Romania is unlikely to restart either reactor at the Cernavodă nuclear plant for at least another 10 days, pushing recovery beyond mid-September. The delay extends the loss of around 1.3-1.4 GW of baseload generation and keeps Romania reliant on imports during the evening peak. Nuclearelectrica technical director Emil Macovei said Danube conditions remained insufficient to support restarting even one unit.
Unit 1 has been offline since July 28, while Unit 2 has been out of service since Aug. 13. Earlier expectations pointed to a reassessment around Sept. 10. The latest hydrological outlook now points to a meaningful nuclear recovery occurring beyond mid-September.
Cernavodă outage shifts Romania’s power balance during evening hours
Cernavodă normally provides a large block of Romania’s low-marginal-cost baseload generation. With both reactors offline, its absence has materially changed the country’s power balance. Romania has increased reliance on coal, gas, hydro, renewables and cross-border imports since the reactors went offline.
The impact is strongest during evening hours after solar production declines. Recent day-ahead markets have repeatedly shown prices above €250/MWh during the evening peak across Romania and neighbouring markets. The prolonged outage increases exposure to those higher-price periods.
Regional import pressure and hydrological constraints elsewhere
The extended shutdown also increases pressure on Hungary and Bulgaria, which are among Romania’s main potential import sources. As a result, Cernavodă availability has become a regional rather than purely domestic trading factor. The wider shutdown follows low Danube levels that affected nuclear generation elsewhere in the region.
Hungary’s Paks plant and Bulgaria’s Kozloduy faced hydrological restrictions during August. Kozloduy has since restored part of the lost output, but Romania remains the most severe case.
Cooling-water risk and implications for market pricing
The situation reflects a growing climate-risk issue for large thermal and nuclear plants that depend on river water for cooling. Nuclear generation is normally treated as firm supply, but prolonged drought can reduce that firmness when hydro output may also be weak. This creates correlated hydrological risk across multiple technologies.
Romania has already been forced to consider emergency measures, including water-management interventions and temporary support for thermal generation. As the nuclear outage continues, those measures become more important for balancing supply and demand.
The impact extends into forward power prices as traders factor in uncertainty over restart timing, hydrology and the availability of flexible thermal generation. Even a partial restart would improve Romania’s position, but until there is enough water to operate safely, the system remains exposed.
The key risk is tied not only to the lost 1.3-1.4 GW of nuclear capacity but also to where that capacity sits in the supply stack. The missing output comes from the portion of supply that normally provides stable, low-cost power around the clock. That configuration leaves Romania unusually dependent on imports and expensive flexibility during evening scarcity hours.
