Technology

Please provide those "studies and researches" that backup your claim, because a simple calculation shows that the world's largest WWTP, Hongrin-Leman (100GWh in capacity and 480MW in power, over a 90km² basin) contains just 10% of the capacity needed and only 0.7% of the power required for a country like France to last a winter night (~70GW during ~14h of night).

So we'd need “only” 10 Hongrin-Léman stations in terms of capacity, but 142 Hongrin-Léman stations in terms of power. In other words, we'd need to flood at best 8.5x the surface area of Paris, and at worst the entire surface area of the Île de France department, home to 12 million inhabitants. And that's just for one night without wind (which happens very regularly), assuming we rely on solar and wind power.

Then we need to find enough water and enough energy to pump it to fill the STEP completely in 10 hours of daylight, otherwise we'll have a blackout the following night.

Wind and solar power cannot form the basis of a country's energy production, because they are intermittent energies, and the storage needed to smooth out production is titanic. These energies rely on hydroelectricity, nuclear power and fossil fuels to be viable on a national scale.