Hawaiian Electric’s Waena Battery Energy Storage System project has reached a construction milestone with the arrival and installation of the first six Tesla Megapacks at the project site along Pulehu Road in Central Maui.

The project will be Maui’s first standalone load-shifting battery energy storage system. The 40-megawatt (MW), 160-megawatt-hour (MWh) system will consist of 54 battery units and is expected to help shift renewable energy to periods when electricity demand is higher.

The first six batteries were delivered by semi-truck and lifted into place by crane in late August. Each unit is roughly the size of a 40-foot shipping container.

The project was approved by the Public Utilities Commission in 2023 and is the first battery storage project being developed by Hawaiian Electric. The project is part of the company’s plans to reduce carbon emissions and use renewable resources to generate 100% of electricity by 2045.

About 41% of Maui County’s electricity currently comes from renewable resources, including more than 18,000 customer solar systems. The Waena system also will incorporate grid-forming technology, which can help maintain grid stability as the island uses more variable energy resources, including wind and solar.

Battery storage can store excess electricity and return it to the grid when it is needed. The system will shift energy from resources such as solar and wind, which can be more 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 are expected to arrive in phases over the coming months as construction continues. The project is expected to enter service in 2027.