Investing in the Future

North Kohala Microgrid

Kohala Scenic View

(Updated: Jan. 20, 2023)

Hawaiian Electric is developing a microgrid project to improve reliability and resilience in North Kohala on Hawaii Island. It would be the first utility microgrid based on storage in the state of Hawaii, if approved.

North Kohala is served by a 34.5 kilovolt (kV) sub-transmission line built in the 1950s. The line spans 24 miles, from the Waimea Substation to the Hawi and Halaula Substations and extends to the Hawi Renewable Development wind farm. It is a radial line and the only line sending electricity to North Kohala.

Annual maintenance work and emergency repairs require power outages that impact about 2,000 customers in the area. Hawaiian Electric recognized the challenges these outages create for the community and since 2007 has worked closely with local stakeholders to develop a solution that meets the needs of both the North Kohala community and Hawaiian Electric. After multiple outreach and engagement events with government officials, community groups and community stakeholders, the option to rebuild the existing sub-transmission line and create a microgrid supported by a battery energy storage system (BESS) was identified as the preferred solution.

Kohala Map

The North Kohala microgrid project would allow Hawaiian Electric to better serve its customers in North Kohala while the existing sub-transmission line is rebuilt and when the line is impacted by planned or unplanned events. The microgrid project should lead to fewer outages and shorter outage durations when an outage is necessary. It is designed specifically to operate as a microgrid to provide electric service to North Kohala when power cannot be provided by the interconnected island grid.

In October 2021, Hawaiian Electric filed a draft Request for Proposals (RFP) with the Public Utilities Commission for the BESS portion of the microgrid, seeking a standalone energy storage capacity for integration with a microgrid controller system owned and operated by Hawaiian Electric. The microgrid project would be located next to the Hawaiian Electric Hawi Substation, if approved. In January 2022, the Commission opened Docket No. 2022-0012 for the North Kohala Microgrid RFP proceeding.

Pursuant to PUC Order No. 38699, Hawaiian Electric filed re-study results on December 30, 2022, recommending a change of BESS size from 5 megawatts (MW) / 22 megawatt-hours (MWh) of energy storage capacity to 5 MW / 30 MWh. A second draft RFP, with this revised sizing and an updated guaranteed commercial operations date of September 2025, among other things, was filed with the Commission on January 13, 2023.

For more information, visit our North Kohala Energy Storage RFP page. If you have questions or comments, please email renewableacquisition@hawaiianelectric.com.