California's Battery Array Is as Powerful as 12 Nuclear Power Plants
zolairenergy.com44 points by zingerlio 19 hours ago
44 points by zingerlio 19 hours ago
> 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.
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.
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?
This rollout occured in the last 10 years.
Some legislation in 2010 set small targets for 2020 and it grew rapidly from there.
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.)
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.
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…
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.
> 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.
> > 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).
Seriously, watts aren’t energy.
That’s like saying “my gas tank can hold 500 horsepower”
> 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.
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.
A graph is easier.
Here's California: https://www.gridstatus.io/live/caiso?date=2026-05-15
Here's Texas: https://www.gridstatus.io/live/ercot?date=2026-05-15
This series of graphs shows grid batteries quickly displacing peaker gas plants in Queensland over 24 months / two years.
This isn't the most advanced grid in the country, but it's just good business to displace the most expensive and dirtiest gas plants even if you still use gas for other tasks on the grid.
https://reneweconomy.com.au/wp-content/uploads/2026/05/open-...
The only problem with that is that coal plants are increasingly priced out at midday and no alternative exists for overnight.
Coal plants were mostly displaced by natural gas, but several states still rely on them for base load.
https://www.eia.gov/todayinenergy/detail.php?id=54919
Independently of its horrendous impact on the environment, more people die from coal mining accidents every year than in the entire history of nuclear power (yes, including Chernobyl).
Not to mention that the waste product from coal-burning power is radioactive. https://www.osti.gov/etdeweb/servlets/purl/21557305
I feel like batteries, while they won’t work for weeks, exist overnight as well.
The most interesting insight from this chart is that Texas actually produces more solar electricity than California.
But much less in terms of proportion of total energy usage. It's jarring how much less energy efficient TX is than CA. Over 2x the energy usage despite having a substantially smaller population.
> California's Battery Array Is as Powerful as 12 Nuclear Power Plants
From this graph we see that in the evening when solar power goes out, for next 3 hours (7 pm to 10 pm) California's battery array is as powerful as 12 nuclear reactors. Then the batteries are drained empty, and the rest of the night California survives by importing electricity from other states. And partially by running hydro power only during the nights, keeping it at zero during the day.
The net storage graph clearly shows they aren't drained empty after 3 hours. They keep their remaining charge for the more expensive morning peak rather than compete with cheap imports overnight (there's a graph showing the cost over the time range too).
Good point, and good financial strategy. But the morning discharge seems to be about 5%–7% of the evening discharge, so I assume the batteries near empty.
It is a direct correlation with the electricity price. As the evening peak is saturated the morning peak will follow. Followed by the night.
Why are green articles always written so poorly? 12 GW of power is great however.
Most nuclear reactors are about a gigawatt, but most nuclear power plants have multiple reactors. 3-6 GW per plant is perhaps a more likely measure.
California's demand commonly goes from 18GW to 30GW in the same day.
Lets take your smallest "Nuclear plant" idea, if California owns 6 of those they run all the time but it needs 12GW extra at peak, where does that come from? If California owns 10 of those they run intermittently, you're still paying to have ten but not getting almost twice the benefit so your prices soar.
So the way you'd presumably fix it would be to... build loads of storage and own say 9 of these 3GW nuclear plants, drawing from batteries at peak then refilling them overnight. But wait, that's already what California did that you're unhappy about - so what gives?
Then we notice that in reality although you think "most nuclear power plants" would produce 3-6GW in fact California doesn't own ten, or eight, or six, but one such plant and it produces... drum roll... 2.2GW nameplate.
> California's demand commonly goes from 18GW to 30GW in the same day.
That extreme intra-day variation is also partially caused by California's cheap solar power: Cheaper prices draw demand to those hours.
In other locations, (some) people (partially) adjust their consumption patters to follow the cheap wind energy hours, and this leads to different consumption patters. Less intra-day variation but but inter-day variation.
If California's prices were wind-dominated (typically a little more wind at nightime), or nuclear or burning dominated (stable), it would not cause such large variation in the intra-day consumption pattern.
This electricity price figure is readable, but 10 years old, so today the variation in California must be larger than it shows:
Weird units.
Batteries are normally talked about in terms of energy storage, not power.
