Originally published February 4, 2015. Updated July 9, 2026.
Nearly half of Oahu’s single-family homes have solar panels on the roof. Hawaiian Electric counted 118,841 small-scale solar systems connected across its five islands as of September 2025, up from roughly 40,000 rooftop systems in 2014. Renewables supplied 37% of the power Hawaiian Electric delivered in 2025. Getting there took a rockier path than that growth curve suggests. Hawaii shut down the program that started the rooftop rush, then rebuilt the incentives twice.
How much of Hawaii’s power comes from solar right now
Renewables made up 37% of the electricity Hawaiian Electric supplied in 2025, up from 36% the year before. Solar specifically is harder to pin to one number. SEIA puts solar’s share of Hawaii’s generation at 23.67% in a recent update, while a Wikipedia summary of EIA data puts it at 19.5% for 2024. Those two trackers use different methods and different years, so they aren’t the same line on a chart, but both describe a state where solar carries more of the daily load than in most of the country. That’s a long way from 2007, when solar supplied 0.07% of Hawaii’s electricity. Installed solar capacity has grown too, from 1,808 megawatts in 2023 to 2,313 megawatts in SEIA’s latest count, though those two figures come from different trackers and different years as well. Nearly half of Oahu’s single-family homes carry part of that capacity on their own roofs, among the 118,841 solar systems Hawaiian Electric had connected across the islands by the end of September 2025. This is a small grid to be running those numbers on. Hawaii’s utilities generated a combined 9,160,979 megawatt-hours of electricity in 2024, all of it split across five separate island systems rather than one connected network.
A slow start with Hawaii’s first solar incentive
Hawaii’s push into solar didn’t start with homeowners rushing to install panels. In 2011, Clean Energy Experts analyst Reginald Norris described a new statewide feed-in tariff that paid solar system owners a fixed rate for every kilowatt-hour they produced: $0.218 for smaller residential systems and $0.189 for larger ones, spread across an 80-megawatt allocation split among the state’s three utilities. Uptake was slow. Only about 2.6 megawatts of applications came in during the program’s first months, a small fraction of the 80 megawatts on offer, and the World Future Council graded it a D. Energy analyst Geoffrey Styles argued at the time that feed-in tariffs like Hawaii’s were regressive, shifting costs onto ratepayers who didn’t own solar. Hawaii’s Public Utilities Commission chose to keep the program running and adjust it rather than shut it down.
What happened when solar hit the grid’s limits
By 2014, more than 40,000 rooftop solar systems were connected in Hawaii, covering more than 10% of Hawaiian Electric’s customers. The pace didn’t slow after that. Hawaiian Electric added 73 megawatts of new distributed energy, mostly rooftop solar, in 2025 alone, pushing the statewide count to 118,841 systems and the share of Oahu single-family homes with solar to roughly 49%. That growth didn’t pause when the rules around exporting solar power changed, either. Rooftop installations kept climbing straight through the net-metering shutdown in 2015 and the tariff overhauls that followed it, right up through Hawaiian Electric’s own count of connected systems today.
All that rooftop solar created a grid problem few utilities had faced before. In a 2014 analysis for Greentech Media, cross-posted on POWER magazine, journalist Jeff St. John described how the state’s grid, split across five separate island systems instead of one continental network, produced a sharper version of the duck curve that utility planners were starting to track on the mainland, as midday rooftop generation flooded the system. St. John called the exaggerated version the Nessie curve. Wikipedia’s own entry on the duck curve still credits Hawaii as the reason for the name, noting that “…significant adoption of solar generation has led to the more pronounced curve known as the Nessie curve.”
The end of net metering and what replaced it
Hawaiian Electric stopped signing up new customers for net metering in October 2015. Under that program, homeowners had been credited at the full retail rate, about $0.27 per kilowatt-hour, for solar power they sent back to the grid. Its replacement, Customer Grid Supply, paid new solar customers up to $0.15 per kilowatt-hour for exported power. Two years later, Hawaiian Electric rolled out a second round of tariffs. Smart Export, built for systems paired with a battery, paid nothing for power sent to the grid between 9 a.m. and 4 p.m. and about $0.15 per kilowatt-hour the rest of the day, capped at 25 megawatts statewide. Customer Grid Supply Plus, for systems without storage, paid roughly $0.101 per kilowatt-hour on Oahu, capped at 35 megawatts.
Batteries become the new export strategy
Rooftop adoption kept climbing even after full-rate net metering ended, and the industry adapted by pairing batteries with new systems rather than exporting to the grid at a discount. In Honolulu County, 92.4% of new residential solar permits included a battery in 2025, up from 26.8% in 2017 and 62.7% the year after that. Hawaiian Electric encouraged that move toward paired batteries with Battery Bonus, a program that paid solar customers $850 per kilowatt of battery capacity up front, plus $5 per kilowatt every month for 10 years, in exchange for letting the utility draw on the battery during evening peaks. The program closed to new applicants on July 1, 2024. For homeowners, a battery bank now does the job net metering used to do. It stores the power a rooftop system makes at midday so the house can run on it after sundown, instead of sending it to the grid for a lower rate.
Retiring coal and reaching for 100% by 2045
Hawaii shut down its last coal plant, AES Barbers Point on Oahu, in 2022. The plant had supplied up to 20% of Oahu’s electricity before it closed. Hawaii is now working toward a legally required target of 100% renewable electricity by 2045, a law signed in June 2015. The law set an early checkpoint of 30% renewable by 2020, and the next one due is 40% by 2030. A later checkpoint calls for 70% by 2040, ahead of the full 100% deadline five years after that.
None of this comes cheap. Hawaii’s average electricity price was 38.00 cents per kilowatt-hour in 2024, the highest of any US state, and the average household paid $213 a month for power, compared with a national average of $144. Anyone wondering how that compares with other places can check how US electricity prices stack up against other countries.
What would change the answer next
The 37% figure for 2025 came with a warning attached. Hawaiian Electric’s own announcement paired that renewable gain with a spike in electricity demand, and the next few years will show whether rooftop solar and batteries keep growing faster than the islands’ appetite for power. Battery attachment on new Honolulu rooftop permits already runs at 92.4%, up from 26.8% in 2017, and that share is one more number worth watching alongside the demand spike. Hawaii’s next legal checkpoint, 40% renewable by 2030, is only four years off.
