Updated: 17 September 2026 la 11:17. Articolul a fost revizuit pentru a reflecta informațiile disponibile la această dată.
Romania is facing one of the most unusual situations of recent years for its National Energy System: neither of the two nuclear reactors at Cernavodă is producing electricity.
Unit 1 was shut down in a controlled manner on 28 July 2026, and on the morning of 13 August, Nuclearelectrica began procedures to shut down Unit 2. The reason is the same in both cases: the Danube’s extremely low level, caused by severe drought, no longer allows the units to operate within the limits set by safety procedures.
Data published by Transelectrica for 16 August 2026 still showed 0 MW of nuclear generation, meaning Romania must temporarily make up for one of the system’s most important and stable electricity sources.
How much power Romania lost when Cernavodă shut down
The Cernavodă Nuclear Power Plant operates two CANDU reactors, each with an output of around 706 MW.
Together, the two units can provide approximately:
1,400 MW of nuclear capacity.
Under normal conditions, Cernavodă provides around 20% of Romania’s electricity generation, which explains the significance of both reactors being shut down simultaneously.
Nuclear power also has a major advantage for the system: unlike solar and wind power, it can generate electricity almost constantly, regardless of whether it is night-time, cloudy or windless.
That is why the temporary loss of around 1,400 MW of nuclear generation must be continuously offset by other sources.
Why the reactors were shut down
The problem was not caused by a nuclear malfunction.
The drought and the exceptionally low level of the Danube are the main cause.
Nuclearelectrica officially stated that Unit 1 was shut down because of the Danube’s unprecedentedly low level, and that the measure was taken in accordance with procedures applicable to severe drought conditions.
In Unit 2’s case, the company announced on 13 August that the continued and significant decline in the Danube’s level had led it to begin controlled shutdown operations.
Danube water is essential to the cooling systems associated with the plant’s operation.
When water-level parameters approach permitted limits, plant procedures provide, among other measures, for the possible shutdown of a reactor in order to preserve safety margins.
Is there a nuclear danger?
No.
The shutdown of both reactors does not mean there has been an accident or a nuclear safety problem.
Nuclearelectrica explicitly states that keeping the two units in a safe shutdown state does not affect nuclear safety parameters and has no impact on staff, the public or the environment.
In practice, the reactors were shut down as a precaution precisely to ensure that all safety limits and margins are observed.
Is there a risk of power cuts in Romania?
Shutting down both reactors places serious pressure on the National Energy System, but does not automatically mean Romania will experience power cuts.
After Unit 2 was shut down, the Ministry of Energy said the National Power System was stable and that, based on available forecasts, demand could be covered by alternative domestic generation and imports.
For the evening peak in demand on 13 August, authorities estimated import needs of no more than 2,300 MW, while cross-border capacity available for imports was around 4,000 MW.
This gives the system a significant margin.
However, the situation must be monitored daily because renewable generation can vary considerably.
How Cernavodă generation is being replaced
The roughly 1,400 MW that the two reactors could generate must be replaced by a combination of several sources.
Authorities are relying mainly on:
- electricity imports;
- hydropower generation, to the extent water reserves allow;
- coal- and lignite-fired power plants;
- gas- and hydrocarbon-fired power plants;
- wind power;
- solar photovoltaic power during the day.
The Ministry of Energy also brought online around 330 MW of lignite-fired capacity, while wind, hydropower and imports are being used to offset the nuclear shortfall.
The problem arises especially when several adverse factors coincide.
For example, on a very hot evening, demand may be high because of air-conditioning use, while solar photovoltaic output declines rapidly after sunset.
If wind generation is also low at the same time, import needs may rise significantly.
Why evenings are the most sensitive period
Solar power has become an important component of Romania’s generation mix, but it has an obvious limitation: after sunset, photovoltaic output falls towards zero.
At the same time, household consumption may remain high.
This is why authorities have called for voluntary reductions in consumption during peak periods, especially in the evening. Romania is under an energy alert in August, and energy-saving measures are intended to ease pressure on the system.
This does not mean people must switch off all electrical appliances, but moving some large loads outside peak hours can help the system.
Could large companies’ consumption be limited?
There is also a contingency plan.
In the event of a severe deterioration in the energy situation, authorities have prepared for the possibility of phased, pre-announced reductions in the consumption of certain large industrial users. Reuters reported that the government had prepared this option as a last-resort measure if energy supply became insufficient.
The priority, however, is to avoid such measures by using available domestic generation and imports.
For households, authorities have not announced a programme of controlled interruptions at this time.
Could electricity prices rise?
Pressure on prices may increase.
Nuclear power from Cernavodă is a large and relatively steady source of electricity.
When around 1,400 MW disappears from domestic generation, Romania must buy more electricity from other sources or through imports.
During periods when other countries in the region also have high consumption or low generation, electricity available on the market may become more expensive.
Reuters warned as early as late July that the reactor shutdowns could increase Romania’s dependence on imports and put pressure on energy prices.
For household consumers, this does not necessarily mean an immediate and uniform change in bills, because the final price also depends on supply contracts and the mechanisms in place in the energy market.
Romania tried to avoid shutting down Reactor 2
Before the last operating unit was shut down, unusual measures were attempted to increase the amount of water available near the plant.
Authorities intervened in the Danube’s course, including through dredging work, the controlled detonation of obstacles and the use of barges loaded with material to redirect flow towards the Cernavodă area.
