Danube Drought Takes 2 GW of Nuclear Offline in SE Europe, Lifting Romanian Day-Ahead to €141/MWh
Record low water levels on the Danube have cut reactor cooling supplies in Romania and Hungary, removing close to one-third of southeast European nuclear baseload.
PV magazine's analysis published Saturday (2026-08-01) warned that Europe's electricity markets face greater Q3 volatility as weather disruptions and limited flexibility resources widen the gap between renewable output peaks and evening demand. Southeast European prices were already pricing in that warning. Romanian day-ahead power closed Friday's (2026-08-01) session at €140.98/MWh, and Hungarian prices reached their highest level in three and a half years on Thursday (2026-07-31), Montel reported.5,4
Both moves trace to the same event. Nearly one-third of southeast Europe's nuclear capacity — approximately 2 GW — went offline by Thursday (2026-07-30) after record low water levels in the Danube basin restricted cooling water supplies to reactors in Romania and Hungary, forcing shutdowns, Montel reported.3
Reactors across the Danube basin depend on river water for cooling. When levels fall below operational thresholds, plants must curtail or halt generation to prevent thermal damage to the waterway. Prolonged dry spells expose that dependency most acutely in summer, when the grid has the least capacity to absorb the loss.
This is not the first outage in the region this year. A separate Romanian nuclear interruption of 1.3 GW on Monday (2026-05-12) strained the system, Montel reported at the time. The present shortfall is wider in scope, covering two countries and representing a larger share of sub-regional baseload.1
Market observers had already flagged heat-driven demand surges as the dominant Q3 risk heading into summer. In early July (2026-07-03), analysts told Montel that extreme weather would set southeast European power prices in the third quarter, with renewed heatwaves likely to trigger fresh spikes even if nuclear availability improved between episodes.2 The drought-driven supply contraction arrived before any heat spike has compounded the problem.
With nuclear capacity offline, gas-fired units become the natural backstop for southeast European utilities. ICE Endex TTF front-month gas closed Friday (2026-08-01) at €59.05/MWh. At 2 GW of lost baseload, the additional gas burn in the regional power stack is material, though the depth of that draw depends on how quickly Danube water levels recover and whether reactor restarts can follow before demand peaks intensify.3
Europe's thin grid-scale storage base limits the region's ability to buffer sudden baseload losses. PV magazine data published Saturday (2026-08-01) noted that the United States holds 137 GW of installed grid-scale storage capacity and China approximately 213 GW, both well above European levels. When a sub-region loses 2 GW of baseload without adequate storage reserves, adjustment falls to cross-border imports and thermal generation — neither cheap when regional supply contracts simultaneously.5
German day-ahead power closed Friday (2026-08-01) at €138.31/MWh, barely below Romanian levels. The narrow spread suggests the outage is pushing costs into the wider European grid rather than remaining contained within the sub-region, with southeast European buyers bidding for imports to cover the nuclear shortfall.
With Danube water levels sitting at record lows, the timeline for reactor restarts in Romania and Hungary stays uncertain. Both countries face extended stints as net importers in a quarter when analysts had already pencilled in elevated prices. The pace of river recovery is the primary input southeast European power traders will track when markets reopen on Monday (2026-08-03).3,4