France's nuclear: where it sits, who it powers, when it dips
France runs on a handful of big nuclear sites instead of scattered renewables. This view shows where that power is made, which régions lean on it, and what happens to the whole country when the fleet goes down for maintenance — or a heatwave warms the rivers. The matched twin of the German north–south view.
Régional generation, consumption and balance come from RTE's éCO2mix via ODRÉ (production-based; French fields translated once in the pipeline). Nuclear site locations are public; reactor counts and capacity change over time — figures are current to the build. Pre-computed and static — no live backend.
A handful of large sites on the Loire, the Rhône, the eastern rivers and the north coast power the entire country — the centralised opposite of Germany's scattered wind and solar. Red circles are demand centres; note how much Île-de-France consumes with almost no local generation.
France made a deliberate, state-led bet in the 1970s–80s: a large fleet of reactors supplying most of its electricity. The result is a highly centralised, low-carbon grid — a handful of big sites on rivers and the coast powering the whole country, the structural opposite of Germany's distributed wind and solar. This view shows where that power is made and which régions lean on it; it takes no position on nuclear policy.
Generation minus consumption by région. Nuclear-dense régions (Centre-Val de Loire, Auvergne-Rhône-Alpes, Normandie, Grand Est) run large surpluses; demand-heavy Île-de-France and generation-poor régions lean on the rest of the country.
France is a single bidding zone: one wholesale price nationwide. A région's surplus or deficit here is a physical balance (generation − consumption), not a regional price — the same reason Germany's north–south split doesn't show up in prices.
Nuclear isn't "always on". Output falls in spring and summer for refuelling and maintenance — concentrated in the lower-demand months by design. France keeps exporting through the dip (demand drops too, and solar rises), so the seasonal swing rarely strains supply; the sharper risk is heatwaves, when warm rivers limit cooling.
can't always move its wind to the demand
can't always keep its nuclear cool
"Available capacity" is how much of the fleet could run; "output" is how much actually did. Dips come from planned maintenance and refuelling (concentrated in the lower-demand months), unplanned outages, and — in heatwaves — environmental limits on how much warm water reactors may return to rivers, which forces output down. These are operational and environmental constraints, not safety failures.
The ranking depends on what you count. Plant-level "sticker price" is one number; add the costs usually left out — waste & decommissioning, the system cost of running a grid on variable renewables, and implicit support — applied symmetrically to every technology, and the order shifts.
Plant-level cost is only the sticker price. This view adds the costs headline figures leave out — waste & decommissioning, the system cost of running a grid on variable renewables, and implicit public support — applied to every technology, not just one. Nuclear's waste and decommissioning are large in total (the Cigéo repository ≈ €33–37 bn) but small per MWh, and they are provisioned and already in France's official cost figures; the real question is whether the provisions are adequate. Renewables' system costs rise as their share grows. Figures are illustrative central values from published studies (Lazard, Cour des comptes, ANDRA, OECD-NEA, IRENA), each with a wide, assumption-dependent range — curated estimates, not a live feed. It takes no side; the point is that the ranking depends on what you count.