IE: Batteries overall have 0 power. Everything they make had to come from somewhere else. Actually, because of losses in the 20%ish range, it's probably more accurate to say that California's Battery Array is __COSTING__ 2 nuclear power plants worth of power in electrical waste.
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Talk about GW-hrs of storage. You know, the value people actually cares about?
In practice, it can be very relevant. With my own household solar/battery system, I am sometimes frustrated more by limits on how much current I can draw, not by capacity. I could add more batteries, but it seems that the inverter is the limiting factor. And 12MW of inverter is impressive, no?
No?
Natural Gas would crush these numbers at far less $$ invested.
All of this crap is apples vs bananas. It's all fake made up metrics
Strangely enough: natural gas is probably the better comparison because at least natural gas is a peaker / grid stabilization technology.
Batteries are energy storage while nuclear I base load. It's the most nonsensical comparison I can possibly think of.
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Energy storage should be compared vs energy storage. How is a battery vs compressed air? How is Li-ion vs Lead Acid? How is Pumped Hydro vs Li Ion?
Batteries must always be talked about while mentioning both the stored energy and the maximum power.
These 2 battery parameters depend on different constructive details of the batteries. The stored energy depends on the volume of the electrodes (or of electrolyte in flow batteries), while the maximum power depends on the area of the electrodes.
All combinations are possible, e.g. batteries with high maximum power and low stored energy or with low maximum power and high stored energy or with both high maximum power and high stored energy.
For specific kinds of batteries, it may be easier to build them for high stored energy than for high power, or vice-versa.
Because for any kind of energy storage device both these parameters matter, the animals, like humans, have not much less than a dozen of combinations of energy storage and energy conversion methods, each of them providing different capabilities for the maximum power and for the total stored energy, so that they are chosen for use based on the duration and the intensity of the required effort.
If all you have is a lawnmower engine, it doesn't matter how much gas you have. You won't be going very fast.
Same deal with energy storage. Yes energy capacity matters. But if you can’t put stored energy into the grid fast enough you get a brown or black out right away.
Except we have flywheels to solve the power problem (single digit minutes of storage, extremely high power).
The reason why batteries are being talked at all is because we are missing the energy storage problem (hours, or even days. Some people want seasonal storage but that's impossible with our current levels of tech).
The so called lawnmower engine that stores energy slowly in the summer but delivers it slowly in Winter would be more useful than you might think. Especially because we have solutions for every other tier (capacitors/supercaps for seconds of storage, flywheels for small minutes of storage, batteries for large minutes of storage, pumped hydro / compressed air energy storage for hours of storage).
They use power units to make it comparable with the non-storage sources, see https://news.ycombinator.com/item?id=48157824
Yes. People misuse units to compare apples with bananas.
Bad comparisons are bad.
We need something like this in the UK given the constant abundance of renewable energy.
UK is up there in the world rankings for batteries.
I think they have slightly more grid batteries installed than California. UK have more people, but less money and less electricity used so I'd say they're doing better than California on battery deployment.
I do not think so. There is BESS here and it's hard to be sure from the available data but it sure looks like less than 10GWh of BESS, maybe much less. There is now more BESS here than pumped storage, which was installed as a Black Start† rather than specifically storage but it's just not very much compared to California from what I can see. So maybe I'm wrong about how much capacity it is, because the Pumped Storage is like 20GWh top to bottom.
† Most modern power stations perversely need electricity in order to start them, so if your whole grid goes offline you're fucked, you go dark and your civilisation is now on a clock - a Black Start facility is a station which can go from black (no electricity) to running. In the case of Britain's pumped storage that's because "all" we need to do is allow the water to run through the generator. Once one or two Black Start sites are up you can use that power to start the other generators and restore supply to residents, and things get back to normal in a few hours.
[Edited to say that since we know there's about 20GWh of PSH the larger BESS can't be as small as I thought unless it's run a lot harder...]
It hard to get exact numbers because the rollout is fast in both places but it looks like they have strikingly similar targets for 2030 and 2040 in terms of GW but California both started earlier so is still ahead in GW deployed and their regulations mean that 4 hour is more common so they're actually about 2x on storage duration in California.
Both doing well, but UK would need much more of a handicap for GDP than I thought to claim a win. Solar and batteries do generally pair better than wind.
