It's going to be solar + wind + battery. That's where the economics are at. Sodium batteries are just coming online now https://en.m.wikipedia.org/wiki/Sodium-ion_battery - lithium is getting phased out.
Maybe in some far off future nuclear will have a role... But the global energy investment markets paint a very clear picture: solar + wind + battery is the way.
Nuclear costs are largely due to regulatory burdens created for reactor designs that are not safe. That is no longer the case. Also, attempts to exploit economies of scale could also improve baseline costs, although these attempts haven't been funded enough yet to actually scale.
Enough batteries to last with no nuclear, coal, or natural gas on a still winter night? There are not enough grid scale batteries yet. There’s ~8 hours of daylight at the 45th parallel in December.
I don’t feel like doing napkin math on Saturday morning, but you’d need an obscene amount of batteries, the US uses 500+ GWh per day.
Ideally battery storage density will keep advancing to the point where we can use grid scale backup batteries for long durations but we are not there yet.
A typical car battery stores 60 kWh (the average capacity of models is increasing), so, charged during the day using inexpensive renewable electricity (particularly solar), it can power a household during one of the rare winter nights with insufficient wind.
Case in point: France. A household consumes an average of 14 kWh of electricity per day. The capacity of electric cars will exceed 500 GWh before 2035 and 2000 GWh between 2040 and 2050.
Trucks, utility vehicles, and stationary batteries (domestic and industrial) will add to this. Batteries from retired vehicles will increasingly be converted into static batteries before being recycled (see "Redwood Materials" in the US).
In California, when the sun is at its peak (midday), solar power produces up to three-quarters of the electricity. Batteries are charged in the afternoon, when solar electricity is cheap, and released in the evening, when Californians return home. At their peak consumption, around 8 p.m., batteries can supply up to 30% of the state's electricity.
In the next years, it doesn't make sense to use batteries to sustain winter load: it would be way too expensive. But batteries get cheaper quickly, such that it doesn't make sense to build expensive nuclear plants just for winter. What does make sense, until batteries are cheap enough, is natural gas during winter, plus (where available) wind energy and hydro / pumped storage, existing nuclear plants (optimised for winter), biomass (wood), photovoltaics in the mountain, and geothermal.
You do realize HVDC grids can do 3,000km energy travel, right? That's basically anywhere to anywhere, continental US. There's already installs like the PDCI https://en.wikipedia.org/wiki/Pacific_DC_Intertie that take 3GW from north oregon to LA.
> so the 3.2GWh battery grid storage array, in operation, this is still 1/100th what is needed?
That's closer to 1% of what California needs by itself then even 1% of the USA's need. We aren't even taking into account the large and continual growth in electricity demand yet either.
Nuclear costs would be way higher if the plant operators would need to have insurance for catastrophic failures. Right now, they don't need that. The state (the population) just takes this risk.
Even ignoring all of that, there's "time to first watt" - essentially if you break ground now, how quickly can you start producing power? Nuclear has years scale, wind and solar has weeks, if not days.
And also when better tech comes along, you can partially transition a farm to newer panels and resell the old ones after market.
Plus you don't have to build Onkalo Repository like systems to store waste for 100,000 years after you've produced your electricity.
"Years" is technically correct I guess - recent EPRs have taken 18 years from license to grid. Hinkley C 2012-2031 (projected). Flamanville 3 2006-2024.
Olkiluoto 3 2005-2023.
This is way too much latency. Every little bit helps of cours but it's hopeless optimism to think nuclear meaningfully helps the climate disaster for the foreseeable future.
I have this same issue with fusion. Who cares if the fuel is practically free, when building and operating the plant is extremely expensive and prone to failures due to the sheer complexity.
Of course the tech and science is cool, possibly useful in space or other niche environments, but whenever I see fusion proposed as some general energy solution, I just roll my eyes and move on.
