Romania has deployed emergency engineering measures to keep its remaining Cernavodă nuclear reactor in operation amid persistently low Danube water levels. The measures include dredging, removing underwater obstructions and positioning rock-loaded barges to redirect Danube water towards the reactor’s cooling-water intake.
The intervention is expected to extend the reactor’s operation by approximately nine to ten days, rather than the previously anticipated five to six days. While this provides additional time, it does not change the underlying hydrological situation. Danube flows have fallen to roughly one-third of their normal August level and could remain depressed beyond mid-August.
A shutdown of the second reactor would remove another 680 MW of dependable baseload capacity, leaving the entire 1.36 GW Cernavodă nuclear fleet unavailable. Romania would then become significantly more dependent on gas-fired generation, coal, electricity imports and demand-side measures, particularly during the evening peak.
The government has already authorised staged reductions in industrial consumption and could impose export restrictions if the country’s adequacy position deteriorates. This introduces an additional physical-delivery risk for cross-border electricity trading. Market participants holding commercial transmission capacity from Romania cannot assume that exports will remain available if emergency system-security measures are activated.
The risk also extends to neighbouring markets. Moldova remains heavily dependent on Romanian electricity supplies, while Hungary is structurally short and regularly imports more than 2 GW. Serbia can provide exports during selected hours, but its own hydrological position is weak and coal availability remains operationally sensitive.
Bulgaria currently represents the strongest alternative regional supplier, supported by Kozloduy nuclear generation, lignite-fired capacity, hydropower and a year-to-date electricity surplus. However, its ability to compensate for Romania’s lost nuclear generation is limited. Bulgaria cannot simultaneously replace Cernavodă output, meet its own evening demand and supply every neighbouring market at unconstrained volumes.
The situation highlights the growing importance of regional flexibility and cross-border security margins as low hydropower availability, nuclear constraints and extreme weather conditions increasingly overlap across Southeast Europe.
