Corrosion found in French nuclear plant: EDF investigates the scale of the issue
Short term:
Both the power and gas markets moved last week for different reasons. Power prices in France surged after new corrosion was detected at the French nuclear reactor Civaux 2. On Thursday, EDF announced it would investigate three similar N4-type reactors for potential corrosion issues. At Civaux 2, cracks of 2 to 3 millimeters were found in the welds of pipes. The total capacity of the four affected reactors (Civaux 1 and 2, and Chooz 1 and 2) is around 6 GW. Surprisingly, these pipelines were repaired just two years ago, when much of France’s nuclear fleet was offline due to a similar corrosion problem. This sparked market concerns, pushing the French baseload price for July up by around 6 euros to 46.5 €/MWh. The Q4-25 contract, which had closed just under 75 €/MWh the week before, rose to 83 €/MWh. Winter contracts could rise significantly if further corrosion is found—particularly in other reactor types.
Meanwhile, the escalating conflict between Israel and Iran also influenced markets. The Strait of Hormuz remains a key route for oil and LNG shipments. Given the tensions, it is not unthinkable that Iran could attempt to block the strait. Houthi rebels in Yemen, supported by Iran, may also try to target vessels headed for the Suez Canal. In December 2023, several drone attacks forced oil tankers to reroute around the Cape of Good Hope. As a result, gas became nearly 2 euros more expensive, with the contract for the upcoming month closing at 37.9 €/MWh. CO2 prices rose by 2.5 euros to 76 €/EUA.
Dutch power prices for the coming months increased by roughly 2 to 4 euros. July closed at 79 €/MWh, and August at 82.4 €/MWh. Clean spark spreads for these months became more negative, at around -20 and -18 €/MWh. Winter contracts saw sharper increases, with Q4-25 and Q1-26 closing at 101.9 and 102.4 €/MWh, respectively. Clean spark spreads for those quarters widened by around 1 to 1.5 euros.
Electricity (€/MWh)
Gas (€/MWh)
Long term:
Gas for 2026 also increased, though less dramatically than the short-term contracts. TTF closed a little over 1 euro higher at 36.1 €/MWh. CO2 finished the week at 78 €/EUA. Dutch power rose by 4 euros to 88.9 €/MWh, and the clean spark spread for next year improved slightly to around -8 €/MWh.
Weekly changes
Base (€/MWh)
Peak (€/MWh)
Gas (€/MWh)
CO2 (€/MWh)
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