People really love scifi on hn, and that's fine ... but the investment capital has spoken and renewables are being funded 30x nuclear. Not 30% more, 3,000% more. It's even 2x over ogc infra (oil, gas, coal)
We'll have direct antimatter annihilation at scale before we have fusion. It's basically a physics research project, with zero potential for commercial use.
There's already a convenient fusion reactor fairly close by, and it's unlikely to stop operating any time soon.
> Even ignoring all of that, there's "time to first watt" - essentially if you break ground now, how quickly can you start producing power? Nuclear has years scale, wind and solar has weeks, if not days.
France and China have built nuclear plants in 6 years, and they provide stable power for over 40 years, unlike wind turbines and panels which last maybe 20 for panels (if you're lucky), and a few years for turbine failures, and neither provide stable power.
Renewables have their place but people really need to stop with this panacea nonsense.
Panels are warrantied for 25 or 30 years at a specific level of performance, with 30 year old installs still working today and 40 years is an expected lifetime for a modern panel before it will dip below that warranted level but still be producing energy with minimal upkeep.
Why do think the two countries you mention as being capable of quickly building nuclear are in fact much more quickly deploying renewables?
Nuclear operators do need insurance to cover incidents, so they're already paying that cost on top of the absurd regulatory burdens. Current gen nuclear designs are basically meltdown proof, so not only should insurance costs be lower, but regulatory burden should also be lower.
The liability is capped at a certain amount. In the US, that is around $450 million per reactor. They also have to buy in to a fond. In France, the cap is 700 million euro. Above that, the federal government _could_ step in. The problem is, no private insurer (or even pool of insurers) could cover the absolute worst-case GAU, and not even the government really.
In Fukushima, TEPCO was required pay $1.5 billion. But the real cost is / was around $150 billion. So, the bulk of the disaster was not covered / covered by the taxpayer. So: the public.
Right. If the only way a business is profitable is because the public has been convinced to pick up the tab, please excuse me for not being interested.
But now you have a probabilistic system. Your battery part is designed for n numbers of low/no solar/wind input. So you are paying for a system that would be sufficient for x% of typical/historical years.
Which has to factor in the design and cost calculation.
nuclear is also probabilistic: in 2022 half of France nuclear reactor capacity was offline because of premature aging of some components in a design used in many reactors.
Note in case SMR become part of our grid: what if something similar happens to your hundreds of produced and deployed SMR?
There are always unknown unknowns that might be correlated, like that flaw in the component. Weather systems like a https://en.wikipedia.org/wiki/Dunkelflaute are known facts. The good thing is that we do have excellent weather data for the last 75 years, so it is totally feasible for proponents of renewables to run their models through that historical data and say: Look, if we have that amount of renewables and that amount of batteries that would have been enough for the last 3 quarters of a century.
Wind + solar is just adding another failure mode for when there is no wind. There are many places without adequate wind speed. Nuclear does not care about either, and has the highest energy density on top of that.
Nuclear has its own failure modes. In Switzerland, one of the nuclear plants will be offline for winter (!) due to "unplanned repairs". This will cost the owners of the plant millions.
Nuclear also have weather failures: low water levels, and high river temperature. In both cases the power plant needs to reduce output or be turned off.
Those aren't weather failures but environmental regulations, there's nothing preventing the plant to work of you really want to, it's just not needed, especially in summer.
If you remove environmental regulations, then (pumped) hydro, wind, and photovoltaics would also be much cheaper, and much faster to build. For windmills, it's birds and whatnot, for photovoltaics (specially large-scale in the mounts) it's wildlife and other environmental impact.
FUD about "what about where renewables aren't available " is just rhetorical handwaving. The answer, which already exists at nation-level scale is storage and infrastructure.
The increase in renewable generation is great, but some of these are kind of cheating by importing energy to cover shortfalls. You need some kind of baseload generation that’s not dependent on weather, and borrowing this from a neighbour while pretending you don’t need it is like those ‘tiny house’ guys.
