This is a complete myth, somebody pulled "a week" out of their butt a decade ago, it gets repeated a ton, but it's not based on reality or studies or numbers. This is a consistent problem with online nuclear advocacy: there's no basis for the numbers, nobody calculates anything, and if they bother to do a calculation they only calculate the upper bound and then assert "see look a big number" and say that's a proof of impossibility.
What event requires a week of storage? Nobody can name one! When has there been a week with zero generation? No one can name it! The assumptions that one has to make up in order to make a "week" even sound plausible are in turn themselves so implausible.
> There isn't enough battery capacity in the world to do this for a state like California, let alone the whole country.
Imagining there's a fixed battery capacity is a very short sighted view, it's growing by 10x every year.
So let's take your "week" as the measure, even though it's wrong. If we're at 2-3 TWh of world battery production capacity in 2025, that's 4 days of California demand. By 2031 or 2032, we're going to have 20-30TWh of battery production.
The 2,200 GWh of batteries produced in 2025 amounts to a bit under 3 days of California's average 750GWh daily electricity consumption, not 4 days. And more broadly, I'm not sure how pointing out that a year's worth of global battery production amounts to just 3 days of one US state's electricity demand is supposed to demonstrate that battery storage is feasible.
To put this in perspective, global daily electricity demand is 60,000 GWh. Of the ~2,200 GWh of batteries produced in 2025, only ~300 GWh was used for grid storage. Most of it went to EVs.
Battery production costs are already dominated by the cost of anode and cathode material. The bottleneck is resource extraction. And the nature of scaling resource extraction is that the easiest-to-exploit reserves are extracted first, and increasing producing involves reaching for the more and more difficult to access reserves.
Even if production continues to rise, any serious investment into battery grid storage will delay EV adoption as batteries are diverted to grid storage instead of EVs.
It was pointing out that the comment making off-the-wall requirements of battery storage was already not aware of the order of magnitude of existing batteries.
You don't know the exact
> To put this in perspective, global daily electricity demand is 60,000 GWh. Of the ~2,200 GWh of batteries produced in 2025, only ~300 GWh was used for grid storage. Most of it went to EVs.
What's your implication here? If you are trying to say this means that batteries can never scale, it's certainly not making that point. Even the distinction between grid and EVs is immaterial, because where do EVs get their power? The grid. That's all flexible demand, that can be shifted a huge amount.
> Battery production costs are already dominated by the cost of anode and cathode material. The bottleneck is resource extraction. And the nature of scaling resource extraction is that the easiest-to-exploit reserves are extracted first, and increasing producing involves reaching for the more and more difficult to access reserves.
The implication seems to be that batteries will get more expensive at some point. Perhaps. Or more chemistries will be discovered or used. Lithium got very expensive for a short while, then cheap. The cure for high prices is high prices, because unlike oil there are tons of substitutions available for all aspects of batteries.
Unlike oil, we are in the early days of discovery for battery materials, because we never looked for them before. Just recently fracking in the southeast quarter of the US turned out to be producing a fair amount of lithium, which nobody had bothered to even investigate before.
Batteries are a new technology, not an old technology like oil, and the dynamics are far different. One can't simply recycle reasoning that applies in oil without examining the first princiles.
> Even if production continues to rise, any serious investment into battery grid storage will delay EV adoption as batteries are diverted to grid storage instead of EVs.
"Even if" is a preposterous thing to say, of course it will!
EVs are higher value destination for grid batteries, so more batteries will go towards that right now. And as long as there might be "diversion" as you say, there is need for more production capacity, and production capacity will expand.
Such as? Is your proposal that we use lead acid batteries instead of lithium based batteries? Those have much shorter lifespans, which drives up cost. Sodium batteries? 9 GWh of sodium batteries were shipped in 2025.
To be blunt, you're just hand waving away the massive disparity in scale between battery production and the storage demands of a predominantly wind and solar grid.
We’re seeing the Cambrian explosion of battery technology. From early BEVs utilizing the highest performance to even deliver a viable product to a plethora of options depending on your use case.
https://www.pv-magazine.com/2026/02/25/google-to-deploy-worl...
Wasting trillions of tax money and decades of opportunity cost on new built nuclear handouts is extremely shortsighted.
Of course, there's no guarantee that any of those fission ideas will actually pan out. Likewise with these battery chemistries. Investing loads of money into intermittent sources with just the hope that some future battery chemistry will solve storage at grid scale is not what I'd call a wise plan.
https://www.eia.gov/todayinenergy/detail.php?id=67205
Anybody who over the past few decades has been saying that we could not deploy batteries on a massive scale needs to reevaluate their bad assumptions, because they are wrong, and moreover we should not trust any of their current assessments until they can reconcile what they got wrong. The tech curves of batteries have been clear for decades, this tech development should not have been unexpected.
* The USA uses 12,000 GWh of electricity per day
* The world uses 60,000 GWh of electricity per day.
