[throwaway2037]

    > For the first time, California discharged just over 12,000 megawatts, equivalent to 12 large nuclear plants, of energy from its battery arrays. That’s enough to meet over 40 percent of the state’s energy demand. 

For how long? 100 millis, 1 minutes, 1 hour, 1 day? There is a HUGE difference. This stuff reads like PR.

[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…

[tristanj]

I agree, this article is horrifically misleading.

An array of batteries discharging 12,000 megawatts for ... 5 minutes? 1 hour? 1 day? is not comparable to a nuclear power plant generating 1,000 megawatts continuously 24/7 for months without refueling.

Also batteries are storage. They do not generate electricity. They store excess energy produced elsewhere, by actual electrical generation facilities, then release it later. You can't compare batteries to actual power plants.

[rainsford]

> You can't compare batteries to actual power plants.

Sure you can. It makes as much sense as comparing EVs to gasoline powered cars. Which is to say that it's perfectly fine if the question you're trying to answer is whether one can replace the other, which is in fact the question here. As long as the lights come on when it's dark out and your car goes when you hit the accelerator, does it really matter to you as a user whether the power to do those things was created right that second or created hours ago and stored until you needed it? An EV doesn't produce its own energy either, but that's irrelevant to the question of whether it can replace your gas powered car and that's why people directly compare them.

[tristanj]

Batteries can never replace actual electrical generation, which is what the article is misleadingly implying.

Your ICE/EV analogy is flawed and doesn't work here. Neither EVs nor ICE vehicles produce energy. Both release stored energy, produced at an earlier point in time. ICE vehicles release energy stored by photosynthesis millions of years prior. You imply ICE vehicles are classified differently than EVs because they create energy in the moment, which is untrue.

[spiderfarmer]

> The batteries are [used] during the peak period, which is in the evening, typically around seven o’clock, producing as much as 40 percent of the peak capacity requirements.

In most countries the peak period is a 4-5 hour window.

[rented_mule]

Yep. PG&E is the electric company for most of Northern California. Their "time of use" plans typically specify 4 PM to 9 PM as the peak period.

[lr1970]

> > For the first time, California discharged just over 12,000 megawatts, equivalent to 12 large nuclear plants, of energy from its battery arrays.

Clueless journalist conflates power (megawatts) with energy. They need physics 101. For electrical energy common unit is megawattHour (megawatt drawn for entire hour). A smaller unit would be megaJoule (megawatt drawn for 1 second).

[CalRobert]

Seriously, watts aren’t energy.

That’s like saying “my gas tank can hold 500 horsepower”