Glenarm Battery Energy Storage System (BESS)

The Glenarm Battery Storage System (BESS) Project features construction of a 25-Megawatt, four-hour lithium-iron-phosphate system that will support electric reliability during extreme events, help restore power in the event of a complete shutdown, and store excess daytime solar generation for discharge during evening peak hours.  The project represents Pasadena’s first City-owned utility-scale BESS, which will be located adjacent to the historic Glenarm Power Plant.

Project Background and History

The City of Pasadena has owned and operated the Glenarm Power Plant since 1906. To support local power generation and ongoing investments in renewable energy, PWP continues to explore energy storage options to support capacity requirements and local reliability needs. In July 2025, the Glenarm BESS project was selected by the California Energy Commission to receive up to $9.66 million in project funding through its Distributed Electricity Backup Assets program

In February 2026, PWP conducted a public meeting to invite community input on the proposed landscaping design and visual screening elements of the project. This valuable feedback helps ensure that the community’s ideas and concerns are taken into consideration during planning.

Impact

Construction, which began in September 2026, will continue weekdays between the hours of 7:00 a.m. and 5:00 p.m.  Every effort will be made to minimize disruptions to local traffic, and nearby residences and businesses during this time.

The project is expected to be completed in the summer of 2027.