* Global battery production in 2025 was ~1,600 GWh, of which 300 GWh was used for grid storage [1].
At our present production rates, it'll take 100 years to provision 12 hours worth of storage at 300 GWh per year. Batter production is set to increase to 6.8 TWh per year [2], but only 12% of that is predicted to go to grid storage, or about 800 GWh per year. Even at 2035 rates, we're looking at 37 years of production to fill 12 hours of storage (12 hour of electricity storage for 2025 electricity demand rates, which will be higher in 2035).
Yes, batteries are being deployed at a massive scale today. But electricity generation is on an even more massive scale that dwarfs battery production rates.
1. https://source.benchmarkminerals.com/article/global-lithium-...
2. https://www.mckinsey.com/features/mckinsey-center-for-future...
Mmmhmm, grid scale deployment is not grid scale now? You are redefining terms, which means you don't work in the field and are not at all familiar with the field, yet you make broad and sweep proclamations of incredulity that have no factual backing, and we are supposed to trust you purely on judgement?
You cite last year's deployment rate, without noting a massive increase in planned deployments for this year. You neglect to cite the year before it, which was much smaller. You looking at a puck headed to the goal, under a continuous accelerant force, and saying, "the puck is here, therefore it will never hit the goal." That's a ridiculous thing to assert, because you don't hold that afactual standard for any other technology, just batteries, yet seem to understand that all other technologies have continually changing amounts of producition.
BTW, your link is "demand" and disagrees with most other sources.
> At our present production rates
That kind of says it all, doesn't it? You think that present production rates are indicative of future production rates, which is an insane statement.
If nuclear has 0 GW new this year, how do you think it could ever get to 2GW/year, right?
You have no reasons for these strange beliefs that defy data and trends, you just assert incredulity. It's completely irrational.
I'm not expecting readers to trust me purely on judgement, I'm expecting them to do the math and realize that battery storage deployment and electricity demand are multiple orders of magnitude off, even with the projected increases in battery projection.
> That kind of says it all, doesn't it? You think that present production rates are indicative of future production rates, which is an insane statement.
Again, I did cite the projected production figures for 2035. Did you miss that part?
Battery technology seems like a proven technology to me?
What's the annual production figures for iron air batteries, flow batteries, etc.? Sodium batteries are at 9 GWh delivered in 2025. Google tells me that flow battery capacity is 500 MWh to 1 GWh, but doesn't provide any figures on actual production deliveries (production capacity is not the same as actual delivered production). There are no iron air battery facilities currently in production, with the earliest plant trying to open in 2028 with 500 MWh per year annual production.
None of your suggestions are remotely close to operating at grid scale, and there is zero guarantee that any of them will prove more feasible than lithium based battery chemistry.
Meanwhile, the statement that "fusion has been achieved in a lab" is optimism and wishful thinking beyond words. What energy return did that get? What was the cost? When will there be GE of generation, mic less basic safety engineering?
Those who advocate against the shipping reality of batteries, and moreover assume that they will get more expensive, are not using numerical thinking and are not thinking like scientists, engineers, or technologists. They are merely rooting for a tech like a sports team. Nuclear does not need any more fans, it needs engineers and scientists that can achieve some sort of radical breakthrough that makes it a desirable tech.
You're inventing a straw man that's easier for you to attack.
No goalposts are being moved. My point was, and still is, that batteries do not presently scale sufficiently to make a predominantly wind and solar grid feasible, and our current projections even a decade out do not see them scale to that point either.
We don't know if some breakthrough in battery chemistry will make it scale. Could such a breakthrough transpire? Sure. But will it happen? We don't know. And thus we should not gamble massive infrastructure spending on the assumption that this breakthrough will happen.
What’s the source on this? I just googled it, and the sources I see are saying 5TWh by 2036, with increasing supply chain risks over time…
https://finance.yahoo.com/news/global-lithium-ion-battery-ca...
https://www.iea.org/commentaries/global-battery-markets-are-...
I heard the projection on a podcast from a battery builder (maybe Form Energy's CEO?) in 2021 that we were at 200-300 GWh in 2021, and would have 2-3 TWh 2026, and 20-30 TWh in 2031. His "naive" prediction was correct, all the other projections have been flat wrong.
Another example, sci fi author Ramez Naam in 2020 reviewed his prior projections from 2011 and 2015 here:
https://www.rameznaam.com/p/solars-future-is-insanely-cheap-...
Even just diurnal storage for a completely renewable grid is a truly enormous amount of storage.
We’re seeing the reshaping of the entire global energy system. Either we jump on the train or get run over.
To reiterate, this is just for 12 hours of storage. Seasonal fluctuations can depress renewable generation for days or even weeks.
1. https://www.mckinsey.com/features/mckinsey-center-for-future...
