m/s at the hub against 5.04 m/s here. Per kW, solar panels would make about 1,165 kWh a year here against the turbine's 1,281, so get a solar quote first.
What would have to change
- Power would have to cost 39¢/kWh, 1.3 times what RI pays now.
- Or the average wind at the hub would have to be 5.7 m/s instead of 5.04. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of RI
Bristol County is the 1,436th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. It is the windiest county in RI.
Month by month in Bristol County
January is the strongest month here, at 5.79 m/s and about 1,540 kWh. August is the weakest, 4.13 m/s and 617 kWh, so the best month makes 2.5 times the worst. November to March brings in 55% of the year's output in Bristol County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.79 m/s | 1,540 kWh | $447 |
| February | 5.81 m/s | 1,401 kWh | $407 |
| March | 5.72 m/s | 1,497 kWh | $435 |
| April | 5.24 m/s | 1,164 kWh | $338 |
| May | 4.64 m/s | 866 kWh | $252 |
| June | 4.31 m/s | 676 kWh | $196 |
| July | 4.20 m/s | 649 kWh | $189 |
| August | 4.13 m/s | 617 kWh | $179 |
| September | 4.44 m/s | 738 kWh | $214 |
| October | 5.16 m/s | 1,156 kWh | $336 |
| November | 5.45 m/s | 1,286 kWh | $374 |
| December | 5.70 m/s | 1,486 kWh | $432 |
What a taller tower would buy
Measured at 10 m the wind in Bristol County averages 3.79 m/s; at 50 m it is 5.76 m/s. That gives a shear exponent of 0.260, typical of ordinary open country. Going from 20 m to 50 m takes output from 9,574 to 17,932 kWh a year, 87% 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 | 4.54 m/s | 9,574 kWh | 36 years |
| 30 m | 5.04 m/s | 12,830 kWh | 27 years |
| 40 m | 5.44 m/s | 15,572 kWh | 22 years |
| 50 m | 5.76 m/s | 17,932 kWh | 19 years |
Counties around Bristol County
None of the 6 closest counties is windier than Bristol County.
- Bristol County, MA: 5.04 m/s, 12,805 kWh, payback 26 years (11 mi)
- Newport County, RI: 5.04 m/s, 12,805 kWh, payback 27 years (14 mi)
- Kent County, RI: 4.21 m/s, 7,678 kWh, payback 45 years (15 mi)
- Providence County, RI: 3.58 m/s, 4,653 kWh, payback 74 years (19 mi)
- Washington County, RI: 4.21 m/s, 7,678 kWh, payback 45 years (28 mi)
- Norfolk County, MA: 3.88 m/s, 5,989 kWh, payback 55 years (33 mi)
Sun versus wind in Bristol County
Bristol County gets 3.99 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,165 kWh a year; one kW of the turbine above makes 1,281. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.1 times. 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.