The 38 reactors in operation on Thursday provide 62.6% of France's installed nuclear capacity, or 38.4 gigawatts (GW) out of 61.4 GW;
37.4% of the power was therefore unavailable.
A month ago, EDF planned to be further ahead of the restart of its reactors with 72.9% of power available.
But as was the case with other reactors this fall, the relaunch of several units has been postponed, sometimes for a few days.
Reactor number 3 of the Dampierre power plant must restart Friday morning, instead of Monday.
Another reactor, Bugey 3, is due to restart on Saturday morning, which will reduce the number of unavailable reactors to 16 and increase the number of reactors in operation to 40 on Monday's crucial day.
This Monday is the first day of autumn/winter for which the manager of high and very high voltage lines, RTE, could launch an orange "Ecowatt" alert, the first level which means that the supply will be "tight ".
This signal is used to call on French people, businesses and households, to multiply eco-gestures to reduce their electricity consumption, in order to avoid load shedding or targeted cuts.
Mainly by reducing their heating or postponing their consumption (washing machine, etc.) outside peak demand in the morning (8 a.m. to 1 p.m.) and in the evening around 7 p.m.
This decision to launch an orange Ecowatt signal would be taken three days before, i.e. Friday, because it depends on the cold and the strength of the expected wind, which makes it possible to precisely anticipate the power that the wind turbines will provide.
“We do this on D-3 because it is only then that we have weather chronicles in which we can have confidence on the temperatures but also on the wind. Because the wind forecasts are forecasts that 'We are very late,' explained Xavier Piechaczyk, president of RTE, on Wednesday.
"The colors of the EcoWatt signal, it's on D-3 and it's not otherwise."
An orange warning signal had already been triggered on April 4, during a very cold day.
© 2022 AFP