Wind Turbine Payback in Kalawao County, HI
Wind turbine payback in Kalawao County
Yes. A small turbine pays for itself here.
At 30 m, the height a home turbine tower usually reaches, the wind in Kalawao County, HI averages 6.46 m/s (14.5 mph). A 10 kW turbine there would make about 23,112 kWh a year, worth $10,726 at HI's 46.41¢/kWh. Against an installed cost of about $100,000, that is a payback of 9 years, and the turbine is built to last about 20.
What to do in Kalawao 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 22¢/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
Kalawao County is the 239th windiest of 3,144 US counties at turbine height; the national middle is 4.79 m/s. The windiest in HI is Honolulu County at 6.85 m/s, payback 8 years.
Month by month in Kalawao County
July is the strongest month here, at 7.33 m/s and about 2,494 kWh. January is the weakest, 5.73 m/s and 1,503 kWh, so the best month makes 1.7 times the worst. November to March brings in 37% of the year's output in Kalawao County.
| Month | Wind at 30 m | Output | Worth |
|---|---|---|---|
| January | 5.73 m/s | 1,503 kWh | $698 |
| February | 6.15 m/s | 1,598 kWh | $742 |
| March | 6.17 m/s | 1,782 kWh | $827 |
| April | 6.74 m/s | 2,069 kWh | $960 |
| May | 6.10 m/s | 1,739 kWh | $807 |
| June | 7.12 m/s | 2,291 kWh | $1,063 |
| July | 7.33 m/s | 2,494 kWh | $1,157 |
| August | 7.17 m/s | 2,397 kWh | $1,112 |
| September | 6.37 m/s | 1,848 kWh | $858 |
| October | 5.94 m/s | 1,636 kWh | $759 |
| November | 6.42 m/s | 1,877 kWh | $871 |
| December | 6.33 m/s | 1,879 kWh | $872 |
What a taller tower would buy
Measured at 10 m the wind in Kalawao County averages 5.98 m/s; at 50 m it is 6.7 m/s. That gives a shear exponent of 0.071, typical of very open, smooth ground where height adds little. Going from 20 m to 50 m takes output from 21,766 to 24,874 kWh a year, 14% more, before counting the extra cost of the taller tower.
| Hub height | Average wind | Output | Payback |
|---|---|---|---|
| 20 m | 6.28 m/s | 21,766 kWh | 10 years |
| 30 m | 6.46 m/s | 23,122 kWh | 9 years |
| 40 m | 6.59 m/s | 24,103 kWh | 9 years |
| 50 m | 6.7 m/s | 24,874 kWh | 9 years |
Counties around Kalawao County
3 of the 6 closest counties are windier at turbine height; the windiest, Honolulu County, averages 6.85 m/s.
- Maui County, HI: 6.46 m/s, 23,112 kWh, payback 9 years (35 mi)
- Honolulu County, HI: 6.85 m/s, 25,964 kWh, payback 8 years (81 mi)
- Hawaii County, HI: 3.43 m/s, 4,056 kWh, payback 53 years (147 mi)
- Kauai County, HI: 6.64 m/s, 24,436 kWh, payback 9 years (184 mi)
- San Francisco County, CA: 6.53 m/s, 23,628 kWh, payback 13 years (2320 mi)
- Mendocino County, CA: 3.87 m/s, 5,942 kWh, payback 52 years (2342 mi)
Sun versus wind in Kalawao County
Kalawao County gets 5.74 kWh of sunshine per square metre a day on average. One kW of solar panels here would make roughly 1,676 kWh a year; one kW of the turbine above makes 2,311. This is one of the rare places where a kilowatt of turbine out-produces a kilowatt of panels, by 1.4 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.