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Comment by maelito | Hacker News Reader

On the long-term, the French option of just running a low-carbon grid remains the obvious solution.

Sure, but I don't think the two ideas are really in conflict. A low-carbon grid should absolutely be the end goal, but even a mostly clean grid has hours that are cleaner than others

These approaches always measure the wrong thing though - the average carbon cost of electricity.

What you need to know is the marginal carbon cost, which will be much less variable as almost all dispatchable generation is fossil.

So yes, you should avoiding adding load when there is a severe supply crunch and the marginal power is generated by gas peaker plants (often gas turbine based), and use power when renewable generation is otherwise being curtailed, but most of the time the grid is firmly in the middle regime with a fairly average marginal cost.

They are in conflict, because you can spend the same Euro only once. You could build a lot of batteries, solar panels and wind turbines for the cost of one nuclear plant

Money doesn't work like that.

Spending 19 billion € over 18 years to build 1.65GW Flamanville 3 is not quite obvious to me.

https://en.wikipedia.org/wiki/EPR_(nuclear_reactor)#Flamanvi...

Edit: compare this with China: they added 315 GW of Solar capacity in a single year (2025; see page 34 of the PDF).

https://www.irena.org/Publications/2026/Mar/Renewable-capaci...

(You can't compare nameplate capacity directly, but it can be safely assumed that 2 orders of magnitude more is ... actually more)

French nuclear supply chain atrophied quite lot in the last 30 years. Don't forget that even in France, president Hollande promised in 2014 to the voters to slash nuclear's contribution of power generation by 2025.

https://spectrum.ieee.org/renewables-up-nuclear-down-in-fren...

It was only when Russia started invasion in 2022, that the politicians in France started to change their opinion.

If you want build a nuclear power plant you go to nuclear supplier with uninterrupted experience in building nuclear power plants, like South Korea, China or Russia.

The South Koreans build Barakah nuclear power plant 5600 MWe for $32bn.

https://en.wikipedia.org/wiki/Barakah_nuclear_power_plant

https://www.powermag.com/uaes-first-reactor-gets-go-ahead/

> French nuclear supply chain atrophied quite lot in the last 30 years.

Because today it makes no economic sense. Supply chain for horse carts is also very atrophied.

>The South Koreans build Barakah nuclear power plant 5600 MWe for $32bn.

Still very expensive. Flamanville is an extreme when things go really bad, but 175 MWe for 1 bn is also very high. 1 bn buys ~1 GW of solar, ~1 GW of onshore wind, or ~3 GW of battery capacity. You should only build new nuclear either to get a better mix in the grid (up to 5% is the nuclear lobby recommendation), or because you have no sun and no wind.

What would you need to replace a 1 GW nuclear power plant with 98% capacity factor?

Probably 1 GW solar power plant, together with 1 GW onshore wind and 1 GW of gas power plant. Then you have to also pay the natural gas to compensate for times of low solar + wind production. You can build battery storage to decrease the natural gas consumption, but how much battery storage do you have to build and how much can you reduce the natural gas consumption strongly depends latitude and local weather patterns.

https://solarbatteryatlas.electrotech-revolution.com/deploym...

France exports about 60TWh of electricity yearly for about 4B€.

Flamanville running at 100% generates 32TWh. It is amortized in 9 years. I'd say it's doing pretty okay even with its ballooning cost.

Not really. Nuclear power requires massive subsidies. In Germany, the "De Height" wind farm was completed in August. Sixty-four 15-MW turbines generate about 4 TWh of electricity annually, which is sold entirely on the open market without any EEG funding.

The market for baseload electricity has disappeared in Germany, as renewables push the residual load to zero or below for almost the entire year:

https://www.energy-charts.info/charts/power/chart.htm?c=DE&l...

The base load is an imaginary line passing through the troughs of the residual load curve.

Yes, but then when the wind doesn't blow, you miss upto 960MW of capacity, you can choose how to fill that; solar, coal, gas, waterpower, diesel, nuclear.

