An upcoming partial solar eclipse set for August 12, 2026, threatens to reduce European solar power generation by up to 9.3 gigawatts, compounding an existing regional energy crisis driven by severe heatwaves and low river levels. According to the Financial Times, the celestial event will coincide with high afternoon electricity demand, placing significant strain on transmission operators across the continent.
Solar Output Losses Expected Across Western Europe
The partial eclipse will take place during the late afternoon of August 12, obscuring up to 90% of the sun across the United Kingdom, France, and northern Italy, while a total eclipse will be visible in northern Spain and northeastern Portugal. French utility provider RTE estimates that the drop in solar radiation will trigger a 9.3-gigawatt power loss across Europe during the peak two-hour window beginning at 7:30 p.m. local time. Because a standard nuclear reactor generates approximately 1 gigawatt of electricity, the anticipated solar deficit is equivalent to the sudden offline capacity of nine nuclear plants. In Spain, national grid operator Red Eléctrica projects a supply reduction of up to 5 gigawatts, which accounts for roughly 13% of the country’s average August power demand for a Wednesday.
Heatwaves Force Thermal and Nuclear Plant Outages
The impending solar dip arrives as European power grids struggle against persistent high temperatures and drought conditions that have restricted conventional generation. According to regional reports, rising river temperatures and declining water levels have forced the temporary suspension or reduction of thermal and nuclear power plants in Hungary, Romania, France, and Poland. Hungarian Prime Minister noted on social media that the 2-gigawatt Paks nuclear plant, which relies on water from the Danube River, narrowly avoided a mandatory shutdown after water levels dropped within millimeters of critical safety thresholds before recovering. In Romania, authorities deployed explosives to alter the course of the Danube River to secure cooling water for the Cernavodă nuclear facility. Meanwhile, dropping water levels on the Vistula River forced the shutdown of two major coal-fired power plants in Poland, while French operators curtailed output at three nuclear reactors due to cooling constraints.
Hydroelectric Reserves Fall to Multi-Year Lows
Compounding the generation bottlenecks, Norway—one of Europe’s primary electricity exporters—is facing severe hydrological deficits. According to industry data, water reservoir levels dedicated to hydroelectric generation have dropped to their lowest point in 30 years following months of below-average precipitation. Grid operators across the interconnected European network are preparing to manage the combined pressures of diminished hydroelectric capacity, offline thermal assets, and the sudden, temporary loss of photovoltaic output during the August 12 celestial alignment.