Cernavodă Stays Online By Centimetres

Romanian military divers blew up a rock formation in the Danube on 3 August, lifting the water level near Cernavodă by about two centimetres (Euronews România, Financial Intelligence). In normal politics, two centimetres is nothing. At Cernavodă, Romania's only nuclear power station and its biggest source of steady electricity, it can mean another day of cooling water. The Danube had been falling by 2-3 cm a day, leaving the plant about four to five days away from losing enough flow to keep running (AGERPRES).

Hungary has already shown what happens when the water is no longer there. Paks, which normally supplies roughly half the country's electricity (World Nuclear Association), began shutting down in stages from 27 July after the Danube dropped too low for the pumps drawing cooling water from the river. By 2 August, only one of eight turbogenerators was still running (MVM). Both Romania and Hungary asked factories to cut consumption so households could keep the lights on.

Engineering the river

The Pârjoaia rock sat near the point where the Danube splits into the Old Danube, which feeds Cernavodă's cooling intake, and the Bala Branch, which had been taking most of what flow remained. The explosion was the part people could see. Around it sat the actual mechanism: crews dredged the silted intake channel and sank four barges loaded with stone to form a temporary underwater wall (Curs de Guvernare, Libertatea). The government put aside about 7 million lei for the work, not much for emergency river engineering and far less than the cost of replacing Cernavodă's output with imported power.

Energy Minister Radu Miruță said the gain reached about +4 cm once the water moved downstream (Digi24). The full package is meant to produce 10-12 cm of extra water (HotNews). But the Danube is still falling. Hydrologists expect the river at Baziaș to drop to 1,350 m³/s by 10 August, below the 1,400 m³/s historic minimum recorded in 1985 (AGERPRES). The blast bought Romania time. It did not change the river's direction.

Hungary's missing megawatts became everyone's price problem

At one peak hour on 4 August, Hungary imported 3,195 MW while producing 3,049 MW at home. More than half the country's electricity was coming from outside its borders (Portfolio).

That demand fed straight into regional prices. Central and south-eastern European grids are tied together through cross-border auctions: when one country needs more electricity than it can generate, it bids for imports, and the price rises across connected zones. By 29 July, day-ahead prices, meaning the auction price set the day before electricity is delivered, in the Hungarian-Serbian corridor averaged €132/MWh, with hourly spikes reaching €268/MWh (Serbia Energy). Forward contracts for the following week climbed into the €250-263/MWh range (Argus). Replacing 2 GW of nuclear power with spot imports during a heatwave, when air conditioners are pushing demand up across the region, is costly. Those forward prices show traders expected the squeeze to continue.

Not every plant is equally exposed

Bulgaria's Kozloduy nuclear plant draws cooling water through a pumping station in a deep bay, leaving it less exposed than Cernavodă's open channel. Bulgaria's energy ministry said it expected no significant reduction for at least three weeks (BTA). Austria shows the other side of the ledger. VERBUND, the country's biggest hydropower operator, reported first-half 2026 generation 9.8% below the previous year (VERBUND), yet Austria was still exporting power in June (APG). It had enough other generation and grid flexibility to absorb the same drought.

Romania can buy days with barges, dredging and military divers. It cannot keep treating cooling water as an emergency repair job if hotter, lower summers become a regular part of Europe's energy system.