And the question is, are those wind turbines without subsidy?

Here in the Netherlands some big energy users like Aldel already have stopped, those big users are also good in up and down scaling energy usage on demand, and also those products have to come from somewhere else now, so in the end the question is about energy and availability.

Some (or a lot of) subsidies can be justified.

A single wind turbine or a single PV module obviously provides only variable amounts of electricity. However, this is not the case for many PV modules and wind turbines spread across the entire continent. Wind and PV complement each other very well in Europe because of regular weather fronts; when there is little wind, there is more sunshine.

https://www.energy-charts.info/charts/energy/chart.htm?l=de&...

In Europe, the average weekly electricity generation in 2025 was 14.0 TWh, and no week fell below 10.2 TWh. In 2026, the average output was about 15.5 TWh, and so far, no week has fallen below 12.5 TWh.

Of course, batteries are needed for short-term storage, but with the creation of excess capacity in wind and solar power, the troughs below the load curve become narrower and shallower, drastically reducing the need for storage.

> when the wind doesn't blow

During day hours and with clear weather it's solar.

Currently at night in Germany it's: imports from other countries + coal power plants + gas power plants + little bit of hydro/biomass.

The plan for coming decade is to replace coal power plants with new subsidized gas power plants.

https://table.media/en/europe/news/gas-fired-power-plants-eu...

So, relying on others to fix your mess + catastrophic emissions + catastrophic but less so emissions + something pretty much at full capacity.

Or they could get with the times and build a ton of battery like California. Down to 25% fossil in 2026 due to the massive success of shifting solar into the night with batteries.

the answers exist, euro states just can’t get out of their own way and actually build things

It's expensive to build enough batteries to cover a few days with very little generation. Hydrogen and gas turbines currently look cheaper.

and thats fine by me! if we covered just the average daily cycle with batteries (like cali is closing in on) then you're talking like a 95% non-fossil production for the year. We've effectively won the climate crisis at that point. Or at least, can spend our efforts in other sectors while technology keeps giving us more options for the last 5%

France has been offering lower prices at night to make the most of their nuclear since the 1960s.

Australia used similar tech to make the most of baseload coal overnight since the 1950s.

It's just a good idea, and should be used to get cheaper cleaner power in grids today too.

It is not even an "idea". Is the consequence of nuclear power being so difficult to modulate to consumption. You give it for free by night, hoping that at least some people consumes, because the country is sleeping.

Solar energy aligns so much better, peaking its production when the consumption is high, going to zero when the consumption gets low, except for the diner time. In Spain we get really low prices (sometimes near 0) in the middle of the day, you don't have to plan or incentivize night consumption.

Yep. Poisoning the planet with nuclear wast for a million years. 40,000 generations of our children will be happy and thankful.

Germany is currently operating the world biggest permanent storage for dangerous waste UTD Herfa-Neurode. Contains at least 690,000 tons of waste containing dioxins and furans, 220,000 tons of waste containing mercury, 127,000 tons of waste containing cyanide, and 83,000 tons of toxic waste containing arsenic. Nuclear waste is currently excluded, but I think it would not make a difference, especially because after about 400 years most dangerous fission products (Caesium-137, Strontium-90, and Iodine-131) decay away and only Plutonium and minor actinides stays. Mercury, arsenic, dioxins and furans stay forever.

https://de.wikipedia.org/wiki/Untertagedeponie_Herfa-Neurode

https://radioactivity.eu.com/articles/radioactive_waste/acti...

We learned quite lot about underground migration of plutonium over millennia because we studied the remnants of the natural nuclear fission reactor which nature run about approximately 1.7 billion years ago in Oklo, Gabon.

https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto...

"Plutonium has moved less than ten feet from where it was formed almost two billion years ago contained in the sedimentary rocks that kept them from being dissolved or spread by groundwater."

http://large.stanford.edu/courses/2018/ph241/voigt2/

I mean yeah. Nuclear waste is much safer than fossil fuel waste - deaths caused, radioactivity, etc

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