Waena battery storage project hits key milestone, will strengthen Maui grid and support renewables

Hawaiian Electric’s Waena Battery Energy Storage System project reached a major construction milestone with the arrival and installation of the project’s first six Tesla Megapacks at the project site along Pūlehu Road in Central Maui. The project will be the island’s first standalone load-shifting battery energy storage system that will enable more renewable energy to be used during periods of peak energy demand.

The batteries were delivered by semi-truck and carefully lifted into place by crane in late August. Roughly the size of a 40-foot shipping container, they are the first of 54 units that will make up the 40-megawatt (MW), 160-megawatt-hour (MWh) battery energy storage system, one of the largest in Hawai‘i.

Approved by the Public Utilities Commission in 2023, the project is the first battery storage project to be developed by Hawaiian Electric and part of the company’s plans to reduce carbon emissions and to use renewable resources to generate 100% of electricity by 2045. Currently, about 41% of Maui County’s electricity comes from renewables, including more than 18,000 customer solar systems. The system will also incorporate grid-forming technology, which can help maintain grid stability as the island uses more variable energy resources, including wind and solar.

As Maui continues its transition to clean energy, battery storage is becoming increasingly important. Once in service, the system will store excess energy and deliver it back to the grid when it is needed most. The battery doesn’t generate electricity but stores it, shifting energy from resources such as solar and wind, which are often abundant during daylight hours, to better align with customer demand at night.

“This project has been years in the making, and seeing the batteries arrive on site brings us one step closer to providing Maui with a more renewable electric grid,” said Shelley Takasato, manager of Generation Project Development for Hawaiian Electric.

The remaining battery units will arrive in phases over the coming months as construction continues. The project is expected to enter service in 2027.

The arrival of the first battery units marks an important step toward a more renewable energy future for Maui.