Transmission system operators across Europe are bracing for the total solar eclipse that will sweep across swathes of Europe on Wednesday and is forecast to cut solar PV output by up to 9.7 gigawatts (GW).
The August 12 solar eclipse will occur during the early evening and will sweep across Greenland, Iceland, northern Russia, the Atlantic Ocean, Spain, and a small corner of Portugal, according to NASA. A partial eclipse will be visible across much of the rest of the European continent.
As with any eclipse, its timing has been known well in advance, giving Europe’s transmission system operators (TSOs) time to prepare for the sudden drop in solar irradiance and generation. In 2025, a solar eclipse accounted for 13 per cent of generation across the European Union.
According to the European Network of Transmission System Operators for Electricity (ENTSO-E), assuming clear skies during the eclipse, solar PV output across Europe could decrease by up to 9.7 GW creating what the organisation describes as “a rapid but predictable change in generation patterns between 19:15-21:30 CEST.”
However, thanks to “well-established coordination mechanisms and proactive preparations”, both ENTSO-E and the continent’s TSOs have long been prepared for the event. So as to ensure continued system operation during the eclipse, TSOs across Europe have implemented a “range of coordinated measures” including heightened awareness in control rooms and shared information with market participants.
