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HI — Power Infrastructure Updated January 2026

Hawaii

HECO Solar Wind Geothermal Storage Queue Bottlenecks

Overview

Hawaii’s power buildout centers on biofuel-ready combustion turbines, utility-scale solar paired with multi-hour battery storage, and a handful of geothermal and wind projects. The state’s utility, Hawaiian Electric (HECO), is retiring coal capacity and replacing it with renewable-plus-storage projects procured through competitive solicitations. For large new loads like data centers, the small interconnection queue and limited transmission corridors on Oahu mean power will come from utility-led generation upgrades, not speculative queue projects.

Generation Projects

Solar

Four large solar-plus-storage projects are in negotiation or recently approved on Oahu, Maui, and Hawaii Island.

  • Mahi Solar and Storage (Oahu): 120 MW solar paired with battery storage, estimated completion 2028.[1]
  • Keamuku Solar (Hawaii Island): 86 MW solar paired with battery storage, estimated completion 2030.[1]
  • Kuihelani Phase 2 (Maui): 40 MW solar paired with battery storage, estimated completion 2028.[1]
  • Waiawa Phase 2 Solar (Oahu): 30 MW PV with 240 MWh battery storage, approved by regulators, estimated completion 2026.[1]

Four solar-plus-storage projects entered service in 2024-2025: Hoohana (52 MW/208 MWh), Kupono (42 MW/168 MWh), AES Kuihelani (60 MW/240 MWh), and Hale Kuawehi (30 MW/120 MWh).[1]

Dispatchable Thermal

Hawaii is building biofuel-capable combustion turbines to replace retired coal capacity and provide firm power when solar and wind are offline.

  • Waiau Repower (Oahu): 253 MW combustion turbine designed to run on biofuel, in negotiation, estimated completion 2033.[1]
  • Kalaeloa Partners (Oahu): 208 MW combustion turbine (biofuel), in negotiation, estimated completion 2033.[1]
  • Puuloa Energy (Oahu): 99 MW internal combustion (biofuel), in negotiation, estimated completion 2027.[1]
  • Ukiu Energy (Maui): 40 MW internal combustion (biofuel), in negotiation, estimated completion 2027.[1]
  • Hamakua Firm Renewable Energy (Hawaii Island): 60 MW combined cycle plus battery storage, in negotiation, estimated completion 2030.[1]

Geothermal

  • Puna Geothermal Venture (Hawaii Island): 46 MW, approved by regulators, estimated completion 2026.[1]

Wind

  • Kaheawa Wind 1 (Maui): 30 MW wind project in negotiation, estimated completion 2026.[1]

Transmission and Grid

HECO operates two primary transmission corridors on Oahu (north and south), with redundancy provided by sub-transmission systems. Three active upgrade projects address load growth and line relocations.

  • AES-CEIP 1 138 kV relocation (Oahu): HECO will relocate about 5,940 circuit feet of 138 kV transmission line and 4,100 circuit feet of 46 kV sub-transmission line, with new poles and conductor work between AES and CEIP substations.[2]
  • Waimomi Substation Project (Oahu): New Waimomi substation and 46 kV sub-transmission extensions at Joint Base Pearl Harbor-Hickam to serve new Dry Dock 5 load.[3]
  • Farrington Highway Widening (Oahu): Relocation of 46 kV overhead and underground sub-transmission lines and installation of a new 138 kV pole along Farrington Highway.[4]

Battery Storage

Hawaii has deployed large standalone battery storage and continues to pair batteries with solar projects.

  • Kapolei Energy Storage (Oahu): 185 MW / 565 MWh battery storage came online in 2023, replacing capacity from the retired coal plant.[6]
  • Waena BESS (Maui): 40 MW / 160 MWh battery project approved by regulators, estimated completion 2027.[1]

All recent solar projects include multi-hour battery storage, providing dispatchable capacity that can support steady loads like data centers.[1]

Interconnection Queue

HECO’s Integrated Interconnection Queue (IIQ) covers distribution-level interconnections, from rooftop solar to utility-scale projects, and is updated monthly.[7]

The Oahu queue has 10,527 entries totaling about 228 MW, with only 41 entries above 1 MW (about 113.5 MW). Maui shows 2,491 entries totaling about 24.8 MW (two entries above 1 MW), while Hawaii Island shows 1,646 entries totaling about 36.2 MW (two entries above 1 MW).[8]

Many projects are stuck in PI (pending installation) or CAR (customer action required) status, slowing queue turnover.[7] With small total queued capacity and few large projects, new large loads on Oahu will depend on utility-led generation and transmission upgrades, not speculative interconnection projects.

What to Watch

  • Final contracts and in-service dates for the Waiau Repower and Kalaeloa Partners biofuel turbines, which will provide critical firm capacity on Oahu.
  • PUC approvals for the Mahi Solar and Keamuku Solar projects, the largest solar-plus-storage additions in negotiation.
  • Any Hawaii-based data center or hyperscaler PPAs emerging from HECO’s Stage 3 procurement process.

Sources

[1] Hawaiian Electric. “Renewable Project Status Board.” (n.d.). https://www.hawaiianelectric.com/clean-energy-hawaii/our-clean-energy-portfolio/renewable-project-status-board. Accessed January 8, 2026.

[2] Hawaiian Electric. “AES-CEIP 1 138 kV Overhead Transmission Line Relocation.” (n.d.). https://www.hawaiianelectric.com/about-us/our-vision-and-commitment/investing-in-the-future/aes-ceip-1-138-kv-overhead-transmission-line-relocation. Accessed January 8, 2026.

[3] Hawaii Public Utilities Commission. “Notice of Public Hearing - Sub-transmission line construction at Joint Base Pearl Harbor-Hickam, Docket No. 2023-0335 (Application of HECO to Commit Excess Funds for Waimomi Substation Project).” March 14, 2024. https://puc.hawaii.gov/public-notice/notice-of-public-hearing-sub-transmission-line-construction-at-joint-base-pearl-harbor-hickam-docket-no-2023-0335-application-of-heco-to-commit-excess-funds-for-waimomi-substation-projec/. Accessed January 8, 2026.

[4] State of Hawaii Department of Commerce and Consumer Affairs, Division of Consumer Advocacy. “Notice of Public Hearing: Hawaiian Electric’s Farrington Highway Widening Project.” May 8, 2024. https://cca.hawaii.gov/dca/publichearing-farrington/. Accessed January 8, 2026.

[5] Hawaiian Electric. “Power Delivery.” (n.d.). https://www.hawaiianelectric.com/about-us/power-facts/power-delivery. Accessed January 8, 2026.

[6] Hawaiian Electric. 2023-2024 West Oahu Report. 2024. https://www.hawaiianelectric.com/documents/about_us/our_vision_and_commitment/2024_west_oahu_report.pdf. Accessed January 8, 2026.

[7] Hawaii AHE. “Hawaiian Electric Companies Launch Online Integrated Interconnection Queues.” January 31, 2015. https://hawaiiahe.com/hawaiian-electric-companies-launch-online-integrated-interconnection-queues/. Accessed January 8, 2026.

[8] Hawaiian Electric Companies. “Integrated Interconnection Queue” data files (HawaiianElectricData.json, MauiElectricData.json, HawaiiElectricLightData.json). (n.d.). https://iiqheco.blob.core.windows.net/production/. Accessed January 8, 2026.