Under what conditions would the electricity mix planned for France under the Energy Transition Act work?

The energy transition plans to reduce the share of nuclear power in the electricity mix to 50%, and increase the share of wind and solar power. These intermittent energies require resources to rebalance the grid. We are using a method developed for the German energy transition (Energiewende) to work out the orders of magnitude. With regard to the mix adopted for France, a quarter of intermittent production, 44 TWh, should be transferred between periods of surplus and shortage. This would be possible with large-scale storage - 15 TWh in volume and 45 GW in power - which unfortunately far exceeds known resources (hydroelectric dams, batteries, etc.). Without such storage, fossil fuel power stations would be used to meet demand, thereby worsening the carbon footprint. This can already be seen in the results of the past decade in Germany and Europe.