Think B.I.G. Hawaiʻi · Energy Self-Reliance (ESR) framework · Kauaʻi
How Kauaʻi’s power grid got here, where today’s plans take it, and what 95% self-reliance would take
Every power plant on Kauaʻi since 2000, sized by capacity and colored by fuel. Kauaʻi’s grid is run by KIUC, a member-owned cooperative, not Hawaiian Electric. Play the history, then the buildout of projects KIUC has under contract. 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.
Share of electricity sales by source
KIUC filings, 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 but never built, not yet built, or offline. Contours are schematic (a simple cone model of Kauaʻi’s central shield volcano), not survey data. Green dots: rooftop solar, one dot ≈ 1 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 KIUC planned, and what happened
Renewable share of Kauaʻi’s electricity: plans vs. actual
As KIUC reported it: share of sales through 2021, share of generation from 2022 (Act 240). Hollow points are interpolated years.
Each plan for Kauaʻi, in brief
2008 board goal: 50% renewable by 2023. Reached in 2019, four years early.
2017–2021, dispatchable solar: Tesla’s Kapaia plant (13 MW + 52 MWh, 2017), AES Lāwaʻi (20 MW + 100 MWh, 2019) and AES PMRF (14 MW + 70 MWh, 2021) carry renewables to a 69.5% peak in 2021.
West Kauaʻi Energy Project (PPA 2021): 35 MW of solar with 240 MWh of pumped hydro, meant to take Kauaʻi past 80% “by 2024.” Delayed by water-rights litigation; KIUC dropped the flow-through hydro part on Dec 13, 2023, and the rest is uncertain.
2023–2033 Strategic Plan (adopted Jan 17, 2023): 100% renewable by 2033, 12 years ahead of the state mandate.
Kaʻawanui and Mānā (PUC-approved Mar and Apr 2026): 43 MW + 172 MWh and 35 MW + 140 MWh of solar + storage. KIUC says Kauaʻi could approach 90% by 2030 if both are built.
KIUC is not part of Hawaiian Electric’s PSIP or IGP process; it plans through its own strategic plans and PUC-approved contracts.
2035 on current plans
Kaʻawanui and Mānā lift the grid to the high 80s by 2030. Without more projects it stays in the mid-80s, and KIUC’s 100%-by-2033 goal is missed. Cars, trucks, boats, planes and industry still run on imported fuel, so all-energy self-reliance stays near a quarter.
Simulator: what gets Kauaʻi 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: biomass, hydro and wind serve load around the clock; solar serves the daytime half of what’s left; batteries and pumped hydro (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.
2025 starting point matches KIUC’s 2025 filing: 52.8% renewable (24.5% utility solar, 14.3% rooftop, 9% hydro, 5% biomass), on an estimated 566 GWh of generation.
Key assumptions (low confidence flagged)
Total 2025 generation ≈ 566 GWh: EIA-923 utility-scale generation (485.5 GWh) divided by the non-rooftop share (low).
Base demand +0.5%/yr before electrification.
Road fuel: 29.4M gal gasoline + 2.2M gal highway diesel (DoTax 2024, Kauaʻi County). 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 349 GWh-eq (Kauaʻi’s 7.4% share of state aviation fuel applied to the ESR workbook’s interisland total) and marine 86 GWh-eq (low).
Propane ~2.8M gal (7% of ~40M gal statewide) and ~2M gal of off-road diesel outside power plants; most of Kauaʻi’s 18M gal of off-road diesel feeds KIUC’s engines (low).
Mahipapa biomass returns to ~50 GWh a year from 2026 (about 9–10% of generation, as in 2022). Hydro held at its 2025 level (9%); it was 12% in 2023.
Kaʻawanui adds 100 GWh/yr and 172 MWh from 2029; Mānā 86 GWh/yr and 140 MWh from 2030 (KIUC/AES figures).
2025 batteries: 222 MWh (Kapaia 52, Lāwaʻi 100, PMRF 70). New rooftop solar adds ~1 MWh of usable home battery per MW (low).
Electrifying industry and boats uses 0.4 units of electricity per unit of fuel replaced; electric aircraft the same.
Plant capacities for hydro are approximate; Kauaʻi has a little over 16 MW of hydro in total.
Think B.I.G. Hawaiʻi, ESR Framework workbook (draft, May 2026): sector scope and interisland aviation and marine totals.
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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