Now you're just empirically lying, by equating the behaviour of solar and wind with that of hydro.
That table also doesn't say what you apparently think it does: it lists Luxembourg as 89% renewable, which is true, but does not include that Luxembourg only covers about 28% of the electricity it uses, and imports the rest.
Thus Luxembourg's production being 89% renewable is worthless information as to the viability and reliability of wind and solar for baseload: Luxembourg relies on its neighbours for reliable electricity supply.
right, there's a vibrant international real time energy market with thousands of km of energy travel on the GW scale which also invalidates the "what if it's cloudy right where I am" argument.
That's genuinely not how it works. You can see it every spring as Germany wholesale prices go negative to try and offload as much electricity as fast as possible to keep their grid from falling over.
Wind turbines can, and are, turned off (by turning, feathering the blades, and braking). There are two main cases: high wind / storm, and too much electricity in the grid. Photovoltaics can also be turned off.
The main reason for negative electricity prices are inflexible generators, eg. nuclear and coal, because they can't easily (cheaply) ramp down or shut off. Sometimes it is cheaper to let prices go negative than to use emergency mechanisms (that do exist).
Negative prices are not all bad: they are an incentive for storage / flexible demand to step in. Specially, a negative price does not mean the grid is melting.
'Too much electricity in the grid' is a wrong way of expressing it, just like you can't have 'too much fluid in a pipe'. What happens is that the line voltage creeps up because loads are lagging further behind compared to generation.
And like you wrote, that's controlled. Agreed with the rest of your comment, especially the bit that pricing is mostly controlled by the worst parties, not by the best. What we are simply finding out is that a grid designed mostly for baseline loads needs fast response generation (for instance: half of the UK putting their kettle on during half time requires so much extra power that pumped storage becomes a good alternative). And conversely, that if you change the mix considerably that you're going to have to have more control over the cumulative effect of many smaller generators.
But there are already standards for dealing with that even absent remote control of resources: as soon as the local grid voltage that the inverters in modern wind and solar plants see exceeds a very specific maximum for a proscribed period of time they fully autonomously back off their capacity until they are well below those maximums again, and then slowly ramp up to avoid causing grid instability due to oscillation.
What grid balancing is all about is to make this all financially optimal, it has relatively little to do with the safety of the grid, it is simply a way to extract maximum capacity without affecting that safety. A coarser mechanism would simply incur some more waste, but given the amounts of money involved it pays off to tune this.
> Negative prices are not all bad: they are an incentive for storage / flexible demand to step in.
Maybe that'll happen, but currently such events only keep increasing in frequency (https://www.pv-magazine.com/2025/08/26/germany-records-453-h...), and as neighbours also install more solar and wind the ability for germany to maintain their grid stability through exports is going to worsen not improve.
That's genuinely exactly how it works. There are companies that provide that offloading-as-a-service who make good money on this concept and the grid isn't anywhere near falling over. Your 'grid melting' comment upthread is nonsense. Nothing is melting.
Melting would imply that currents exceed rated capacity of the lines that is entirely impossible due to how the grid is set up. What does happen is that loads that are otherwise not economical to run get turned on and that sources that are remote controllable (which is all wind installations > 2 MW and all solar farms > 10 KW except for residential) are switched off. This is a fascinating subject and worth some study, the thing you want to read up on is called grid balancing.
Typically the day-ahead and the 15 minute ahead markets take care of this with pricing alone and there have been no meaningful excursions due to overproduction of renewables, that's just FUD and it does not contribute to the discussion.
What you could argue if you had read up on this is that there are market operators that do both sides of the market, which sets you up for an Enron like situation because they can make money by front-running. After all, they have a little bit of time between the moment where they know what they're going to do and the moment when they actually do it. Market makers that are also traders is always a dangerous combination and this has already led to some trouble, especially early on in the energy balancing market process. Now it is much better.