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Rooftop solar at Ala Moana, Honolulu. Photo: Daniel Ramirez, CC BY 2.0

Think B.I.G. Hawaiʻi · Energy Self-Reliance map · Oʻahu

How energy self-reliant is Oʻahu?

Oʻahu uses more than 70% of the electricity generated in Hawaiʻi, and about a third of it is now renewable. Count the gasoline, diesel and jet fuel too, and only about one unit of energy in eight used on the island is made here. See how we got here, where today’s plans lead, and what 95% would take.

32%of the grid’s power is renewable2025, share of generation
12%of all energy used comes from island sources2025, every fuel counted
51%renewable grid by 2035 on current plansmodel projection
20%all-energy self-reliance by 2035 on current plansmodel projection
▶ Play the map Try the 95% simulator Plans vs. reality
Where we are

Most of the power still comes from oil

Oʻahu’s grid runs on rooftop solar, utility solar-plus-battery plants such as Hoʻohana Solar (52 MW with 208 MWh of batteries, finished in 2025), and wind farms at Kahuku and Kawailoa. Together they made 32% of the power generated in 2025, by the state’s official measure. The rest still comes from oil burned at plants like Kahe in Kapolei; the island’s last coal plant closed in 2022.

And the grid is only one slice. Cars and trucks, boats, flights out of Honolulu and industry run almost entirely on imported fuel. Count every fuel, and only about 12% of the energy used on Oʻahu comes from island sources.

Renewable share of the grid32%
Island-made share of all energy12%
The Kahe oil-fired power plant beside Farrington Highway, with its tall stacks
Hawaiian Electric’s oil-fired Kahe Power Plant at Kapolei. Photo: The Eloquent Peasant, CC BY-SA 4.0
How the model works

Every fuel, in the same units

The model starts from 2025 data, including utility renewable-energy reports and state fuel-tax records for gasoline, diesel and aviation fuel. It converts every fuel to the same energy units, so electricity, transport, shipping, flights and industry can be added together.

A simple year-by-year model then adds the projects Hawaiian Electric has under contract or out to bid, including its latest round of solar-and-storage awards, plus steady rooftop growth and gradual EV adoption. On those plans the grid climbs to roughly half renewable in the 2030s and then stalls in the low 50s, while all-energy self-reliance reaches only about a fifth by 2035.

GeothermalWindHydroSolar + batteriesBiomassImported oil
Wind turbines on a green ridge above the North Shore
Kawailoa Wind Farm on the North Shore, seen from near Haleʻiwa. Photo: Treys0408, CC BY-SA 4.0
Where it could go

What 95% would take

The 95% pathway goes further: faster solar and storage, firm renewable power, electrified industry, island-made fuels for boats and planes, and EV sales climbing along an S-curve, from today’s 14% of new cars to about 63% in 2035 and 91% in 2040. Oʻahu has little open land, so the pathway also counts on the ocean: a 50 MW wave farm from 2038 and floating offshore wind in two 400 MW phases, in 2041 and 2044.

Those offshore dates are deliberately cautious: no lease area has been named, and federal waters have been closed to new wind leasing since January 2025. With ocean energy, the grid reaches the model’s 99% ceiling in 2041 instead of the early 2050s. Because cars stay on the road about 22 years, Oʻahu reaches 95% of all its energy in 2060 on this path; add trade-ins of old cars and more island-made fuel, and the simulator gets there by 2041. These are planning sketches, not utility forecasts; the assumptions and sources are listed below the simulator.

Try the simulator →
floating windwave buoy
Illustration: floating offshore wind and a wave-energy buoy, the two ocean options in Oʻahu’s 95% pathway.
2025

Share of electricity sales by source

Hawaiian Electric, 2005–2025.

2025

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Renewable share of grid
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All-energy self-reliance
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Battery storage
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Icons show the technology; the colored halo’s area = nameplate MW. Dashed halos: planned or not yet built. Contours are schematic (simple cones along the Waiʻanae and Koʻolau ranges), not survey data. Green dots: rooftop solar, one dot ≈ 12 GWh a year; grey dots: off-grid homes (estimate). Moving cars, planes and boats are colored by what powers them: green = electric, light green = island-made fuel, terracotta = imported fuel; their share of each color follows the model, not counts of real vehicles. EV shares before 2025 are approximate. Plant locations are approximate.

