Low Danube levels threaten power supplies across Central and Southeastern Europe
Low Danube levels, heat and drought are reducing generation at river-cooled plants and forcing production cuts in Hungary and Romania while countries with storage and different cooling systems fare better.
Historic drought, record heat and an unusually low Danube are straining power systems across Central and Southeastern Europe, threatening supplies and forcing industry to scale back output. Hungary and Romania face the most acute risks, while neighboring states feel varied impacts depending on their energy mix and storage capacity.
The combination of months without significant rain and successive heat waves has already reduced agricultural yields—especially for maize and sunflower—and disrupted road, rail and river transport as watercourses shrink and asphalt softens. But the most immediate danger for some countries is to electricity production, where falling river levels have curtailed hydro and cooling-water-dependent generation.
Critical outages in cooling-dependent plants
Hungary is the hardest hit. Much of the country has seen virtually no rain for months and on 5 August 2026 Budapest registered 43 degrees Celsius, with many locations exceeding 40 degrees. The Paks nuclear power plant, south of Budapest, has had to almost halt operations because the Danube no longer provides sufficient cooling water and river temperatures are too high; it is currently operating at only about 12 percent capacity. If the Danube level continues to fall, the plant could be forced offline entirely.
Paks supplies roughly half of Hungary's domestically produced electricity and covers about one third of total consumption. That concentration, combined with limited storage, comparatively little flexible gas capacity and modest wind and hydro reserves, has prompted the Hungarian government to repeatedly call on large consumers to cut usage. Several major manufacturers, including Audi Győr and the oil and chemical group MOL, have already reduced output. Even once river levels recover, restarting reactors will take time, meaning Hungary may need to import costly power for weeks.
Romania is facing a similar, though slightly less severe, situation. The Cernavodă nuclear plant—located on the Danube—generates roughly one fifth of Romania's electricity. Last week one of the two 700-megawatt units had to be taken offline because of low water levels. Romanian authorities excavated rock southwest of the plant and dropped tens of tonnes of stones into the river to steer more flow toward Cernavodă; the navy used underwater explosives to break up rock in the Danube to improve water supply to the plant. Romania’s diversified mix—hydro, nuclear, gas, coal and wind—offers some resilience, but its substantial hydro share makes it vulnerable to prolonged drought and land drying.
Serbia also feels the strain. Around 65 percent of its electricity comes from coal and about 25 percent from hydro, yet Danube-fed plants such as the Đerdap hydropower complex are producing only a fraction of their usual output. Thermal plants at Kostolac A and B, which also draw cooling water from the Danube, have been forced to reduce production. Low river levels additionally limit the cargo ships that move coal and petrochemical goods along the Danube, reducing freight capacity and complicating fuel logistics.
By contrast, Slovakia and Austria have been less disrupted. Slovakia’s nuclear fleet provides about 60 percent of generation and its Bohunice and Mochovce plants use cooling towers rather than once-through river cooling, lessening exposure; however the Gabcíkovo hydropower plant on the Danube is heavily affected and currently only one of eight turbines is operating, with production about 12 percent lower than in the same period last year. Austria relies on roughly 60 percent hydro but benefits from reservoir and pumped-storage plants that can manage peaks, and renewable sources contribute about 30 percent.
Bulgaria has so far avoided a major energy emergency. The Kozloduy nuclear plant, also on the Danube, has cooling systems better adapted to low river levels and is operating near full capacity. Crucially, Bulgaria has invested in large battery storage: the country currently has storage installations rated at 3.4 gigawatts with 8.6 gigawatt-hours of capacity—about 16 percent of the nation’s installed power—which helps to balance shortages and peak demand without relying on expensive imports. That infrastructure is positioning Bulgaria as a regional stabilizer and a developing hub for new energy concepts.
Photo: press material from the event