BESS increased 45% y/y in 2025, and is looking like higher growth than that in 2026 already ~60% (1). Im optimistic that the mckinsey conservative linear estimates of growth are missing the s-curve of scaling new tech, just like they did for solar. They only have to be wrong by a little y/y and we get to 1000ghw a year by 2030 (note, they released a more recent study that pulled 800gwh/year in to closer to 2030 [2], the previous study was already too conservative) . At 1twh a year we're seriously chipping away at emissions, we're done in 15 years if nothing else changes (which of course it will, both on the demand and supply side). Still, thats actually incredible!
1 https://www.energy-storage.news/over-17gwh-of-bess-deployed-... 2 https://www.mckinsey.com/featured-insights/week-in-charts/ba...
The projections for battery growth might be off, sure. But it's also possible the growth is a little bit under the projections year over year, and then we're looking at much less battery production five years. You're invoking uncertainty, but only considering it in one direction.
Yes, im explicitly considering it only in one direction, as I said I’m optimistic. I have seen plenty of data, my own & others reasoning that leads me to believe in the optimistic case here.
EDIT: look at the graph in that second McKinsey link. Look at the step for 2024, and then the massive step for 2025. And then they project much tinier steps for 26 and beyond? That’s obviously nonsense. And we can tell it’s nonsense as the number for 26 are coming in at another 60% increase y/y, and all reports point to huge increases in deployed capacity this year. And they have it at like 20%. Cmon, that’s nonsense.
Rather than just proclaiming the projection as "nonsense" it'd be a lot more productive if you shared an alternate projection and explained why it's methods are superior.
And this also disregards that second life automotive batteries are incredibly hot on the market. All those TWh of batteries will become available for stationary use when the cars are scrapped.
Maybe not in western markets due to labor costs, but definitely in developing economies.
https://www.pv-magazine.com/2026/04/17/new-metric-shows-rene...
Batteries are cheap, getting cheaper, and are the biggest disruption and innovation on the grid in more than half a century. You can use them to reduce transmission costs, to reduce the load on distribution substations and increase distribution usage capacity, you can use storage to make everything a lot cheaper by allowing smaller sizes for expensive T&D equipment that sees less than 30% average utilization.
Calling batteries "unrealistic" is not based in reality, it's just being stuck in decades past.
The only situation where deliberately operating a nuclear plant at under 100% output is when nuclear makes up a very large chunk of a country's generation capacity. It's not that only French nuclear plants can reduce output it's that only the French have ever been in the situation where their nuclear capacity exceeds their minimum electricity demand.
And that is France which has been actively shielding its inflexible aging nuclear fleet from renewable competition, and it still leaks in on pure economics.
The difference is that nuclear will keep running at night, in the winter, regardless of how strong the wind is blowing. A cheap, but intermittent source of carbon-free energy is not comparable on a dollar-by-dollar basis to a non-intermittent source of carbon-free energy.
The common retort is to use batteries, but let's put this in perspective: France uses 1,219 GWh of electricity daily (note that this is just electricity and doesn't include things like transportation, fuels in smelters, chemical feedstock etc.). 12 hours of storage would be 600 GWh. Seasonal fluctuations in wind and solar are even more extreme, and might need days worth of stored energy. But let's be humble and just see what it'll take to provision 12 hours:
At $150/kWh that'll be 90 billion dollars. These batteries will be good for 2,000 to 5,000 cycles. Let's say 4,000, so it has an 11 year life span. Over the course of 55 years that'd cost $450 billion. Just for the storage, mind you, France has to build the renewable generation on top of the storage.
On the flip side, the Flamanville Nuclear plant has a lifespan of 60 years. You could build 12 Flamanville nuclear plants and satisfy 100% of France's electricity demand. At €19 billion euros, or about $22 billion USD building 12 Flamanville plants would work out to $264 billion. The cost of storage to even out intermittent sources is much more expensive than just building the nuclear plants.
Even with a 7% cost of capital that gives a levelized cost of storage of $65/MWh or an additional $33/MWh on top of the levelized cost of electricity of solar to spread it across day and night [1].
With a 4% cost of capital the still being designed EPR2 with 30% savings over Flamanville 3 comes in at €93/MWh or $110/MWh [2].
So solar costing less than $77/MWh or €66/MWh + storage should be cheaper than EPR2.
[1] https://ember-energy.org/latest-insights/how-cheap-is-batter...
[2] https://itif.org/publications/2025/09/02/lessons-from-france...
Building a series of nuclear reactors with overlapping schedules (about one completion every year or two) in one country should help. But it’s simply far easier to find cost reductions for wind turbines which are manufactured in the thousands per year or solar panels and batteries which are manufactured in the millions.
Within a generation costs lowered, but between generations they exploded.
And the reductions were to small to make a dent in how horrifyingly expensive new built nuclear power is in 2026.
I'll be sure to read oil daily about the benefits of LNG plants too.
https://www.sciencedirect.com/science/article/pii/S036054422...