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...