Wind Turbine Payback in Honolulu County, HI
Wind turbine payback in Honolulu County
Yes. A small turbine pays for itself here.
At 30 m, the height a home turbine tower usually reaches, the wind in Honolulu County, HI averages 6.85 m/s (15.3 mph). A 10 kW turbine there would make about 25,964 kWh a year, worth $12,050 at HI's 46.41¢/kWh. Against an installed cost of about $100,000, that is a payback of 8 years, and the turbine is built to last about 20.
What to do in Honolulu County
The numbers work, so the next step is proof. Before you buy, get a site assessment that logs wind at your actual tower spot for a few months, and check your county's zoning for tower height limits. If the logger reads below 4.7 m/s, walk away.
What would have to change
- Power already costs enough here: break-even is 19¢/kWh and HI pays 46.41¢.
- The wind clears the break-even speed of 4.7 m/s at today's price.
Against the rest of HI
Honolulu County is the 27th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. It is the windiest county in HI.
Month by month in Honolulu County
July is the strongest month here, at 7.81 m/s and about 2,771 kWh. January is the weakest, 6.09 m/s and 1,728 kWh, so the best month makes 1.6 times the worst. November to March brings in 38% of the year's output in Honolulu County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 6.09 m/s | 1,728 kWh | $802 |
| February | 6.53 m/s | 1,811 kWh | $840 |
| March | 6.59 m/s | 2,047 kWh | $950 |
| April | 7.08 m/s | 2,272 kWh | $1,054 |
| May | 6.37 m/s | 1,909 kWh | $886 |
| June | 7.55 m/s | 2,535 kWh | $1,176 |
| July | 7.81 m/s | 2,771 kWh | $1,286 |
| August | 7.60 m/s | 2,653 kWh | $1,231 |
| September | 6.83 m/s | 2,119 kWh | $983 |
| October | 6.30 m/s | 1,861 kWh | $864 |
| November | 6.80 m/s | 2,102 kWh | $976 |
| December | 6.68 m/s | 2,101 kWh | $975 |
What a taller tower would buy
Measured at 10 m the wind in Honolulu County averages 6.28 m/s; at 50 m it is 7.14 m/s. That gives a shear exponent of 0.080, typical of very open, smooth ground where height adds little. Going from 20 m to 50 m takes output from 24,401 to 28,038 kWh a year, 15% more, before counting the extra cost of the taller tower.
| Hub height | Average wind | Output | Payback |
|---|---|---|---|
| 20 m | 6.64 m/s | 24,401 kWh | 9 years |
| 30 m | 6.85 m/s | 25,994 kWh | 8 years |
| 40 m | 7.01 m/s | 27,141 kWh | 8 years |
| 50 m | 7.14 m/s | 28,038 kWh | 8 years |
Counties around Honolulu County
1 of the 6 closest counties is windier at turbine height; the windiest, Aleutians East Borough, averages 7.73 m/s.
- Kalawao County, HI: 6.46 m/s, 23,112 kWh, payback 9 years (81 mi)
- Kauai County, HI: 6.64 m/s, 24,436 kWh, payback 9 years (104 mi)
- Maui County, HI: 6.46 m/s, 23,112 kWh, payback 9 years (111 mi)
- Hawaii County, HI: 3.43 m/s, 4,056 kWh, payback 53 years (217 mi)
- Aleutians East Borough, AK: 7.73 m/s, 32,079 kWh, payback 11 years (2343 mi)
- San Francisco County, CA: 6.53 m/s, 23,628 kWh, payback 13 years (2373 mi)
Sun versus wind in Honolulu County
Honolulu County gets 5.84 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,705 kWh a year; one kW of the turbine above makes 2,596. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.5 times. Panel output assumes an 80% system performance ratio.
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.