This reads like the end of the fossil fueled, grid.
Managing the california grid is now completly different than any traditional grid in that peak power is managed seamlessly from solar/wind/battery power, not counting providing a significant, most?, of the daytime power, leaving just the nightime load running street lights and background loads. The stabilisation of costs, especialy durring a fuel crisis, is an invisible benifit that poorer countrys will be looking at as they plan there future grid updates, while struggling to keep the lights on right now.
This is a seriously impressive achievement. I wish there was a more comprehensive engineering deep dive, but I wasn't able to find one.
So why is California's electricity the most expensive in the country?
California imports a third of its electricity, and that's expensive. It gets almost another third from natural gas. They've been changing rapidly from fossil fuels and nuclear to renewables and that's pretty capital intensive. And there have been some huge costs associated with the wildfires.
There's a bit more technical info on California battery storage here:
https://www.ess-news.com/2025/04/11/california-battery-domin...
It appears expensive electricity is mostly a policy decision. Schemes to support low carbon energy, strict emissions controls etc.
Let everyone do what they were doing in 1980, and prices would be rock bottom by now.
Yeah I don’t understand why the first priority of any policy maker isn’t to make the cost of electricity as low as possible. We certainly have the technology to do this.
In general, imports are cheaper than the alternative, because if you have local gas plants that aren't maxed out, then you'd use those rather than pay more to import.
Some quick googling suggests this holds in California too.
The problem with renewables I have is that "what's good for the earth" and capitalism simply don't mix.
Solar was fundamentally supposed to be almost-free electricity. You put a bunch of panels up and free energy from the nearest star. The stark reality though is that the people and institutions in control of solar equipment (this includes manufacturers, tariffs, etc.) reprice their stuff to match the price of the dirty electricity. And then they reprice their stuff again to assume that everyone loves to borrow money. At that point it becomes not worth it at all.
No, I don't want a solar installation to pay for itself in 15 years. I want equipment that gives me free electricity starting next month. If it costs less than a months' worth of electricity and I won't have an electricity bill starting next month, I'm interested. If not, it's outside my budget and planning horizon.
How do you explain that solar got 50% less expensive in the last 10 years?
Why would people and institutions in control of solar equipment reprice their stuff to match the price of dirty electricity? You think there is no competition? Or you confuse it with the system that has been put in place where the price of electricity in the grid is set up by the most expensive producer at the time (which does make sense although you can argue against it).
Solar installation should pay for itself in less than 15 years in most cases, half the time according to that article: https://pv-magazine-usa.com/2024/10/03/average-u-s-residenti... (and residential solar is much less cost-effective than large-scale solar farms).
> less than 15 years
But can it pay itself in a month or two? That's the bar. I cannot financially plan for even one year later. Too many unknowns.
A really good coffee machine that can do lattes costs maybe $200. If lattes at coffee shops cost $8 including stupid high CA taxes and the stupid puppy face guilt tips, it pays for itself after ~35 lattes including supply costs, or just over a month. That's the bar for pretty much anything.
Figure out how to sell me $500 in solar panels that generates $500 worth of electricity over the next month and make it tax deductible with no income limits. That is how you cover the country in clean energy. FAST. Until politicians can get their act together, slam the hammer and make exactly this happen, we're going to be on dirty electricity for a long time.
That should especially be the bar for clean energy. Clean energy shouldn't be a luxury for the wealthy.
Well first of all TFA is not talking about individuals buying solar or anything, so do we at least agree that renewables make sense for countries/state?
It seems like you have set an impossible bar for renewables so I don't know what to say to you. I do not think you'll be able to put a mini nuclear station, gas or coal one in your garden for less than the monthly electricity fee, so it's unclear to me what you are comparing it to.
The problem with giving money to individuals for their rooftop solar is that rooftop solar is not cost effective compared to large scale solar, if you really care about the planet and money is limited you should maximise the bang for your buck and help solar farms instead. But it's no secret that the current US administration is loudly anti-renewable and not keen on helping either of them.
I'm just saying what needs to happen in order for people to be lining up for solar in hordes and convert the country to renewable overnight.
The IRS needs to say: "We value clean energy in our country, we can live without nickel-and-diming people on the income used to make their solar purchase"
The Fed needs to say: "We value clean energy in our country, we can lend money to businesses at 0% interest, for the sake of supporting our country's clean future. Heck, -10% interest if you deploy today!"
