The state Public Utilities Commission has approved a microgrid services tariff, offering Hawaiian Electric more ways to power its grid during an emergency.

A microgrid, Hawaii Electric said, can “generate, distribute, and regulate the supply of electricity to customers, but locally and on a smaller scale.”

The U.S. Department of Energy defines a microgrid as “a group of interconnected loads and distributed energy resources within clearly defined electrical boundaries that act as a single controllable entity with respect to the grid, and that can connect and disconnect from the grid to enable it to operate in both grid-connected and ‘island’ mode.”

The approval was part of a two-year process following the state Legislature’s passage of a bill in 2018 that became Act 200, which directed the development of microgrids in Hawaii.

“The commission’s approval of the first stage of a microgrid services tariff underscores the importance of these technically advanced systems,” said Ken Aramaki, Hawaiian Electric director of transmission, distribution and interconnection planning, in a news release. “They’ll provide more choices for customers and help Hawaii reach 100% renewable energy by 2045 with a grid that provides reliability and resilience for all.”

The new tariff defines two types of microgrids: a customer microgrid where the customer’s infrastructure (solar rooftop system and battery, for example) is exclusively used to supply their own electricity needs during emergencies, and a hybrid microgrid in which infrastructure from the utility and customer are combined to supply electricity during an emergency.

Hawaiian Electric said it will help identify areas on Oahu suited for developing microgrids, including areas prone to prolonged outages during weather events that have clusters of customers and the potential availability of renewable energy resources.

Hawaii is the second state after California to implement a formal microgrid services tariff, according to Microgrid Knowledge, and could serve as a model for other states to follow.

Following this approval, the PUC is now evaluating how microgrids can provide services in nonemergency situations, as well as how customers providing power to the grid would be compensated.