Hungary nuclear plant nears shutdown as Danube drought triggers regional energy emergency

Hungary’s only nuclear power plant is operating at barely one-tenth of its normal capacity and could shut down completely within days as record-low water levels in the Danube River undermine the facility’s cooling system. The Paks Nuclear Power Plant, which normally generates close to half of Hungary’s electricity, had reduced output from approximately 2,000 megawatts to around 240 megawatts by August 3, 2026. Prime Minister Péter Magyar warned that the country was entering several critical days as extreme heat simultaneously increased electricity demand and reduced the amount of river water available for energy production. The crisis is spreading across southeastern Europe, where drought has also forced Romania to shut one nuclear reactor and take extraordinary steps to divert more Danube water toward another.

Hungarian authorities initially expected Paks to stop producing electricity entirely over the weekend, but voluntary consumption cuts by businesses and households provided a temporary reprieve. Officials said the plant may be able to operate at its sharply reduced level for another day or two, although there is no guarantee that river conditions will improve before the remaining units must be taken offline.

The emergency exposes a difficult climate paradox for Europe. Nuclear power is a major source of low-carbon electricity, but many reactors depend on large and reliable supplies of water to remove heat. As droughts become longer and heatwaves become more intense, rivers can become too shallow or too warm to support normal reactor operations, weakening electricity supplies at the moment cooling demand is highest.

Record-low Danube levels have reduced Paks nuclear output to barely 10%

The Paks Nuclear Power Plant operates four Russian-designed reactors with combined capacity of approximately 2 gigawatts. Under normal conditions, the facility supplies about 40% to 50% of Hungary’s electricity, making it the country’s single most important power-generating asset.

The plant draws cooling water from the Danube and returns warmer water to the river after it has passed through the facility. Falling river levels reduce the amount of cooling water available, while extreme heat raises the temperature of the water entering the plant. Both conditions limit how much electricity the reactors can produce safely.

Water levels in Budapest fell to approximately 10 centimeters, substantially below the previous record, as prolonged drought reduced the Danube across the region. Hungarian operators responded by gradually cutting output at Paks rather than shutting the entire station immediately.

The controlled reduction does not mean the reactors are experiencing a nuclear accident or uncontrolled safety failure. Operators lower output or shut reactors down when environmental conditions no longer provide the cooling margins required by regulation. The risk for Hungary comes primarily from the sudden loss of electricity generation rather than an immediate radiological emergency.

A complete shutdown would be the first caused by river conditions during more than four decades of operation at Paks. Officials have warned that the plant could remain unavailable for weeks because meaningful recovery depends on sustained rainfall upstream rather than a brief change in temperature.

That uncertainty makes the crisis harder to manage. Hungary can plan for a short reduction by importing electricity and asking industrial users to conserve power. A shutdown lasting several weeks would require more expensive imports, greater fossil-fuel generation and potentially mandatory restrictions on large consumers.

Electricity conservation has delayed the shutdown but cannot replace Hungary’s largest power source

The government has asked companies, public institutions and households to reduce electricity use, particularly during the evening when solar generation declines and air-conditioning demand remains high. More than 300 businesses reportedly agreed to voluntary reductions, helping stabilize the grid and allowing Paks to remain partly operational.

Major companies participating in the conservation effort include MOL Group, Samsung SDI, Audi and Denso. Hungarian pharmaceutical manufacturer Gedeon Richter also announced significant reductions in electricity consumption. Public buildings have turned off decorative lighting, and authorities have considered slowing or suspending some freight-rail operations during peak periods.

These measures can reduce the immediate demand placed on the grid, but they cannot replicate the continuous output normally supplied by the nuclear plant. Hungary has expanded solar capacity rapidly, yet solar farms produce little or no power after sunset, precisely when households continue using air conditioning and other appliances.

The country must therefore rely more heavily on natural gas plants, coal generation and imported electricity when Paks output declines. Regional imports are limited because neighboring countries are facing the same heatwave, drought and power-demand pressures.

The cost of replacing lost nuclear generation could reach between 100 billion and 200 billion Hungarian forints, equivalent to roughly $315 million to $630 million, depending on the duration of the shutdown and wholesale electricity prices.

Those expenses would arrive as Hungary is already dealing with inflation, budget pressure and the wider economic consequences of drought. Higher electricity prices could affect factories, transportation, food production and household bills even if the government prevents immediate rolling blackouts.

Mandatory restrictions remain possible if voluntary measures are not sufficient. Authorities would probably prioritize essential services such as hospitals, water utilities, telecommunications and emergency facilities while requiring energy-intensive industrial customers to reduce or suspend production.

Romania used explosives to redirect Danube water toward its last operating reactor

The Danube crisis is not confined to Hungary. Romania has already shut one of the two reactors at its Cernavodă Nuclear Power Plant because falling water levels restricted cooling capacity.

On August 3, Romanian naval forces carried out a controlled explosion involving approximately 180 kilograms of explosives to remove rock and redirect water toward the plant’s remaining operating reactor. The operation was intended to create enough flow for authorities to build a temporary dam and keep the second unit functioning for several more days.