The president needs to say: "We value clean energy in our country, we want solar as fast as possible, we will impose 0% tariffs on panels regardless of wherever they came from"
Wall Street needs to say: "We value clean energy in our country, it is saving the country from a multi-trillion dollar climate disaster, therefore we value solar companies at 100X their current valuations because that's what they are truly worth"
Solar companies need to say: "We aren't here to optimize profits; our only KPI is deploy solar as fast as possible"
The government needs to say to solar companies: "Do it! And don't worry if you're unprofitable, we value averting a 10 trillion climate crisis and will subsidize your losses from that 10 trillion loss that we averted"
Yeah, I know, it sounds impossible. Humans are shits, and they won't do the above. That's why the climate disaster is happening.
The break even for home solar is too long for me also. Every now and again I look at it, and even with subsidies it's gonna be about 12 to 15 years before I see any cost saving.
What if you drive electric?
I drive an electric. It doesn't save money because the car itself is more expensive by exactly as much as you would save over the life of the car. And then the $700/year registration fees because you don't pay the fuel tax. Again, stupid capitalism.
Let me translate that four people who don’t speak “capitalism BAD”: Why don’t other people work for free for me? Why don’t Chinese and African miners work for free so I can get free minerals from the earth? Why don’t workers in refineries work for free so that I can get free metals and free silicon of highest purity? Why don’t all the companies that produce solar cells from raw materials, construct modules from the cells, install the modules on roofs, do the electrical wiring, stabilize the grid, provide electrical storage… WHY DON’T THEY WORK FOR FREE EVEN THOUGH I’VE CRITICISED CAPITALISM?
Paying for wildfires is a big part of it.
Another less obvious thing is that Californians don't use much electricity due to mild climate and efficiency programs.
Fixed costs therefore get spread across fewer units.
This is a topic in some nations where electrification is seen as a way of driving down per unit electricity costs even as you use more for heating or transport.
Just for a moment, try to imagine how much wind, solar and battery storage can be bought with the money required to build just one regular nuclear power plant (gigawatt output).
The real thing delaying the energy transition is politics, we have the technology.
And on a really small scale, here in NL we can build our own home battery storage systems with cheap 15kWh or 32kWh battery kits from China. Combine that with dynamic energy contracts it's amazing.
A 15kWh setup is maybe 3500 Euro, and 32kWh around 4500 Euro. Lasts at least 15+ years counting battery cycles.
> Just for a moment, try to imagine how much wind, solar and battery storage can be bought with the money required to build just one regular nuclear power plant (gigawatt output).
Assuming the most expensive nuclear power plant in the world, assuming the solar is free and you are only paying for the batteries, assuming costs in line with the cheapest grid-scale battery storage in the world, about 6.5h worth of that nuclear plant's output.
That's on the right scale to power California with renewables alone! That's within sight. Anywhere less sunny, powering things with solar and batteries alone would still be very expensive.
Hinkley Point C in the UK is costing £48bn at current prices, providing 3GW.
Building 3GW * 2 hours of battery storage at current prices is £1.75bn, so for the same money we get about 48 hours of storage.
https://en.wikipedia.org/wiki/Hinkley_Point_C_nuclear_power_...
While we're sleeping splitting hairs about whether it's possible to pull 12 megawatts from a D cell battery for 2 attoseconds I'll throw my hat in the ring and claim that nuclear pellets are batteries if we redefine what a battery means (just like that other recent article about heritability was redefined)
Garbage article.
Using a measurement for power as opposed to energy is dumb with batteries
I can build a capacitor bank in my garage that produces more power than a nuclear power plant. For a millisecond.
Not when you are talking about compensating for short term peaks. Of course the amount of time it can do this is also important but, unlike batteries used for shifting solar energy to night time use for instance, it is not the most important feature.
this seems misleading. the article claims:
12,000 megawatts, equivalent to 12 large nuclear plants, of energy from its battery arrays.
watts are power, not energy. for example, a tea kettle might require 2kilowatts. this does not tell you how much does it cost you to use the tea kettle, because it does not tell you how long the tea kettle is consuming 2kilowatts.