What Hawaiian Electric planned for Oʻahu, and what happened

Renewable share of Oʻahu’s electricity: plans vs. actual

Actual: share of sales to 2021, share of generation from 2022 (Act 240). The PSIP and statutory targets were set for all of Hawaiian Electric’s islands together, not Oʻahu alone. Hollow points are estimates.

The plans, in brief

  • Aug 2014 PSIPs (HECO, Maui Electric, HELCO): about 65–67% renewable by 2030 across the three utilities, with imported LNG as a bridge fuel. LNG was dropped; Oʻahu reached 32.3% in 2025.
  • 2016 PSIP update: 48% by 2020 and 72% by 2030 utility-wide, 100% by 2045. Utility-wide, 2020 came in at 34.5% of sales.
  • Coal exit: HECO decided in 2016 not to renew the AES coal contract. The plant closed Sept 1, 2022, before most replacement solar was online, so oil burned more for a time.
  • Stage 1–3 procurements (2018–2023): Stage 1 finished only in July 2025 (Hoʻohana). Stage 3 for Oʻahu adds Mahi Solar (120 MW, 2028) but also three new combustion plants: Puʻuloa Energy (99 MW, 2028), Waiau Repower (253 MW) and a repowered Kalaeloa (2033).
  • IGP RFP (filed July 17, 2026; PUC-approved Aug 2026): 750 GWh a year of renewables and 350 MW of grid-forming resources for Oʻahu by Nov 1, 2031, plus 81 MW of firm capacity. The PUC declined HECO’s request to add 500 MW of fuel-flexible firm generation.
  • The land problem: a fully electrified Oʻahu would need more power than NREL’s most restrictive estimate of its rooftop, ground-mount solar and onshore wind potential combined, pointing to offshore wind, more land, or an undersea cable.

2035 on current plans

Contracted solar and the IGP RFP push Oʻahu’s grid to roughly half renewable in the 2030s. Without much more, it stalls in the low 50s, and the new combustion plants keep burning oil unless biofuel is bought. Cars, trucks, boats, planes and industry still run on imported fuel, so all-energy self-reliance stays near a fifth.

Simulator: what gets Oʻahu to 95% self-reliance?

Choose what to build and when. Results update as you move the controls. Start from a preset, then adjust.

Goal
Firm renewable power and long storage
Million gallons a year, reached by the year set under boats and flights. Waiau, Kalaeloa, CIP and Schofield can burn biofuel; today they mostly burn oil.
Solar, wind and storage
NREL’s most restrictive estimate of Oʻahu’s onshore wind potential is ~230 MW; 123 MW is built.
Ocean energy

Oʻahu uses about 70% of the state’s electricity on about 6% of its land. NREL’s most restrictive estimate says its onshore solar and wind can’t cover a fully electrified island on their own, so the ocean around it matters.

No offshore wind farm is built or permitted in Hawaiʻi, and there is no federal lease. BOEM never named a lease area, and a January 2025 presidential memorandum withdrew all federal waters from new wind leasing. This model sites it south of Oʻahu, in BOEM’s 2016 Oahu South Call Area (about 7 to 35 nautical miles south of Diamond Head), where developers first proposed 400 MW floating farms. The Navy objected to wind farms there, which pushed the leading developer, Aukahi Energy, to a Kaiwi Channel site that drew strong community opposition. A south-shore farm would need a defense agreement first. Built here in 400 MW phases three years apart, at a 45% capacity factor.
Cautious default: 2041. Leasing would have to reopen, then site surveys, permits and construction typically take most of a decade.
The Navy’s Wave Energy Test Site off Kāneʻohe has fed test buoys into the grid since 2010, but no commercial wave farm runs anywhere in the U.S. yet. Modeled at a 30% capacity factor. Waves keep rolling after sunset, so wave power helps most at night.
Cars and trucks

EV share of new-vehicle sales over time: pick a curve, or shape your own.

The year sales are halfway from today’s 14% to the long-run share. Sales follow an S-curve: slow, then fast, then leveling off.

Not part of the Hawaii EV Association calculator, and off in every preset except “All levers”. It would take a trade-in (cash-for-clunkers) program: 1% of all cars a year is about 11,000 extra cars statewide.
Buildings and industry
Boats and interisland flights
Million gallons a year made on-island.
All-energy self-reliance in goal year
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Self-reliance over time

All energy used on the island, by where it comes from (GWh-equivalent)

What this scenario asks the island to build

ItemThis scenarioReality check
How this works, assumptions, and sources

Method

All-energy self-reliance = island renewable electricity actually used, plus off-grid solar and fuels made on-island, divided by all energy used on the island: grid electricity, road gasoline and diesel, marine fuel, interisland jet fuel, gas/propane and off-road diesel. Energy-content basis, as in the ESR framework. Transpacific flights and shipping, and the refinery’s own fuel use, are out of scope.

