Romania Blasts the Danube for Nuclear Power

Romania's two nuclear reactors at Cernavodă have been offline since mid-August, and the government is now physically reshaping the Danube riverbed to get them running again. Crews are blasting underwater rock and releasing reservoir water to push enough flow toward the plant's cooling intake. The bill for replacing 1.4 GW of cheap, steady power that normally runs day and night is landing on importers, industrial buyers and electricity markets across the region (World Nuclear Association).

How a river shuts down a reactor

Cernavodă supplies about a fifth of Romania's electricity (World Nuclear Association). The plant works like any nuclear station: the reactor boils water into steam, the steam spins turbines, and then the Danube cools that steam back into water so the cycle can repeat. When the river drops too low for the intake pumps, the plant stops producing power. There is no safety problem. There is just no coolant.

Unit 1 went offline on 28 July. Unit 2 followed on 13 August, after river flow at Baziaș fell to roughly 1,350 m³/s, about a third of the normal August average (Agerpres, Digi24). Nuclearelectrica's Romeo Urjan told the BBC he did not expect a restart within ten days (BBC). Romanian reporting as of 21 August said a restart before September looked unlikely (Recorder).

Earlier emergency works, including underwater blasts and rock-filled barges, bought about 8 cm of extra water level and nine more days of operation for Unit 2 before it had to stop (HotNews). On 22 August, Romania's emergency committee approved a new round: more dredging, plus releasing extra water from Olt reservoirs at 50 m³/s for five days (Agerpres, News.ro). Each reservoir release borrows water that would otherwise serve irrigation or downstream hydro. Romania is buying time with infrastructure margins, not solving drought.

Who pays for the missing power

The lights stayed on. That does not mean the replacement power was cheap. On the first evening without nuclear, imports covered about 1,839 MW at peak, or 27.4% of consumption (Curs de Guvernare). Day-ahead prices on the OPCOM exchange (power bought for delivery the next day) topped 1,700 lei/MWh for the evening peak on 13 August (Gândul). Romania restarted a ~300 MW coal unit at Rovinari to cut reliance on those imports (Romania Insider).

Nuclearelectrica invoked force majeure (a legal claim that an extraordinary event prevents it from fulfilling contracts), warning customers it might not meet delivery obligations (ZF). Large industrial consumers carry the next layer of risk: Romania's emergency framework allows curbing industrial demand and suspending exports if needed (Balkan Green Energy News).

The winners are those with power to sell. Bulgarian and Hungarian traders sought 3,500–4,000 MW of cross-border capacity (the right to move electricity across interconnectors) as Romanian and Hungarian nuclear output dropped, making Bulgaria's Kozloduy plant temporarily one of the region's most valuable generators (Mediapool). On 17 August, regional day-ahead prices ran from €153/MWh in Greece to €173/MWh in Romania and roughly €184/MWh in Hungary (Newmoney).

The same drought, different borders

Hungary's Paks plant shows the same physics. MVM began reducing output on 27 July when its Danube gauge hit -106 cm; by 2 August, only one of eight turbogenerators was still running (MVM Paks, MVM Paks). Hungary's daily net import bill rose from about HUF 0.6 billion in late July to nearly HUF 4 billion by early August (Telex/G7). In France, Le Monde's analysis of EDF data found environmental constraints peaked at 12.8 GW of unavailable nuclear capacity on 16 August (Le Monde).

Every country found a workaround: dredging, coal restarts, reservoir releases, imports. Romania's coal restart collides with EU recovery-fund commitments to close those same plants; Bucharest has already told the European Commission it wants to delay those closures (HotNews). The Commission's Electricity Coordination Group said the wider system remained stable (European Commission). Europe's grid can absorb this kind of climate shock, but only by paying more for imports, coal, gas and scarce interconnector space. Each fix draws on someone else's reservoir, coal allowance or export surplus.