The extraordinary intervention illustrates how rapidly an environmental problem has developed into a national energy emergency. Romania declared a state of alert and asked businesses and citizens to conserve power while officials attempted to preserve the remaining nuclear output.

Automakers Dacia and Ford suspended production to reduce electricity demand by approximately 200 megawatts. Industrial shutdowns may protect the grid, but they also reduce economic output, interrupt supply chains and affect workers whose facilities cannot operate normally.

Serbia is confronting similar pressure. Hydroelectric production at its largest facilities reportedly fell to about 20% of normal output as river levels declined. Hydropower and nuclear energy use water differently, but both can become vulnerable when drought reduces river flow.

The simultaneous disruption of nuclear and hydroelectric generation weakens the region’s ability to compensate from one low-carbon source when another becomes unavailable. Countries must instead compete for imported power or increase fossil-fuel generation, driving prices higher across interconnected European markets.

Europe’s heatwave is creating an electricity shortage when cooling demand is highest

The immediate crisis has been created by the collision of falling supply and rising demand. Extreme temperatures increase the use of air conditioners, refrigeration equipment, pumps and cooling systems. At the same time, drought reduces hydropower output and limits water-cooled nuclear and thermal power plants.

Hungarian officials warned that electricity demand could rise by approximately 20% during peak evening hours as temperatures approached 40 degrees Celsius. Solar generation helps during daylight hours, but the system becomes more vulnerable when the sun sets and demand remains elevated.

This pattern can create a steep evening shortfall. Grid operators must rapidly replace disappearing solar production with nuclear, gas, coal, hydroelectric or imported power. With Paks operating near minimum capacity and neighboring countries under similar pressure, Hungary has fewer reliable options.

The problem extends beyond electricity generation. Low Danube levels are disrupting cargo shipping, industrial water use and municipal supplies in more than 100 communities. Agriculture is also suffering as heat and drought damage crops and increase irrigation demand.

Wildfires across Europe are adding another strain by damaging power lines, forcing evacuations and consuming emergency resources. The combined effects show how a prolonged climate event can place pressure on several infrastructure systems simultaneously rather than creating one isolated problem.

Energy conservation becomes more difficult during dangerous heat because reducing electricity use can also mean reducing cooling. Governments must avoid measures that expose older people, hospital patients and other vulnerable residents to heat-related illness.

Nuclear power remains low carbon, but climate resilience is becoming an urgent design requirement

Nuclear plants provide large amounts of electricity without the direct carbon emissions associated with coal or natural gas. They also operate continuously under normal conditions, helping stabilize grids that include variable wind and solar generation.

The Paks crisis does not erase those advantages. It shows that low-carbon infrastructure must also be designed for the physical conditions created by a warming climate.

Plants that rely on rivers may need improved cooling towers, larger reservoirs, alternative water sources or systems capable of operating with lower flows and higher temperatures. These upgrades can be technically difficult and expensive, particularly at older facilities designed using historical climate assumptions.

Hungary is already planning to expand Paks through two additional Russian-built reactors. The present emergency is likely to increase scrutiny of whether the new units will be sufficiently protected from prolonged drought and extreme Danube conditions.

Cooling technology will become a central issue in that debate. Once-through systems withdraw large quantities of river water and return it at a higher temperature. Cooling towers can reduce direct dependence on river flow, but they still consume water and require substantial infrastructure.

Europe may also need stronger regional interconnections and additional energy storage so countries can share electricity during climate-driven emergencies. The challenge is that extreme heat and drought frequently affect several neighboring countries at once, limiting how much assistance any one market can provide.

The energy emergency therefore carries a broader warning. Replacing fossil fuels is essential for reducing future warming, but the low-carbon system being built must also survive the heat, drought and water scarcity that are already occurring.

Key takeaways from Hungary’s Paks nuclear plant emergency

• Hungary’s only nuclear power plant was operating at around 240 megawatts on August 3, barely 10% of its normal 2,000-megawatt capacity.
• Paks normally supplies approximately 40% to 50% of Hungary’s electricity, making a complete shutdown a major threat to national power reliability.
• Record-low Danube levels have reduced the cooling water available to the plant, while extreme heat has increased the temperature of the remaining river flow.
• The reduced output is a controlled safety response rather than evidence of a nuclear accident, but the loss of generation could produce shortages and higher electricity costs.
• Voluntary electricity reductions by more than 300 companies helped delay a complete shutdown, although officials warned the reprieve may last only one or two days.
• Hungary could spend hundreds of millions of dollars replacing lost nuclear generation through more expensive imports and fossil-fuel production.
• Romania has already shut one reactor and used a controlled explosion to redirect Danube water toward the remaining unit at the Cernavodă Nuclear Power Plant.
• Automobile manufacturers and other major industrial users have halted or reduced production to protect regional electricity grids.
• The crisis demonstrates how heatwaves can raise power demand while simultaneously reducing nuclear and hydroelectric generation.
• Europe’s low-carbon energy strategy will increasingly depend on whether nuclear plants, grids and water systems can withstand prolonged drought and extreme heat.