Solar eclipse: how the power system absorbs a sudden loss of photovoltaic generation

On 5 August 2026, RTE published an analysis of the impact of the 12 August solar eclipse on the power system. Part of Europe was crossed by the phenomenon in the early evening, with the sun obscured by up to 99% over France.

Behind the spectacle lies a demanding balancing exercise. Within a few tens of minutes, the fall and then the return of sunlight cause rapid swings in photovoltaic generation, which must be offset instantly to maintain the balance between generation and consumption.

RTE's forecasts put the drop, under clear skies, at around 1,800 MW of French photovoltaic generation and close to 9,700 MW across Europe at the peak of the eclipse, between 19:30 and 21:30. The timing, close to nightfall, mechanically limited the scale of the phenomenon.

The historical record is instructive: the partial eclipse of 20 March 2015 led to a drop of around 2,000 MW in France and close to 35 GW in Europe, while the 2021 eclipse was limited to around 550 MW. Each event has helped refine forecasting methods and system operation arrangements.

European coordination, provided through ENTSO-E, the network of transmission system operators, remains decisive. Initial analyses from 2026 ultimately show a more limited impact on solar generation than expected.

For industrial sites, this type of event illustrates an underlying reality: the greater the share of variable generation, the greater the value of consumption that is controllable and well measured.