Romania’s Cernavodă nuclear power station has remained fully unavailable after exceptionally low Danube flows disrupted access to cooling water. The outage removes approximately 1,400 MW of baseload capacity from the national electricity system.
Unit 1 entered a controlled shutdown in July, followed by disconnection of Unit 2 as severe drought pushed river flows to critically low levels. Together, the two CANDU reactors normally account for around 20% of Romanian electricity production.
Market impact from lost nuclear output
The simultaneous loss of both units has required Romania to cover part of the deficit through electricity imports and higher generation from gas- and coal-fired plants. The change has increased exposure to regional spot prices while European natural gas remains expensive.
Nuclearelectrica has invoked force majeure under its electricity supply contracts. The measure protects the company from penalties for volumes it cannot physically deliver and avoids an obligation to buy replacement power on the day-ahead market at exceptionally high prices.
Commercial exposure has shifted to suppliers that contracted nuclear electricity, including Electrica Furnizare, PPC Energie and Engie. Those companies must source replacement volumes from the wholesale market to meet customer obligations, raising procurement costs and potentially influencing future retail pricing.
Timeline for restart and cooling-water conditions
Government estimates indicate that Cernavodă could remain unavailable until at least the end of September. Restarting operations depends on sustained hydrological improvement sufficient to restore the technical safety margin required by the cooling system.
Local assessments indicate that a Danube flow of approximately 1,700–1,800 cubic metres per second could allow at least one reactor to return.
Regional balancing effects and water constraints
The disruption also affects wider regional power balances because Romania is normally an important producer and occasional exporter. Increased import needs can tighten supply-demand conditions in Bulgaria, Hungary and Serbia, particularly during evening peaks.
The shutdown highlights how nuclear generation depends on climate-related water constraints. While nuclear output is described as stable and low-carbon, large thermal plants still rely on reliable cooling-water availability, affecting investment priorities for cooling infrastructure, water-management systems and alternative flexibility sources.
