Battery storage in California delivering as a daily workhorse, details IEEFA report

According to new analysis from the US-based Institute for Energy Economics and Financial Analysis (IEEFA), drawing on Energy Information Administration (EIA) data and regional grid operator statistics, battery storage deployment and utilization reached new milestones in 2024, with outcomes tied to increasing grid storage.
IEEFA’s report correlates with recent data from the Volta Foundation and Wood Mackenzie’s Energy Storage Monitor, with the nonprofit agency noting US installed capacity likely exceeded 30 GW by the end of 2024. IEEFA’s analysis of market trends indicates an additional 15 GW of storage capacity will be added by the end of 2025.

California focus
California Energy Commission and California Independent System Operator or CAISO data, both cited in the IEEFA report, shows the state reached 13.4 GW of total installed storage capacity by end-2024, with deployments mixed heavily in favors utility-scale installations at 11.4 GW, with the remainder distributed between residential and commercial applications.
Where the IEEFA report offers deeper insight is around certain key dates.
For example, CAISO data highlighted in the IEEFA analysis shows a new battery discharge record set on October 7, 2024, during a late-season heat wave. The system delivered 8,354 MW at 6:10 PM Pacific time – strategically timed with declining solar generation falling off the grid. The report notes that without that stored capacity, imports or local gas generation would have been required to meet that 8.3 GW of demand, which delivers better price and availability certainty, and overall better and greener outcomes.

The CAISO operational data also reveals key trends being seen across the globe:
- Batteries are now regularly capturing otherwise-curtailed solar generation, creating new value streams
- The technology has become integral to daily grid operations, not just emergency response
To illustrate, CAISO data from January 15 shows batteries providing 3,970 MW during the morning ramp (14.6% of demand) and sustaining over 4,000 MW for more than three hours during the evening peak, contributing at least 16% of demand during that period. This capacity would likely have come from gas-fired generation just two or three years ago.
The IEEFA report also digs into data released by the Electric Reliability Council of Texas (ERCOT) showing solar in Texas alone generates more than the total generation in 19 other US states. That has seen an ongoing boom in battery storage in the Lonestar State.