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Solar panels in Honolulu, HI

Every figure below is produced by simulating a full year — 8,760 hours — of sun angles, cloud cover, air temperature and wind for Honolulu, then running the result through a panel and inverter model. No rules of thumb.

1,542kWh per kW / year
10,792kWh from a 7 kW roof
0.768performance ratio

What a system actually produces here

Solar output in Honolulu peaks in August and bottoms out in December, a swing of about 1.4×. That seasonal shape matters more than the annual total if your utility settles exports monthly rather than annually — a big summer surplus can be worth much less than the same energy spread evenly.

MonthSun (kWh/m²/day)kWh per kW7 kW system
Jan3.9114797
Feb4.6113792
Mar5.4135944
Apr5.9131919
May6.4138966
Jun6.7135943
Jul6.7141984
Aug6.61451,017
Sep6.1140978
Oct5.1132924
Nov4.1111778
Dec3.6107750

Electricity rates that shape the payback

What a solar system saves in Honolulu depends less on how much it produces than on when it produces, and what your utility pays for the surplus. These are the HI schedules modelled by the calculator:

Hawaiian Electric — Residential R + Smart Renewable Export

The strongest evening export signal in America: 32.9¢/kWh for exports between 5 and 9pm on Oahu. Fixed charge $12.50/month. Summer Flat $0.42. Winter Flat $0.41.
Source: Hawaiian Electric Smart Renewable Energy Export, Oahu block rates

Export rule: Hawaiian Electric — time-varying export credit — about 32.9¢/kWh in the 5–9pm window, 13.5¢ midday, under Smart Renewable Export. Under net billing, exported kilowatt-hours earn far less than the retail price you pay to import them — which is why self-consumption and batteries change the maths so much. The calculator settles every hour individually rather than netting annually.

Run your own numbers

Payback depends on what you pay for the system, how much power your household uses after dark, and which incentives you qualify for — none of which a city page can know. The calculator asks for those and settles all 8,760 hours against your actual rate.

Open the payback calculator

See also: solar incentives in Hawaii — the state credit, the export rules, and what the §25D expiry changed for buyers here.

Other cities

Method

Irradiance is decomposed into beam and diffuse components and projected onto the array plane with the Perez model, with incidence-angle losses, a cell-temperature model driven by air temperature and wind, and an inverter efficiency curve including clipping. Annual yield is checked against NREL PVWatts v8 across all 18 modelled cities; RMS error is 2.70%. See the glossary for what each term means.