Hungary’s state utility company MVM was forced to shut down one of four blocks at the Paks power plant with 500 MW capacity for the first time ever due to environmental regulations as water levels on the Danube fell to historic low levels, state news agency MTI writes on July 29.

The state-owned operator had begun scaling production earlier this week. Output of block 1 was cut by 254 MW, followed by a 237 MW reduction at unit 3 before that latter block was fully shut down. This means that Hungary’s sole power plant, accounting for 40% of electricity consumption, was operating at 60% of capacity during the day, and further measures could be taken if the situation deteriorates.

The latest disruption highlights the increasing pressure that climate extremes are placing on thermal power generation across Europe. Nuclear power plants rely on rivers for cooling, but environmental regulations restrict the temperature of discharged cooling water to safeguard aquatic ecosystems. In Hungary, cooling water returned to the Danube must not raise the river's temperature above the regulatory limit of 30°C at the designated downstream monitoring points.

Energy analyst Zsolt Harfas told MTI that MVM has repeatedly reduced output during previous summers because of high river temperatures, but this is the first time an entire block was taken offline due to exceptionally low water levels. The measure was taken to ensure the safe operation of the remaining units and comply with environmental regulations. This time, the operator cut the output not because of the river's high temperature, as in previous cases.

Citing data from grid operator Mavir, Harfas said that lower output was replaced by higher electricity imports and by ramping up production at gas-fired power plants. Imports were expected to approach 4 GW during the evening peak as solar generation declined sharply after sunset. After 6 pm, PV plants were producing only about 1 GW, while wind generation remained negligible at just 20-25 MW despite 325 MW of installed capacity.

During last month’s heatwave, the grid operator reported a record 7,488 MW consumption at one stage, surpassing the previous summer record of 7,036 MW set in July 2024. Analysts said that the summer consumption record is unlikely to be broken as many Hungarians are abroad on holiday.

Environment Minister Laszlo Gajdos said water authorities have deployed four floating pumping units and two floating cranes near Paks while placing 55 specialists on 24-hour standby. Although pumping is not yet required, the equipment is ready to secure cooling water supplies should river conditions deteriorate further.

Other analysts did not rule out further production cuts at Paks if extreme weather conditions persist. Paks, which was considered insulated from weather-related disruptions, has become increasingly vulnerable to prolonged droughts and rising river temperatures.

Paks, which supplies roughly half of Hungary's domestic electricity generation in normal operating conditions, has become increasingly exposed to periods of low river flow and elevated water temperatures as summers become hotter and drier. The country is simultaneously expanding renewable energy and preparing to build two new Russian-designed VVER-1200 reactors under the long-delayed Paks 2 project.

The shutdown comes as Hungary faces its most severe drought on record, with another extreme heatwave expected to hit the country in the coming days, with temperatures in the upper 30s.

The government has declared the highest level of drought emergency after 66 of the country's 84 water management districts exceeded critical drought thresholds. This means that emergency defence measures were taken across 74% of the country to combat the drought.

Prime Minister Peter Magyar, in a Facebook post, sought to reassure the public that electricity supplies remain secure, stressing that Hungary's 3.6-3.8 GW of cross-border import capacity would allow the country to maintain supply even under more adverse scenarios.

Under clear rules, only major industrial consumers may have their usage temporarily restricted in an emergency, he said, adding that the public could also help by using energy more efficiently. Magyar said the government was not asking people to stop using electricity or air conditioning, but was recommending restructuring consumption where possible to ease pressure on the grid during the evening demand peak.

Low water levels are also threatening drinking water supplies in some areas. Regional response committees are assessing the settlements affected, while water works and the Hungarian Armed Forces are prepared to refill reservoirs and, if necessary, provide drinking water via tankers, the prime minister said.

The minister for the living environment will meet with the 10 water utility providers on July 30 to finalise a list of major industrial consumers whose usage could be restricted if the situation worsens.

The government has established an Energy Supply Operational Unit to coordinate contingency planning and, if needed, prepare emergency demand-management measures.

Hungary’s chief medical officer has declared a third-level heat alert for the entire country from midnight on July 30 until midnight on August 4, based on the latest weather forecast.