Think B.I.G. Hawaiʻi · Energy Self-Reliance (ESR) framework · Big Island
How the Big Island’s power grid got here, where today’s plans take it, and what 95% self-reliance would take
Every power plant on Big Island since 2000, sized by capacity and colored by fuel. Play the history, then the buildout of projects already approved or out to bid. Below the map, a simulator lets you choose what to build and how fast, to see when the island could get 95% of all its energy — electricity, cars and trucks, boats, interisland flights and industry — from island sources.
Renewable share of electricity, by source
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 but never built, not yet built, or offline. Contours are schematic (a simple cone model of the five volcanoes), not survey data. Green dots: rooftop solar, one dot ≈ 3 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 the utility’s plans said, and what happened
Renewable share of Big Island electricity sales: plans vs. actual
PSIP-era targets were stated on the old sales basis, so actuals are shown on that basis too. The official RPS has used a generation basis since 2022 (Act 240); the hollow point shows 2025 on that basis.
Each plan for the Big Island, in brief
Aug 2014 PSIP (HELCO): renewables from 60% of sales in 2015 to 92% in 2030. Add 20 MW of wind (2020), 25 MW of geothermal in West Hawaiʻi (2025), Hu Honua biomass (2015) and batteries; deactivate all oil-fired steam units. None of the new wind, geothermal or biomass was built.
Apr 2016 PSIP Update: Big Island “could achieve a 100% RPS by 2040”; 20 MW of firm renewable capacity in 2022; Puna steam unit deactivated.
Dec 2016 PSIP Update: statewide 100% by 2040. Big Island 2017–21 additions: 30.3 MW rooftop, 5.7 MW feed-in-tariff solar, 10.6 MW demand response, 1 MW grid-scale solar, 22 MW wind.
Stage 3 RFP (2023–25 awards): Keʻāmuku Solar 86 MW / 344 MWh (2030) and Hāmākua Firm Renewable Energy 60 MW + batteries.
IGP RFP (filed July 17, 2026; PUC-approved Aug 2026): for Big Island, 435 GWh/yr of renewable energy, up to 115 MW of grid-forming resources, 30 MW of firm capacity and 20 MW for 6 hours in East Hawaiʻi, in service 2031–2034. The RFP notes new firm capacity could let older oil units retire sooner.
2035 on current plans
Approved and solicited projects push the grid past 90% renewable by the early 2030s. Cars, trucks, boats, planes and industry still run on imported fuel, so all-energy self-reliance stays near a quarter.
Simulator: what gets the Big Island to 95% self-reliance?
Choose what to build and when. Results update as you move the controls. Start from a preset, then adjust.
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
Item
This scenario
Reality 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, propane and off-road diesel. Energy-content basis, as in the ESR framework. Transpacific flights and shipping are out of scope.
Grid dispatch is annual, with a simple day/night split: geothermal, hydro and wind 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 plants fill the rest. Surplus solar is curtailed unless e-fuels are switched on (50% conversion). This is a planning sketch, not a reliability study.
Road fuel: 80.4M gal gasoline + 12.2M gal highway diesel (DoTax 2024). EVs use 7.3 kWh per gallon of gasoline replaced and 12 kWh per gallon of diesel. 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 708 GWh-eq and marine 108 GWh-eq in 2025, from the ESR workbook’s statewide figures and Big Island shares (low).
Propane ~8M gal (20% of ~40M gal statewide) and off-road diesel ~9M gal outside power plants (low).
Off-grid homes ≈ 17.5 GWh/yr of solar, growing 3%/yr. There is no official count (low).
PGV returns to 2024 output in 2026 and reaches 46 MW at 90% capacity factor in 2027 (timing).
Hāmākua firm plant (2029) burns today’s amount of biofuel unless you add more. The IGP’s 30 MW of firm capacity adds reliability, not renewable energy, unless it burns biofuel.
IGP RFP energy (435 GWh/yr) is modeled as solar + storage ramping in 2032–33, with 460 MWh of batteries. Part of it is meant to replace expiring contracts; to test that, tick “Existing wind farms shut down”.
New rooftop solar comes with about 1 MWh of usable home battery per MW (low). Capacity factors: rooftop 20%, utility solar 24–25%, wind 38%, geothermal 90%.
Electrifying industry and boats uses 0.4 units of electricity per unit of fuel replaced; electric aircraft the same.
Think B.I.G. Hawaiʻi, Big Island ESR Framework workbook (draft, May 2026): sector scope, aviation and marine inputs.
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.
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