Romania closes last reactor as Hungary builds emergency barrier to protect Paks
Southeast Europe has lost more than 2 GW of nuclear capacity to Danube drought in weeks, leaving grid operators dependent on imports and thermal backup.
Romania's Nuclearelectric shut down its only remaining operating reactor on Thursday (2026-08-13). The closure added to a drought-driven outage crisis that has left central and eastern European grids scrambling for replacement generation since late July, according to oilprice.com.6
The roots of the crisis trace to a gauge reading. Hungary's water managers recorded 31 centimetres at Budapest on Tuesday morning (2026-07-28), the lowest level ever measured on the Danube at that point, shattering the previous record of 33 centimetres set on October 25, 2018, according to techtimes.com. Nuclear plants along the river draw cooling water directly from the Danube; when levels fall far enough, reactors cannot operate at full capacity or at all.7
Hungary's 2 GW Paks nuclear plant took the first blow. Paks normally covers close to half of Hungary's electricity supply, but by Monday (2026-08-03) it was running at roughly a tenth of capacity as engineers fought to keep just one 240 MW reactor alive, Prime Minister Péter Magyar said, Montel reported. The same morning, about 2.44 GW, or 40%, of total southeast European nuclear generating capacity was simultaneously offline, Montel's data showed.1
The near-total loss of Paks triggered alarm in Budapest and Brussels. Hungarian PM Magyar warned of an energy crisis and the European Commission said it was prepared to convene an emergency meeting of its Electricity Coordination Group, euronews.com reported. By late on Tuesday (2026-08-04), Magyar told Montel that Paks's last operating reactor could shut within 48 hours unless rainfall in Austria raised the Danube fast enough.8,2
Rain arrived before that deadline. Magyar announced on Monday (2026-08-10) that one of Paks's turbines would be switched on that evening, with Hungary expecting to resume nuclear power generation, according to oilprice.com. Power restrictions had been lifted by Friday (2026-08-07), though Paks still faced the risk of a full shutdown if water levels retreated, Montel reported.4,3
But the recovery remains precarious. Hungary began construction of an emergency barrier to protect the Paks facility on Wednesday (2026-08-12), Montel News reported. Building a barrier is an engineering hedge against a second episode of low Danube flow, not evidence that the hydrological risk has passed.5
Romania's closure complicates the regional picture further. Cernavodă, like Paks, depends on Danube water for reactor cooling. Nuclearelectric's decision to shut its last unit shows drought conditions along the river remained severe enough by mid-August to threaten generation south of Hungary as well, oilprice.com reported. Both countries are now covering the nuclear gap through alternative sources.6
ICE Endex TTF front-month was unchanged at €63.62/MWh in the mid-morning European session on Wednesday (2026-08-19). European gas markets have not priced in acute supply stress from the southeast European nuclear outages. Power deficits in the region feed into TTF indirectly through gas-fired generation demand; that the benchmark is unchanged suggests the thermal substitution has not yet required a meaningful step-up in gas burn, or that other supply factors have offset it.
The Danube gauge at Budapest is the live risk indicator. If river levels retreat toward the record low of 31 centimetres set on Tuesday (2026-07-28), Paks re-enters crisis with only its newly started emergency barrier as a physical buffer and Romania's reactor already offline. Whether the summer rains have conclusively broken the low-water pattern, or merely paused it, is what grid operators and power traders are now calculating. Hungary's construction works buy time. They do not guarantee water.5,76