Grid dispatch is annual, with a simple day/night split: waste-to-energy, wind (onshore and offshore), wave energy and any new firm plant serve load around the clock; solar serves the daytime half of what’s left; batteries (one cycle a day, 88% round trip) move surplus solar into the night; biofuel and then oil fill the rest. Surplus solar is curtailed unless e-fuels are switched on (50% conversion). A planning sketch, not a reliability study. Backup floor: each grid tops out at 99% renewable. We assume fuel-fired backup plants still supply at least 1% of each year’s electricity (storms, outages, maintenance, long windless or cloudy spells), and that every island keeps some backup for caution and diversity.

2025 starting point matches Hawaiian Electric’s 2025 RPS report for Oʻahu: 32.3% of 7,846 GWh (rooftop ~16.6%, utility solar ~8.5%, waste/biofuel ~4.2%, wind ~3.1%).

Key assumptions (low confidence flagged)

  • Base demand +0.5%/yr before electrification; data centers or other new industry can be added in the simulator.
  • Road fuel: 249.8M gal gasoline + 23.1M gal highway diesel (DoTax CY2024, City & County of Honolulu). 3.6% of cars electric at the end of 2025 (DBEDT: 42,919 of 1,082,932 passenger vehicles by Sept 2026). Fleet turnover, using the same method as the Hawaii EV Association site calculator: about 50,000 new vehicles join each year and stay ~22 years; today’s EVs leave the road at ~6% a year; the EV share of new sales (13.8% in 2025, HADA) drives the fleet. Even 100% EV sales from 2027 leaves 10% of cars on gas until about 2046. Trucks and buses are assumed to lag cars by five years. “Current plans” holds EV sales at today’s ~14%; the ESR pathway’s EV sales follow the “Steady” S-curve (about 26% of new cars in 2030, 63% in 2035, 91% in 2040), with no early retirement. Island-made fuels go to boats and planes; a switch extends them to the remaining gas and diesel vehicles.
  • Interisland jet fuel 2,528 GWh-eq (Oʻahu’s 53% share of state aviation fuel applied to the ESR workbook’s interisland total) and marine 396 GWh-eq (55% of the state estimate) (low).
  • Utility gas and propane ~26M gal propane-equivalent and ~12M gal off-road diesel outside power plants (low).
  • Contracted projects at 25% solar capacity factor; the IGP RFP adds 750 GWh/yr and ~1,400 MWh (350 MW × 4 h, assumed) from 2031.
  • Waiau Repower, Kalaeloa repower and Puʻuloa Energy count as fossil unless the biofuel slider supplies fuel.
  • 2024 generation-basis share (31%) is estimated; HECO did not publish it for Oʻahu.
  • Plant locations in Campbell Industrial Park are spread apart slightly so each icon can be seen.

Sources

  1. Hawaiian Electric, historical RPS data by island 2005–2024 (“historical_03_RPS”), sales basis.
  2. Hawaiian Electric 2025 RPS Status Report (PUC Docket 2007-0008); 2022–2023 generation-basis figures from HECO RPS releases.
  3. Hawaiian Electric Power Facts (Oʻahu plant capacities, Feb 2025).
  4. Renewable Project Status Board (Dec 2025) and Stage 1 completion release (July 22, 2025).
  5. IGP RFP release (July 17, 2026); Hawaiʻi Tribune-Herald on PUC approval (island targets; 500 MW firm request declined).
  6. HECO, Grid-forming resources on HECO grids (ESIG 2026): Kapolei Energy Storage, Kūpono.
  7. Star-Advertiser on the AES coal plant closure (Sept 1, 2022).
  8. Utility Dive on the 2014 PSIPs; the 2016 PSIP update (48% by 2020, 72% by 2030).
  9. Hawaiʻi Department of Taxation, Liquid Fuel Tax Base, CY2024.
  10. NREL (2021), Assessment of Wind and Photovoltaic Technical Potential for the Hawaiian Electric Company; Think B.I.G. ESR Framework workbook (sector scope).

Export your results

Save the year-by-year numbers for current plans and the scenario now set in the simulator, as a spreadsheet or a short PDF report. The map picture shows the year currently selected on the map’s slider.