[internet_points]

Two to four hours per day.

Source: https://www.energy.ca.gov/data-reports/energy-almanac/califo... under Additional Information about the Data:

> The use of the terms megawatts and kilowatts as descriptive of battery energy storage is to effectively convey the instantaneous power contribution of battery storage as comparable to the power produced by grid-level generators. We recognize that energy capacity in the context of energy storage typically refers to the total energy a battery can hold in watt-hours, kilowatt-hours, megawatt-hours, etc. However, for statewide planning and reliability purposes, understanding the peak power capability of battery energy storage systems allows for the integration of data with the nameplate capacity of traditional power generation units serving the grid. It is in this context that battery systems are able to be effectively compared for their ability to serve the grid over short periods of time, typically two to four hours per day depending upon system conditions.

[throwaway2037]

Hat tip. This is a perfect follow-up. This confirms to me: Yes, it is a major achievement. Batteries with capacity of 24-48 MW-hours is HUGE! Probably none of this infra existed 25 years ago. I wonder: What is/was the total cost (in 2026 dollars) to build this battery infra?

[ZeroGravitas]

This rollout occured in the last 10 years.

Some legislation in 2010 set small targets for 2020 and it grew rapidly from there.

[throwaway2037]

Joke follow-up: According to a few sources a standard D battery holds about 24 watt-hours of energy. Thus, a single battery can supply the energy of 12 nuclear power plants for about 2 nanoseconds. Awesome! (I hope that my math is correct here.)

[stavros]

It's not, one battery won't output 12GW no matter for how brief a period you want it. This is the achievement here, that the battery can supply that much current for a time.

[therealpygon]

Battery array, not battery. The achievement is not that it came from “a battery”, it’s that amount of power — 40% of their state power — came “from batteries” for a period of time. An array is a collection of batteries just like putting three D batteries in a flashlight forms a battery array.

The facetious remarks that the same could be said of a D battery are absolutely on the mark…for the point of being a joke about the headline…