The measures temporarily extended Unit 2’s operation, but the Danube level continued to fall.
Ultimately, Nuclearelectrica decided on a controlled shutdown.
When will the Cernavodă reactors restart?
At present, there is no firm restart date.
Nuclearelectrica says Cernavodă NPP specialists will decide when to reconnect the units on the basis of forecasts for the Danube level, while observing all nuclear safety margins.
The company said it would inform the public when Units 1 and 2 are reconnected to the National Energy System.
As of 16 August 2026, Transelectrica data still indicated 0 MW of nuclear generation, showing that the reactors had not returned to National Energy System generation by that point.
Everything now depends on the Danube
The situation at Cernavodă shows how important water is to energy generation, including at nuclear plants.
The issue is made even more complex because the same drought affecting Cernavodă can also reduce hydropower generation.
As a result, two major low-carbon energy sources can be affected simultaneously.
In addition, heatwaves raise electricity consumption through air-conditioning use.
The result is a difficult combination for the system:
zero nuclear generation + pressure on hydropower + high consumption + greater import needs.
What happens if the drought continues
If the Danube’s flow remains very low, the reactors may stay shut down until the parameters required for safe operation are met again.
During this period, Romania will have to rely more heavily on:
coal + gas + hydropower + wind + solar + imports.
In the short term, the main challenge is not an absolute lack of capacity, but maintaining a constant balance between generation and consumption, especially during peak hours.
A period of weak winds, reduced hydropower generation, high temperatures and lower import availability could place additional strain on the system.
Romania has no nuclear generation, but the system continues to operate
The shutdown of both Cernavodă reactors means the temporary loss of around 1,400 MW of nuclear capacity and of a source that normally provides around 20% of Romania’s electricity generation.
The situation is unusual and places considerable pressure on the National Energy System, but it does not mean Romania has run out of electricity, nor that power cuts are inevitable.
The Ministry of Energy said the system remains stable and that the shortfall is being offset by generation from other power plants and imports.
The most important indicator in the coming days will be the level of the Danube.
Only once conditions again allow operation with all necessary safety margins will Nuclearelectrica be able to begin reconnecting the reactors.
Until then, Romania remains in a rare situation for its energy system: 0 MW of nuclear generation and far greater dependence on other energy sources and imports.
For more information about Cernavodă, see also Cernavodă Nuclear Power Plant Has Shut Down Completely: Romania Temporarily Without Nuclear Power, which provides additional details on this subject.
See Romania’s energy generation in real time
The shutdown of both Cernavodă reactors requires the National Energy System to replace around 1,400 MW of nuclear capacity with other sources and imports.
On InfoBuz, you can follow Romania’s electricity generation and consumption in near real time, including the contribution of hydropower, wind, solar, coal and hydrocarbons, as well as the level of electricity imports and exports.
The dashboard is particularly useful during this period because it makes it possible to directly observe how Romania’s energy mix changes when nuclear generation is unavailable.
The energy situation was already strained before Cernavodă’s complete shutdown
The shutdown of both reactors comes at a time when the National Energy System is already facing high temperatures, increased consumption, hydropower generation affected by drought and greater dependence on imports.
InfoBuz previously analysed the risk of power cuts in Romania and the energy alert situation in August 2026, including the scenarios considered in the event of a significant generation shortfall.
At present, the complete shutdown of nuclear generation makes this situation even more significant, especially during evening peak-demand hours.
Short version for direct insertion in the middle of the article
To see in real time how the absence of nuclear generation is being offset, follow Romania’s LIVE electricity generation, consumption and energy mix, which displays the main energy sources and electricity exchanges with neighbouring countries.
Link version to the energy alert article
The current problems did not begin with the shutdown of the second reactor. Romania was already dealing with a strained energy system, and in a separate analysis we explained why Romania entered an energy alert and how real the risk of power cuts is.
Frequently asked questions
Why are both Cernavodă reactors shut down?
Both units were shut down in a controlled manner because of the Danube’s very low level, which affects the conditions required for the plant to operate safely. The shutdown was not caused by a nuclear accident.
How much power did the two Cernavodă reactors generate?
Together, Units 1 and 2 can provide around 1,400 MW, normally representing about 20% of Romania’s electricity generation.
Does Romania risk power cuts after the reactors’ shutdown?
Shutting down the two reactors puts additional pressure on the National Energy System, but it does not automatically mean there will be power cuts. The shortfall can be offset by other domestic sources and electricity imports.
How is Romania making up for the lack of nuclear power?
The missing energy is being offset through a combination of hydropower, gas, coal, wind power, solar power and electricity imports. The share of each source can change from one hour to the next.
Is there a nuclear danger to the public?
No. The reactors were shut down in a controlled manner and are being kept in a safe state. The precautionary shutdown is a protective measure and does not indicate a nuclear accident or a radiological danger to the public.
When will the Cernavodă reactors restart?
There is not yet a firm date for a restart. Reconnection to the National Energy System depends on changes in the Danube level and on meeting all nuclear safety conditions.
Could electricity prices increase?
Yes. The shutdown of a steady source of around 1,400 MW may increase reliance on imports and on power plants with higher generation costs. This may put pressure on wholesale-market prices, although the effect on consumer bills depends on contracts and supply mechanisms.
Where can I see Romania’s electricity generation in real time?
InfoBuz’s Romania Energy LIVE dashboard displays generation, consumption, the main energy sources and electricity exchanges with other countries.
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