Eclipse adds to Europe's power grid crisis as heat wave, drought strain supply

Europe's power grid is facing mounting pressure as a solar eclipse threatens to sharply cut solar generation, compounding an electricity supply crunch already driven by record heat and drought.

According to the Financial Times, a solar eclipse visible across Europe on Wednesday afternoon will temporarily slash solar output. Grid operators warn the drop could add further strain to a system already struggling after the heat wave disrupted nuclear, thermal and hydroelectric generation.

Parts of Spain will experience a total eclipse, while much of Europe — including the United Kingdom, France and northern Italy — will see a partial eclipse that blocks most of the sun.

Spain's grid operator Red Eléctrica estimates the eclipse could reduce the country's solar output by up to 5 GW, equivalent to roughly 13 percent of Spain's average Wednesday electricity demand in August.

France's grid operator RTE projects that up to 9.3 GW of generation capacity could disappear across Europe for about two hours around 7:30 p.m., when the eclipse reaches its peak — a loss comparable to the combined output of roughly nine nuclear power plants. Solar output in the United Kingdom could also fall by as much as 1.3 GW.

The eclipse arrives as Europe's power situation is already stretched thin by heat and drought. Falling river levels have left nuclear and thermal plants in Hungary, Romania, France, Italy and Poland unable to secure adequate cooling water, forcing shutdowns or output cuts at multiple facilities.

In Hungary, the 2 GW Paks nuclear power plant, which relies on Danube River water for cooling, came within millimeters of the threshold that would have triggered a full shutdown. Prime Minister Péter Magyar said the river level had dropped to within a few millimeters of the mandatory cutoff before rising again, narrowly averting the worst-case scenario.

In Romania, operators used explosives to divert Danube water to the Cernavodă nuclear power plant, avoiding a shutdown of the country's key power source. In Poland, two large thermal power plants went offline as the Vistula River ran low. In France, three nuclear reactors shut down due to insufficient cooling water.

Norway, a major electricity exporter to the continent, is also under pressure. Reservoir levels needed for hydroelectric generation have fallen to their lowest point in 30 years, raising concerns that the country may have less surplus power available to supply neighboring countries.

Grid operators across Europe are mobilizing alternative power sources to offset the solar shortfall during the eclipse window, the Financial Times reported. For now, however, a large-scale blackout directly caused by the eclipse is not considered likely.