France-Germany day-ahead power spread

The France-Germany day-ahead power spread is the differential between the day-ahead electricity clearing prices published by EPEX SPOT for France and Germany, settled each afternoon for next-day delivery. France's grid is structurally nuclear-long, giving it a near-permanent baseload cost floor and making it the traditional cheaper leg, while Germany's price is set by its gas-and-carbon CCGT stack, tracking EUA carbon allowances and TTF gas prices at the margin. The spread is therefore a live read on relative nuclear availability versus gas-and-carbon costs, and a core relative-value trade for European power desks, which take a position on the gap persisting or reverting.

The spread has moved through an extreme volatility regime since June 2026. It set a series record of EUR 96.20/MWh on 8 June (France EUR 28.05, Germany EUR 124.25), just five days after the prior record of EUR 93.68 on 3 June. It then inverted entirely on 15 June, French cooling-water curtailment risk making France the dearer leg by EUR 1.6/MWh, before resetting to Germany dearer by EUR 19.31 on 17 June as EDF's fleet ran without curtailment. On 22 June, with EDF nuclear revenues still below the EUR 78/MWh VNU trigger, France held the cheaper leg by EUR 17.29. A 30 June heatwave and a 12% nuclear output cut (Bugey 3 offline) widened the gap to its peak of EUR 71.50, with France still cheaper at EUR 123.50 against Germany's EUR 195. That peak then unwound fast: as the heat broke, the spread compressed roughly 70% by 4-5 July to around EUR 18-26/MWh, with German day-ahead falling from EUR 195 to roughly EUR 62-64 and France holding the cheaper leg throughout. The next structural test is Flamanville-3's year-long overhaul from September 2026, which removes 1.6 GW of French nuclear capacity just as heating-season demand begins; the open question for the desk is whether France keeps its discount once that capacity is offline.

That test arrived early. On 12 July, EDF took Chooz, Golfech and Bugey fully offline on cooling-water discharge limits, and the spread inverted outright: France cleared roughly EUR 7/MWh above Germany, a full reversal of the EUR 18-26/MWh France-cheaper reading from just a week earlier on 5 July. The mechanism is now well established from repeated episodes: when enough reactors come off for cooling-water compliance, gas-fired plant sets the French marginal price instead of nuclear, and France loses its structural discount to Germany. That inversion also unwinds the standard desk trade, long French nuclear exposure against short German carbon-linked power, which depends on France holding the cheaper leg. By 13 July the spread had partly reset, with France back to roughly EUR 3/MWh cheaper as some curtailed capacity returned, but the round-trip confirms the spread now flips on any cooling-water curtailment episode rather than settling into a stable discount, with Flamanville-3's September outage set to test how durable any recovery proves.