Wind Turbine Payback in Kent County, RI
Wind turbine payback in Kent 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 Kent County, RI averages 4.21 m/s (9.4 mph). A 10 kW turbine there would make about 7,678 kWh a year, worth $2,230 at RI's 29.05¢/kWh. Against an installed cost of about $100,000, that is a payback of 45 years, and the turbine is built to last about 20.
What to do in Kent County
A home turbine is not worth buying for savings in Kent County unless your spot is far windier than the county average, 5.7 m/s at the hub against 4.21 m/s here. Per kW, solar panels would make about 1,165 kWh a year here against the turbine's 768, so get a solar quote first.
What would have to change
- Power would have to cost 65¢/kWh, 2.2 times what RI pays now.
- Or the average wind at the hub would have to be 5.7 m/s instead of 4.21. A taller tower or an exposed ridge can add some of that; a rooftop never will.
Against the rest of RI
Kent County is the 1,944th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in RI is Bristol County at 5.04 m/s, payback 27 years.
Month by month in Kent County
January is the strongest month here, at 5.00 m/s and about 1,066 kWh. July is the weakest, 3.34 m/s and 316 kWh, so the best month makes 3.4 times the worst. November to March brings in 60% of the year's output in Kent County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.00 m/s | 1,066 kWh | $310 |
| February | 5.05 m/s | 989 kWh | $287 |
| March | 4.90 m/s | 1,009 kWh | $293 |
| April | 4.40 m/s | 718 kWh | $209 |
| May | 3.76 m/s | 461 kWh | $134 |
| June | 3.42 m/s | 332 kWh | $96 |
| July | 3.34 m/s | 316 kWh | $92 |
| August | 3.36 m/s | 321 kWh | $93 |
| September | 3.63 m/s | 401 kWh | $116 |
| October | 4.30 m/s | 693 kWh | $201 |
| November | 4.57 m/s | 800 kWh | $232 |
| December | 4.83 m/s | 971 kWh | $282 |
What a taller tower would buy
Measured at 10 m the wind in Kent County averages 2.89 m/s; at 50 m it is 5.02 m/s. That gives a shear exponent of 0.343, typical of rough, sheltered ground: trees or buildings slow the low wind a lot. Going from 20 m to 50 m takes output from 5,017 to 12,670 kWh a year, 153% 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 | 3.67 m/s | 5,017 kWh | 69 years |
| 30 m | 4.21 m/s | 7,695 kWh | 45 years |
| 40 m | 4.65 m/s | 10,258 kWh | 34 years |
| 50 m | 5.02 m/s | 12,670 kWh | 27 years |
Counties around Kent County
3 of the 6 closest counties are windier at turbine height; the windiest, Bristol County, averages 5.04 m/s.
- Providence County, RI: 3.58 m/s, 4,653 kWh, payback 74 years (13 mi)
- Bristol County, RI: 5.04 m/s, 12,805 kWh, payback 27 years (15 mi)
- Washington County, RI: 4.21 m/s, 7,678 kWh, payback 45 years (19 mi)
- Newport County, RI: 5.04 m/s, 12,805 kWh, payback 27 years (20 mi)
- Northeastern Connecticut Planning Region, CT: 3.58 m/s, 4,653 kWh, payback 78 years (23 mi)
- Bristol County, MA: 5.04 m/s, 12,805 kWh, payback 26 years (26 mi)
Sun versus wind in Kent County
Kent 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 768. Kilowatt for kilowatt, panels make 1.5 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.