daily · Grid & Storage

Pasadena starts 25 MW four-hour battery project, with completion expected in 2027

The October 8 city release marks a construction milestone, not an operating battery. Up to $9.66 million in state support is separate from household bill savings.

By Greener Numbers Editorial Team · Published October 10, 2026 · Updated 10/10/2026

Pasadena marked construction of its Glenarm Battery Energy Storage System with an October 7 kickoff event, described in an October 8 city release. Pasadena Water and Power says construction began in September. The development is a construction milestone, not evidence that the battery is already delivering electricity to customers.

The utility describes a 25-megawatt, four-hour lithium iron phosphate system beside the historic Glenarm Power Plant. Megawatts describe power output, while the four-hour figure describes the stated duration. Neither number should be presented as a count of homes guaranteed continuous backup through an outage.

Pasadena Water and Power says the battery will store excess daytime solar generation for use during evening peak hours. The utility also describes reliability support during extreme events and help restoring power after a complete shutdown. These are intended uses, not published measurements of performance from an operating system.

The city says the project has support for up to $9.66 million from the California Energy Commission's Distributed Electricity Backup Assets program. The phrase "up to" matters: the release describes a funding ceiling, not a statement that the entire amount has already been paid. It does not establish a rebate owed to individual electricity customers.

The city release says completion is planned by mid-2027; the utility project page says summer 2027. Those are expected project dates, not confirmation that commercial operation has started. The utility says construction takes place on weekdays from 7 a.m. to 5 p.m. and that it will try to reduce disruption to nearby traffic and properties.

Limits: the cited city and utility pages do not quantify household bill savings, provide a completed independent battery-performance test or guarantee outage-free electricity. Pasadena's carbon-free electricity goal is separate from a single project reaching construction. The useful confirmed step is local storage development with a stated power rating, duration and expected completion window.

Official source: cityofpasadena.net ↗